Kahan's exp quotient

Percentage Accurate: 53.1% → 100.0%

Time: 11.3s

Alternatives: 13

Speedup: 8.8×

• 25.3% of points produce a very large (infinite) output. You may want to add a precondition.

Specification

Math

\[\begin{array}{l} \\ \frac{e^{x} - 1}{x} \end{array} \]

FPCore

(FPCore (x) :precision binary64 (/ (- (exp x) 1.0) x))

C

double code(double x) {
	return (exp(x) - 1.0) / x;
}

Fortran

real(8) function code(x)
    real(8), intent (in) :: x
    code = (exp(x) - 1.0d0) / x
end function

Java

public static double code(double x) {
	return (Math.exp(x) - 1.0) / x;
}

Python

def code(x):
	return (math.exp(x) - 1.0) / x

Julia

function code(x)
	return Float64(Float64(exp(x) - 1.0) / x)
end

MATLAB

function tmp = code(x)
	tmp = (exp(x) - 1.0) / x;
end

Wolfram

code[x_] := N[(N[(N[Exp[x], $MachinePrecision] - 1.0), $MachinePrecision] / x), $MachinePrecision]

Initial Program: 53.1% accurate, 1.0× speedup

Math

\[\begin{array}{l} \\ \frac{e^{x} - 1}{x} \end{array} \]

FPCore

(FPCore (x) :precision binary64 (/ (- (exp x) 1.0) x))

C

double code(double x) {
	return (exp(x) - 1.0) / x;
}

Fortran

real(8) function code(x)
    real(8), intent (in) :: x
    code = (exp(x) - 1.0d0) / x
end function

Java

public static double code(double x) {
	return (Math.exp(x) - 1.0) / x;
}

Python

def code(x):
	return (math.exp(x) - 1.0) / x

Julia

function code(x)
	return Float64(Float64(exp(x) - 1.0) / x)
end

MATLAB

function tmp = code(x)
	tmp = (exp(x) - 1.0) / x;
end

Wolfram

code[x_] := N[(N[(N[Exp[x], $MachinePrecision] - 1.0), $MachinePrecision] / x), $MachinePrecision]

Alternative 1: 100.0% accurate, 1.0× speedup

Math

\[\begin{array}{l} \\ \frac{\mathsf{expm1}\left(x\right)}{x} \end{array} \]

FPCore

(FPCore (x) :precision binary64 (/ (expm1 x) x))

C

double code(double x) {
	return expm1(x) / x;
}

Java

public static double code(double x) {
	return Math.expm1(x) / x;
}

Python

def code(x):
	return math.expm1(x) / x

Julia

function code(x)
	return Float64(expm1(x) / x)
end

Wolfram

code[x_] := N[(N[(Exp[x] - 1), $MachinePrecision] / x), $MachinePrecision]

Derivation

1. Initial program 51.9%

   \[\frac{e^{x} - 1}{x} \]
2. Add Preprocessing
3. Step-by-step derivation

   1. accelerator-lowering-expm1.f64 100.0

      \[\leadsto \frac{\color{blue}{\mathsf{expm1}\left(x\right)}}{x} \]

4. Applied egg-rr 100.0%

   \[\leadsto \frac{\color{blue}{\mathsf{expm1}\left(x\right)}}{x} \]
5. Add Preprocessing

Alternative 2: 69.9% accurate, 0.8× speedup

Math

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\frac{e^{x} + -1}{x} \leq 2:\\ \;\;\;\;1\\ \mathbf{else}:\\ \;\;\;\;\frac{0.041666666666666664 \cdot \left(x \cdot \left(x \cdot \left(x \cdot x\right)\right)\right)}{x}\\ \end{array} \end{array} \]

FPCore

(FPCore (x)
 :precision binary64
 (if (<= (/ (+ (exp x) -1.0) x) 2.0)
   1.0
   (/ (* 0.041666666666666664 (* x (* x (* x x)))) x)))

C

double code(double x) {
	double tmp;
	if (((exp(x) + -1.0) / x) <= 2.0) {
		tmp = 1.0;
	} else {
		tmp = (0.041666666666666664 * (x * (x * (x * x)))) / x;
	}
	return tmp;
}

Fortran

real(8) function code(x)
    real(8), intent (in) :: x
    real(8) :: tmp
    if (((exp(x) + (-1.0d0)) / x) <= 2.0d0) then
        tmp = 1.0d0
    else
        tmp = (0.041666666666666664d0 * (x * (x * (x * x)))) / x
    end if
    code = tmp
end function

Java

public static double code(double x) {
	double tmp;
	if (((Math.exp(x) + -1.0) / x) <= 2.0) {
		tmp = 1.0;
	} else {
		tmp = (0.041666666666666664 * (x * (x * (x * x)))) / x;
	}
	return tmp;
}

Python

def code(x):
	tmp = 0
	if ((math.exp(x) + -1.0) / x) <= 2.0:
		tmp = 1.0
	else:
		tmp = (0.041666666666666664 * (x * (x * (x * x)))) / x
	return tmp

Julia

function code(x)
	tmp = 0.0
	if (Float64(Float64(exp(x) + -1.0) / x) <= 2.0)
		tmp = 1.0;
	else
		tmp = Float64(Float64(0.041666666666666664 * Float64(x * Float64(x * Float64(x * x)))) / x);
	end
	return tmp
end

MATLAB

function tmp_2 = code(x)
	tmp = 0.0;
	if (((exp(x) + -1.0) / x) <= 2.0)
		tmp = 1.0;
	else
		tmp = (0.041666666666666664 * (x * (x * (x * x)))) / x;
	end
	tmp_2 = tmp;
end

Wolfram

code[x_] := If[LessEqual[N[(N[(N[Exp[x], $MachinePrecision] + -1.0), $MachinePrecision] / x), $MachinePrecision], 2.0], 1.0, N[(N[(0.041666666666666664 * N[(x * N[(x * N[(x * x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / x), $MachinePrecision]]

Derivation

1. Split input into 2 regimes

2. if (/.f64 (-.f64 (exp.f64 x) #s(literal 1 binary64)) x) < 2

   1. Initial program 37.2%

      \[\frac{e^{x} - 1}{x} \]
   2. Add Preprocessing

   3. Taylor expanded in x around 0

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

   5. Simplified 67.2%

      \[\leadsto \color{blue}{1} \]

   if 2 < (/.f64 (-.f64 (exp.f64 x) #s(literal 1 binary64)) x)

   1. Initial program 100.0%

      \[\frac{e^{x} - 1}{x} \]
   2. Add Preprocessing
   3. Step-by-step derivation

      1. accelerator-lowering-expm1.f64 100.0

         \[\leadsto \frac{\color{blue}{\mathsf{expm1}\left(x\right)}}{x} \]

   4. Applied egg-rr 100.0%

      \[\leadsto \frac{\color{blue}{\mathsf{expm1}\left(x\right)}}{x} \]

   5. Taylor expanded in x around 0

      \[\leadsto \frac{\color{blue}{x \cdot \left(1 + x \cdot \left(\frac{1}{2} + x \cdot \left(\frac{1}{6} + \frac{1}{24} \cdot x\right)\right)\right)}}{x} \]
   6. Step-by-step derivation

      1. *-lowering-*.f64 N/A

         \[\leadsto \frac{\color{blue}{x \cdot \left(1 + x \cdot \left(\frac{1}{2} + x \cdot \left(\frac{1}{6} + \frac{1}{24} \cdot x\right)\right)\right)}}{x} \]

      2. +-commutative N/A

         \[\leadsto \frac{x \cdot \color{blue}{\left(x \cdot \left(\frac{1}{2} + x \cdot \left(\frac{1}{6} + \frac{1}{24} \cdot x\right)\right) + 1\right)}}{x} \]

