Jmat.Real.erf

Percentage Accurate: 79.0% → 99.7%

Time: 11.9s

Alternatives: 12

Speedup: 29.1×

Specification

Math

\[\begin{array}{l} \\ \begin{array}{l} t_0 := \frac{1}{1 + 0.3275911 \cdot \left|x\right|}\\ 1 - \left(t\_0 \cdot \left(0.254829592 + t\_0 \cdot \left(-0.284496736 + t\_0 \cdot \left(1.421413741 + t\_0 \cdot \left(-1.453152027 + t\_0 \cdot 1.061405429\right)\right)\right)\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|} \end{array} \end{array} \]

FPCore

(FPCore (x)
 :precision binary64
 (let* ((t_0 (/ 1.0 (+ 1.0 (* 0.3275911 (fabs x))))))
   (-
    1.0
    (*
     (*
      t_0
      (+
       0.254829592
       (*
        t_0
        (+
         -0.284496736
         (*
          t_0
          (+ 1.421413741 (* t_0 (+ -1.453152027 (* t_0 1.061405429)))))))))
     (exp (- (* (fabs x) (fabs x))))))))

C

double code(double x) {
	double t_0 = 1.0 / (1.0 + (0.3275911 * fabs(x)));
	return 1.0 - ((t_0 * (0.254829592 + (t_0 * (-0.284496736 + (t_0 * (1.421413741 + (t_0 * (-1.453152027 + (t_0 * 1.061405429))))))))) * exp(-(fabs(x) * fabs(x))));
}

Fortran

real(8) function code(x)
    real(8), intent (in) :: x
    real(8) :: t_0
    t_0 = 1.0d0 / (1.0d0 + (0.3275911d0 * abs(x)))
    code = 1.0d0 - ((t_0 * (0.254829592d0 + (t_0 * ((-0.284496736d0) + (t_0 * (1.421413741d0 + (t_0 * ((-1.453152027d0) + (t_0 * 1.061405429d0))))))))) * exp(-(abs(x) * abs(x))))
end function

Java

public static double code(double x) {
	double t_0 = 1.0 / (1.0 + (0.3275911 * Math.abs(x)));
	return 1.0 - ((t_0 * (0.254829592 + (t_0 * (-0.284496736 + (t_0 * (1.421413741 + (t_0 * (-1.453152027 + (t_0 * 1.061405429))))))))) * Math.exp(-(Math.abs(x) * Math.abs(x))));
}

Python

def code(x):
	t_0 = 1.0 / (1.0 + (0.3275911 * math.fabs(x)))
	return 1.0 - ((t_0 * (0.254829592 + (t_0 * (-0.284496736 + (t_0 * (1.421413741 + (t_0 * (-1.453152027 + (t_0 * 1.061405429))))))))) * math.exp(-(math.fabs(x) * math.fabs(x))))

Julia

function code(x)
	t_0 = Float64(1.0 / Float64(1.0 + Float64(0.3275911 * abs(x))))
	return Float64(1.0 - Float64(Float64(t_0 * Float64(0.254829592 + Float64(t_0 * Float64(-0.284496736 + Float64(t_0 * Float64(1.421413741 + Float64(t_0 * Float64(-1.453152027 + Float64(t_0 * 1.061405429))))))))) * exp(Float64(-Float64(abs(x) * abs(x))))))
end

MATLAB

function tmp = code(x)
	t_0 = 1.0 / (1.0 + (0.3275911 * abs(x)));
	tmp = 1.0 - ((t_0 * (0.254829592 + (t_0 * (-0.284496736 + (t_0 * (1.421413741 + (t_0 * (-1.453152027 + (t_0 * 1.061405429))))))))) * exp(-(abs(x) * abs(x))));
end

Wolfram

code[x_] := Block[{t$95$0 = N[(1.0 / N[(1.0 + N[(0.3275911 * N[Abs[x], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]}, N[(1.0 - N[(N[(t$95$0 * N[(0.254829592 + N[(t$95$0 * N[(-0.284496736 + N[(t$95$0 * N[(1.421413741 + N[(t$95$0 * N[(-1.453152027 + N[(t$95$0 * 1.061405429), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * N[Exp[(-N[(N[Abs[x], $MachinePrecision] * N[Abs[x], $MachinePrecision]), $MachinePrecision])], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]

Initial Program: 79.0% accurate, 1.0× speedup

Math

\[\begin{array}{l} \\ \begin{array}{l} t_0 := \frac{1}{1 + 0.3275911 \cdot \left|x\right|}\\ 1 - \left(t\_0 \cdot \left(0.254829592 + t\_0 \cdot \left(-0.284496736 + t\_0 \cdot \left(1.421413741 + t\_0 \cdot \left(-1.453152027 + t\_0 \cdot 1.061405429\right)\right)\right)\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|} \end{array} \end{array} \]

FPCore

(FPCore (x)
 :precision binary64
 (let* ((t_0 (/ 1.0 (+ 1.0 (* 0.3275911 (fabs x))))))
   (-
    1.0
    (*
     (*
      t_0
      (+
       0.254829592
       (*
        t_0
        (+
         -0.284496736
         (*
          t_0
          (+ 1.421413741 (* t_0 (+ -1.453152027 (* t_0 1.061405429)))))))))
     (exp (- (* (fabs x) (fabs x))))))))

C

double code(double x) {
	double t_0 = 1.0 / (1.0 + (0.3275911 * fabs(x)));
	return 1.0 - ((t_0 * (0.254829592 + (t_0 * (-0.284496736 + (t_0 * (1.421413741 + (t_0 * (-1.453152027 + (t_0 * 1.061405429))))))))) * exp(-(fabs(x) * fabs(x))));
}

Fortran

real(8) function code(x)
    real(8), intent (in) :: x
    real(8) :: t_0
    t_0 = 1.0d0 / (1.0d0 + (0.3275911d0 * abs(x)))
    code = 1.0d0 - ((t_0 * (0.254829592d0 + (t_0 * ((-0.284496736d0) + (t_0 * (1.421413741d0 + (t_0 * ((-1.453152027d0) + (t_0 * 1.061405429d0))))))))) * exp(-(abs(x) * abs(x))))
end function

Java

public static double code(double x) {
	double t_0 = 1.0 / (1.0 + (0.3275911 * Math.abs(x)));
	return 1.0 - ((t_0 * (0.254829592 + (t_0 * (-0.284496736 + (t_0 * (1.421413741 + (t_0 * (-1.453152027 + (t_0 * 1.061405429))))))))) * Math.exp(-(Math.abs(x) * Math.abs(x))));
}

Python

def code(x):
	t_0 = 1.0 / (1.0 + (0.3275911 * math.fabs(x)))
	return 1.0 - ((t_0 * (0.254829592 + (t_0 * (-0.284496736 + (t_0 * (1.421413741 + (t_0 * (-1.453152027 + (t_0 * 1.061405429))))))))) * math.exp(-(math.fabs(x) * math.fabs(x))))

Julia

function code(x)
	t_0 = Float64(1.0 / Float64(1.0 + Float64(0.3275911 * abs(x))))
	return Float64(1.0 - Float64(Float64(t_0 * Float64(0.254829592 + Float64(t_0 * Float64(-0.284496736 + Float64(t_0 * Float64(1.421413741 + Float64(t_0 * Float64(-1.453152027 + Float64(t_0 * 1.061405429))))))))) * exp(Float64(-Float64(abs(x) * abs(x))))))
end

MATLAB

function tmp = code(x)
	t_0 = 1.0 / (1.0 + (0.3275911 * abs(x)));
	tmp = 1.0 - ((t_0 * (0.254829592 + (t_0 * (-0.284496736 + (t_0 * (1.421413741 + (t_0 * (-1.453152027 + (t_0 * 1.061405429))))))))) * exp(-(abs(x) * abs(x))));
end

Wolfram

code[x_] := Block[{t$95$0 = N[(1.0 / N[(1.0 + N[(0.3275911 * N[Abs[x], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]}, N[(1.0 - N[(N[(t$95$0 * N[(0.254829592 + N[(t$95$0 * N[(-0.284496736 + N[(t$95$0 * N[(1.421413741 + N[(t$95$0 * N[(-1.453152027 + N[(t$95$0 * 1.061405429), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * N[Exp[(-N[(N[Abs[x], $MachinePrecision] * N[Abs[x], $MachinePrecision]), $MachinePrecision])], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]

Alternative 1: 99.7% accurate, 0.6× speedup

Math

\[\begin{array}{l} x_m = \left|x\right| \\ \begin{array}{l} \mathbf{if}\;\left|x\_m\right| \leq 10^{-8}:\\ \;\;\;\;\mathsf{fma}\left(\mathsf{fma}\left(-0.00011824394398844293, x\_m, 1.128386358070218\right), x\_m, 10^{-9}\right)\\ \mathbf{else}:\\ \;\;\;\;1 - \left({\left(1 + 0.3275911 \cdot \left|x\_m\right|\right)}^{-1} \cdot \left(0.254829592 - \frac{\mathsf{fma}\left(\frac{\frac{\mathsf{fma}\left(\frac{1.061405429}{0.10731592879921 \cdot \left(x\_m \cdot x\_m\right) - 1}, x\_m \cdot 0.3275911 - 1, -1.453152027\right)}{\mathsf{fma}\left(x\_m, 0.3275911, 1\right)} + 1.421413741}{\mathsf{fma}\left(x\_m, 0.3275911, 1\right)}, -\mathsf{fma}\left(x\_m, 0.3275911, 1\right), \mathsf{fma}\left(x\_m, 0.3275911, 1\right) \cdot 0.284496736\right)}{\mathsf{fma}\left(x\_m, 0.3275911, 1\right) \cdot \left(\left({x\_m}^{-1} + 0.3275911\right) \cdot x\_m\right)}\right)\right) \cdot e^{\left(-x\_m\right) \cdot x\_m}\\ \end{array} \end{array} \]

FPCore

x_m = (fabs.f64 x)
(FPCore (x_m)
 :precision binary64
 (if (<= (fabs x_m) 1e-8)
   (fma (fma -0.00011824394398844293 x_m 1.128386358070218) x_m 1e-9)
   (-
    1.0
    (*
     (*
      (pow (+ 1.0 (* 0.3275911 (fabs x_m))) -1.0)
      (-
       0.254829592
       (/
        (fma
         (/
          (+
           (/
            (fma
             (/ 1.061405429 (- (* 0.10731592879921 (* x_m x_m)) 1.0))
             (- (* x_m 0.3275911) 1.0)
             -1.453152027)
            (fma x_m 0.3275911 1.0))
           1.421413741)
          (fma x_m 0.3275911 1.0))
         (- (fma x_m 0.3275911 1.0))
         (* (fma x_m 0.3275911 1.0) 0.284496736))
        (* (fma x_m 0.3275911 1.0) (* (+ (pow x_m -1.0) 0.3275911) x_m)))))
     (exp (* (- x_m) x_m))))))

C

x_m = fabs(x);
double code(double x_m) {
	double tmp;
	if (fabs(x_m) <= 1e-8) {
		tmp = fma(fma(-0.00011824394398844293, x_m, 1.128386358070218), x_m, 1e-9);
	} else {
		tmp = 1.0 - ((pow((1.0 + (0.3275911 * fabs(x_m))), -1.0) * (0.254829592 - (fma((((fma((1.061405429 / ((0.10731592879921 * (x_m * x_m)) - 1.0)), ((x_m * 0.3275911) - 1.0), -1.453152027) / fma(x_m, 0.3275911, 1.0)) + 1.421413741) / fma(x_m, 0.3275911, 1.0)), -fma(x_m, 0.3275911, 1.0), (fma(x_m, 0.3275911, 1.0) * 0.284496736)) / (fma(x_m, 0.3275911, 1.0) * ((pow(x_m, -1.0) + 0.3275911) * x_m))))) * exp((-x_m * x_m)));
	}
	return tmp;
}

Julia

x_m = abs(x)
function code(x_m)
	tmp = 0.0
	if (abs(x_m) <= 1e-8)
		tmp = fma(fma(-0.00011824394398844293, x_m, 1.128386358070218), x_m, 1e-9);
	else
		tmp = Float64(1.0 - Float64(Float64((Float64(1.0 + Float64(0.3275911 * abs(x_m))) ^ -1.0) * Float64(0.254829592 - Float64(fma(Float64(Float64(Float64(fma(Float64(1.061405429 / Float64(Float64(0.10731592879921 * Float64(x_m * x_m)) - 1.0)), Float64(Float64(x_m * 0.3275911) - 1.0), -1.453152027) / fma(x_m, 0.3275911, 1.0)) + 1.421413741) / fma(x_m, 0.3275911, 1.0)), Float64(-fma(x_m, 0.3275911, 1.0)), Float64(fma(x_m, 0.3275911, 1.0) * 0.284496736)) / Float64(fma(x_m, 0.3275911, 1.0) * Float64(Float64((x_m ^ -1.0) + 0.3275911) * x_m))))) * exp(Float64(Float64(-x_m) * x_m))));
	end
	return tmp
end

Wolfram

x_m = N[Abs[x], $MachinePrecision]
code[x$95$m_] := If[LessEqual[N[Abs[x$95$m], $MachinePrecision], 1e-8], N[(N[(-0.00011824394398844293 * x$95$m + 1.128386358070218), $MachinePrecision] * x$95$m + 1e-9), $MachinePrecision], N[(1.0 - N[(N[(N[Power[N[(1.0 + N[(0.3275911 * N[Abs[x$95$m], $MachinePrecision]), $MachinePrecision]), $MachinePrecision], -1.0], $MachinePrecision] * N[(0.254829592 - N[(N[(N[(N[(N[(N[(N[(1.061405429 / N[(N[(0.10731592879921 * N[(x$95$m * x$95$m), $MachinePrecision]), $MachinePrecision] - 1.0), $MachinePrecision]), $MachinePrecision] * N[(N[(x$95$m * 0.3275911), $MachinePrecision] - 1.0), $MachinePrecision] + -1.453152027), $MachinePrecision] / N[(x$95$m * 0.3275911 + 1.0), $MachinePrecision]), $MachinePrecision] + 1.421413741), $MachinePrecision] / N[(x$95$m * 0.3275911 + 1.0), $MachinePrecision]), $MachinePrecision] * (-N[(x$95$m * 0.3275911 + 1.0), $MachinePrecision]) + N[(N[(x$95$m * 0.3275911 + 1.0), $MachinePrecision] * 0.284496736), $MachinePrecision]), $MachinePrecision] / N[(N[(x$95$m * 0.3275911 + 1.0), $MachinePrecision] * N[(N[(N[Power[x$95$m, -1.0], $MachinePrecision] + 0.3275911), $MachinePrecision] * x$95$m), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * N[Exp[N[((-x$95$m) * x$95$m), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]

Derivation

1. Split input into 2 regimes

2. if (fabs.f64 x) < 1e-8

   1. Initial program 57.7%

      \[1 - \left(\frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(0.254829592 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(-0.284496736 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(1.421413741 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(-1.453152027 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot 1.061405429\right)\right)\right)\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|} \]
   2. Add Preprocessing

   4. Applied rewrites 57.3%

      \[\leadsto \color{blue}{\frac{1 - {\left(\frac{\frac{\frac{\frac{\frac{1.061405429}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -1.453152027}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 1.421413741}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -0.284496736}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 0.254829592}{{\left(e^{x}\right)}^{x} \cdot \mathsf{fma}\left(x, 0.3275911, 1\right)}\right)}^{2}}{\mathsf{fma}\left({\left(e^{x}\right)}^{x}, \frac{\frac{\frac{\frac{\frac{1.061405429}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -1.453152027}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 1.421413741}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -0.284496736}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 0.254829592}{\mathsf{fma}\left(x, 0.3275911, 1\right)}, 1\right)}} \]

   5. Taylor expanded in x around 0

      \[\leadsto \color{blue}{\frac{1}{1000000000} + x \cdot \left(\frac{564193179035109}{500000000000000} + \frac{-4729757757172838478231131321}{39999999980000000000000000000000} \cdot x\right)} \]
   6. Step-by-step derivation

      1. +-commutative N/A

         \[\leadsto \color{blue}{x \cdot \left(\frac{564193179035109}{500000000000000} + \frac{-4729757757172838478231131321}{39999999980000000000000000000000} \cdot x\right) + \frac{1}{1000000000}} \]

      2. *-commutative N/A

         \[\leadsto \color{blue}{\left(\frac{564193179035109}{500000000000000} + \frac{-4729757757172838478231131321}{39999999980000000000000000000000} \cdot x\right) \cdot x} + \frac{1}{1000000000} \]

      3. lower-fma.f64 N/A

         \[\leadsto \color{blue}{\mathsf{fma}\left(\frac{564193179035109}{500000000000000} + \frac{-4729757757172838478231131321}{39999999980000000000000000000000} \cdot x, x, \frac{1}{1000000000}\right)} \]

      4. +-commutative N/A

         \[\leadsto \mathsf{fma}\left(\color{blue}{\frac{-4729757757172838478231131321}{39999999980000000000000000000000} \cdot x + \frac{564193179035109}{500000000000000}}, x, \frac{1}{1000000000}\right) \]

      5. lower-fma.f64 99.0

         \[\leadsto \mathsf{fma}\left(\color{blue}{\mathsf{fma}\left(-0.00011824394398844293, x, 1.128386358070218\right)}, x, 10^{-9}\right) \]

   7. Applied rewrites 99.0%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\mathsf{fma}\left(-0.00011824394398844293, x, 1.128386358070218\right), x, 10^{-9}\right)} \]

   if 1e-8 < (fabs.f64 x)