      3. accelerator-lowering-fma.f64 N/A

         \[\leadsto \frac{x \cdot \color{blue}{\mathsf{fma}\left(x, \frac{1}{2} + x \cdot \left(\frac{1}{6} + \frac{1}{24} \cdot x\right), 1\right)}}{x} \]

      4. +-commutative N/A

         \[\leadsto \frac{x \cdot \mathsf{fma}\left(x, \color{blue}{x \cdot \left(\frac{1}{6} + \frac{1}{24} \cdot x\right) + \frac{1}{2}}, 1\right)}{x} \]

      5. accelerator-lowering-fma.f64 N/A

         \[\leadsto \frac{x \cdot \mathsf{fma}\left(x, \color{blue}{\mathsf{fma}\left(x, \frac{1}{6} + \frac{1}{24} \cdot x, \frac{1}{2}\right)}, 1\right)}{x} \]

      6. +-commutative N/A

         \[\leadsto \frac{x \cdot \mathsf{fma}\left(x, \mathsf{fma}\left(x, \color{blue}{\frac{1}{24} \cdot x + \frac{1}{6}}, \frac{1}{2}\right), 1\right)}{x} \]

      7. *-commutative N/A

         \[\leadsto \frac{x \cdot \mathsf{fma}\left(x, \mathsf{fma}\left(x, \color{blue}{x \cdot \frac{1}{24}} + \frac{1}{6}, \frac{1}{2}\right), 1\right)}{x} \]

      8. accelerator-lowering-fma.f64 82.4

         \[\leadsto \frac{x \cdot \mathsf{fma}\left(x, \mathsf{fma}\left(x, \color{blue}{\mathsf{fma}\left(x, 0.041666666666666664, 0.16666666666666666\right)}, 0.5\right), 1\right)}{x} \]

   7. Simplified 82.4%

      \[\leadsto \frac{\color{blue}{x \cdot \mathsf{fma}\left(x, \mathsf{fma}\left(x, \mathsf{fma}\left(x, 0.041666666666666664, 0.16666666666666666\right), 0.5\right), 1\right)}}{x} \]

   8. Taylor expanded in x around inf

      \[\leadsto \frac{\color{blue}{\frac{1}{24} \cdot {x}^{4}}}{x} \]
   9. Step-by-step derivation

      1. *-lowering-*.f64 N/A

         \[\leadsto \frac{\color{blue}{\frac{1}{24} \cdot {x}^{4}}}{x} \]

      2. metadata-eval N/A

         \[\leadsto \frac{\frac{1}{24} \cdot {x}^{\color{blue}{\left(3 + 1\right)}}}{x} \]

      3. pow-plus N/A

         \[\leadsto \frac{\frac{1}{24} \cdot \color{blue}{\left({x}^{3} \cdot x\right)}}{x} \]

      4. *-commutative N/A

         \[\leadsto \frac{\frac{1}{24} \cdot \color{blue}{\left(x \cdot {x}^{3}\right)}}{x} \]

      5. *-lowering-*.f64 N/A

         \[\leadsto \frac{\frac{1}{24} \cdot \color{blue}{\left(x \cdot {x}^{3}\right)}}{x} \]

      6. cube-mult N/A

         \[\leadsto \frac{\frac{1}{24} \cdot \left(x \cdot \color{blue}{\left(x \cdot \left(x \cdot x\right)\right)}\right)}{x} \]

      7. unpow2 N/A

         \[\leadsto \frac{\frac{1}{24} \cdot \left(x \cdot \left(x \cdot \color{blue}{{x}^{2}}\right)\right)}{x} \]

      8. *-lowering-*.f64 N/A

         \[\leadsto \frac{\frac{1}{24} \cdot \left(x \cdot \color{blue}{\left(x \cdot {x}^{2}\right)}\right)}{x} \]

      9. unpow2 N/A

         \[\leadsto \frac{\frac{1}{24} \cdot \left(x \cdot \left(x \cdot \color{blue}{\left(x \cdot x\right)}\right)\right)}{x} \]

      10. *-lowering-*.f64 82.4

          \[\leadsto \frac{0.041666666666666664 \cdot \left(x \cdot \left(x \cdot \color{blue}{\left(x \cdot x\right)}\right)\right)}{x} \]

   10. Simplified 82.4%

       \[\leadsto \frac{\color{blue}{0.041666666666666664 \cdot \left(x \cdot \left(x \cdot \left(x \cdot x\right)\right)\right)}}{x} \]
3. Recombined 2 regimes into one program.

4. Final simplification 70.8%

   \[\leadsto \begin{array}{l} \mathbf{if}\;\frac{e^{x} + -1}{x} \leq 2:\\ \;\;\;\;1\\ \mathbf{else}:\\ \;\;\;\;\frac{0.041666666666666664 \cdot \left(x \cdot \left(x \cdot \left(x \cdot x\right)\right)\right)}{x}\\ \end{array} \]
5. Add Preprocessing

Alternative 3: 67.8% accurate, 0.8× speedup

Math

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\frac{e^{x} + -1}{x} \leq 1.5:\\ \;\;\;\;1\\ \mathbf{else}:\\ \;\;\;\;x \cdot \mathsf{fma}\left(x, \mathsf{fma}\left(x, 0.125, 0.25\right), 1\right)\\ \end{array} \end{array} \]

FPCore

(FPCore (x)
 :precision binary64
 (if (<= (/ (+ (exp x) -1.0) x) 1.5) 1.0 (* x (fma x (fma x 0.125 0.25) 1.0))))

C

double code(double x) {
	double tmp;
	if (((exp(x) + -1.0) / x) <= 1.5) {
		tmp = 1.0;
	} else {
		tmp = x * fma(x, fma(x, 0.125, 0.25), 1.0);
	}
	return tmp;
}

Julia

function code(x)
	tmp = 0.0
	if (Float64(Float64(exp(x) + -1.0) / x) <= 1.5)
		tmp = 1.0;
	else
		tmp = Float64(x * fma(x, fma(x, 0.125, 0.25), 1.0));
	end
	return tmp
end

Wolfram

code[x_] := If[LessEqual[N[(N[(N[Exp[x], $MachinePrecision] + -1.0), $MachinePrecision] / x), $MachinePrecision], 1.5], 1.0, N[(x * N[(x * N[(x * 0.125 + 0.25), $MachinePrecision] + 1.0), $MachinePrecision]), $MachinePrecision]]

Derivation

1. Split input into 2 regimes

2. if (/.f64 (-.f64 (exp.f64 x) #s(literal 1 binary64)) x) < 1.5

   1. Initial program 36.9%

      \[\frac{e^{x} - 1}{x} \]
   2. Add Preprocessing

   3. Taylor expanded in x around 0

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

   5. Simplified 67.5%

      \[\leadsto \color{blue}{1} \]

   if 1.5 < (/.f64 (-.f64 (exp.f64 x) #s(literal 1 binary64)) x)

   1. Initial program 100.0%

      \[\frac{e^{x} - 1}{x} \]
   2. Add Preprocessing

   3. Taylor expanded in x around 0

      \[\leadsto \color{blue}{1 + \frac{1}{2} \cdot x} \]
   4. Step-by-step derivation

      1. +-commutative N/A

         \[\leadsto \color{blue}{\frac{1}{2} \cdot x + 1} \]

      2. *-commutative N/A

         \[\leadsto \color{blue}{x \cdot \frac{1}{2}} + 1 \]

      3. accelerator-lowering-fma.f64 6.2

         \[\leadsto \color{blue}{\mathsf{fma}\left(x, 0.5, 1\right)} \]

   5. Simplified 6.2%

      \[\leadsto \color{blue}{\mathsf{fma}\left(x, 0.5, 1\right)} \]
   6. Step-by-step derivation

      1. flip-+ N/A

         \[\leadsto \color{blue}{\frac{\left(x \cdot \frac{1}{2}\right) \cdot \left(x \cdot \frac{1}{2}\right) - 1 \cdot 1}{x \cdot \frac{1}{2} - 1}} \]

      2. metadata-eval N/A

         \[\leadsto \frac{\left(x \cdot \frac{1}{2}\right) \cdot \left(x \cdot \frac{1}{2}\right) - \color{blue}{1}}{x \cdot \frac{1}{2} - 1} \]

      3. div-sub N/A

         \[\leadsto \color{blue}{\frac{\left(x \cdot \frac{1}{2}\right) \cdot \left(x \cdot \frac{1}{2}\right)}{x \cdot \frac{1}{2} - 1} - \frac{1}{x \cdot \frac{1}{2} - 1}} \]

      4. sub-neg N/A

         \[\leadsto \color{blue}{\frac{\left(x \cdot \frac{1}{2}\right) \cdot \left(x \cdot \frac{1}{2}\right)}{x \cdot \frac{1}{2} - 1} + \left(\mathsf{neg}\left(\frac{1}{x \cdot \frac{1}{2} - 1}\right)\right)} \]

      5. flip3-- N/A

         \[\leadsto \frac{\left(x \cdot \frac{1}{2}\right) \cdot \left(x \cdot \frac{1}{2}\right)}{\color{blue}{\frac{{\left(x \cdot \frac{1}{2}\right)}^{3} - {1}^{3}}{\left(x \cdot \frac{1}{2}\right) \cdot \left(x \cdot \frac{1}{2}\right) + \left(1 \cdot 1 + \left(x \cdot \frac{1}{2}\right) \cdot 1\right)}}} + \left(\mathsf{neg}\left(\frac{1}{x \cdot \frac{1}{2} - 1}\right)\right) \]

      6. associate-/r/ N/A

         \[\leadsto \color{blue}{\frac{\left(x \cdot \frac{1}{2}\right) \cdot \left(x \cdot \frac{1}{2}\right)}{{\left(x \cdot \frac{1}{2}\right)}^{3} - {1}^{3}} \cdot \left(\left(x \cdot \frac{1}{2}\right) \cdot \left(x \cdot \frac{1}{2}\right) + \left(1 \cdot 1 + \left(x \cdot \frac{1}{2}\right) \cdot 1\right)\right)} + \left(\mathsf{neg}\left(\frac{1}{x \cdot \frac{1}{2} - 1}\right)\right) \]

      7. accelerator-lowering-fma.f64 N/A

         \[\leadsto \color{blue}{\mathsf{fma}\left(\frac{\left(x \cdot \frac{1}{2}\right) \cdot \left(x \cdot \frac{1}{2}\right)}{{\left(x \cdot \frac{1}{2}\right)}^{3} - {1}^{3}}, \left(x \cdot \frac{1}{2}\right) \cdot \left(x \cdot \frac{1}{2}\right) + \left(1 \cdot 1 + \left(x \cdot \frac{1}{2}\right) \cdot 1\right), \mathsf{neg}\left(\frac{1}{x \cdot \frac{1}{2} - 1}\right)\right)} \]

   7. Applied egg-rr 1.4%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\frac{x \cdot \left(x \cdot 0.25\right)}{\mathsf{fma}\left(0.125, x \cdot \left(x \cdot x\right), -1\right)}, \mathsf{fma}\left(x, \mathsf{fma}\left(x, 0.25, 0.5\right), 1\right), -\frac{1}{\mathsf{fma}\left(x, 0.5, -1\right)}\right)} \]

   8. Taylor expanded in x around 0

      \[\leadsto \mathsf{fma}\left(\frac{x \cdot \left(x \cdot \frac{1}{4}\right)}{\mathsf{fma}\left(\frac{1}{8}, x \cdot \left(x \cdot x\right), -1\right)}, \mathsf{fma}\left(x, \mathsf{fma}\left(x, \frac{1}{4}, \frac{1}{2}\right), 1\right), \color{blue}{1 + x \cdot \left(\frac{1}{2} + x \cdot \left(\frac{1}{4} + \frac{1}{8} \cdot x\right)\right)}\right) \]
   9. Step-by-step derivation

      1. +-commutative N/A

         \[\leadsto \mathsf{fma}\left(\frac{x \cdot \left(x \cdot \frac{1}{4}\right)}{\mathsf{fma}\left(\frac{1}{8}, x \cdot \left(x \cdot x\right), -1\right)}, \mathsf{fma}\left(x, \mathsf{fma}\left(x, \frac{1}{4}, \frac{1}{2}\right), 1\right), \color{blue}{x \cdot \left(\frac{1}{2} + x \cdot \left(\frac{1}{4} + \frac{1}{8} \cdot x\right)\right) + 1}\right) \]

      2. accelerator-lowering-fma.f64 N/A

         \[\leadsto \mathsf{fma}\left(\frac{x \cdot \left(x \cdot \frac{1}{4}\right)}{\mathsf{fma}\left(\frac{1}{8}, x \cdot \left(x \cdot x\right), -1\right)}, \mathsf{fma}\left(x, \mathsf{fma}\left(x, \frac{1}{4}, \frac{1}{2}\right), 1\right), \color{blue}{\mathsf{fma}\left(x, \frac{1}{2} + x \cdot \left(\frac{1}{4} + \frac{1}{8} \cdot x\right), 1\right)}\right) \]

      3. +-commutative N/A

         \[\leadsto \mathsf{fma}\left(\frac{x \cdot \left(x \cdot \frac{1}{4}\right)}{\mathsf{fma}\left(\frac{1}{8}, x \cdot \left(x \cdot x\right), -1\right)}, \mathsf{fma}\left(x, \mathsf{fma}\left(x, \frac{1}{4}, \frac{1}{2}\right), 1\right), \mathsf{fma}\left(x, \color{blue}{x \cdot \left(\frac{1}{4} + \frac{1}{8} \cdot x\right) + \frac{1}{2}}, 1\right)\right) \]

      4. accelerator-lowering-fma.f64 N/A

         \[\leadsto \mathsf{fma}\left(\frac{x \cdot \left(x \cdot \frac{1}{4}\right)}{\mathsf{fma}\left(\frac{1}{8}, x \cdot \left(x \cdot x\right), -1\right)}, \mathsf{fma}\left(x, \mathsf{fma}\left(x, \frac{1}{4}, \frac{1}{2}\right), 1\right), \mathsf{fma}\left(x, \color{blue}{\mathsf{fma}\left(x, \frac{1}{4} + \frac{1}{8} \cdot x, \frac{1}{2}\right)}, 1\right)\right) \]

      5. +-commutative N/A

         \[\leadsto \mathsf{fma}\left(\frac{x \cdot \left(x \cdot \frac{1}{4}\right)}{\mathsf{fma}\left(\frac{1}{8}, x \cdot \left(x \cdot x\right), -1\right)}, \mathsf{fma}\left(x, \mathsf{fma}\left(x, \frac{1}{4}, \frac{1}{2}\right), 1\right), \mathsf{fma}\left(x, \mathsf{fma}\left(x, \color{blue}{\frac{1}{8} \cdot x + \frac{1}{4}}, \frac{1}{2}\right), 1\right)\right) \]

      6. *-commutative N/A

         \[\leadsto \mathsf{fma}\left(\frac{x \cdot \left(x \cdot \frac{1}{4}\right)}{\mathsf{fma}\left(\frac{1}{8}, x \cdot \left(x \cdot x\right), -1\right)}, \mathsf{fma}\left(x, \mathsf{fma}\left(x, \frac{1}{4}, \frac{1}{2}\right), 1\right), \mathsf{fma}\left(x, \mathsf{fma}\left(x, \color{blue}{x \cdot \frac{1}{8}} + \frac{1}{4}, \frac{1}{2}\right), 1\right)\right) \]