   1. Initial program 99.7%

      \[1 - \left(\frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(0.254829592 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(-0.284496736 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(1.421413741 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(-1.453152027 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot 1.061405429\right)\right)\right)\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|} \]
   2. Add Preprocessing

   4. Applied rewrites 98.5%

      \[\leadsto 1 - \left(\frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(0.254829592 + \color{blue}{\frac{\mathsf{fma}\left(\frac{\frac{\frac{1.061405429}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -1.453152027}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 1.421413741}{\mathsf{fma}\left(x, 0.3275911, 1\right)}, -\mathsf{fma}\left(x, 0.3275911, 1\right), \mathsf{fma}\left(x, 0.3275911, 1\right) \cdot 0.284496736\right)}{\mathsf{fma}\left(x, 0.3275911, 1\right) \cdot \left(-\mathsf{fma}\left(x, 0.3275911, 1\right)\right)}}\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|} \]
   5. Step-by-step derivation

      1. lift-+.f64 N/A

         \[\leadsto 1 - \left(\frac{1}{1 + \frac{3275911}{10000000} \cdot \left|x\right|} \cdot \left(\frac{31853699}{125000000} + \frac{\mathsf{fma}\left(\frac{\frac{\color{blue}{\frac{\frac{1061405429}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{-1453152027}{1000000000}}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{1421413741}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)}, -\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right), \mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right) \cdot \frac{8890523}{31250000}\right)}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right) \cdot \left(-\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)\right)}\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|} \]

      2. lift-/.f64 N/A

         \[\leadsto 1 - \left(\frac{1}{1 + \frac{3275911}{10000000} \cdot \left|x\right|} \cdot \left(\frac{31853699}{125000000} + \frac{\mathsf{fma}\left(\frac{\frac{\color{blue}{\frac{\frac{1061405429}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)}} + \frac{-1453152027}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{1421413741}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)}, -\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right), \mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right) \cdot \frac{8890523}{31250000}\right)}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right) \cdot \left(-\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)\right)}\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|} \]

      3. lift-fma.f64 N/A

         \[\leadsto 1 - \left(\frac{1}{1 + \frac{3275911}{10000000} \cdot \left|x\right|} \cdot \left(\frac{31853699}{125000000} + \frac{\mathsf{fma}\left(\frac{\frac{\frac{\frac{1061405429}{1000000000}}{\color{blue}{x \cdot \frac{3275911}{10000000} + 1}} + \frac{-1453152027}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{1421413741}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)}, -\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right), \mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right) \cdot \frac{8890523}{31250000}\right)}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right) \cdot \left(-\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)\right)}\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|} \]

      4. lift-*.f64 N/A

         \[\leadsto 1 - \left(\frac{1}{1 + \frac{3275911}{10000000} \cdot \left|x\right|} \cdot \left(\frac{31853699}{125000000} + \frac{\mathsf{fma}\left(\frac{\frac{\frac{\frac{1061405429}{1000000000}}{\color{blue}{x \cdot \frac{3275911}{10000000}} + 1} + \frac{-1453152027}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{1421413741}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)}, -\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right), \mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right) \cdot \frac{8890523}{31250000}\right)}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right) \cdot \left(-\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)\right)}\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|} \]

      5. flip-+ N/A

         \[\leadsto 1 - \left(\frac{1}{1 + \frac{3275911}{10000000} \cdot \left|x\right|} \cdot \left(\frac{31853699}{125000000} + \frac{\mathsf{fma}\left(\frac{\frac{\frac{\frac{1061405429}{1000000000}}{\color{blue}{\frac{\left(x \cdot \frac{3275911}{10000000}\right) \cdot \left(x \cdot \frac{3275911}{10000000}\right) - 1 \cdot 1}{x \cdot \frac{3275911}{10000000} - 1}}} + \frac{-1453152027}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{1421413741}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)}, -\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right), \mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right) \cdot \frac{8890523}{31250000}\right)}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right) \cdot \left(-\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)\right)}\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|} \]

      6. lift--.f64 N/A

         \[\leadsto 1 - \left(\frac{1}{1 + \frac{3275911}{10000000} \cdot \left|x\right|} \cdot \left(\frac{31853699}{125000000} + \frac{\mathsf{fma}\left(\frac{\frac{\frac{\frac{1061405429}{1000000000}}{\frac{\left(x \cdot \frac{3275911}{10000000}\right) \cdot \left(x \cdot \frac{3275911}{10000000}\right) - 1 \cdot 1}{\color{blue}{x \cdot \frac{3275911}{10000000} - 1}}} + \frac{-1453152027}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{1421413741}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)}, -\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right), \mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right) \cdot \frac{8890523}{31250000}\right)}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right) \cdot \left(-\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)\right)}\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|} \]

      7. associate-/r/ N/A

         \[\leadsto 1 - \left(\frac{1}{1 + \frac{3275911}{10000000} \cdot \left|x\right|} \cdot \left(\frac{31853699}{125000000} + \frac{\mathsf{fma}\left(\frac{\frac{\color{blue}{\frac{\frac{1061405429}{1000000000}}{\left(x \cdot \frac{3275911}{10000000}\right) \cdot \left(x \cdot \frac{3275911}{10000000}\right) - 1 \cdot 1} \cdot \left(x \cdot \frac{3275911}{10000000} - 1\right)} + \frac{-1453152027}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{1421413741}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)}, -\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right), \mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right) \cdot \frac{8890523}{31250000}\right)}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right) \cdot \left(-\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)\right)}\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|} \]

      8. lower-fma.f64 N/A

         \[\leadsto 1 - \left(\frac{1}{1 + \frac{3275911}{10000000} \cdot \left|x\right|} \cdot \left(\frac{31853699}{125000000} + \frac{\mathsf{fma}\left(\frac{\frac{\color{blue}{\mathsf{fma}\left(\frac{\frac{1061405429}{1000000000}}{\left(x \cdot \frac{3275911}{10000000}\right) \cdot \left(x \cdot \frac{3275911}{10000000}\right) - 1 \cdot 1}, x \cdot \frac{3275911}{10000000} - 1, \frac{-1453152027}{1000000000}\right)}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{1421413741}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)}, -\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right), \mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right) \cdot \frac{8890523}{31250000}\right)}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right) \cdot \left(-\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)\right)}\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|} \]

   6. Applied rewrites 98.5%

      \[\leadsto 1 - \left(\frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(0.254829592 + \frac{\mathsf{fma}\left(\frac{\frac{\color{blue}{\mathsf{fma}\left(\frac{1.061405429}{0.10731592879921 \cdot \left(x \cdot x\right) - 1}, x \cdot 0.3275911 - 1, -1.453152027\right)}}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 1.421413741}{\mathsf{fma}\left(x, 0.3275911, 1\right)}, -\mathsf{fma}\left(x, 0.3275911, 1\right), \mathsf{fma}\left(x, 0.3275911, 1\right) \cdot 0.284496736\right)}{\mathsf{fma}\left(x, 0.3275911, 1\right) \cdot \left(-\mathsf{fma}\left(x, 0.3275911, 1\right)\right)}\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|} \]

   7. Taylor expanded in x around inf

      \[\leadsto 1 - \left(\frac{1}{1 + \frac{3275911}{10000000} \cdot \left|x\right|} \cdot \left(\frac{31853699}{125000000} + \frac{\mathsf{fma}\left(\frac{\frac{\mathsf{fma}\left(\frac{\frac{1061405429}{1000000000}}{\frac{10731592879921}{100000000000000} \cdot \left(x \cdot x\right) - 1}, x \cdot \frac{3275911}{10000000} - 1, \frac{-1453152027}{1000000000}\right)}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{1421413741}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)}, -\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right), \mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right) \cdot \frac{8890523}{31250000}\right)}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right) \cdot \left(-\color{blue}{x \cdot \left(\frac{3275911}{10000000} + \frac{1}{x}\right)}\right)}\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|} \]
   8. Step-by-step derivation

      1. *-commutative N/A

         \[\leadsto 1 - \left(\frac{1}{1 + \frac{3275911}{10000000} \cdot \left|x\right|} \cdot \left(\frac{31853699}{125000000} + \frac{\mathsf{fma}\left(\frac{\frac{\mathsf{fma}\left(\frac{\frac{1061405429}{1000000000}}{\frac{10731592879921}{100000000000000} \cdot \left(x \cdot x\right) - 1}, x \cdot \frac{3275911}{10000000} - 1, \frac{-1453152027}{1000000000}\right)}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{1421413741}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)}, -\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right), \mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right) \cdot \frac{8890523}{31250000}\right)}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right) \cdot \left(-\color{blue}{\left(\frac{3275911}{10000000} + \frac{1}{x}\right) \cdot x}\right)}\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|} \]

      2. lower-*.f64 N/A

         \[\leadsto 1 - \left(\frac{1}{1 + \frac{3275911}{10000000} \cdot \left|x\right|} \cdot \left(\frac{31853699}{125000000} + \frac{\mathsf{fma}\left(\frac{\frac{\mathsf{fma}\left(\frac{\frac{1061405429}{1000000000}}{\frac{10731592879921}{100000000000000} \cdot \left(x \cdot x\right) - 1}, x \cdot \frac{3275911}{10000000} - 1, \frac{-1453152027}{1000000000}\right)}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{1421413741}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)}, -\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right), \mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right) \cdot \frac{8890523}{31250000}\right)}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right) \cdot \left(-\color{blue}{\left(\frac{3275911}{10000000} + \frac{1}{x}\right) \cdot x}\right)}\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|} \]

      3. +-commutative N/A

         \[\leadsto 1 - \left(\frac{1}{1 + \frac{3275911}{10000000} \cdot \left|x\right|} \cdot \left(\frac{31853699}{125000000} + \frac{\mathsf{fma}\left(\frac{\frac{\mathsf{fma}\left(\frac{\frac{1061405429}{1000000000}}{\frac{10731592879921}{100000000000000} \cdot \left(x \cdot x\right) - 1}, x \cdot \frac{3275911}{10000000} - 1, \frac{-1453152027}{1000000000}\right)}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{1421413741}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)}, -\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right), \mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right) \cdot \frac{8890523}{31250000}\right)}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right) \cdot \left(-\color{blue}{\left(\frac{1}{x} + \frac{3275911}{10000000}\right)} \cdot x\right)}\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|} \]

      4. lower-+.f64 N/A

         \[\leadsto 1 - \left(\frac{1}{1 + \frac{3275911}{10000000} \cdot \left|x\right|} \cdot \left(\frac{31853699}{125000000} + \frac{\mathsf{fma}\left(\frac{\frac{\mathsf{fma}\left(\frac{\frac{1061405429}{1000000000}}{\frac{10731592879921}{100000000000000} \cdot \left(x \cdot x\right) - 1}, x \cdot \frac{3275911}{10000000} - 1, \frac{-1453152027}{1000000000}\right)}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{1421413741}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)}, -\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right), \mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right) \cdot \frac{8890523}{31250000}\right)}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right) \cdot \left(-\color{blue}{\left(\frac{1}{x} + \frac{3275911}{10000000}\right)} \cdot x\right)}\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|} \]

      5. lower-/.f64 98.5

         \[\leadsto 1 - \left(\frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(0.254829592 + \frac{\mathsf{fma}\left(\frac{\frac{\mathsf{fma}\left(\frac{1.061405429}{0.10731592879921 \cdot \left(x \cdot x\right) - 1}, x \cdot 0.3275911 - 1, -1.453152027\right)}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 1.421413741}{\mathsf{fma}\left(x, 0.3275911, 1\right)}, -\mathsf{fma}\left(x, 0.3275911, 1\right), \mathsf{fma}\left(x, 0.3275911, 1\right) \cdot 0.284496736\right)}{\mathsf{fma}\left(x, 0.3275911, 1\right) \cdot \left(-\left(\color{blue}{\frac{1}{x}} + 0.3275911\right) \cdot x\right)}\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|} \]

   9. Applied rewrites 98.5%

      \[\leadsto 1 - \left(\frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(0.254829592 + \frac{\mathsf{fma}\left(\frac{\frac{\mathsf{fma}\left(\frac{1.061405429}{0.10731592879921 \cdot \left(x \cdot x\right) - 1}, x \cdot 0.3275911 - 1, -1.453152027\right)}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 1.421413741}{\mathsf{fma}\left(x, 0.3275911, 1\right)}, -\mathsf{fma}\left(x, 0.3275911, 1\right), \mathsf{fma}\left(x, 0.3275911, 1\right) \cdot 0.284496736\right)}{\mathsf{fma}\left(x, 0.3275911, 1\right) \cdot \left(-\color{blue}{\left(\frac{1}{x} + 0.3275911\right) \cdot x}\right)}\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|} \]
3. Recombined 2 regimes into one program.

4. Final simplification 98.8%

   \[\leadsto \begin{array}{l} \mathbf{if}\;\left|x\right| \leq 10^{-8}:\\ \;\;\;\;\mathsf{fma}\left(\mathsf{fma}\left(-0.00011824394398844293, x, 1.128386358070218\right), x, 10^{-9}\right)\\ \mathbf{else}:\\ \;\;\;\;1 - \left({\left(1 + 0.3275911 \cdot \left|x\right|\right)}^{-1} \cdot \left(0.254829592 - \frac{\mathsf{fma}\left(\frac{\frac{\mathsf{fma}\left(\frac{1.061405429}{0.10731592879921 \cdot \left(x \cdot x\right) - 1}, x \cdot 0.3275911 - 1, -1.453152027\right)}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 1.421413741}{\mathsf{fma}\left(x, 0.3275911, 1\right)}, -\mathsf{fma}\left(x, 0.3275911, 1\right), \mathsf{fma}\left(x, 0.3275911, 1\right) \cdot 0.284496736\right)}{\mathsf{fma}\left(x, 0.3275911, 1\right) \cdot \left(\left({x}^{-1} + 0.3275911\right) \cdot x\right)}\right)\right) \cdot e^{\left(-x\right) \cdot x}\\ \end{array} \]
5. Add Preprocessing

Alternative 2: 99.7% accurate, 0.6× speedup

Math

\[\begin{array}{l} x_m = \left|x\right| \\ \begin{array}{l} t_0 := {\left(1 + 0.3275911 \cdot \left|x\_m\right|\right)}^{-1}\\ \mathbf{if}\;\left|x\_m\right| \leq 10^{-8}:\\ \;\;\;\;\mathsf{fma}\left(\mathsf{fma}\left(-0.00011824394398844293, x\_m, 1.128386358070218\right), x\_m, 10^{-9}\right)\\ \mathbf{else}:\\ \;\;\;\;1 - \left(t\_0 \cdot \left(0.254829592 + t\_0 \cdot \left(-0.284496736 + \frac{\frac{\mathsf{fma}\left(\frac{1.061405429}{0.10731592879921 \cdot \left(x\_m \cdot x\_m\right) - 1}, x\_m \cdot 0.3275911 - 1, -1.453152027\right)}{\mathsf{fma}\left(x\_m, 0.3275911, 1\right)} + 1.421413741}{\mathsf{fma}\left(x\_m, 0.3275911, 1\right)}\right)\right)\right) \cdot e^{\left(-x\_m\right) \cdot x\_m}\\ \end{array} \end{array} \]

FPCore

x_m = (fabs.f64 x)
(FPCore (x_m)
 :precision binary64
 (let* ((t_0 (pow (+ 1.0 (* 0.3275911 (fabs x_m))) -1.0)))
   (if (<= (fabs x_m) 1e-8)
     (fma (fma -0.00011824394398844293 x_m 1.128386358070218) x_m 1e-9)
     (-
      1.0
      (*
       (*
        t_0
        (+
         0.254829592
         (*
          t_0
          (+
           -0.284496736
           (/
            (+
             (/
              (fma
               (/ 1.061405429 (- (* 0.10731592879921 (* x_m x_m)) 1.0))
               (- (* x_m 0.3275911) 1.0)
               -1.453152027)
              (fma x_m 0.3275911 1.0))
             1.421413741)
            (fma x_m 0.3275911 1.0))))))
       (exp (* (- x_m) x_m)))))))

C

x_m = fabs(x);
double code(double x_m) {
	double t_0 = pow((1.0 + (0.3275911 * fabs(x_m))), -1.0);
	double tmp;
	if (fabs(x_m) <= 1e-8) {
		tmp = fma(fma(-0.00011824394398844293, x_m, 1.128386358070218), x_m, 1e-9);
	} else {
		tmp = 1.0 - ((t_0 * (0.254829592 + (t_0 * (-0.284496736 + (((fma((1.061405429 / ((0.10731592879921 * (x_m * x_m)) - 1.0)), ((x_m * 0.3275911) - 1.0), -1.453152027) / fma(x_m, 0.3275911, 1.0)) + 1.421413741) / fma(x_m, 0.3275911, 1.0)))))) * exp((-x_m * x_m)));
	}
	return tmp;
}

Julia

x_m = abs(x)
function code(x_m)
	t_0 = Float64(1.0 + Float64(0.3275911 * abs(x_m))) ^ -1.0
	tmp = 0.0
	if (abs(x_m) <= 1e-8)
		tmp = fma(fma(-0.00011824394398844293, x_m, 1.128386358070218), x_m, 1e-9);
	else
		tmp = Float64(1.0 - Float64(Float64(t_0 * Float64(0.254829592 + Float64(t_0 * Float64(-0.284496736 + Float64(Float64(Float64(fma(Float64(1.061405429 / Float64(Float64(0.10731592879921 * Float64(x_m * x_m)) - 1.0)), Float64(Float64(x_m * 0.3275911) - 1.0), -1.453152027) / fma(x_m, 0.3275911, 1.0)) + 1.421413741) / fma(x_m, 0.3275911, 1.0)))))) * exp(Float64(Float64(-x_m) * x_m))));
	end
	return tmp
end