      7. accelerator-lowering-fma.f64 13.1

         \[\leadsto \mathsf{fma}\left(\frac{x \cdot \left(x \cdot 0.25\right)}{\mathsf{fma}\left(0.125, x \cdot \left(x \cdot x\right), -1\right)}, \mathsf{fma}\left(x, \mathsf{fma}\left(x, 0.25, 0.5\right), 1\right), \mathsf{fma}\left(x, \mathsf{fma}\left(x, \color{blue}{\mathsf{fma}\left(x, 0.125, 0.25\right)}, 0.5\right), 1\right)\right) \]

   10. Simplified 13.1%

       \[\leadsto \mathsf{fma}\left(\frac{x \cdot \left(x \cdot 0.25\right)}{\mathsf{fma}\left(0.125, x \cdot \left(x \cdot x\right), -1\right)}, \mathsf{fma}\left(x, \mathsf{fma}\left(x, 0.25, 0.5\right), 1\right), \color{blue}{\mathsf{fma}\left(x, \mathsf{fma}\left(x, \mathsf{fma}\left(x, 0.125, 0.25\right), 0.5\right), 1\right)}\right) \]

   11. Taylor expanded in x around inf

       \[\leadsto \color{blue}{{x}^{3} \cdot \left(\frac{1}{8} + \left(\frac{1}{4} \cdot \frac{1}{x} + \frac{1}{{x}^{2}}\right)\right)} \]
   12. Step-by-step derivation

       1. cube-mult N/A

          \[\leadsto \color{blue}{\left(x \cdot \left(x \cdot x\right)\right)} \cdot \left(\frac{1}{8} + \left(\frac{1}{4} \cdot \frac{1}{x} + \frac{1}{{x}^{2}}\right)\right) \]

       2. unpow2 N/A

          \[\leadsto \left(x \cdot \color{blue}{{x}^{2}}\right) \cdot \left(\frac{1}{8} + \left(\frac{1}{4} \cdot \frac{1}{x} + \frac{1}{{x}^{2}}\right)\right) \]

       3. associate-*l* N/A

          \[\leadsto \color{blue}{x \cdot \left({x}^{2} \cdot \left(\frac{1}{8} + \left(\frac{1}{4} \cdot \frac{1}{x} + \frac{1}{{x}^{2}}\right)\right)\right)} \]

       4. *-lowering-*.f64 N/A

          \[\leadsto \color{blue}{x \cdot \left({x}^{2} \cdot \left(\frac{1}{8} + \left(\frac{1}{4} \cdot \frac{1}{x} + \frac{1}{{x}^{2}}\right)\right)\right)} \]

       5. associate-+r+ N/A

          \[\leadsto x \cdot \left({x}^{2} \cdot \color{blue}{\left(\left(\frac{1}{8} + \frac{1}{4} \cdot \frac{1}{x}\right) + \frac{1}{{x}^{2}}\right)}\right) \]

       6. distribute-lft-in N/A

          \[\leadsto x \cdot \color{blue}{\left({x}^{2} \cdot \left(\frac{1}{8} + \frac{1}{4} \cdot \frac{1}{x}\right) + {x}^{2} \cdot \frac{1}{{x}^{2}}\right)} \]

       7. unpow2 N/A

          \[\leadsto x \cdot \left(\color{blue}{\left(x \cdot x\right)} \cdot \left(\frac{1}{8} + \frac{1}{4} \cdot \frac{1}{x}\right) + {x}^{2} \cdot \frac{1}{{x}^{2}}\right) \]

       8. associate-*l* N/A

          \[\leadsto x \cdot \left(\color{blue}{x \cdot \left(x \cdot \left(\frac{1}{8} + \frac{1}{4} \cdot \frac{1}{x}\right)\right)} + {x}^{2} \cdot \frac{1}{{x}^{2}}\right) \]

       9. rgt-mult-inverse N/A

          \[\leadsto x \cdot \left(x \cdot \left(x \cdot \left(\frac{1}{8} + \frac{1}{4} \cdot \frac{1}{x}\right)\right) + \color{blue}{1}\right) \]

       10. accelerator-lowering-fma.f64 N/A

           \[\leadsto x \cdot \color{blue}{\mathsf{fma}\left(x, x \cdot \left(\frac{1}{8} + \frac{1}{4} \cdot \frac{1}{x}\right), 1\right)} \]

       11. distribute-lft-in N/A

           \[\leadsto x \cdot \mathsf{fma}\left(x, \color{blue}{x \cdot \frac{1}{8} + x \cdot \left(\frac{1}{4} \cdot \frac{1}{x}\right)}, 1\right) \]

       12. *-commutative N/A

           \[\leadsto x \cdot \mathsf{fma}\left(x, x \cdot \frac{1}{8} + x \cdot \color{blue}{\left(\frac{1}{x} \cdot \frac{1}{4}\right)}, 1\right) \]

       13. associate-*r* N/A

           \[\leadsto x \cdot \mathsf{fma}\left(x, x \cdot \frac{1}{8} + \color{blue}{\left(x \cdot \frac{1}{x}\right) \cdot \frac{1}{4}}, 1\right) \]

       14. rgt-mult-inverse N/A

           \[\leadsto x \cdot \mathsf{fma}\left(x, x \cdot \frac{1}{8} + \color{blue}{1} \cdot \frac{1}{4}, 1\right) \]

       15. metadata-eval N/A

           \[\leadsto x \cdot \mathsf{fma}\left(x, x \cdot \frac{1}{8} + \color{blue}{\frac{1}{4}}, 1\right) \]

       16. accelerator-lowering-fma.f64 75.4

           \[\leadsto x \cdot \mathsf{fma}\left(x, \color{blue}{\mathsf{fma}\left(x, 0.125, 0.25\right)}, 1\right) \]

   13. Simplified 75.4%

       \[\leadsto \color{blue}{x \cdot \mathsf{fma}\left(x, \mathsf{fma}\left(x, 0.125, 0.25\right), 1\right)} \]
3. Recombined 2 regimes into one program.

4. Final simplification 69.4%

   \[\leadsto \begin{array}{l} \mathbf{if}\;\frac{e^{x} + -1}{x} \leq 1.5:\\ \;\;\;\;1\\ \mathbf{else}:\\ \;\;\;\;x \cdot \mathsf{fma}\left(x, \mathsf{fma}\left(x, 0.125, 0.25\right), 1\right)\\ \end{array} \]
5. Add Preprocessing

Alternative 4: 67.8% accurate, 0.8× speedup

Math

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\frac{e^{x} + -1}{x} \leq 2:\\ \;\;\;\;1\\ \mathbf{else}:\\ \;\;\;\;\left(x \cdot x\right) \cdot \mathsf{fma}\left(x, 0.125, 0.25\right)\\ \end{array} \end{array} \]

FPCore

(FPCore (x)
 :precision binary64
 (if (<= (/ (+ (exp x) -1.0) x) 2.0) 1.0 (* (* x x) (fma x 0.125 0.25))))

C

double code(double x) {
	double tmp;
	if (((exp(x) + -1.0) / x) <= 2.0) {
		tmp = 1.0;
	} else {
		tmp = (x * x) * fma(x, 0.125, 0.25);
	}
	return tmp;
}

Julia

function code(x)
	tmp = 0.0
	if (Float64(Float64(exp(x) + -1.0) / x) <= 2.0)
		tmp = 1.0;
	else
		tmp = Float64(Float64(x * x) * fma(x, 0.125, 0.25));
	end
	return tmp
end

Wolfram

code[x_] := If[LessEqual[N[(N[(N[Exp[x], $MachinePrecision] + -1.0), $MachinePrecision] / x), $MachinePrecision], 2.0], 1.0, N[(N[(x * x), $MachinePrecision] * N[(x * 0.125 + 0.25), $MachinePrecision]), $MachinePrecision]]

Derivation

1. Split input into 2 regimes

2. if (/.f64 (-.f64 (exp.f64 x) #s(literal 1 binary64)) x) < 2

   1. Initial program 37.2%

      \[\frac{e^{x} - 1}{x} \]
   2. Add Preprocessing

   3. Taylor expanded in x around 0

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

   5. Simplified 67.2%

      \[\leadsto \color{blue}{1} \]

   if 2 < (/.f64 (-.f64 (exp.f64 x) #s(literal 1 binary64)) x)

   1. Initial program 100.0%

      \[\frac{e^{x} - 1}{x} \]
   2. Add Preprocessing

   3. Taylor expanded in x around 0

      \[\leadsto \color{blue}{1 + \frac{1}{2} \cdot x} \]
   4. Step-by-step derivation

      1. +-commutative N/A

         \[\leadsto \color{blue}{\frac{1}{2} \cdot x + 1} \]

      2. *-commutative N/A

         \[\leadsto \color{blue}{x \cdot \frac{1}{2}} + 1 \]

      3. accelerator-lowering-fma.f64 5.9

         \[\leadsto \color{blue}{\mathsf{fma}\left(x, 0.5, 1\right)} \]

   5. Simplified 5.9%

      \[\leadsto \color{blue}{\mathsf{fma}\left(x, 0.5, 1\right)} \]
   6. Step-by-step derivation

      1. flip-+ N/A

         \[\leadsto \color{blue}{\frac{\left(x \cdot \frac{1}{2}\right) \cdot \left(x \cdot \frac{1}{2}\right) - 1 \cdot 1}{x \cdot \frac{1}{2} - 1}} \]

      2. metadata-eval N/A

         \[\leadsto \frac{\left(x \cdot \frac{1}{2}\right) \cdot \left(x \cdot \frac{1}{2}\right) - \color{blue}{1}}{x \cdot \frac{1}{2} - 1} \]

      3. div-sub N/A

         \[\leadsto \color{blue}{\frac{\left(x \cdot \frac{1}{2}\right) \cdot \left(x \cdot \frac{1}{2}\right)}{x \cdot \frac{1}{2} - 1} - \frac{1}{x \cdot \frac{1}{2} - 1}} \]

      4. sub-neg N/A

         \[\leadsto \color{blue}{\frac{\left(x \cdot \frac{1}{2}\right) \cdot \left(x \cdot \frac{1}{2}\right)}{x \cdot \frac{1}{2} - 1} + \left(\mathsf{neg}\left(\frac{1}{x \cdot \frac{1}{2} - 1}\right)\right)} \]

      5. flip3-- N/A

         \[\leadsto \frac{\left(x \cdot \frac{1}{2}\right) \cdot \left(x \cdot \frac{1}{2}\right)}{\color{blue}{\frac{{\left(x \cdot \frac{1}{2}\right)}^{3} - {1}^{3}}{\left(x \cdot \frac{1}{2}\right) \cdot \left(x \cdot \frac{1}{2}\right) + \left(1 \cdot 1 + \left(x \cdot \frac{1}{2}\right) \cdot 1\right)}}} + \left(\mathsf{neg}\left(\frac{1}{x \cdot \frac{1}{2} - 1}\right)\right) \]

      6. associate-/r/ N/A

         \[\leadsto \color{blue}{\frac{\left(x \cdot \frac{1}{2}\right) \cdot \left(x \cdot \frac{1}{2}\right)}{{\left(x \cdot \frac{1}{2}\right)}^{3} - {1}^{3}} \cdot \left(\left(x \cdot \frac{1}{2}\right) \cdot \left(x \cdot \frac{1}{2}\right) + \left(1 \cdot 1 + \left(x \cdot \frac{1}{2}\right) \cdot 1\right)\right)} + \left(\mathsf{neg}\left(\frac{1}{x \cdot \frac{1}{2} - 1}\right)\right) \]

      7. accelerator-lowering-fma.f64 N/A

         \[\leadsto \color{blue}{\mathsf{fma}\left(\frac{\left(x \cdot \frac{1}{2}\right) \cdot \left(x \cdot \frac{1}{2}\right)}{{\left(x \cdot \frac{1}{2}\right)}^{3} - {1}^{3}}, \left(x \cdot \frac{1}{2}\right) \cdot \left(x \cdot \frac{1}{2}\right) + \left(1 \cdot 1 + \left(x \cdot \frac{1}{2}\right) \cdot 1\right), \mathsf{neg}\left(\frac{1}{x \cdot \frac{1}{2} - 1}\right)\right)} \]

   7. Applied egg-rr 1.0%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\frac{x \cdot \left(x \cdot 0.25\right)}{\mathsf{fma}\left(0.125, x \cdot \left(x \cdot x\right), -1\right)}, \mathsf{fma}\left(x, \mathsf{fma}\left(x, 0.25, 0.5\right), 1\right), -\frac{1}{\mathsf{fma}\left(x, 0.5, -1\right)}\right)} \]

   8. Taylor expanded in x around 0

      \[\leadsto \mathsf{fma}\left(\frac{x \cdot \left(x \cdot \frac{1}{4}\right)}{\mathsf{fma}\left(\frac{1}{8}, x \cdot \left(x \cdot x\right), -1\right)}, \mathsf{fma}\left(x, \mathsf{fma}\left(x, \frac{1}{4}, \frac{1}{2}\right), 1\right), \color{blue}{1 + x \cdot \left(\frac{1}{2} + x \cdot \left(\frac{1}{4} + \frac{1}{8} \cdot x\right)\right)}\right) \]
   9. Step-by-step derivation

      1. +-commutative N/A

         \[\leadsto \mathsf{fma}\left(\frac{x \cdot \left(x \cdot \frac{1}{4}\right)}{\mathsf{fma}\left(\frac{1}{8}, x \cdot \left(x \cdot x\right), -1\right)}, \mathsf{fma}\left(x, \mathsf{fma}\left(x, \frac{1}{4}, \frac{1}{2}\right), 1\right), \color{blue}{x \cdot \left(\frac{1}{2} + x \cdot \left(\frac{1}{4} + \frac{1}{8} \cdot x\right)\right) + 1}\right) \]

      2. accelerator-lowering-fma.f64 N/A

         \[\leadsto \mathsf{fma}\left(\frac{x \cdot \left(x \cdot \frac{1}{4}\right)}{\mathsf{fma}\left(\frac{1}{8}, x \cdot \left(x \cdot x\right), -1\right)}, \mathsf{fma}\left(x, \mathsf{fma}\left(x, \frac{1}{4}, \frac{1}{2}\right), 1\right), \color{blue}{\mathsf{fma}\left(x, \frac{1}{2} + x \cdot \left(\frac{1}{4} + \frac{1}{8} \cdot x\right), 1\right)}\right) \]

      3. +-commutative N/A

         \[\leadsto \mathsf{fma}\left(\frac{x \cdot \left(x \cdot \frac{1}{4}\right)}{\mathsf{fma}\left(\frac{1}{8}, x \cdot \left(x \cdot x\right), -1\right)}, \mathsf{fma}\left(x, \mathsf{fma}\left(x, \frac{1}{4}, \frac{1}{2}\right), 1\right), \mathsf{fma}\left(x, \color{blue}{x \cdot \left(\frac{1}{4} + \frac{1}{8} \cdot x\right) + \frac{1}{2}}, 1\right)\right) \]