Wolfram

x_m = N[Abs[x], $MachinePrecision]
code[x$95$m_] := Block[{t$95$0 = N[Power[N[(1.0 + N[(0.3275911 * N[Abs[x$95$m], $MachinePrecision]), $MachinePrecision]), $MachinePrecision], -1.0], $MachinePrecision]}, If[LessEqual[N[Abs[x$95$m], $MachinePrecision], 1e-8], N[(N[(-0.00011824394398844293 * x$95$m + 1.128386358070218), $MachinePrecision] * x$95$m + 1e-9), $MachinePrecision], N[(1.0 - N[(N[(t$95$0 * N[(0.254829592 + N[(t$95$0 * N[(-0.284496736 + N[(N[(N[(N[(N[(1.061405429 / N[(N[(0.10731592879921 * N[(x$95$m * x$95$m), $MachinePrecision]), $MachinePrecision] - 1.0), $MachinePrecision]), $MachinePrecision] * N[(N[(x$95$m * 0.3275911), $MachinePrecision] - 1.0), $MachinePrecision] + -1.453152027), $MachinePrecision] / N[(x$95$m * 0.3275911 + 1.0), $MachinePrecision]), $MachinePrecision] + 1.421413741), $MachinePrecision] / N[(x$95$m * 0.3275911 + 1.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * N[Exp[N[((-x$95$m) * x$95$m), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]]

Derivation

1. Split input into 2 regimes

2. if (fabs.f64 x) < 1e-8

   1. Initial program 57.7%

      \[1 - \left(\frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(0.254829592 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(-0.284496736 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(1.421413741 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(-1.453152027 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot 1.061405429\right)\right)\right)\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|} \]
   2. Add Preprocessing

   4. Applied rewrites 57.3%

      \[\leadsto \color{blue}{\frac{1 - {\left(\frac{\frac{\frac{\frac{\frac{1.061405429}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -1.453152027}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 1.421413741}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -0.284496736}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 0.254829592}{{\left(e^{x}\right)}^{x} \cdot \mathsf{fma}\left(x, 0.3275911, 1\right)}\right)}^{2}}{\mathsf{fma}\left({\left(e^{x}\right)}^{x}, \frac{\frac{\frac{\frac{\frac{1.061405429}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -1.453152027}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 1.421413741}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -0.284496736}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 0.254829592}{\mathsf{fma}\left(x, 0.3275911, 1\right)}, 1\right)}} \]

   5. Taylor expanded in x around 0

      \[\leadsto \color{blue}{\frac{1}{1000000000} + x \cdot \left(\frac{564193179035109}{500000000000000} + \frac{-4729757757172838478231131321}{39999999980000000000000000000000} \cdot x\right)} \]
   6. Step-by-step derivation

      1. +-commutative N/A

         \[\leadsto \color{blue}{x \cdot \left(\frac{564193179035109}{500000000000000} + \frac{-4729757757172838478231131321}{39999999980000000000000000000000} \cdot x\right) + \frac{1}{1000000000}} \]

      2. *-commutative N/A

         \[\leadsto \color{blue}{\left(\frac{564193179035109}{500000000000000} + \frac{-4729757757172838478231131321}{39999999980000000000000000000000} \cdot x\right) \cdot x} + \frac{1}{1000000000} \]

      3. lower-fma.f64 N/A

         \[\leadsto \color{blue}{\mathsf{fma}\left(\frac{564193179035109}{500000000000000} + \frac{-4729757757172838478231131321}{39999999980000000000000000000000} \cdot x, x, \frac{1}{1000000000}\right)} \]

      4. +-commutative N/A

         \[\leadsto \mathsf{fma}\left(\color{blue}{\frac{-4729757757172838478231131321}{39999999980000000000000000000000} \cdot x + \frac{564193179035109}{500000000000000}}, x, \frac{1}{1000000000}\right) \]

      5. lower-fma.f64 99.0

         \[\leadsto \mathsf{fma}\left(\color{blue}{\mathsf{fma}\left(-0.00011824394398844293, x, 1.128386358070218\right)}, x, 10^{-9}\right) \]

   7. Applied rewrites 99.0%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\mathsf{fma}\left(-0.00011824394398844293, x, 1.128386358070218\right), x, 10^{-9}\right)} \]

   if 1e-8 < (fabs.f64 x)

   1. Initial program 99.7%

      \[1 - \left(\frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(0.254829592 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(-0.284496736 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(1.421413741 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(-1.453152027 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot 1.061405429\right)\right)\right)\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|} \]
   2. Add Preprocessing

   4. Applied rewrites 98.7%

      \[\leadsto 1 - \left(\frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(0.254829592 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(-0.284496736 + \color{blue}{\frac{\frac{\frac{1.061405429}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -1.453152027}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 1.421413741}{\mathsf{fma}\left(x, 0.3275911, 1\right)}}\right)\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|} \]
   5. Step-by-step derivation

      1. lift-+.f64 N/A

         \[\leadsto 1 - \left(\frac{1}{1 + \frac{3275911}{10000000} \cdot \left|x\right|} \cdot \left(\frac{31853699}{125000000} + \frac{1}{1 + \frac{3275911}{10000000} \cdot \left|x\right|} \cdot \left(\frac{-8890523}{31250000} + \frac{\frac{\color{blue}{\frac{\frac{1061405429}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{-1453152027}{1000000000}}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{1421413741}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)}\right)\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|} \]

      2. lift-/.f64 N/A

         \[\leadsto 1 - \left(\frac{1}{1 + \frac{3275911}{10000000} \cdot \left|x\right|} \cdot \left(\frac{31853699}{125000000} + \frac{1}{1 + \frac{3275911}{10000000} \cdot \left|x\right|} \cdot \left(\frac{-8890523}{31250000} + \frac{\frac{\color{blue}{\frac{\frac{1061405429}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)}} + \frac{-1453152027}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{1421413741}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)}\right)\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|} \]

      3. lift-fma.f64 N/A

         \[\leadsto 1 - \left(\frac{1}{1 + \frac{3275911}{10000000} \cdot \left|x\right|} \cdot \left(\frac{31853699}{125000000} + \frac{1}{1 + \frac{3275911}{10000000} \cdot \left|x\right|} \cdot \left(\frac{-8890523}{31250000} + \frac{\frac{\frac{\frac{1061405429}{1000000000}}{\color{blue}{x \cdot \frac{3275911}{10000000} + 1}} + \frac{-1453152027}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{1421413741}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)}\right)\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|} \]

      4. lift-*.f64 N/A

         \[\leadsto 1 - \left(\frac{1}{1 + \frac{3275911}{10000000} \cdot \left|x\right|} \cdot \left(\frac{31853699}{125000000} + \frac{1}{1 + \frac{3275911}{10000000} \cdot \left|x\right|} \cdot \left(\frac{-8890523}{31250000} + \frac{\frac{\frac{\frac{1061405429}{1000000000}}{\color{blue}{x \cdot \frac{3275911}{10000000}} + 1} + \frac{-1453152027}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{1421413741}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)}\right)\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|} \]

      5. flip-+ N/A

         \[\leadsto 1 - \left(\frac{1}{1 + \frac{3275911}{10000000} \cdot \left|x\right|} \cdot \left(\frac{31853699}{125000000} + \frac{1}{1 + \frac{3275911}{10000000} \cdot \left|x\right|} \cdot \left(\frac{-8890523}{31250000} + \frac{\frac{\frac{\frac{1061405429}{1000000000}}{\color{blue}{\frac{\left(x \cdot \frac{3275911}{10000000}\right) \cdot \left(x \cdot \frac{3275911}{10000000}\right) - 1 \cdot 1}{x \cdot \frac{3275911}{10000000} - 1}}} + \frac{-1453152027}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{1421413741}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)}\right)\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|} \]

      6. lift--.f64 N/A

         \[\leadsto 1 - \left(\frac{1}{1 + \frac{3275911}{10000000} \cdot \left|x\right|} \cdot \left(\frac{31853699}{125000000} + \frac{1}{1 + \frac{3275911}{10000000} \cdot \left|x\right|} \cdot \left(\frac{-8890523}{31250000} + \frac{\frac{\frac{\frac{1061405429}{1000000000}}{\frac{\left(x \cdot \frac{3275911}{10000000}\right) \cdot \left(x \cdot \frac{3275911}{10000000}\right) - 1 \cdot 1}{\color{blue}{x \cdot \frac{3275911}{10000000} - 1}}} + \frac{-1453152027}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{1421413741}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)}\right)\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|} \]

      7. associate-/r/ N/A

         \[\leadsto 1 - \left(\frac{1}{1 + \frac{3275911}{10000000} \cdot \left|x\right|} \cdot \left(\frac{31853699}{125000000} + \frac{1}{1 + \frac{3275911}{10000000} \cdot \left|x\right|} \cdot \left(\frac{-8890523}{31250000} + \frac{\frac{\color{blue}{\frac{\frac{1061405429}{1000000000}}{\left(x \cdot \frac{3275911}{10000000}\right) \cdot \left(x \cdot \frac{3275911}{10000000}\right) - 1 \cdot 1} \cdot \left(x \cdot \frac{3275911}{10000000} - 1\right)} + \frac{-1453152027}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{1421413741}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)}\right)\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|} \]

      8. lower-fma.f64 N/A

         \[\leadsto 1 - \left(\frac{1}{1 + \frac{3275911}{10000000} \cdot \left|x\right|} \cdot \left(\frac{31853699}{125000000} + \frac{1}{1 + \frac{3275911}{10000000} \cdot \left|x\right|} \cdot \left(\frac{-8890523}{31250000} + \frac{\frac{\color{blue}{\mathsf{fma}\left(\frac{\frac{1061405429}{1000000000}}{\left(x \cdot \frac{3275911}{10000000}\right) \cdot \left(x \cdot \frac{3275911}{10000000}\right) - 1 \cdot 1}, x \cdot \frac{3275911}{10000000} - 1, \frac{-1453152027}{1000000000}\right)}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{1421413741}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)}\right)\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|} \]

   6. Applied rewrites 98.7%

      \[\leadsto 1 - \left(\frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(0.254829592 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(-0.284496736 + \frac{\frac{\color{blue}{\mathsf{fma}\left(\frac{1.061405429}{0.10731592879921 \cdot \left(x \cdot x\right) - 1}, x \cdot 0.3275911 - 1, -1.453152027\right)}}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 1.421413741}{\mathsf{fma}\left(x, 0.3275911, 1\right)}\right)\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|} \]
3. Recombined 2 regimes into one program.

4. Final simplification 98.9%

   \[\leadsto \begin{array}{l} \mathbf{if}\;\left|x\right| \leq 10^{-8}:\\ \;\;\;\;\mathsf{fma}\left(\mathsf{fma}\left(-0.00011824394398844293, x, 1.128386358070218\right), x, 10^{-9}\right)\\ \mathbf{else}:\\ \;\;\;\;1 - \left({\left(1 + 0.3275911 \cdot \left|x\right|\right)}^{-1} \cdot \left(0.254829592 + {\left(1 + 0.3275911 \cdot \left|x\right|\right)}^{-1} \cdot \left(-0.284496736 + \frac{\frac{\mathsf{fma}\left(\frac{1.061405429}{0.10731592879921 \cdot \left(x \cdot x\right) - 1}, x \cdot 0.3275911 - 1, -1.453152027\right)}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 1.421413741}{\mathsf{fma}\left(x, 0.3275911, 1\right)}\right)\right)\right) \cdot e^{\left(-x\right) \cdot x}\\ \end{array} \]
5. Add Preprocessing

Alternative 3: 99.7% accurate, 0.6× speedup

Math

\[\begin{array}{l} x_m = \left|x\right| \\ \begin{array}{l} t_0 := {\left(1 + 0.3275911 \cdot \left|x\_m\right|\right)}^{-1}\\ \mathbf{if}\;\left|x\_m\right| \leq 10^{-8}:\\ \;\;\;\;\mathsf{fma}\left(\mathsf{fma}\left(-0.00011824394398844293, x\_m, 1.128386358070218\right), x\_m, 10^{-9}\right)\\ \mathbf{else}:\\ \;\;\;\;1 - \left(t\_0 \cdot \left(0.254829592 + t\_0 \cdot \left(-0.284496736 + \frac{\frac{\frac{1.061405429}{\mathsf{fma}\left(x\_m, 0.3275911, 1\right)} + -1.453152027}{\mathsf{fma}\left(x\_m, 0.3275911, 1\right)} + 1.421413741}{\mathsf{fma}\left(x\_m, 0.3275911, 1\right)}\right)\right)\right) \cdot e^{\left(-x\_m\right) \cdot x\_m}\\ \end{array} \end{array} \]

FPCore

x_m = (fabs.f64 x)
(FPCore (x_m)
 :precision binary64
 (let* ((t_0 (pow (+ 1.0 (* 0.3275911 (fabs x_m))) -1.0)))
   (if (<= (fabs x_m) 1e-8)
     (fma (fma -0.00011824394398844293 x_m 1.128386358070218) x_m 1e-9)
     (-
      1.0
      (*
       (*
        t_0
        (+
         0.254829592
         (*
          t_0
          (+
           -0.284496736
           (/
            (+
             (/
              (+ (/ 1.061405429 (fma x_m 0.3275911 1.0)) -1.453152027)
              (fma x_m 0.3275911 1.0))
             1.421413741)
            (fma x_m 0.3275911 1.0))))))
       (exp (* (- x_m) x_m)))))))

C

x_m = fabs(x);
double code(double x_m) {
	double t_0 = pow((1.0 + (0.3275911 * fabs(x_m))), -1.0);
	double tmp;
	if (fabs(x_m) <= 1e-8) {
		tmp = fma(fma(-0.00011824394398844293, x_m, 1.128386358070218), x_m, 1e-9);
	} else {
		tmp = 1.0 - ((t_0 * (0.254829592 + (t_0 * (-0.284496736 + (((((1.061405429 / fma(x_m, 0.3275911, 1.0)) + -1.453152027) / fma(x_m, 0.3275911, 1.0)) + 1.421413741) / fma(x_m, 0.3275911, 1.0)))))) * exp((-x_m * x_m)));
	}
	return tmp;
}

Julia

x_m = abs(x)
function code(x_m)
	t_0 = Float64(1.0 + Float64(0.3275911 * abs(x_m))) ^ -1.0
	tmp = 0.0
	if (abs(x_m) <= 1e-8)
		tmp = fma(fma(-0.00011824394398844293, x_m, 1.128386358070218), x_m, 1e-9);
	else
		tmp = Float64(1.0 - Float64(Float64(t_0 * Float64(0.254829592 + Float64(t_0 * Float64(-0.284496736 + Float64(Float64(Float64(Float64(Float64(1.061405429 / fma(x_m, 0.3275911, 1.0)) + -1.453152027) / fma(x_m, 0.3275911, 1.0)) + 1.421413741) / fma(x_m, 0.3275911, 1.0)))))) * exp(Float64(Float64(-x_m) * x_m))));
	end
	return tmp
end

Wolfram

x_m = N[Abs[x], $MachinePrecision]
code[x$95$m_] := Block[{t$95$0 = N[Power[N[(1.0 + N[(0.3275911 * N[Abs[x$95$m], $MachinePrecision]), $MachinePrecision]), $MachinePrecision], -1.0], $MachinePrecision]}, If[LessEqual[N[Abs[x$95$m], $MachinePrecision], 1e-8], N[(N[(-0.00011824394398844293 * x$95$m + 1.128386358070218), $MachinePrecision] * x$95$m + 1e-9), $MachinePrecision], N[(1.0 - N[(N[(t$95$0 * N[(0.254829592 + N[(t$95$0 * N[(-0.284496736 + N[(N[(N[(N[(N[(1.061405429 / N[(x$95$m * 0.3275911 + 1.0), $MachinePrecision]), $MachinePrecision] + -1.453152027), $MachinePrecision] / N[(x$95$m * 0.3275911 + 1.0), $MachinePrecision]), $MachinePrecision] + 1.421413741), $MachinePrecision] / N[(x$95$m * 0.3275911 + 1.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * N[Exp[N[((-x$95$m) * x$95$m), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]]

Derivation

1. Split input into 2 regimes

2. if (fabs.f64 x) < 1e-8

   1. Initial program 57.7%

      \[1 - \left(\frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(0.254829592 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(-0.284496736 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(1.421413741 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(-1.453152027 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot 1.061405429\right)\right)\right)\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|} \]
   2. Add Preprocessing

   4. Applied rewrites 57.3%

      \[\leadsto \color{blue}{\frac{1 - {\left(\frac{\frac{\frac{\frac{\frac{1.061405429}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -1.453152027}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 1.421413741}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -0.284496736}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 0.254829592}{{\left(e^{x}\right)}^{x} \cdot \mathsf{fma}\left(x, 0.3275911, 1\right)}\right)}^{2}}{\mathsf{fma}\left({\left(e^{x}\right)}^{x}, \frac{\frac{\frac{\frac{\frac{1.061405429}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -1.453152027}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 1.421413741}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -0.284496736}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 0.254829592}{\mathsf{fma}\left(x, 0.3275911, 1\right)}, 1\right)}} \]

   5. Taylor expanded in x around 0

      \[\leadsto \color{blue}{\frac{1}{1000000000} + x \cdot \left(\frac{564193179035109}{500000000000000} + \frac{-4729757757172838478231131321}{39999999980000000000000000000000} \cdot x\right)} \]
   6. Step-by-step derivation