      4. accelerator-lowering-fma.f64 N/A

         \[\leadsto \mathsf{fma}\left(\frac{x \cdot \left(x \cdot \frac{1}{4}\right)}{\mathsf{fma}\left(\frac{1}{8}, x \cdot \left(x \cdot x\right), -1\right)}, \mathsf{fma}\left(x, \mathsf{fma}\left(x, \frac{1}{4}, \frac{1}{2}\right), 1\right), \mathsf{fma}\left(x, \color{blue}{\mathsf{fma}\left(x, \frac{1}{4} + \frac{1}{8} \cdot x, \frac{1}{2}\right)}, 1\right)\right) \]

      5. +-commutative N/A

         \[\leadsto \mathsf{fma}\left(\frac{x \cdot \left(x \cdot \frac{1}{4}\right)}{\mathsf{fma}\left(\frac{1}{8}, x \cdot \left(x \cdot x\right), -1\right)}, \mathsf{fma}\left(x, \mathsf{fma}\left(x, \frac{1}{4}, \frac{1}{2}\right), 1\right), \mathsf{fma}\left(x, \mathsf{fma}\left(x, \color{blue}{\frac{1}{8} \cdot x + \frac{1}{4}}, \frac{1}{2}\right), 1\right)\right) \]

      6. *-commutative N/A

         \[\leadsto \mathsf{fma}\left(\frac{x \cdot \left(x \cdot \frac{1}{4}\right)}{\mathsf{fma}\left(\frac{1}{8}, x \cdot \left(x \cdot x\right), -1\right)}, \mathsf{fma}\left(x, \mathsf{fma}\left(x, \frac{1}{4}, \frac{1}{2}\right), 1\right), \mathsf{fma}\left(x, \mathsf{fma}\left(x, \color{blue}{x \cdot \frac{1}{8}} + \frac{1}{4}, \frac{1}{2}\right), 1\right)\right) \]

      7. accelerator-lowering-fma.f64 13.0

         \[\leadsto \mathsf{fma}\left(\frac{x \cdot \left(x \cdot 0.25\right)}{\mathsf{fma}\left(0.125, x \cdot \left(x \cdot x\right), -1\right)}, \mathsf{fma}\left(x, \mathsf{fma}\left(x, 0.25, 0.5\right), 1\right), \mathsf{fma}\left(x, \mathsf{fma}\left(x, \color{blue}{\mathsf{fma}\left(x, 0.125, 0.25\right)}, 0.5\right), 1\right)\right) \]

   10. Simplified 13.0%

       \[\leadsto \mathsf{fma}\left(\frac{x \cdot \left(x \cdot 0.25\right)}{\mathsf{fma}\left(0.125, x \cdot \left(x \cdot x\right), -1\right)}, \mathsf{fma}\left(x, \mathsf{fma}\left(x, 0.25, 0.5\right), 1\right), \color{blue}{\mathsf{fma}\left(x, \mathsf{fma}\left(x, \mathsf{fma}\left(x, 0.125, 0.25\right), 0.5\right), 1\right)}\right) \]

   11. Taylor expanded in x around inf

       \[\leadsto \color{blue}{{x}^{3} \cdot \left(\frac{1}{8} + \frac{1}{4} \cdot \frac{1}{x}\right)} \]
   12. Step-by-step derivation

       1. unpow3 N/A

          \[\leadsto \color{blue}{\left(\left(x \cdot x\right) \cdot x\right)} \cdot \left(\frac{1}{8} + \frac{1}{4} \cdot \frac{1}{x}\right) \]

       2. unpow2 N/A

          \[\leadsto \left(\color{blue}{{x}^{2}} \cdot x\right) \cdot \left(\frac{1}{8} + \frac{1}{4} \cdot \frac{1}{x}\right) \]

       3. associate-*l* N/A

          \[\leadsto \color{blue}{{x}^{2} \cdot \left(x \cdot \left(\frac{1}{8} + \frac{1}{4} \cdot \frac{1}{x}\right)\right)} \]

       4. *-lowering-*.f64 N/A

          \[\leadsto \color{blue}{{x}^{2} \cdot \left(x \cdot \left(\frac{1}{8} + \frac{1}{4} \cdot \frac{1}{x}\right)\right)} \]

       5. unpow2 N/A

          \[\leadsto \color{blue}{\left(x \cdot x\right)} \cdot \left(x \cdot \left(\frac{1}{8} + \frac{1}{4} \cdot \frac{1}{x}\right)\right) \]

       6. *-lowering-*.f64 N/A

          \[\leadsto \color{blue}{\left(x \cdot x\right)} \cdot \left(x \cdot \left(\frac{1}{8} + \frac{1}{4} \cdot \frac{1}{x}\right)\right) \]

       7. distribute-lft-in N/A

          \[\leadsto \left(x \cdot x\right) \cdot \color{blue}{\left(x \cdot \frac{1}{8} + x \cdot \left(\frac{1}{4} \cdot \frac{1}{x}\right)\right)} \]

       8. *-commutative N/A

          \[\leadsto \left(x \cdot x\right) \cdot \left(x \cdot \frac{1}{8} + x \cdot \color{blue}{\left(\frac{1}{x} \cdot \frac{1}{4}\right)}\right) \]

       9. associate-*r* N/A

          \[\leadsto \left(x \cdot x\right) \cdot \left(x \cdot \frac{1}{8} + \color{blue}{\left(x \cdot \frac{1}{x}\right) \cdot \frac{1}{4}}\right) \]

       10. rgt-mult-inverse N/A

           \[\leadsto \left(x \cdot x\right) \cdot \left(x \cdot \frac{1}{8} + \color{blue}{1} \cdot \frac{1}{4}\right) \]

       11. metadata-eval N/A

           \[\leadsto \left(x \cdot x\right) \cdot \left(x \cdot \frac{1}{8} + \color{blue}{\frac{1}{4}}\right) \]

       12. accelerator-lowering-fma.f64 76.3

           \[\leadsto \left(x \cdot x\right) \cdot \color{blue}{\mathsf{fma}\left(x, 0.125, 0.25\right)} \]

   13. Simplified 76.3%

       \[\leadsto \color{blue}{\left(x \cdot x\right) \cdot \mathsf{fma}\left(x, 0.125, 0.25\right)} \]
3. Recombined 2 regimes into one program.

4. Final simplification 69.3%

   \[\leadsto \begin{array}{l} \mathbf{if}\;\frac{e^{x} + -1}{x} \leq 2:\\ \;\;\;\;1\\ \mathbf{else}:\\ \;\;\;\;\left(x \cdot x\right) \cdot \mathsf{fma}\left(x, 0.125, 0.25\right)\\ \end{array} \]
5. Add Preprocessing

Alternative 5: 67.8% accurate, 0.8× speedup

Math

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\frac{e^{x} + -1}{x} \leq 2:\\ \;\;\;\;1\\ \mathbf{else}:\\ \;\;\;\;\left(x \cdot \left(x \cdot x\right)\right) \cdot 0.125\\ \end{array} \end{array} \]

FPCore

(FPCore (x)
 :precision binary64
 (if (<= (/ (+ (exp x) -1.0) x) 2.0) 1.0 (* (* x (* x x)) 0.125)))

C

double code(double x) {
	double tmp;
	if (((exp(x) + -1.0) / x) <= 2.0) {
		tmp = 1.0;
	} else {
		tmp = (x * (x * x)) * 0.125;
	}
	return tmp;
}

Fortran

real(8) function code(x)
    real(8), intent (in) :: x
    real(8) :: tmp
    if (((exp(x) + (-1.0d0)) / x) <= 2.0d0) then
        tmp = 1.0d0
    else
        tmp = (x * (x * x)) * 0.125d0
    end if
    code = tmp
end function

Java

public static double code(double x) {
	double tmp;
	if (((Math.exp(x) + -1.0) / x) <= 2.0) {
		tmp = 1.0;
	} else {
		tmp = (x * (x * x)) * 0.125;
	}
	return tmp;
}

Python

def code(x):
	tmp = 0
	if ((math.exp(x) + -1.0) / x) <= 2.0:
		tmp = 1.0
	else:
		tmp = (x * (x * x)) * 0.125
	return tmp

Julia

function code(x)
	tmp = 0.0
	if (Float64(Float64(exp(x) + -1.0) / x) <= 2.0)
		tmp = 1.0;
	else
		tmp = Float64(Float64(x * Float64(x * x)) * 0.125);
	end
	return tmp
end

MATLAB

function tmp_2 = code(x)
	tmp = 0.0;
	if (((exp(x) + -1.0) / x) <= 2.0)
		tmp = 1.0;
	else
		tmp = (x * (x * x)) * 0.125;
	end
	tmp_2 = tmp;
end

Wolfram

code[x_] := If[LessEqual[N[(N[(N[Exp[x], $MachinePrecision] + -1.0), $MachinePrecision] / x), $MachinePrecision], 2.0], 1.0, N[(N[(x * N[(x * x), $MachinePrecision]), $MachinePrecision] * 0.125), $MachinePrecision]]

Derivation

1. Split input into 2 regimes

2. if (/.f64 (-.f64 (exp.f64 x) #s(literal 1 binary64)) x) < 2

   1. Initial program 37.2%

      \[\frac{e^{x} - 1}{x} \]
   2. Add Preprocessing

   3. Taylor expanded in x around 0

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

   5. Simplified 67.2%

      \[\leadsto \color{blue}{1} \]

   if 2 < (/.f64 (-.f64 (exp.f64 x) #s(literal 1 binary64)) x)

   1. Initial program 100.0%

      \[\frac{e^{x} - 1}{x} \]
   2. Add Preprocessing

   3. Taylor expanded in x around 0

      \[\leadsto \color{blue}{1 + \frac{1}{2} \cdot x} \]
   4. Step-by-step derivation

      1. +-commutative N/A

         \[\leadsto \color{blue}{\frac{1}{2} \cdot x + 1} \]

      2. *-commutative N/A

         \[\leadsto \color{blue}{x \cdot \frac{1}{2}} + 1 \]

      3. accelerator-lowering-fma.f64 5.9

         \[\leadsto \color{blue}{\mathsf{fma}\left(x, 0.5, 1\right)} \]

   5. Simplified 5.9%

      \[\leadsto \color{blue}{\mathsf{fma}\left(x, 0.5, 1\right)} \]
   6. Step-by-step derivation

      1. flip-+ N/A

         \[\leadsto \color{blue}{\frac{\left(x \cdot \frac{1}{2}\right) \cdot \left(x \cdot \frac{1}{2}\right) - 1 \cdot 1}{x \cdot \frac{1}{2} - 1}} \]

      2. metadata-eval N/A

         \[\leadsto \frac{\left(x \cdot \frac{1}{2}\right) \cdot \left(x \cdot \frac{1}{2}\right) - \color{blue}{1}}{x \cdot \frac{1}{2} - 1} \]

      3. div-sub N/A

         \[\leadsto \color{blue}{\frac{\left(x \cdot \frac{1}{2}\right) \cdot \left(x \cdot \frac{1}{2}\right)}{x \cdot \frac{1}{2} - 1} - \frac{1}{x \cdot \frac{1}{2} - 1}} \]

      4. sub-neg N/A

         \[\leadsto \color{blue}{\frac{\left(x \cdot \frac{1}{2}\right) \cdot \left(x \cdot \frac{1}{2}\right)}{x \cdot \frac{1}{2} - 1} + \left(\mathsf{neg}\left(\frac{1}{x \cdot \frac{1}{2} - 1}\right)\right)} \]

      5. flip3-- N/A

         \[\leadsto \frac{\left(x \cdot \frac{1}{2}\right) \cdot \left(x \cdot \frac{1}{2}\right)}{\color{blue}{\frac{{\left(x \cdot \frac{1}{2}\right)}^{3} - {1}^{3}}{\left(x \cdot \frac{1}{2}\right) \cdot \left(x \cdot \frac{1}{2}\right) + \left(1 \cdot 1 + \left(x \cdot \frac{1}{2}\right) \cdot 1\right)}}} + \left(\mathsf{neg}\left(\frac{1}{x \cdot \frac{1}{2} - 1}\right)\right) \]

      6. associate-/r/ N/A

         \[\leadsto \color{blue}{\frac{\left(x \cdot \frac{1}{2}\right) \cdot \left(x \cdot \frac{1}{2}\right)}{{\left(x \cdot \frac{1}{2}\right)}^{3} - {1}^{3}} \cdot \left(\left(x \cdot \frac{1}{2}\right) \cdot \left(x \cdot \frac{1}{2}\right) + \left(1 \cdot 1 + \left(x \cdot \frac{1}{2}\right) \cdot 1\right)\right)} + \left(\mathsf{neg}\left(\frac{1}{x \cdot \frac{1}{2} - 1}\right)\right) \]

      7. accelerator-lowering-fma.f64 N/A

         \[\leadsto \color{blue}{\mathsf{fma}\left(\frac{\left(x \cdot \frac{1}{2}\right) \cdot \left(x \cdot \frac{1}{2}\right)}{{\left(x \cdot \frac{1}{2}\right)}^{3} - {1}^{3}}, \left(x \cdot \frac{1}{2}\right) \cdot \left(x \cdot \frac{1}{2}\right) + \left(1 \cdot 1 + \left(x \cdot \frac{1}{2}\right) \cdot 1\right), \mathsf{neg}\left(\frac{1}{x \cdot \frac{1}{2} - 1}\right)\right)} \]

   7. Applied egg-rr 1.0%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\frac{x \cdot \left(x \cdot 0.25\right)}{\mathsf{fma}\left(0.125, x \cdot \left(x \cdot x\right), -1\right)}, \mathsf{fma}\left(x, \mathsf{fma}\left(x, 0.25, 0.5\right), 1\right), -\frac{1}{\mathsf{fma}\left(x, 0.5, -1\right)}\right)} \]

   8. Taylor expanded in x around 0

      \[\leadsto \mathsf{fma}\left(\frac{x \cdot \left(x \cdot \frac{1}{4}\right)}{\mathsf{fma}\left(\frac{1}{8}, x \cdot \left(x \cdot x\right), -1\right)}, \mathsf{fma}\left(x, \mathsf{fma}\left(x, \frac{1}{4}, \frac{1}{2}\right), 1\right), \color{blue}{1 + x \cdot \left(\frac{1}{2} + x \cdot \left(\frac{1}{4} + \frac{1}{8} \cdot x\right)\right)}\right) \]
   9. Step-by-step derivation

      1. +-commutative N/A

         \[\leadsto \mathsf{fma}\left(\frac{x \cdot \left(x \cdot \frac{1}{4}\right)}{\mathsf{fma}\left(\frac{1}{8}, x \cdot \left(x \cdot x\right), -1\right)}, \mathsf{fma}\left(x, \mathsf{fma}\left(x, \frac{1}{4}, \frac{1}{2}\right), 1\right), \color{blue}{x \cdot \left(\frac{1}{2} + x \cdot \left(\frac{1}{4} + \frac{1}{8} \cdot x\right)\right) + 1}\right) \]

      2. accelerator-lowering-fma.f64 N/A

         \[\leadsto \mathsf{fma}\left(\frac{x \cdot \left(x \cdot \frac{1}{4}\right)}{\mathsf{fma}\left(\frac{1}{8}, x \cdot \left(x \cdot x\right), -1\right)}, \mathsf{fma}\left(x, \mathsf{fma}\left(x, \frac{1}{4}, \frac{1}{2}\right), 1\right), \color{blue}{\mathsf{fma}\left(x, \frac{1}{2} + x \cdot \left(\frac{1}{4} + \frac{1}{8} \cdot x\right), 1\right)}\right) \]