      1. +-commutative N/A

         \[\leadsto \color{blue}{x \cdot \left(\frac{564193179035109}{500000000000000} + \frac{-4729757757172838478231131321}{39999999980000000000000000000000} \cdot x\right) + \frac{1}{1000000000}} \]

      2. *-commutative N/A

         \[\leadsto \color{blue}{\left(\frac{564193179035109}{500000000000000} + \frac{-4729757757172838478231131321}{39999999980000000000000000000000} \cdot x\right) \cdot x} + \frac{1}{1000000000} \]

      3. lower-fma.f64 N/A

         \[\leadsto \color{blue}{\mathsf{fma}\left(\frac{564193179035109}{500000000000000} + \frac{-4729757757172838478231131321}{39999999980000000000000000000000} \cdot x, x, \frac{1}{1000000000}\right)} \]

      4. +-commutative N/A

         \[\leadsto \mathsf{fma}\left(\color{blue}{\frac{-4729757757172838478231131321}{39999999980000000000000000000000} \cdot x + \frac{564193179035109}{500000000000000}}, x, \frac{1}{1000000000}\right) \]

      5. lower-fma.f64 99.0

         \[\leadsto \mathsf{fma}\left(\color{blue}{\mathsf{fma}\left(-0.00011824394398844293, x, 1.128386358070218\right)}, x, 10^{-9}\right) \]

   7. Applied rewrites 99.0%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\mathsf{fma}\left(-0.00011824394398844293, x, 1.128386358070218\right), x, 10^{-9}\right)} \]

   if 1e-8 < (fabs.f64 x)

   1. Initial program 99.7%

      \[1 - \left(\frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(0.254829592 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(-0.284496736 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(1.421413741 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(-1.453152027 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot 1.061405429\right)\right)\right)\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|} \]
   2. Add Preprocessing

   4. Applied rewrites 98.7%

      \[\leadsto 1 - \left(\frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(0.254829592 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(-0.284496736 + \color{blue}{\frac{\frac{\frac{1.061405429}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -1.453152027}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 1.421413741}{\mathsf{fma}\left(x, 0.3275911, 1\right)}}\right)\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|} \]
   5. Step-by-step derivation

      1. lift-*.f64 N/A

         \[\leadsto 1 - \left(\frac{1}{1 + \frac{3275911}{10000000} \cdot \left|x\right|} \cdot \left(\frac{31853699}{125000000} + \frac{1}{1 + \frac{3275911}{10000000} \cdot \left|x\right|} \cdot \left(\frac{-8890523}{31250000} + \frac{\frac{\frac{\frac{1061405429}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{-1453152027}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{1421413741}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)}\right)\right)\right) \cdot e^{-\color{blue}{\left|x\right| \cdot \left|x\right|}} \]

      2. lift-fabs.f64 N/A

         \[\leadsto 1 - \left(\frac{1}{1 + \frac{3275911}{10000000} \cdot \left|x\right|} \cdot \left(\frac{31853699}{125000000} + \frac{1}{1 + \frac{3275911}{10000000} \cdot \left|x\right|} \cdot \left(\frac{-8890523}{31250000} + \frac{\frac{\frac{\frac{1061405429}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{-1453152027}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{1421413741}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)}\right)\right)\right) \cdot e^{-\color{blue}{\left|x\right|} \cdot \left|x\right|} \]

      3. lift-fabs.f64 N/A

         \[\leadsto 1 - \left(\frac{1}{1 + \frac{3275911}{10000000} \cdot \left|x\right|} \cdot \left(\frac{31853699}{125000000} + \frac{1}{1 + \frac{3275911}{10000000} \cdot \left|x\right|} \cdot \left(\frac{-8890523}{31250000} + \frac{\frac{\frac{\frac{1061405429}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{-1453152027}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{1421413741}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)}\right)\right)\right) \cdot e^{-\left|x\right| \cdot \color{blue}{\left|x\right|}} \]

      4. sqr-abs N/A

         \[\leadsto 1 - \left(\frac{1}{1 + \frac{3275911}{10000000} \cdot \left|x\right|} \cdot \left(\frac{31853699}{125000000} + \frac{1}{1 + \frac{3275911}{10000000} \cdot \left|x\right|} \cdot \left(\frac{-8890523}{31250000} + \frac{\frac{\frac{\frac{1061405429}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{-1453152027}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{1421413741}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)}\right)\right)\right) \cdot e^{-\color{blue}{x \cdot x}} \]

      5. lower-*.f64 98.7

         \[\leadsto 1 - \left(\frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(0.254829592 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(-0.284496736 + \frac{\frac{\frac{1.061405429}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -1.453152027}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 1.421413741}{\mathsf{fma}\left(x, 0.3275911, 1\right)}\right)\right)\right) \cdot e^{-\color{blue}{x \cdot x}} \]

   6. Applied rewrites 98.7%

      \[\leadsto 1 - \left(\frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(0.254829592 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(-0.284496736 + \frac{\frac{\frac{1.061405429}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -1.453152027}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 1.421413741}{\mathsf{fma}\left(x, 0.3275911, 1\right)}\right)\right)\right) \cdot e^{-\color{blue}{x \cdot x}} \]
3. Recombined 2 regimes into one program.

4. Final simplification 98.9%

   \[\leadsto \begin{array}{l} \mathbf{if}\;\left|x\right| \leq 10^{-8}:\\ \;\;\;\;\mathsf{fma}\left(\mathsf{fma}\left(-0.00011824394398844293, x, 1.128386358070218\right), x, 10^{-9}\right)\\ \mathbf{else}:\\ \;\;\;\;1 - \left({\left(1 + 0.3275911 \cdot \left|x\right|\right)}^{-1} \cdot \left(0.254829592 + {\left(1 + 0.3275911 \cdot \left|x\right|\right)}^{-1} \cdot \left(-0.284496736 + \frac{\frac{\frac{1.061405429}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -1.453152027}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 1.421413741}{\mathsf{fma}\left(x, 0.3275911, 1\right)}\right)\right)\right) \cdot e^{\left(-x\right) \cdot x}\\ \end{array} \]
5. Add Preprocessing

Alternative 4: 99.7% accurate, 0.7× speedup

Math

\[\begin{array}{l} x_m = \left|x\right| \\ \begin{array}{l} \mathbf{if}\;\left|x\_m\right| \leq 10^{-8}:\\ \;\;\;\;\mathsf{fma}\left(\mathsf{fma}\left(-0.00011824394398844293, x\_m, 1.128386358070218\right), x\_m, 10^{-9}\right)\\ \mathbf{else}:\\ \;\;\;\;1 - \left({\left(1 + 0.3275911 \cdot \left|x\_m\right|\right)}^{-1} \cdot \left(0.254829592 - \frac{\mathsf{fma}\left(\frac{\frac{\mathsf{fma}\left(\frac{1.061405429}{0.10731592879921 \cdot \left(x\_m \cdot x\_m\right) - 1}, x\_m \cdot 0.3275911 - 1, -1.453152027\right)}{\mathsf{fma}\left(x\_m, 0.3275911, 1\right)} + 1.421413741}{\mathsf{fma}\left(x\_m, 0.3275911, 1\right)}, -\mathsf{fma}\left(x\_m, 0.3275911, 1\right), \mathsf{fma}\left(0.0931985986926496, x\_m, 0.284496736\right)\right)}{\mathsf{fma}\left(x\_m, 0.3275911, 1\right) \cdot \mathsf{fma}\left(x\_m, 0.3275911, 1\right)}\right)\right) \cdot e^{\left(-x\_m\right) \cdot x\_m}\\ \end{array} \end{array} \]

FPCore

x_m = (fabs.f64 x)
(FPCore (x_m)
 :precision binary64
 (if (<= (fabs x_m) 1e-8)
   (fma (fma -0.00011824394398844293 x_m 1.128386358070218) x_m 1e-9)
   (-
    1.0
    (*
     (*
      (pow (+ 1.0 (* 0.3275911 (fabs x_m))) -1.0)
      (-
       0.254829592
       (/
        (fma
         (/
          (+
           (/
            (fma
             (/ 1.061405429 (- (* 0.10731592879921 (* x_m x_m)) 1.0))
             (- (* x_m 0.3275911) 1.0)
             -1.453152027)
            (fma x_m 0.3275911 1.0))
           1.421413741)
          (fma x_m 0.3275911 1.0))
         (- (fma x_m 0.3275911 1.0))
         (fma 0.0931985986926496 x_m 0.284496736))
        (* (fma x_m 0.3275911 1.0) (fma x_m 0.3275911 1.0)))))
     (exp (* (- x_m) x_m))))))

C

x_m = fabs(x);
double code(double x_m) {
	double tmp;
	if (fabs(x_m) <= 1e-8) {
		tmp = fma(fma(-0.00011824394398844293, x_m, 1.128386358070218), x_m, 1e-9);
	} else {
		tmp = 1.0 - ((pow((1.0 + (0.3275911 * fabs(x_m))), -1.0) * (0.254829592 - (fma((((fma((1.061405429 / ((0.10731592879921 * (x_m * x_m)) - 1.0)), ((x_m * 0.3275911) - 1.0), -1.453152027) / fma(x_m, 0.3275911, 1.0)) + 1.421413741) / fma(x_m, 0.3275911, 1.0)), -fma(x_m, 0.3275911, 1.0), fma(0.0931985986926496, x_m, 0.284496736)) / (fma(x_m, 0.3275911, 1.0) * fma(x_m, 0.3275911, 1.0))))) * exp((-x_m * x_m)));
	}
	return tmp;
}

Julia

x_m = abs(x)
function code(x_m)
	tmp = 0.0
	if (abs(x_m) <= 1e-8)
		tmp = fma(fma(-0.00011824394398844293, x_m, 1.128386358070218), x_m, 1e-9);
	else
		tmp = Float64(1.0 - Float64(Float64((Float64(1.0 + Float64(0.3275911 * abs(x_m))) ^ -1.0) * Float64(0.254829592 - Float64(fma(Float64(Float64(Float64(fma(Float64(1.061405429 / Float64(Float64(0.10731592879921 * Float64(x_m * x_m)) - 1.0)), Float64(Float64(x_m * 0.3275911) - 1.0), -1.453152027) / fma(x_m, 0.3275911, 1.0)) + 1.421413741) / fma(x_m, 0.3275911, 1.0)), Float64(-fma(x_m, 0.3275911, 1.0)), fma(0.0931985986926496, x_m, 0.284496736)) / Float64(fma(x_m, 0.3275911, 1.0) * fma(x_m, 0.3275911, 1.0))))) * exp(Float64(Float64(-x_m) * x_m))));
	end
	return tmp
end

Wolfram

x_m = N[Abs[x], $MachinePrecision]
code[x$95$m_] := If[LessEqual[N[Abs[x$95$m], $MachinePrecision], 1e-8], N[(N[(-0.00011824394398844293 * x$95$m + 1.128386358070218), $MachinePrecision] * x$95$m + 1e-9), $MachinePrecision], N[(1.0 - N[(N[(N[Power[N[(1.0 + N[(0.3275911 * N[Abs[x$95$m], $MachinePrecision]), $MachinePrecision]), $MachinePrecision], -1.0], $MachinePrecision] * N[(0.254829592 - N[(N[(N[(N[(N[(N[(N[(1.061405429 / N[(N[(0.10731592879921 * N[(x$95$m * x$95$m), $MachinePrecision]), $MachinePrecision] - 1.0), $MachinePrecision]), $MachinePrecision] * N[(N[(x$95$m * 0.3275911), $MachinePrecision] - 1.0), $MachinePrecision] + -1.453152027), $MachinePrecision] / N[(x$95$m * 0.3275911 + 1.0), $MachinePrecision]), $MachinePrecision] + 1.421413741), $MachinePrecision] / N[(x$95$m * 0.3275911 + 1.0), $MachinePrecision]), $MachinePrecision] * (-N[(x$95$m * 0.3275911 + 1.0), $MachinePrecision]) + N[(0.0931985986926496 * x$95$m + 0.284496736), $MachinePrecision]), $MachinePrecision] / N[(N[(x$95$m * 0.3275911 + 1.0), $MachinePrecision] * N[(x$95$m * 0.3275911 + 1.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * N[Exp[N[((-x$95$m) * x$95$m), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]

Derivation

1. Split input into 2 regimes

2. if (fabs.f64 x) < 1e-8

   1. Initial program 57.7%

      \[1 - \left(\frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(0.254829592 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(-0.284496736 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(1.421413741 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(-1.453152027 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot 1.061405429\right)\right)\right)\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|} \]
   2. Add Preprocessing

   4. Applied rewrites 57.3%

      \[\leadsto \color{blue}{\frac{1 - {\left(\frac{\frac{\frac{\frac{\frac{1.061405429}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -1.453152027}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 1.421413741}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -0.284496736}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 0.254829592}{{\left(e^{x}\right)}^{x} \cdot \mathsf{fma}\left(x, 0.3275911, 1\right)}\right)}^{2}}{\mathsf{fma}\left({\left(e^{x}\right)}^{x}, \frac{\frac{\frac{\frac{\frac{1.061405429}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -1.453152027}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 1.421413741}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -0.284496736}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 0.254829592}{\mathsf{fma}\left(x, 0.3275911, 1\right)}, 1\right)}} \]

   5. Taylor expanded in x around 0

      \[\leadsto \color{blue}{\frac{1}{1000000000} + x \cdot \left(\frac{564193179035109}{500000000000000} + \frac{-4729757757172838478231131321}{39999999980000000000000000000000} \cdot x\right)} \]
   6. Step-by-step derivation

      1. +-commutative N/A

         \[\leadsto \color{blue}{x \cdot \left(\frac{564193179035109}{500000000000000} + \frac{-4729757757172838478231131321}{39999999980000000000000000000000} \cdot x\right) + \frac{1}{1000000000}} \]

      2. *-commutative N/A

         \[\leadsto \color{blue}{\left(\frac{564193179035109}{500000000000000} + \frac{-4729757757172838478231131321}{39999999980000000000000000000000} \cdot x\right) \cdot x} + \frac{1}{1000000000} \]

      3. lower-fma.f64 N/A

         \[\leadsto \color{blue}{\mathsf{fma}\left(\frac{564193179035109}{500000000000000} + \frac{-4729757757172838478231131321}{39999999980000000000000000000000} \cdot x, x, \frac{1}{1000000000}\right)} \]

      4. +-commutative N/A

         \[\leadsto \mathsf{fma}\left(\color{blue}{\frac{-4729757757172838478231131321}{39999999980000000000000000000000} \cdot x + \frac{564193179035109}{500000000000000}}, x, \frac{1}{1000000000}\right) \]

      5. lower-fma.f64 99.0

         \[\leadsto \mathsf{fma}\left(\color{blue}{\mathsf{fma}\left(-0.00011824394398844293, x, 1.128386358070218\right)}, x, 10^{-9}\right) \]

   7. Applied rewrites 99.0%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\mathsf{fma}\left(-0.00011824394398844293, x, 1.128386358070218\right), x, 10^{-9}\right)} \]

   if 1e-8 < (fabs.f64 x)

   1. Initial program 99.7%

      \[1 - \left(\frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(0.254829592 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(-0.284496736 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(1.421413741 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(-1.453152027 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot 1.061405429\right)\right)\right)\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|} \]
   2. Add Preprocessing

   4. Applied rewrites 98.5%

      \[\leadsto 1 - \left(\frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(0.254829592 + \color{blue}{\frac{\mathsf{fma}\left(\frac{\frac{\frac{1.061405429}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -1.453152027}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 1.421413741}{\mathsf{fma}\left(x, 0.3275911, 1\right)}, -\mathsf{fma}\left(x, 0.3275911, 1\right), \mathsf{fma}\left(x, 0.3275911, 1\right) \cdot 0.284496736\right)}{\mathsf{fma}\left(x, 0.3275911, 1\right) \cdot \left(-\mathsf{fma}\left(x, 0.3275911, 1\right)\right)}}\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|} \]
   5. Step-by-step derivation

      1. lift-+.f64 N/A

         \[\leadsto 1 - \left(\frac{1}{1 + \frac{3275911}{10000000} \cdot \left|x\right|} \cdot \left(\frac{31853699}{125000000} + \frac{\mathsf{fma}\left(\frac{\frac{\color{blue}{\frac{\frac{1061405429}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{-1453152027}{1000000000}}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{1421413741}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)}, -\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right), \mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right) \cdot \frac{8890523}{31250000}\right)}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right) \cdot \left(-\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)\right)}\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|} \]

      2. lift-/.f64 N/A

         \[\leadsto 1 - \left(\frac{1}{1 + \frac{3275911}{10000000} \cdot \left|x\right|} \cdot \left(\frac{31853699}{125000000} + \frac{\mathsf{fma}\left(\frac{\frac{\color{blue}{\frac{\frac{1061405429}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)}} + \frac{-1453152027}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{1421413741}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)}, -\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right), \mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right) \cdot \frac{8890523}{31250000}\right)}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right) \cdot \left(-\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)\right)}\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|} \]

      3. lift-fma.f64 N/A

         \[\leadsto 1 - \left(\frac{1}{1 + \frac{3275911}{10000000} \cdot \left|x\right|} \cdot \left(\frac{31853699}{125000000} + \frac{\mathsf{fma}\left(\frac{\frac{\frac{\frac{1061405429}{1000000000}}{\color{blue}{x \cdot \frac{3275911}{10000000} + 1}} + \frac{-1453152027}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{1421413741}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)}, -\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right), \mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right) \cdot \frac{8890523}{31250000}\right)}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right) \cdot \left(-\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)\right)}\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|} \]

      4. lift-*.f64 N/A

         \[\leadsto 1 - \left(\frac{1}{1 + \frac{3275911}{10000000} \cdot \left|x\right|} \cdot \left(\frac{31853699}{125000000} + \frac{\mathsf{fma}\left(\frac{\frac{\frac{\frac{1061405429}{1000000000}}{\color{blue}{x \cdot \frac{3275911}{10000000}} + 1} + \frac{-1453152027}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{1421413741}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)}, -\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right), \mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right) \cdot \frac{8890523}{31250000}\right)}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right) \cdot \left(-\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)\right)}\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|} \]

      5. flip-+ N/A

         \[\leadsto 1 - \left(\frac{1}{1 + \frac{3275911}{10000000} \cdot \left|x\right|} \cdot \left(\frac{31853699}{125000000} + \frac{\mathsf{fma}\left(\frac{\frac{\frac{\frac{1061405429}{1000000000}}{\color{blue}{\frac{\left(x \cdot \frac{3275911}{10000000}\right) \cdot \left(x \cdot \frac{3275911}{10000000}\right) - 1 \cdot 1}{x \cdot \frac{3275911}{10000000} - 1}}} + \frac{-1453152027}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{1421413741}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)}, -\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right), \mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right) \cdot \frac{8890523}{31250000}\right)}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right) \cdot \left(-\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)\right)}\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|} \]

      6. lift--.f64 N/A

         \[\leadsto 1 - \left(\frac{1}{1 + \frac{3275911}{10000000} \cdot \left|x\right|} \cdot \left(\frac{31853699}{125000000} + \frac{\mathsf{fma}\left(\frac{\frac{\frac{\frac{1061405429}{1000000000}}{\frac{\left(x \cdot \frac{3275911}{10000000}\right) \cdot \left(x \cdot \frac{3275911}{10000000}\right) - 1 \cdot 1}{\color{blue}{x \cdot \frac{3275911}{10000000} - 1}}} + \frac{-1453152027}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{1421413741}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)}, -\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right), \mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right) \cdot \frac{8890523}{31250000}\right)}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right) \cdot \left(-\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)\right)}\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|} \]

      7. associate-/r/ N/A

         \[\leadsto 1 - \left(\frac{1}{1 + \frac{3275911}{10000000} \cdot \left|x\right|} \cdot \left(\frac{31853699}{125000000} + \frac{\mathsf{fma}\left(\frac{\frac{\color{blue}{\frac{\frac{1061405429}{1000000000}}{\left(x \cdot \frac{3275911}{10000000}\right) \cdot \left(x \cdot \frac{3275911}{10000000}\right) - 1 \cdot 1} \cdot \left(x \cdot \frac{3275911}{10000000} - 1\right)} + \frac{-1453152027}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{1421413741}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)}, -\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right), \mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right) \cdot \frac{8890523}{31250000}\right)}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right) \cdot \left(-\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)\right)}\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|} \]

      8. lower-fma.f64 N/A

         \[\leadsto 1 - \left(\frac{1}{1 + \frac{3275911}{10000000} \cdot \left|x\right|} \cdot \left(\frac{31853699}{125000000} + \frac{\mathsf{fma}\left(\frac{\frac{\color{blue}{\mathsf{fma}\left(\frac{\frac{1061405429}{1000000000}}{\left(x \cdot \frac{3275911}{10000000}\right) \cdot \left(x \cdot \frac{3275911}{10000000}\right) - 1 \cdot 1}, x \cdot \frac{3275911}{10000000} - 1, \frac{-1453152027}{1000000000}\right)}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{1421413741}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)}, -\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right), \mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right) \cdot \frac{8890523}{31250000}\right)}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right) \cdot \left(-\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)\right)}\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|} \]

   6. Applied rewrites 98.5%

      \[\leadsto 1 - \left(\frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(0.254829592 + \frac{\mathsf{fma}\left(\frac{\frac{\color{blue}{\mathsf{fma}\left(\frac{1.061405429}{0.10731592879921 \cdot \left(x \cdot x\right) - 1}, x \cdot 0.3275911 - 1, -1.453152027\right)}}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 1.421413741}{\mathsf{fma}\left(x, 0.3275911, 1\right)}, -\mathsf{fma}\left(x, 0.3275911, 1\right), \mathsf{fma}\left(x, 0.3275911, 1\right) \cdot 0.284496736\right)}{\mathsf{fma}\left(x, 0.3275911, 1\right) \cdot \left(-\mathsf{fma}\left(x, 0.3275911, 1\right)\right)}\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|} \]

   7. Taylor expanded in x around 0

      \[\leadsto 1 - \left(\frac{1}{1 + \frac{3275911}{10000000} \cdot \left|x\right|} \cdot \left(\frac{31853699}{125000000} + \frac{\mathsf{fma}\left(\frac{\frac{\mathsf{fma}\left(\frac{\frac{1061405429}{1000000000}}{\frac{10731592879921}{100000000000000} \cdot \left(x \cdot x\right) - 1}, x \cdot \frac{3275911}{10000000} - 1, \frac{-1453152027}{1000000000}\right)}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{1421413741}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)}, -\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right), \color{blue}{\frac{8890523}{31250000} + \frac{29124562091453}{312500000000000} \cdot x}\right)}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right) \cdot \left(-\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)\right)}\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|} \]
   8. Step-by-step derivation

      1. +-commutative N/A

         \[\leadsto 1 - \left(\frac{1}{1 + \frac{3275911}{10000000} \cdot \left|x\right|} \cdot \left(\frac{31853699}{125000000} + \frac{\mathsf{fma}\left(\frac{\frac{\mathsf{fma}\left(\frac{\frac{1061405429}{1000000000}}{\frac{10731592879921}{100000000000000} \cdot \left(x \cdot x\right) - 1}, x \cdot \frac{3275911}{10000000} - 1, \frac{-1453152027}{1000000000}\right)}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{1421413741}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)}, -\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right), \color{blue}{\frac{29124562091453}{312500000000000} \cdot x + \frac{8890523}{31250000}}\right)}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right) \cdot \left(-\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)\right)}\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|} \]

      2. lower-fma.f64 98.5

         \[\leadsto 1 - \left(\frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(0.254829592 + \frac{\mathsf{fma}\left(\frac{\frac{\mathsf{fma}\left(\frac{1.061405429}{0.10731592879921 \cdot \left(x \cdot x\right) - 1}, x \cdot 0.3275911 - 1, -1.453152027\right)}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 1.421413741}{\mathsf{fma}\left(x, 0.3275911, 1\right)}, -\mathsf{fma}\left(x, 0.3275911, 1\right), \color{blue}{\mathsf{fma}\left(0.0931985986926496, x, 0.284496736\right)}\right)}{\mathsf{fma}\left(x, 0.3275911, 1\right) \cdot \left(-\mathsf{fma}\left(x, 0.3275911, 1\right)\right)}\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|} \]

   9. Applied rewrites 98.5%

      \[\leadsto 1 - \left(\frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(0.254829592 + \frac{\mathsf{fma}\left(\frac{\frac{\mathsf{fma}\left(\frac{1.061405429}{0.10731592879921 \cdot \left(x \cdot x\right) - 1}, x \cdot 0.3275911 - 1, -1.453152027\right)}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 1.421413741}{\mathsf{fma}\left(x, 0.3275911, 1\right)}, -\mathsf{fma}\left(x, 0.3275911, 1\right), \color{blue}{\mathsf{fma}\left(0.0931985986926496, x, 0.284496736\right)}\right)}{\mathsf{fma}\left(x, 0.3275911, 1\right) \cdot \left(-\mathsf{fma}\left(x, 0.3275911, 1\right)\right)}\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|} \]
   10. Step-by-step derivation

       1. lift-*.f64 N/A

          \[\leadsto 1 - \left(\frac{1}{1 + \frac{3275911}{10000000} \cdot \left|x\right|} \cdot \left(\frac{31853699}{125000000} + \frac{\mathsf{fma}\left(\frac{\frac{\mathsf{fma}\left(\frac{\frac{1061405429}{1000000000}}{\frac{10731592879921}{100000000000000} \cdot \left(x \cdot x\right) - 1}, x \cdot \frac{3275911}{10000000} - 1, \frac{-1453152027}{1000000000}\right)}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{1421413741}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)}, -\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right), \mathsf{fma}\left(\frac{29124562091453}{312500000000000}, x, \frac{8890523}{31250000}\right)\right)}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right) \cdot \left(-\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)\right)}\right)\right) \cdot e^{-\color{blue}{\left|x\right| \cdot \left|x\right|}} \]

       2. lift-fabs.f64 N/A

          \[\leadsto 1 - \left(\frac{1}{1 + \frac{3275911}{10000000} \cdot \left|x\right|} \cdot \left(\frac{31853699}{125000000} + \frac{\mathsf{fma}\left(\frac{\frac{\mathsf{fma}\left(\frac{\frac{1061405429}{1000000000}}{\frac{10731592879921}{100000000000000} \cdot \left(x \cdot x\right) - 1}, x \cdot \frac{3275911}{10000000} - 1, \frac{-1453152027}{1000000000}\right)}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{1421413741}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)}, -\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right), \mathsf{fma}\left(\frac{29124562091453}{312500000000000}, x, \frac{8890523}{31250000}\right)\right)}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right) \cdot \left(-\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)\right)}\right)\right) \cdot e^{-\color{blue}{\left|x\right|} \cdot \left|x\right|} \]

       3. lift-fabs.f64 N/A

          \[\leadsto 1 - \left(\frac{1}{1 + \frac{3275911}{10000000} \cdot \left|x\right|} \cdot \left(\frac{31853699}{125000000} + \frac{\mathsf{fma}\left(\frac{\frac{\mathsf{fma}\left(\frac{\frac{1061405429}{1000000000}}{\frac{10731592879921}{100000000000000} \cdot \left(x \cdot x\right) - 1}, x \cdot \frac{3275911}{10000000} - 1, \frac{-1453152027}{1000000000}\right)}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{1421413741}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)}, -\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right), \mathsf{fma}\left(\frac{29124562091453}{312500000000000}, x, \frac{8890523}{31250000}\right)\right)}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right) \cdot \left(-\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)\right)}\right)\right) \cdot e^{-\left|x\right| \cdot \color{blue}{\left|x\right|}} \]

       4. sqr-abs-rev N/A

          \[\leadsto 1 - \left(\frac{1}{1 + \frac{3275911}{10000000} \cdot \left|x\right|} \cdot \left(\frac{31853699}{125000000} + \frac{\mathsf{fma}\left(\frac{\frac{\mathsf{fma}\left(\frac{\frac{1061405429}{1000000000}}{\frac{10731592879921}{100000000000000} \cdot \left(x \cdot x\right) - 1}, x \cdot \frac{3275911}{10000000} - 1, \frac{-1453152027}{1000000000}\right)}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{1421413741}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)}, -\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right), \mathsf{fma}\left(\frac{29124562091453}{312500000000000}, x, \frac{8890523}{31250000}\right)\right)}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right) \cdot \left(-\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)\right)}\right)\right) \cdot e^{-\color{blue}{x \cdot x}} \]

       5. lift-*.f64 98.5

          \[\leadsto 1 - \left(\frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(0.254829592 + \frac{\mathsf{fma}\left(\frac{\frac{\mathsf{fma}\left(\frac{1.061405429}{0.10731592879921 \cdot \left(x \cdot x\right) - 1}, x \cdot 0.3275911 - 1, -1.453152027\right)}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 1.421413741}{\mathsf{fma}\left(x, 0.3275911, 1\right)}, -\mathsf{fma}\left(x, 0.3275911, 1\right), \mathsf{fma}\left(0.0931985986926496, x, 0.284496736\right)\right)}{\mathsf{fma}\left(x, 0.3275911, 1\right) \cdot \left(-\mathsf{fma}\left(x, 0.3275911, 1\right)\right)}\right)\right) \cdot e^{-\color{blue}{x \cdot x}} \]

   11. Applied rewrites 98.5%

       \[\leadsto 1 - \left(\frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(0.254829592 + \frac{\mathsf{fma}\left(\frac{\frac{\mathsf{fma}\left(\frac{1.061405429}{0.10731592879921 \cdot \left(x \cdot x\right) - 1}, x \cdot 0.3275911 - 1, -1.453152027\right)}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 1.421413741}{\mathsf{fma}\left(x, 0.3275911, 1\right)}, -\mathsf{fma}\left(x, 0.3275911, 1\right), \mathsf{fma}\left(0.0931985986926496, x, 0.284496736\right)\right)}{\mathsf{fma}\left(x, 0.3275911, 1\right) \cdot \left(-\mathsf{fma}\left(x, 0.3275911, 1\right)\right)}\right)\right) \cdot e^{-\color{blue}{x \cdot x}} \]
3. Recombined 2 regimes into one program.

4. Final simplification 98.8%

   \[\leadsto \begin{array}{l} \mathbf{if}\;\left|x\right| \leq 10^{-8}:\\ \;\;\;\;\mathsf{fma}\left(\mathsf{fma}\left(-0.00011824394398844293, x, 1.128386358070218\right), x, 10^{-9}\right)\\ \mathbf{else}:\\ \;\;\;\;1 - \left({\left(1 + 0.3275911 \cdot \left|x\right|\right)}^{-1} \cdot \left(0.254829592 - \frac{\mathsf{fma}\left(\frac{\frac{\mathsf{fma}\left(\frac{1.061405429}{0.10731592879921 \cdot \left(x \cdot x\right) - 1}, x \cdot 0.3275911 - 1, -1.453152027\right)}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 1.421413741}{\mathsf{fma}\left(x, 0.3275911, 1\right)}, -\mathsf{fma}\left(x, 0.3275911, 1\right), \mathsf{fma}\left(0.0931985986926496, x, 0.284496736\right)\right)}{\mathsf{fma}\left(x, 0.3275911, 1\right) \cdot \mathsf{fma}\left(x, 0.3275911, 1\right)}\right)\right) \cdot e^{\left(-x\right) \cdot x}\\ \end{array} \]
5. Add Preprocessing

Alternative 5: 99.7% accurate, 0.8× speedup

Math

\[\begin{array}{l} x_m = \left|x\right| \\ \begin{array}{l} \mathbf{if}\;\left|x\_m\right| \leq 10^{-8}:\\ \;\;\;\;\mathsf{fma}\left(\mathsf{fma}\left(-0.00011824394398844293, x\_m, 1.128386358070218\right), x\_m, 10^{-9}\right)\\ \mathbf{else}:\\ \;\;\;\;1 - \left({\left(1 + 0.3275911 \cdot \left|x\_m\right|\right)}^{-1} \cdot \left(0.254829592 + \frac{\frac{\frac{\frac{1.061405429}{\mathsf{fma}\left(x\_m, 0.3275911, 1\right)} + -1.453152027}{\mathsf{fma}\left(x\_m, 0.3275911, 1\right)} + 1.421413741}{\mathsf{fma}\left(x\_m, 0.3275911, 1\right)} + -0.284496736}{\mathsf{fma}\left(x\_m, 0.3275911, 1\right)}\right)\right) \cdot e^{\left(-x\_m\right) \cdot x\_m}\\ \end{array} \end{array} \]

FPCore

x_m = (fabs.f64 x)
(FPCore (x_m)
 :precision binary64
 (if (<= (fabs x_m) 1e-8)
   (fma (fma -0.00011824394398844293 x_m 1.128386358070218) x_m 1e-9)
   (-
    1.0
    (*
     (*
      (pow (+ 1.0 (* 0.3275911 (fabs x_m))) -1.0)
      (+
       0.254829592
       (/
        (+
         (/
          (+
           (/
            (+ (/ 1.061405429 (fma x_m 0.3275911 1.0)) -1.453152027)
            (fma x_m 0.3275911 1.0))
           1.421413741)
          (fma x_m 0.3275911 1.0))
         -0.284496736)
        (fma x_m 0.3275911 1.0))))
     (exp (* (- x_m) x_m))))))

C

x_m = fabs(x);
double code(double x_m) {
	double tmp;
	if (fabs(x_m) <= 1e-8) {
		tmp = fma(fma(-0.00011824394398844293, x_m, 1.128386358070218), x_m, 1e-9);
	} else {
		tmp = 1.0 - ((pow((1.0 + (0.3275911 * fabs(x_m))), -1.0) * (0.254829592 + (((((((1.061405429 / fma(x_m, 0.3275911, 1.0)) + -1.453152027) / fma(x_m, 0.3275911, 1.0)) + 1.421413741) / fma(x_m, 0.3275911, 1.0)) + -0.284496736) / fma(x_m, 0.3275911, 1.0)))) * exp((-x_m * x_m)));
	}
	return tmp;
}

Julia

x_m = abs(x)
function code(x_m)
	tmp = 0.0
	if (abs(x_m) <= 1e-8)
		tmp = fma(fma(-0.00011824394398844293, x_m, 1.128386358070218), x_m, 1e-9);
	else
		tmp = Float64(1.0 - Float64(Float64((Float64(1.0 + Float64(0.3275911 * abs(x_m))) ^ -1.0) * Float64(0.254829592 + Float64(Float64(Float64(Float64(Float64(Float64(Float64(1.061405429 / fma(x_m, 0.3275911, 1.0)) + -1.453152027) / fma(x_m, 0.3275911, 1.0)) + 1.421413741) / fma(x_m, 0.3275911, 1.0)) + -0.284496736) / fma(x_m, 0.3275911, 1.0)))) * exp(Float64(Float64(-x_m) * x_m))));
	end
	return tmp
end

Wolfram

x_m = N[Abs[x], $MachinePrecision]
code[x$95$m_] := If[LessEqual[N[Abs[x$95$m], $MachinePrecision], 1e-8], N[(N[(-0.00011824394398844293 * x$95$m + 1.128386358070218), $MachinePrecision] * x$95$m + 1e-9), $MachinePrecision], N[(1.0 - N[(N[(N[Power[N[(1.0 + N[(0.3275911 * N[Abs[x$95$m], $MachinePrecision]), $MachinePrecision]), $MachinePrecision], -1.0], $MachinePrecision] * N[(0.254829592 + N[(N[(N[(N[(N[(N[(N[(1.061405429 / N[(x$95$m * 0.3275911 + 1.0), $MachinePrecision]), $MachinePrecision] + -1.453152027), $MachinePrecision] / N[(x$95$m * 0.3275911 + 1.0), $MachinePrecision]), $MachinePrecision] + 1.421413741), $MachinePrecision] / N[(x$95$m * 0.3275911 + 1.0), $MachinePrecision]), $MachinePrecision] + -0.284496736), $MachinePrecision] / N[(x$95$m * 0.3275911 + 1.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * N[Exp[N[((-x$95$m) * x$95$m), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]

Derivation

1. Split input into 2 regimes

2. if (fabs.f64 x) < 1e-8

   1. Initial program 57.7%

      \[1 - \left(\frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(0.254829592 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(-0.284496736 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(1.421413741 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(-1.453152027 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot 1.061405429\right)\right)\right)\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|} \]
   2. Add Preprocessing

   4. Applied rewrites 57.3%

      \[\leadsto \color{blue}{\frac{1 - {\left(\frac{\frac{\frac{\frac{\frac{1.061405429}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -1.453152027}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 1.421413741}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -0.284496736}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 0.254829592}{{\left(e^{x}\right)}^{x} \cdot \mathsf{fma}\left(x, 0.3275911, 1\right)}\right)}^{2}}{\mathsf{fma}\left({\left(e^{x}\right)}^{x}, \frac{\frac{\frac{\frac{\frac{1.061405429}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -1.453152027}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 1.421413741}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -0.284496736}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 0.254829592}{\mathsf{fma}\left(x, 0.3275911, 1\right)}, 1\right)}} \]

   5. Taylor expanded in x around 0

      \[\leadsto \color{blue}{\frac{1}{1000000000} + x \cdot \left(\frac{564193179035109}{500000000000000} + \frac{-4729757757172838478231131321}{39999999980000000000000000000000} \cdot x\right)} \]
   6. Step-by-step derivation

      1. +-commutative N/A

         \[\leadsto \color{blue}{x \cdot \left(\frac{564193179035109}{500000000000000} + \frac{-4729757757172838478231131321}{39999999980000000000000000000000} \cdot x\right) + \frac{1}{1000000000}} \]

      2. *-commutative N/A

         \[\leadsto \color{blue}{\left(\frac{564193179035109}{500000000000000} + \frac{-4729757757172838478231131321}{39999999980000000000000000000000} \cdot x\right) \cdot x} + \frac{1}{1000000000} \]

      3. lower-fma.f64 N/A

         \[\leadsto \color{blue}{\mathsf{fma}\left(\frac{564193179035109}{500000000000000} + \frac{-4729757757172838478231131321}{39999999980000000000000000000000} \cdot x, x, \frac{1}{1000000000}\right)} \]

      4. +-commutative N/A

         \[\leadsto \mathsf{fma}\left(\color{blue}{\frac{-4729757757172838478231131321}{39999999980000000000000000000000} \cdot x + \frac{564193179035109}{500000000000000}}, x, \frac{1}{1000000000}\right) \]

      5. lower-fma.f64 99.0

         \[\leadsto \mathsf{fma}\left(\color{blue}{\mathsf{fma}\left(-0.00011824394398844293, x, 1.128386358070218\right)}, x, 10^{-9}\right) \]

   7. Applied rewrites 99.0%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\mathsf{fma}\left(-0.00011824394398844293, x, 1.128386358070218\right), x, 10^{-9}\right)} \]

   if 1e-8 < (fabs.f64 x)

   1. Initial program 99.7%

      \[1 - \left(\frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(0.254829592 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(-0.284496736 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(1.421413741 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(-1.453152027 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot 1.061405429\right)\right)\right)\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|} \]
   2. Add Preprocessing

   4. Applied rewrites 98.5%

      \[\leadsto 1 - \left(\frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(0.254829592 + \color{blue}{\frac{\frac{\frac{\frac{1.061405429}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -1.453152027}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 1.421413741}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -0.284496736}{\mathsf{fma}\left(x, 0.3275911, 1\right)}}\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|} \]
   5. Step-by-step derivation

      1. lift-*.f64 N/A

         \[\leadsto 1 - \left(\frac{1}{1 + \frac{3275911}{10000000} \cdot \left|x\right|} \cdot \left(\frac{31853699}{125000000} + \frac{\frac{\frac{\frac{\frac{1061405429}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{-1453152027}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{1421413741}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{-8890523}{31250000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)}\right)\right) \cdot e^{-\color{blue}{\left|x\right| \cdot \left|x\right|}} \]

      2. lift-fabs.f64 N/A

         \[\leadsto 1 - \left(\frac{1}{1 + \frac{3275911}{10000000} \cdot \left|x\right|} \cdot \left(\frac{31853699}{125000000} + \frac{\frac{\frac{\frac{\frac{1061405429}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{-1453152027}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{1421413741}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{-8890523}{31250000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)}\right)\right) \cdot e^{-\color{blue}{\left|x\right|} \cdot \left|x\right|} \]

      3. lift-fabs.f64 N/A

         \[\leadsto 1 - \left(\frac{1}{1 + \frac{3275911}{10000000} \cdot \left|x\right|} \cdot \left(\frac{31853699}{125000000} + \frac{\frac{\frac{\frac{\frac{1061405429}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{-1453152027}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{1421413741}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{-8890523}{31250000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)}\right)\right) \cdot e^{-\left|x\right| \cdot \color{blue}{\left|x\right|}} \]

      4. sqr-abs-rev N/A

         \[\leadsto 1 - \left(\frac{1}{1 + \frac{3275911}{10000000} \cdot \left|x\right|} \cdot \left(\frac{31853699}{125000000} + \frac{\frac{\frac{\frac{\frac{1061405429}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{-1453152027}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{1421413741}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{-8890523}{31250000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)}\right)\right) \cdot e^{-\color{blue}{x \cdot x}} \]

      5. lift-*.f64 98.5

         \[\leadsto 1 - \left(\frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(0.254829592 + \frac{\frac{\frac{\frac{1.061405429}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -1.453152027}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 1.421413741}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -0.284496736}{\mathsf{fma}\left(x, 0.3275911, 1\right)}\right)\right) \cdot e^{-\color{blue}{x \cdot x}} \]

   6. Applied rewrites 98.5%

      \[\leadsto 1 - \left(\frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(0.254829592 + \frac{\frac{\frac{\frac{1.061405429}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -1.453152027}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 1.421413741}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -0.284496736}{\mathsf{fma}\left(x, 0.3275911, 1\right)}\right)\right) \cdot e^{-\color{blue}{x \cdot x}} \]
3. Recombined 2 regimes into one program.

4. Final simplification 98.8%

   \[\leadsto \begin{array}{l} \mathbf{if}\;\left|x\right| \leq 10^{-8}:\\ \;\;\;\;\mathsf{fma}\left(\mathsf{fma}\left(-0.00011824394398844293, x, 1.128386358070218\right), x, 10^{-9}\right)\\ \mathbf{else}:\\ \;\;\;\;1 - \left({\left(1 + 0.3275911 \cdot \left|x\right|\right)}^{-1} \cdot \left(0.254829592 + \frac{\frac{\frac{\frac{1.061405429}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -1.453152027}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 1.421413741}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -0.284496736}{\mathsf{fma}\left(x, 0.3275911, 1\right)}\right)\right) \cdot e^{\left(-x\right) \cdot x}\\ \end{array} \]
5. Add Preprocessing

Alternative 6: 99.7% accurate, 1.2× speedup

Math

\[\begin{array}{l} x_m = \left|x\right| \\ \begin{array}{l} \mathbf{if}\;\left|x\_m\right| \leq 10^{-8}:\\ \;\;\;\;\mathsf{fma}\left(\mathsf{fma}\left(-0.00011824394398844293, x\_m, 1.128386358070218\right), x\_m, 10^{-9}\right)\\ \mathbf{else}:\\ \;\;\;\;1 - \frac{\frac{\frac{\frac{\frac{1.061405429}{\mathsf{fma}\left(x\_m, 0.3275911, 1\right)} + -1.453152027}{\mathsf{fma}\left(x\_m, 0.3275911, 1\right)} + 1.421413741}{\mathsf{fma}\left(x\_m, 0.3275911, 1\right)} + -0.284496736}{\mathsf{fma}\left(x\_m, 0.3275911, 1\right)} + 0.254829592}{\mathsf{fma}\left(x\_m, 0.3275911, 1\right)} \cdot e^{\left(-x\_m\right) \cdot x\_m}\\ \end{array} \end{array} \]

FPCore

x_m = (fabs.f64 x)
(FPCore (x_m)
 :precision binary64
 (if (<= (fabs x_m) 1e-8)
   (fma (fma -0.00011824394398844293 x_m 1.128386358070218) x_m 1e-9)
   (-
    1.0
    (*
     (/
      (+
       (/
        (+
         (/
          (+
           (/
            (+ (/ 1.061405429 (fma x_m 0.3275911 1.0)) -1.453152027)
            (fma x_m 0.3275911 1.0))
           1.421413741)
          (fma x_m 0.3275911 1.0))
         -0.284496736)
        (fma x_m 0.3275911 1.0))
       0.254829592)
      (fma x_m 0.3275911 1.0))
     (exp (* (- x_m) x_m))))))

C

x_m = fabs(x);
double code(double x_m) {
	double tmp;
	if (fabs(x_m) <= 1e-8) {
		tmp = fma(fma(-0.00011824394398844293, x_m, 1.128386358070218), x_m, 1e-9);
	} else {
		tmp = 1.0 - ((((((((((1.061405429 / fma(x_m, 0.3275911, 1.0)) + -1.453152027) / fma(x_m, 0.3275911, 1.0)) + 1.421413741) / fma(x_m, 0.3275911, 1.0)) + -0.284496736) / fma(x_m, 0.3275911, 1.0)) + 0.254829592) / fma(x_m, 0.3275911, 1.0)) * exp((-x_m * x_m)));
	}
	return tmp;
}

Julia

x_m = abs(x)
function code(x_m)
	tmp = 0.0
	if (abs(x_m) <= 1e-8)
		tmp = fma(fma(-0.00011824394398844293, x_m, 1.128386358070218), x_m, 1e-9);
	else
		tmp = Float64(1.0 - Float64(Float64(Float64(Float64(Float64(Float64(Float64(Float64(Float64(Float64(1.061405429 / fma(x_m, 0.3275911, 1.0)) + -1.453152027) / fma(x_m, 0.3275911, 1.0)) + 1.421413741) / fma(x_m, 0.3275911, 1.0)) + -0.284496736) / fma(x_m, 0.3275911, 1.0)) + 0.254829592) / fma(x_m, 0.3275911, 1.0)) * exp(Float64(Float64(-x_m) * x_m))));
	end
	return tmp
end

Wolfram

x_m = N[Abs[x], $MachinePrecision]
code[x$95$m_] := If[LessEqual[N[Abs[x$95$m], $MachinePrecision], 1e-8], N[(N[(-0.00011824394398844293 * x$95$m + 1.128386358070218), $MachinePrecision] * x$95$m + 1e-9), $MachinePrecision], N[(1.0 - N[(N[(N[(N[(N[(N[(N[(N[(N[(N[(1.061405429 / N[(x$95$m * 0.3275911 + 1.0), $MachinePrecision]), $MachinePrecision] + -1.453152027), $MachinePrecision] / N[(x$95$m * 0.3275911 + 1.0), $MachinePrecision]), $MachinePrecision] + 1.421413741), $MachinePrecision] / N[(x$95$m * 0.3275911 + 1.0), $MachinePrecision]), $MachinePrecision] + -0.284496736), $MachinePrecision] / N[(x$95$m * 0.3275911 + 1.0), $MachinePrecision]), $MachinePrecision] + 0.254829592), $MachinePrecision] / N[(x$95$m * 0.3275911 + 1.0), $MachinePrecision]), $MachinePrecision] * N[Exp[N[((-x$95$m) * x$95$m), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]

Derivation

1. Split input into 2 regimes

2. if (fabs.f64 x) < 1e-8

   1. Initial program 57.7%

      \[1 - \left(\frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(0.254829592 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(-0.284496736 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(1.421413741 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(-1.453152027 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot 1.061405429\right)\right)\right)\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|} \]
   2. Add Preprocessing

   4. Applied rewrites 57.3%

      \[\leadsto \color{blue}{\frac{1 - {\left(\frac{\frac{\frac{\frac{\frac{1.061405429}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -1.453152027}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 1.421413741}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -0.284496736}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 0.254829592}{{\left(e^{x}\right)}^{x} \cdot \mathsf{fma}\left(x, 0.3275911, 1\right)}\right)}^{2}}{\mathsf{fma}\left({\left(e^{x}\right)}^{x}, \frac{\frac{\frac{\frac{\frac{1.061405429}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -1.453152027}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 1.421413741}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -0.284496736}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 0.254829592}{\mathsf{fma}\left(x, 0.3275911, 1\right)}, 1\right)}} \]

   5. Taylor expanded in x around 0

      \[\leadsto \color{blue}{\frac{1}{1000000000} + x \cdot \left(\frac{564193179035109}{500000000000000} + \frac{-4729757757172838478231131321}{39999999980000000000000000000000} \cdot x\right)} \]
   6. Step-by-step derivation

      1. +-commutative N/A

         \[\leadsto \color{blue}{x \cdot \left(\frac{564193179035109}{500000000000000} + \frac{-4729757757172838478231131321}{39999999980000000000000000000000} \cdot x\right) + \frac{1}{1000000000}} \]

      2. *-commutative N/A

         \[\leadsto \color{blue}{\left(\frac{564193179035109}{500000000000000} + \frac{-4729757757172838478231131321}{39999999980000000000000000000000} \cdot x\right) \cdot x} + \frac{1}{1000000000} \]

      3. lower-fma.f64 N/A

         \[\leadsto \color{blue}{\mathsf{fma}\left(\frac{564193179035109}{500000000000000} + \frac{-4729757757172838478231131321}{39999999980000000000000000000000} \cdot x, x, \frac{1}{1000000000}\right)} \]

      4. +-commutative N/A

         \[\leadsto \mathsf{fma}\left(\color{blue}{\frac{-4729757757172838478231131321}{39999999980000000000000000000000} \cdot x + \frac{564193179035109}{500000000000000}}, x, \frac{1}{1000000000}\right) \]

      5. lower-fma.f64 99.0

         \[\leadsto \mathsf{fma}\left(\color{blue}{\mathsf{fma}\left(-0.00011824394398844293, x, 1.128386358070218\right)}, x, 10^{-9}\right) \]

   7. Applied rewrites 99.0%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\mathsf{fma}\left(-0.00011824394398844293, x, 1.128386358070218\right), x, 10^{-9}\right)} \]

   if 1e-8 < (fabs.f64 x)

   1. Initial program 99.7%

      \[1 - \left(\frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(0.254829592 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(-0.284496736 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(1.421413741 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(-1.453152027 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot 1.061405429\right)\right)\right)\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|} \]
   2. Add Preprocessing

   4. Applied rewrites 98.5%

      \[\leadsto 1 - \color{blue}{\frac{\frac{\frac{\frac{\frac{1.061405429}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -1.453152027}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 1.421413741}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -0.284496736}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 0.254829592}{\mathsf{fma}\left(x, 0.3275911, 1\right)}} \cdot e^{-\left|x\right| \cdot \left|x\right|} \]
   5. Step-by-step derivation

      1. lift-*.f64 N/A

         \[\leadsto 1 - \frac{\frac{\frac{\frac{\frac{\frac{1061405429}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{-1453152027}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{1421413741}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{-8890523}{31250000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{31853699}{125000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} \cdot e^{-\color{blue}{\left|x\right| \cdot \left|x\right|}} \]

      2. lift-fabs.f64 N/A

         \[\leadsto 1 - \frac{\frac{\frac{\frac{\frac{\frac{1061405429}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{-1453152027}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{1421413741}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{-8890523}{31250000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{31853699}{125000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} \cdot e^{-\color{blue}{\left|x\right|} \cdot \left|x\right|} \]

      3. lift-fabs.f64 N/A

         \[\leadsto 1 - \frac{\frac{\frac{\frac{\frac{\frac{1061405429}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{-1453152027}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{1421413741}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{-8890523}{31250000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{31853699}{125000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} \cdot e^{-\left|x\right| \cdot \color{blue}{\left|x\right|}} \]

      4. sqr-abs N/A

         \[\leadsto 1 - \frac{\frac{\frac{\frac{\frac{\frac{1061405429}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{-1453152027}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{1421413741}{1000000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{-8890523}{31250000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{31853699}{125000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} \cdot e^{-\color{blue}{x \cdot x}} \]

      5. lower-*.f64 98.5

         \[\leadsto 1 - \frac{\frac{\frac{\frac{\frac{1.061405429}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -1.453152027}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 1.421413741}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -0.284496736}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 0.254829592}{\mathsf{fma}\left(x, 0.3275911, 1\right)} \cdot e^{-\color{blue}{x \cdot x}} \]

   6. Applied rewrites 98.5%

      \[\leadsto 1 - \frac{\frac{\frac{\frac{\frac{1.061405429}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -1.453152027}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 1.421413741}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -0.284496736}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 0.254829592}{\mathsf{fma}\left(x, 0.3275911, 1\right)} \cdot e^{-\color{blue}{x \cdot x}} \]
3. Recombined 2 regimes into one program.

4. Final simplification 98.8%

   \[\leadsto \begin{array}{l} \mathbf{if}\;\left|x\right| \leq 10^{-8}:\\ \;\;\;\;\mathsf{fma}\left(\mathsf{fma}\left(-0.00011824394398844293, x, 1.128386358070218\right), x, 10^{-9}\right)\\ \mathbf{else}:\\ \;\;\;\;1 - \frac{\frac{\frac{\frac{\frac{1.061405429}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -1.453152027}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 1.421413741}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -0.284496736}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 0.254829592}{\mathsf{fma}\left(x, 0.3275911, 1\right)} \cdot e^{\left(-x\right) \cdot x}\\ \end{array} \]
5. Add Preprocessing

Alternative 7: 99.3% accurate, 1.4× speedup

Math

\[\begin{array}{l} x_m = \left|x\right| \\ \begin{array}{l} \mathbf{if}\;\left|x\_m\right| \leq 0.005:\\ \;\;\;\;\mathsf{fma}\left(\mathsf{fma}\left(-0.00011824394398844293, x\_m, 1.128386358070218\right), x\_m, 10^{-9}\right)\\ \mathbf{else}:\\ \;\;\;\;1 - \frac{\frac{\frac{\mathsf{fma}\left(-0.2193742730720041, x\_m, 1.029667143\right)}{\mathsf{fma}\left(x\_m, 0.3275911, 1\right)} + -0.284496736}{\mathsf{fma}\left(x\_m, 0.3275911, 1\right)} + 0.254829592}{\mathsf{fma}\left(x\_m, 0.3275911, 1\right)} \cdot e^{\left(-x\_m\right) \cdot x\_m}\\ \end{array} \end{array} \]

FPCore

x_m = (fabs.f64 x)
(FPCore (x_m)
 :precision binary64
 (if (<= (fabs x_m) 0.005)
   (fma (fma -0.00011824394398844293 x_m 1.128386358070218) x_m 1e-9)
   (-
    1.0
    (*
     (/
      (+
       (/
        (+
         (/ (fma -0.2193742730720041 x_m 1.029667143) (fma x_m 0.3275911 1.0))
         -0.284496736)
        (fma x_m 0.3275911 1.0))
       0.254829592)
      (fma x_m 0.3275911 1.0))
     (exp (* (- x_m) x_m))))))

C

x_m = fabs(x);
double code(double x_m) {
	double tmp;
	if (fabs(x_m) <= 0.005) {
		tmp = fma(fma(-0.00011824394398844293, x_m, 1.128386358070218), x_m, 1e-9);
	} else {
		tmp = 1.0 - ((((((fma(-0.2193742730720041, x_m, 1.029667143) / fma(x_m, 0.3275911, 1.0)) + -0.284496736) / fma(x_m, 0.3275911, 1.0)) + 0.254829592) / fma(x_m, 0.3275911, 1.0)) * exp((-x_m * x_m)));
	}
	return tmp;
}

Julia

x_m = abs(x)
function code(x_m)
	tmp = 0.0
	if (abs(x_m) <= 0.005)
		tmp = fma(fma(-0.00011824394398844293, x_m, 1.128386358070218), x_m, 1e-9);
	else
		tmp = Float64(1.0 - Float64(Float64(Float64(Float64(Float64(Float64(fma(-0.2193742730720041, x_m, 1.029667143) / fma(x_m, 0.3275911, 1.0)) + -0.284496736) / fma(x_m, 0.3275911, 1.0)) + 0.254829592) / fma(x_m, 0.3275911, 1.0)) * exp(Float64(Float64(-x_m) * x_m))));
	end
	return tmp
end

Wolfram

x_m = N[Abs[x], $MachinePrecision]
code[x$95$m_] := If[LessEqual[N[Abs[x$95$m], $MachinePrecision], 0.005], N[(N[(-0.00011824394398844293 * x$95$m + 1.128386358070218), $MachinePrecision] * x$95$m + 1e-9), $MachinePrecision], N[(1.0 - N[(N[(N[(N[(N[(N[(N[(-0.2193742730720041 * x$95$m + 1.029667143), $MachinePrecision] / N[(x$95$m * 0.3275911 + 1.0), $MachinePrecision]), $MachinePrecision] + -0.284496736), $MachinePrecision] / N[(x$95$m * 0.3275911 + 1.0), $MachinePrecision]), $MachinePrecision] + 0.254829592), $MachinePrecision] / N[(x$95$m * 0.3275911 + 1.0), $MachinePrecision]), $MachinePrecision] * N[Exp[N[((-x$95$m) * x$95$m), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]

Derivation

1. Split input into 2 regimes

2. if (fabs.f64 x) < 0.0050000000000000001

   1. Initial program 58.1%

      \[1 - \left(\frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(0.254829592 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(-0.284496736 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(1.421413741 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(-1.453152027 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot 1.061405429\right)\right)\right)\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|} \]
   2. Add Preprocessing

   4. Applied rewrites 56.4%

      \[\leadsto \color{blue}{\frac{1 - {\left(\frac{\frac{\frac{\frac{\frac{1.061405429}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -1.453152027}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 1.421413741}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -0.284496736}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 0.254829592}{{\left(e^{x}\right)}^{x} \cdot \mathsf{fma}\left(x, 0.3275911, 1\right)}\right)}^{2}}{\mathsf{fma}\left({\left(e^{x}\right)}^{x}, \frac{\frac{\frac{\frac{\frac{1.061405429}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -1.453152027}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 1.421413741}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -0.284496736}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 0.254829592}{\mathsf{fma}\left(x, 0.3275911, 1\right)}, 1\right)}} \]

   5. Taylor expanded in x around 0

      \[\leadsto \color{blue}{\frac{1}{1000000000} + x \cdot \left(\frac{564193179035109}{500000000000000} + \frac{-4729757757172838478231131321}{39999999980000000000000000000000} \cdot x\right)} \]
   6. Step-by-step derivation

      1. +-commutative N/A

         \[\leadsto \color{blue}{x \cdot \left(\frac{564193179035109}{500000000000000} + \frac{-4729757757172838478231131321}{39999999980000000000000000000000} \cdot x\right) + \frac{1}{1000000000}} \]

      2. *-commutative N/A

         \[\leadsto \color{blue}{\left(\frac{564193179035109}{500000000000000} + \frac{-4729757757172838478231131321}{39999999980000000000000000000000} \cdot x\right) \cdot x} + \frac{1}{1000000000} \]

      3. lower-fma.f64 N/A

         \[\leadsto \color{blue}{\mathsf{fma}\left(\frac{564193179035109}{500000000000000} + \frac{-4729757757172838478231131321}{39999999980000000000000000000000} \cdot x, x, \frac{1}{1000000000}\right)} \]

      4. +-commutative N/A

         \[\leadsto \mathsf{fma}\left(\color{blue}{\frac{-4729757757172838478231131321}{39999999980000000000000000000000} \cdot x + \frac{564193179035109}{500000000000000}}, x, \frac{1}{1000000000}\right) \]

      5. lower-fma.f64 97.5

         \[\leadsto \mathsf{fma}\left(\color{blue}{\mathsf{fma}\left(-0.00011824394398844293, x, 1.128386358070218\right)}, x, 10^{-9}\right) \]

   7. Applied rewrites 97.5%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\mathsf{fma}\left(-0.00011824394398844293, x, 1.128386358070218\right), x, 10^{-9}\right)} \]

   if 0.0050000000000000001 < (fabs.f64 x)

   1. Initial program 100.0%

      \[1 - \left(\frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(0.254829592 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(-0.284496736 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(1.421413741 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(-1.453152027 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot 1.061405429\right)\right)\right)\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|} \]
   2. Add Preprocessing

   4. Applied rewrites 100.0%

      \[\leadsto 1 - \color{blue}{\frac{\frac{\frac{\frac{\frac{1.061405429}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -1.453152027}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 1.421413741}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -0.284496736}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 0.254829592}{\mathsf{fma}\left(x, 0.3275911, 1\right)}} \cdot e^{-\left|x\right| \cdot \left|x\right|} \]

   5. Taylor expanded in x around 0

      \[\leadsto 1 - \frac{\frac{\frac{\color{blue}{\frac{1029667143}{1000000000} + \frac{-2193742730720041}{10000000000000000} \cdot x}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{-8890523}{31250000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{31853699}{125000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} \cdot e^{-\left|x\right| \cdot \left|x\right|} \]
   6. Step-by-step derivation

      1. +-commutative N/A

         \[\leadsto 1 - \frac{\frac{\frac{\color{blue}{\frac{-2193742730720041}{10000000000000000} \cdot x + \frac{1029667143}{1000000000}}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{-8890523}{31250000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{31853699}{125000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} \cdot e^{-\left|x\right| \cdot \left|x\right|} \]

      2. lower-fma.f64 99.4

         \[\leadsto 1 - \frac{\frac{\frac{\color{blue}{\mathsf{fma}\left(-0.2193742730720041, x, 1.029667143\right)}}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -0.284496736}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 0.254829592}{\mathsf{fma}\left(x, 0.3275911, 1\right)} \cdot e^{-\left|x\right| \cdot \left|x\right|} \]

   7. Applied rewrites 99.4%

      \[\leadsto 1 - \frac{\frac{\frac{\color{blue}{\mathsf{fma}\left(-0.2193742730720041, x, 1.029667143\right)}}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -0.284496736}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 0.254829592}{\mathsf{fma}\left(x, 0.3275911, 1\right)} \cdot e^{-\left|x\right| \cdot \left|x\right|} \]
3. Recombined 2 regimes into one program.

4. Final simplification 98.5%

   \[\leadsto \begin{array}{l} \mathbf{if}\;\left|x\right| \leq 0.005:\\ \;\;\;\;\mathsf{fma}\left(\mathsf{fma}\left(-0.00011824394398844293, x, 1.128386358070218\right), x, 10^{-9}\right)\\ \mathbf{else}:\\ \;\;\;\;1 - \frac{\frac{\frac{\mathsf{fma}\left(-0.2193742730720041, x, 1.029667143\right)}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -0.284496736}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 0.254829592}{\mathsf{fma}\left(x, 0.3275911, 1\right)} \cdot e^{\left(-x\right) \cdot x}\\ \end{array} \]
5. Add Preprocessing

Alternative 8: 99.3% accurate, 1.5× speedup

Math

\[\begin{array}{l} x_m = \left|x\right| \\ \begin{array}{l} \mathbf{if}\;\left|x\_m\right| \leq 0.005:\\ \;\;\;\;\mathsf{fma}\left(\mathsf{fma}\left(-0.00011824394398844293, x\_m, 1.128386358070218\right), x\_m, 10^{-9}\right)\\ \mathbf{else}:\\ \;\;\;\;\mathsf{fma}\left(\frac{\frac{\frac{1.029667143}{\mathsf{fma}\left(x\_m, 0.3275911, 1\right)} + -0.284496736}{\mathsf{fma}\left(x\_m, 0.3275911, 1\right)} + 0.254829592}{\mathsf{fma}\left(-0.3275911, x\_m, -1\right)}, e^{\left(-x\_m\right) \cdot x\_m}, 1\right)\\ \end{array} \end{array} \]

FPCore

x_m = (fabs.f64 x)
(FPCore (x_m)
 :precision binary64
 (if (<= (fabs x_m) 0.005)
   (fma (fma -0.00011824394398844293 x_m 1.128386358070218) x_m 1e-9)
   (fma
    (/
     (+
      (/
       (+ (/ 1.029667143 (fma x_m 0.3275911 1.0)) -0.284496736)
       (fma x_m 0.3275911 1.0))
      0.254829592)
     (fma -0.3275911 x_m -1.0))
    (exp (* (- x_m) x_m))
    1.0)))

C

x_m = fabs(x);
double code(double x_m) {
	double tmp;
	if (fabs(x_m) <= 0.005) {
		tmp = fma(fma(-0.00011824394398844293, x_m, 1.128386358070218), x_m, 1e-9);
	} else {
		tmp = fma((((((1.029667143 / fma(x_m, 0.3275911, 1.0)) + -0.284496736) / fma(x_m, 0.3275911, 1.0)) + 0.254829592) / fma(-0.3275911, x_m, -1.0)), exp((-x_m * x_m)), 1.0);
	}
	return tmp;
}

Julia

x_m = abs(x)
function code(x_m)
	tmp = 0.0
	if (abs(x_m) <= 0.005)
		tmp = fma(fma(-0.00011824394398844293, x_m, 1.128386358070218), x_m, 1e-9);
	else
		tmp = fma(Float64(Float64(Float64(Float64(Float64(1.029667143 / fma(x_m, 0.3275911, 1.0)) + -0.284496736) / fma(x_m, 0.3275911, 1.0)) + 0.254829592) / fma(-0.3275911, x_m, -1.0)), exp(Float64(Float64(-x_m) * x_m)), 1.0);
	end
	return tmp
end

Wolfram

x_m = N[Abs[x], $MachinePrecision]
code[x$95$m_] := If[LessEqual[N[Abs[x$95$m], $MachinePrecision], 0.005], N[(N[(-0.00011824394398844293 * x$95$m + 1.128386358070218), $MachinePrecision] * x$95$m + 1e-9), $MachinePrecision], N[(N[(N[(N[(N[(N[(1.029667143 / N[(x$95$m * 0.3275911 + 1.0), $MachinePrecision]), $MachinePrecision] + -0.284496736), $MachinePrecision] / N[(x$95$m * 0.3275911 + 1.0), $MachinePrecision]), $MachinePrecision] + 0.254829592), $MachinePrecision] / N[(-0.3275911 * x$95$m + -1.0), $MachinePrecision]), $MachinePrecision] * N[Exp[N[((-x$95$m) * x$95$m), $MachinePrecision]], $MachinePrecision] + 1.0), $MachinePrecision]]

Derivation

1. Split input into 2 regimes

2. if (fabs.f64 x) < 0.0050000000000000001

   1. Initial program 58.1%

      \[1 - \left(\frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(0.254829592 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(-0.284496736 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(1.421413741 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(-1.453152027 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot 1.061405429\right)\right)\right)\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|} \]
   2. Add Preprocessing

   4. Applied rewrites 56.4%

      \[\leadsto \color{blue}{\frac{1 - {\left(\frac{\frac{\frac{\frac{\frac{1.061405429}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -1.453152027}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 1.421413741}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -0.284496736}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 0.254829592}{{\left(e^{x}\right)}^{x} \cdot \mathsf{fma}\left(x, 0.3275911, 1\right)}\right)}^{2}}{\mathsf{fma}\left({\left(e^{x}\right)}^{x}, \frac{\frac{\frac{\frac{\frac{1.061405429}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -1.453152027}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 1.421413741}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -0.284496736}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 0.254829592}{\mathsf{fma}\left(x, 0.3275911, 1\right)}, 1\right)}} \]

   5. Taylor expanded in x around 0

      \[\leadsto \color{blue}{\frac{1}{1000000000} + x \cdot \left(\frac{564193179035109}{500000000000000} + \frac{-4729757757172838478231131321}{39999999980000000000000000000000} \cdot x\right)} \]
   6. Step-by-step derivation

      1. +-commutative N/A

         \[\leadsto \color{blue}{x \cdot \left(\frac{564193179035109}{500000000000000} + \frac{-4729757757172838478231131321}{39999999980000000000000000000000} \cdot x\right) + \frac{1}{1000000000}} \]

      2. *-commutative N/A

         \[\leadsto \color{blue}{\left(\frac{564193179035109}{500000000000000} + \frac{-4729757757172838478231131321}{39999999980000000000000000000000} \cdot x\right) \cdot x} + \frac{1}{1000000000} \]

      3. lower-fma.f64 N/A

         \[\leadsto \color{blue}{\mathsf{fma}\left(\frac{564193179035109}{500000000000000} + \frac{-4729757757172838478231131321}{39999999980000000000000000000000} \cdot x, x, \frac{1}{1000000000}\right)} \]

      4. +-commutative N/A

         \[\leadsto \mathsf{fma}\left(\color{blue}{\frac{-4729757757172838478231131321}{39999999980000000000000000000000} \cdot x + \frac{564193179035109}{500000000000000}}, x, \frac{1}{1000000000}\right) \]

      5. lower-fma.f64 97.5

         \[\leadsto \mathsf{fma}\left(\color{blue}{\mathsf{fma}\left(-0.00011824394398844293, x, 1.128386358070218\right)}, x, 10^{-9}\right) \]

   7. Applied rewrites 97.5%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\mathsf{fma}\left(-0.00011824394398844293, x, 1.128386358070218\right), x, 10^{-9}\right)} \]

   if 0.0050000000000000001 < (fabs.f64 x)

   1. Initial program 100.0%

      \[1 - \left(\frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(0.254829592 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(-0.284496736 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(1.421413741 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(-1.453152027 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot 1.061405429\right)\right)\right)\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|} \]
   2. Add Preprocessing

   4. Applied rewrites 100.0%

      \[\leadsto 1 - \color{blue}{\frac{\frac{\frac{\frac{\frac{1.061405429}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -1.453152027}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 1.421413741}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -0.284496736}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 0.254829592}{\mathsf{fma}\left(x, 0.3275911, 1\right)}} \cdot e^{-\left|x\right| \cdot \left|x\right|} \]

   5. Taylor expanded in x around 0

      \[\leadsto 1 - \frac{\frac{\frac{\color{blue}{\frac{1029667143}{1000000000}}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{-8890523}{31250000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} + \frac{31853699}{125000000}}{\mathsf{fma}\left(x, \frac{3275911}{10000000}, 1\right)} \cdot e^{-\left|x\right| \cdot \left|x\right|} \]
   6. Step-by-step derivation

   7. Applied rewrites 99.4%

      \[\leadsto 1 - \frac{\frac{\frac{\color{blue}{1.029667143}}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -0.284496736}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 0.254829592}{\mathsf{fma}\left(x, 0.3275911, 1\right)} \cdot e^{-\left|x\right| \cdot \left|x\right|} \]

   9. Applied rewrites 99.4%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\frac{\frac{\frac{1.029667143}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -0.284496736}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 0.254829592}{\mathsf{fma}\left(-0.3275911, x, -1\right)}, e^{\left(-x\right) \cdot x}, 1\right)} \]
3. Recombined 2 regimes into one program.
4. Add Preprocessing

Alternative 9: 99.3% accurate, 12.5× speedup

Math

\[\begin{array}{l} x_m = \left|x\right| \\ \begin{array}{l} \mathbf{if}\;\left|x\_m\right| \leq 1:\\ \;\;\;\;\mathsf{fma}\left(\mathsf{fma}\left(-0.00011824394398844293, x\_m, 1.128386358070218\right), x\_m, 10^{-9}\right)\\ \mathbf{else}:\\ \;\;\;\;1\\ \end{array} \end{array} \]

FPCore

x_m = (fabs.f64 x)
(FPCore (x_m)
 :precision binary64
 (if (<= (fabs x_m) 1.0)
   (fma (fma -0.00011824394398844293 x_m 1.128386358070218) x_m 1e-9)
   1.0))

C

x_m = fabs(x);
double code(double x_m) {
	double tmp;
	if (fabs(x_m) <= 1.0) {
		tmp = fma(fma(-0.00011824394398844293, x_m, 1.128386358070218), x_m, 1e-9);
	} else {
		tmp = 1.0;
	}
	return tmp;
}

Julia

x_m = abs(x)
function code(x_m)
	tmp = 0.0
	if (abs(x_m) <= 1.0)
		tmp = fma(fma(-0.00011824394398844293, x_m, 1.128386358070218), x_m, 1e-9);
	else
		tmp = 1.0;
	end
	return tmp
end

Wolfram

x_m = N[Abs[x], $MachinePrecision]
code[x$95$m_] := If[LessEqual[N[Abs[x$95$m], $MachinePrecision], 1.0], N[(N[(-0.00011824394398844293 * x$95$m + 1.128386358070218), $MachinePrecision] * x$95$m + 1e-9), $MachinePrecision], 1.0]

Derivation

1. Split input into 2 regimes

2. if (fabs.f64 x) < 1

   1. Initial program 58.4%

      \[1 - \left(\frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(0.254829592 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(-0.284496736 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(1.421413741 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(-1.453152027 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot 1.061405429\right)\right)\right)\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|} \]
   2. Add Preprocessing

   4. Applied rewrites 56.1%

      \[\leadsto \color{blue}{\frac{1 - {\left(\frac{\frac{\frac{\frac{\frac{1.061405429}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -1.453152027}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 1.421413741}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -0.284496736}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 0.254829592}{{\left(e^{x}\right)}^{x} \cdot \mathsf{fma}\left(x, 0.3275911, 1\right)}\right)}^{2}}{\mathsf{fma}\left({\left(e^{x}\right)}^{x}, \frac{\frac{\frac{\frac{\frac{1.061405429}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -1.453152027}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 1.421413741}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -0.284496736}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 0.254829592}{\mathsf{fma}\left(x, 0.3275911, 1\right)}, 1\right)}} \]

   5. Taylor expanded in x around 0

      \[\leadsto \color{blue}{\frac{1}{1000000000} + x \cdot \left(\frac{564193179035109}{500000000000000} + \frac{-4729757757172838478231131321}{39999999980000000000000000000000} \cdot x\right)} \]
   6. Step-by-step derivation

      1. +-commutative N/A

         \[\leadsto \color{blue}{x \cdot \left(\frac{564193179035109}{500000000000000} + \frac{-4729757757172838478231131321}{39999999980000000000000000000000} \cdot x\right) + \frac{1}{1000000000}} \]

      2. *-commutative N/A

         \[\leadsto \color{blue}{\left(\frac{564193179035109}{500000000000000} + \frac{-4729757757172838478231131321}{39999999980000000000000000000000} \cdot x\right) \cdot x} + \frac{1}{1000000000} \]

      3. lower-fma.f64 N/A

         \[\leadsto \color{blue}{\mathsf{fma}\left(\frac{564193179035109}{500000000000000} + \frac{-4729757757172838478231131321}{39999999980000000000000000000000} \cdot x, x, \frac{1}{1000000000}\right)} \]

      4. +-commutative N/A

         \[\leadsto \mathsf{fma}\left(\color{blue}{\frac{-4729757757172838478231131321}{39999999980000000000000000000000} \cdot x + \frac{564193179035109}{500000000000000}}, x, \frac{1}{1000000000}\right) \]

      5. lower-fma.f64 96.9

         \[\leadsto \mathsf{fma}\left(\color{blue}{\mathsf{fma}\left(-0.00011824394398844293, x, 1.128386358070218\right)}, x, 10^{-9}\right) \]

   7. Applied rewrites 96.9%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\mathsf{fma}\left(-0.00011824394398844293, x, 1.128386358070218\right), x, 10^{-9}\right)} \]

   if 1 < (fabs.f64 x)

   1. Initial program 100.0%

      \[1 - \left(\frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(0.254829592 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(-0.284496736 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(1.421413741 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(-1.453152027 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot 1.061405429\right)\right)\right)\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|} \]
   2. Add Preprocessing

   4. Applied rewrites 100.0%

      \[\leadsto 1 - \color{blue}{\frac{\frac{\frac{\frac{\frac{1.061405429}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -1.453152027}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 1.421413741}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -0.284496736}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 0.254829592}{\mathsf{fma}\left(x, 0.3275911, 1\right)}} \cdot e^{-\left|x\right| \cdot \left|x\right|} \]

   5. Taylor expanded in x around inf

      \[\leadsto \color{blue}{1} \]
   6. Step-by-step derivation

   7. Applied rewrites 100.0%

      \[\leadsto \color{blue}{1} \]
3. Recombined 2 regimes into one program.
4. Add Preprocessing

Alternative 10: 99.2% accurate, 17.4× speedup

Math

\[\begin{array}{l} x_m = \left|x\right| \\ \begin{array}{l} \mathbf{if}\;\left|x\_m\right| \leq 1:\\ \;\;\;\;\mathsf{fma}\left(1.128386358070218, x\_m, 10^{-9}\right)\\ \mathbf{else}:\\ \;\;\;\;1\\ \end{array} \end{array} \]

FPCore

x_m = (fabs.f64 x)
(FPCore (x_m)
 :precision binary64
 (if (<= (fabs x_m) 1.0) (fma 1.128386358070218 x_m 1e-9) 1.0))

C

x_m = fabs(x);
double code(double x_m) {
	double tmp;
	if (fabs(x_m) <= 1.0) {
		tmp = fma(1.128386358070218, x_m, 1e-9);
	} else {
		tmp = 1.0;
	}
	return tmp;
}

Julia

x_m = abs(x)
function code(x_m)
	tmp = 0.0
	if (abs(x_m) <= 1.0)
		tmp = fma(1.128386358070218, x_m, 1e-9);
	else
		tmp = 1.0;
	end
	return tmp
end

Wolfram

x_m = N[Abs[x], $MachinePrecision]
code[x$95$m_] := If[LessEqual[N[Abs[x$95$m], $MachinePrecision], 1.0], N[(1.128386358070218 * x$95$m + 1e-9), $MachinePrecision], 1.0]

Derivation

1. Split input into 2 regimes

2. if (fabs.f64 x) < 1

   1. Initial program 58.4%

      \[1 - \left(\frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(0.254829592 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(-0.284496736 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(1.421413741 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(-1.453152027 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot 1.061405429\right)\right)\right)\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|} \]
   2. Add Preprocessing

   4. Applied rewrites 56.1%

      \[\leadsto \color{blue}{\frac{1 - {\left(\frac{\frac{\frac{\frac{\frac{1.061405429}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -1.453152027}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 1.421413741}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -0.284496736}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 0.254829592}{{\left(e^{x}\right)}^{x} \cdot \mathsf{fma}\left(x, 0.3275911, 1\right)}\right)}^{2}}{\mathsf{fma}\left({\left(e^{x}\right)}^{x}, \frac{\frac{\frac{\frac{\frac{1.061405429}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -1.453152027}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 1.421413741}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -0.284496736}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 0.254829592}{\mathsf{fma}\left(x, 0.3275911, 1\right)}, 1\right)}} \]

   5. Taylor expanded in x around 0

      \[\leadsto \color{blue}{\frac{1}{1000000000} + \frac{564193179035109}{500000000000000} \cdot x} \]
   6. Step-by-step derivation

      1. +-commutative N/A

         \[\leadsto \color{blue}{\frac{564193179035109}{500000000000000} \cdot x + \frac{1}{1000000000}} \]

      2. lower-fma.f64 96.7

         \[\leadsto \color{blue}{\mathsf{fma}\left(1.128386358070218, x, 10^{-9}\right)} \]

   7. Applied rewrites 96.7%

      \[\leadsto \color{blue}{\mathsf{fma}\left(1.128386358070218, x, 10^{-9}\right)} \]

   if 1 < (fabs.f64 x)

   1. Initial program 100.0%

      \[1 - \left(\frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(0.254829592 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(-0.284496736 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(1.421413741 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(-1.453152027 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot 1.061405429\right)\right)\right)\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|} \]
   2. Add Preprocessing

   4. Applied rewrites 100.0%

      \[\leadsto 1 - \color{blue}{\frac{\frac{\frac{\frac{\frac{1.061405429}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -1.453152027}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 1.421413741}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -0.284496736}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 0.254829592}{\mathsf{fma}\left(x, 0.3275911, 1\right)}} \cdot e^{-\left|x\right| \cdot \left|x\right|} \]

   5. Taylor expanded in x around inf

      \[\leadsto \color{blue}{1} \]
   6. Step-by-step derivation

   7. Applied rewrites 100.0%

      \[\leadsto \color{blue}{1} \]
3. Recombined 2 regimes into one program.
4. Add Preprocessing

Alternative 11: 97.6% accurate, 29.1× speedup

Math

\[\begin{array}{l} x_m = \left|x\right| \\ \begin{array}{l} \mathbf{if}\;\left|x\_m\right| \leq 2.8 \cdot 10^{-5}:\\ \;\;\;\;10^{-9}\\ \mathbf{else}:\\ \;\;\;\;1\\ \end{array} \end{array} \]

FPCore

x_m = (fabs.f64 x)
(FPCore (x_m) :precision binary64 (if (<= (fabs x_m) 2.8e-5) 1e-9 1.0))

C

x_m = fabs(x);
double code(double x_m) {
	double tmp;
	if (fabs(x_m) <= 2.8e-5) {
		tmp = 1e-9;
	} else {
		tmp = 1.0;
	}
	return tmp;
}

Fortran

x_m = abs(x)
real(8) function code(x_m)
    real(8), intent (in) :: x_m
    real(8) :: tmp
    if (abs(x_m) <= 2.8d-5) then
        tmp = 1d-9
    else
        tmp = 1.0d0
    end if
    code = tmp
end function

Java

x_m = Math.abs(x);
public static double code(double x_m) {
	double tmp;
	if (Math.abs(x_m) <= 2.8e-5) {
		tmp = 1e-9;
	} else {
		tmp = 1.0;
	}
	return tmp;
}

Python

x_m = math.fabs(x)
def code(x_m):
	tmp = 0
	if math.fabs(x_m) <= 2.8e-5:
		tmp = 1e-9
	else:
		tmp = 1.0
	return tmp

Julia

x_m = abs(x)
function code(x_m)
	tmp = 0.0
	if (abs(x_m) <= 2.8e-5)
		tmp = 1e-9;
	else
		tmp = 1.0;
	end
	return tmp
end

MATLAB

x_m = abs(x);
function tmp_2 = code(x_m)
	tmp = 0.0;
	if (abs(x_m) <= 2.8e-5)
		tmp = 1e-9;
	else
		tmp = 1.0;
	end
	tmp_2 = tmp;
end

Wolfram

x_m = N[Abs[x], $MachinePrecision]
code[x$95$m_] := If[LessEqual[N[Abs[x$95$m], $MachinePrecision], 2.8e-5], 1e-9, 1.0]

Derivation

1. Split input into 2 regimes

2. if (fabs.f64 x) < 2.79999999999999996e-5

   1. Initial program 57.7%

      \[1 - \left(\frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(0.254829592 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(-0.284496736 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(1.421413741 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(-1.453152027 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot 1.061405429\right)\right)\right)\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|} \]
   2. Add Preprocessing

   4. Applied rewrites 57.3%

      \[\leadsto \color{blue}{\frac{1 - {\left(\frac{\frac{\frac{\frac{\frac{1.061405429}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -1.453152027}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 1.421413741}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -0.284496736}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 0.254829592}{{\left(e^{x}\right)}^{x} \cdot \mathsf{fma}\left(x, 0.3275911, 1\right)}\right)}^{2}}{\mathsf{fma}\left({\left(e^{x}\right)}^{x}, \frac{\frac{\frac{\frac{\frac{1.061405429}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -1.453152027}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 1.421413741}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -0.284496736}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 0.254829592}{\mathsf{fma}\left(x, 0.3275911, 1\right)}, 1\right)}} \]

   5. Taylor expanded in x around 0

      \[\leadsto \color{blue}{\frac{1}{1000000000}} \]
   6. Step-by-step derivation

   7. Applied rewrites 97.3%

      \[\leadsto \color{blue}{10^{-9}} \]

   if 2.79999999999999996e-5 < (fabs.f64 x)

   1. Initial program 99.7%

      \[1 - \left(\frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(0.254829592 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(-0.284496736 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(1.421413741 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(-1.453152027 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot 1.061405429\right)\right)\right)\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|} \]
   2. Add Preprocessing

   4. Applied rewrites 98.5%

      \[\leadsto 1 - \color{blue}{\frac{\frac{\frac{\frac{\frac{1.061405429}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -1.453152027}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 1.421413741}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -0.284496736}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 0.254829592}{\mathsf{fma}\left(x, 0.3275911, 1\right)}} \cdot e^{-\left|x\right| \cdot \left|x\right|} \]

   5. Taylor expanded in x around inf

      \[\leadsto \color{blue}{1} \]
   6. Step-by-step derivation

   7. Applied rewrites 98.1%

      \[\leadsto \color{blue}{1} \]
3. Recombined 2 regimes into one program.
4. Add Preprocessing

Alternative 12: 55.3% accurate, 262.0× speedup

Math

\[\begin{array}{l} x_m = \left|x\right| \\ 1 \end{array} \]

FPCore

x_m = (fabs.f64 x)
(FPCore (x_m) :precision binary64 1.0)

C

x_m = fabs(x);
double code(double x_m) {
	return 1.0;
}

Fortran

x_m = abs(x)
real(8) function code(x_m)
    real(8), intent (in) :: x_m
    code = 1.0d0
end function

Java

x_m = Math.abs(x);
public static double code(double x_m) {
	return 1.0;
}

Python

x_m = math.fabs(x)
def code(x_m):
	return 1.0

Julia

x_m = abs(x)
function code(x_m)
	return 1.0
end

MATLAB

x_m = abs(x);
function tmp = code(x_m)
	tmp = 1.0;
end

Wolfram

x_m = N[Abs[x], $MachinePrecision]
code[x$95$m_] := 1.0

Derivation

1. Initial program 79.4%

   \[1 - \left(\frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(0.254829592 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(-0.284496736 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(1.421413741 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(-1.453152027 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot 1.061405429\right)\right)\right)\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|} \]
2. Add Preprocessing

4. Applied rewrites 78.5%

   \[\leadsto 1 - \color{blue}{\frac{\frac{\frac{\frac{\frac{1.061405429}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -1.453152027}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 1.421413741}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + -0.284496736}{\mathsf{fma}\left(x, 0.3275911, 1\right)} + 0.254829592}{\mathsf{fma}\left(x, 0.3275911, 1\right)}} \cdot e^{-\left|x\right| \cdot \left|x\right|} \]

5. Taylor expanded in x around inf

   \[\leadsto \color{blue}{1} \]
6. Step-by-step derivation

7. Applied rewrites 55.9%

   \[\leadsto \color{blue}{1} \]
8. Add Preprocessing

Reproduce

herbie shell --seed 2024313 
(FPCore (x)
  :name "Jmat.Real.erf"
  :precision binary64
  (- 1.0 (* (* (/ 1.0 (+ 1.0 (* 0.3275911 (fabs x)))) (+ 0.254829592 (* (/ 1.0 (+ 1.0 (* 0.3275911 (fabs x)))) (+ -0.284496736 (* (/ 1.0 (+ 1.0 (* 0.3275911 (fabs x)))) (+ 1.421413741 (* (/ 1.0 (+ 1.0 (* 0.3275911 (fabs x)))) (+ -1.453152027 (* (/ 1.0 (+ 1.0 (* 0.3275911 (fabs x)))) 1.061405429))))))))) (exp (- (* (fabs x) (fabs x)))))))