      3. +-commutative N/A

         \[\leadsto \mathsf{fma}\left(\frac{x \cdot \left(x \cdot \frac{1}{4}\right)}{\mathsf{fma}\left(\frac{1}{8}, x \cdot \left(x \cdot x\right), -1\right)}, \mathsf{fma}\left(x, \mathsf{fma}\left(x, \frac{1}{4}, \frac{1}{2}\right), 1\right), \mathsf{fma}\left(x, \color{blue}{x \cdot \left(\frac{1}{4} + \frac{1}{8} \cdot x\right) + \frac{1}{2}}, 1\right)\right) \]

      4. accelerator-lowering-fma.f64 N/A

         \[\leadsto \mathsf{fma}\left(\frac{x \cdot \left(x \cdot \frac{1}{4}\right)}{\mathsf{fma}\left(\frac{1}{8}, x \cdot \left(x \cdot x\right), -1\right)}, \mathsf{fma}\left(x, \mathsf{fma}\left(x, \frac{1}{4}, \frac{1}{2}\right), 1\right), \mathsf{fma}\left(x, \color{blue}{\mathsf{fma}\left(x, \frac{1}{4} + \frac{1}{8} \cdot x, \frac{1}{2}\right)}, 1\right)\right) \]

      5. +-commutative N/A

         \[\leadsto \mathsf{fma}\left(\frac{x \cdot \left(x \cdot \frac{1}{4}\right)}{\mathsf{fma}\left(\frac{1}{8}, x \cdot \left(x \cdot x\right), -1\right)}, \mathsf{fma}\left(x, \mathsf{fma}\left(x, \frac{1}{4}, \frac{1}{2}\right), 1\right), \mathsf{fma}\left(x, \mathsf{fma}\left(x, \color{blue}{\frac{1}{8} \cdot x + \frac{1}{4}}, \frac{1}{2}\right), 1\right)\right) \]

      6. *-commutative N/A

         \[\leadsto \mathsf{fma}\left(\frac{x \cdot \left(x \cdot \frac{1}{4}\right)}{\mathsf{fma}\left(\frac{1}{8}, x \cdot \left(x \cdot x\right), -1\right)}, \mathsf{fma}\left(x, \mathsf{fma}\left(x, \frac{1}{4}, \frac{1}{2}\right), 1\right), \mathsf{fma}\left(x, \mathsf{fma}\left(x, \color{blue}{x \cdot \frac{1}{8}} + \frac{1}{4}, \frac{1}{2}\right), 1\right)\right) \]

      7. accelerator-lowering-fma.f64 13.0

         \[\leadsto \mathsf{fma}\left(\frac{x \cdot \left(x \cdot 0.25\right)}{\mathsf{fma}\left(0.125, x \cdot \left(x \cdot x\right), -1\right)}, \mathsf{fma}\left(x, \mathsf{fma}\left(x, 0.25, 0.5\right), 1\right), \mathsf{fma}\left(x, \mathsf{fma}\left(x, \color{blue}{\mathsf{fma}\left(x, 0.125, 0.25\right)}, 0.5\right), 1\right)\right) \]

   10. Simplified 13.0%

       \[\leadsto \mathsf{fma}\left(\frac{x \cdot \left(x \cdot 0.25\right)}{\mathsf{fma}\left(0.125, x \cdot \left(x \cdot x\right), -1\right)}, \mathsf{fma}\left(x, \mathsf{fma}\left(x, 0.25, 0.5\right), 1\right), \color{blue}{\mathsf{fma}\left(x, \mathsf{fma}\left(x, \mathsf{fma}\left(x, 0.125, 0.25\right), 0.5\right), 1\right)}\right) \]

   11. Taylor expanded in x around inf

       \[\leadsto \color{blue}{\frac{1}{8} \cdot {x}^{3}} \]
   12. Step-by-step derivation

       1. *-commutative N/A

          \[\leadsto \color{blue}{{x}^{3} \cdot \frac{1}{8}} \]

       2. *-lowering-*.f64 N/A

          \[\leadsto \color{blue}{{x}^{3} \cdot \frac{1}{8}} \]

       3. cube-mult N/A

          \[\leadsto \color{blue}{\left(x \cdot \left(x \cdot x\right)\right)} \cdot \frac{1}{8} \]

       4. unpow2 N/A

          \[\leadsto \left(x \cdot \color{blue}{{x}^{2}}\right) \cdot \frac{1}{8} \]

       5. *-lowering-*.f64 N/A

          \[\leadsto \color{blue}{\left(x \cdot {x}^{2}\right)} \cdot \frac{1}{8} \]

       6. unpow2 N/A

          \[\leadsto \left(x \cdot \color{blue}{\left(x \cdot x\right)}\right) \cdot \frac{1}{8} \]

       7. *-lowering-*.f64 76.3

          \[\leadsto \left(x \cdot \color{blue}{\left(x \cdot x\right)}\right) \cdot 0.125 \]

   13. Simplified 76.3%

       \[\leadsto \color{blue}{\left(x \cdot \left(x \cdot x\right)\right) \cdot 0.125} \]
3. Recombined 2 regimes into one program.

4. Final simplification 69.3%

   \[\leadsto \begin{array}{l} \mathbf{if}\;\frac{e^{x} + -1}{x} \leq 2:\\ \;\;\;\;1\\ \mathbf{else}:\\ \;\;\;\;\left(x \cdot \left(x \cdot x\right)\right) \cdot 0.125\\ \end{array} \]
5. Add Preprocessing

Alternative 6: 67.8% accurate, 0.8× speedup

Math

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\frac{e^{x} + -1}{x} \leq 2:\\ \;\;\;\;1\\ \mathbf{else}:\\ \;\;\;\;x \cdot \left(x \cdot \left(x \cdot 0.041666666666666664\right)\right)\\ \end{array} \end{array} \]

FPCore

(FPCore (x)
 :precision binary64
 (if (<= (/ (+ (exp x) -1.0) x) 2.0)
   1.0
   (* x (* x (* x 0.041666666666666664)))))

C

double code(double x) {
	double tmp;
	if (((exp(x) + -1.0) / x) <= 2.0) {
		tmp = 1.0;
	} else {
		tmp = x * (x * (x * 0.041666666666666664));
	}
	return tmp;
}

Fortran

real(8) function code(x)
    real(8), intent (in) :: x
    real(8) :: tmp
    if (((exp(x) + (-1.0d0)) / x) <= 2.0d0) then
        tmp = 1.0d0
    else
        tmp = x * (x * (x * 0.041666666666666664d0))
    end if
    code = tmp
end function

Java

public static double code(double x) {
	double tmp;
	if (((Math.exp(x) + -1.0) / x) <= 2.0) {
		tmp = 1.0;
	} else {
		tmp = x * (x * (x * 0.041666666666666664));
	}
	return tmp;
}

Python

def code(x):
	tmp = 0
	if ((math.exp(x) + -1.0) / x) <= 2.0:
		tmp = 1.0
	else:
		tmp = x * (x * (x * 0.041666666666666664))
	return tmp

Julia

function code(x)
	tmp = 0.0
	if (Float64(Float64(exp(x) + -1.0) / x) <= 2.0)
		tmp = 1.0;
	else
		tmp = Float64(x * Float64(x * Float64(x * 0.041666666666666664)));
	end
	return tmp
end

MATLAB

function tmp_2 = code(x)
	tmp = 0.0;
	if (((exp(x) + -1.0) / x) <= 2.0)
		tmp = 1.0;
	else
		tmp = x * (x * (x * 0.041666666666666664));
	end
	tmp_2 = tmp;
end

Wolfram

code[x_] := If[LessEqual[N[(N[(N[Exp[x], $MachinePrecision] + -1.0), $MachinePrecision] / x), $MachinePrecision], 2.0], 1.0, N[(x * N[(x * N[(x * 0.041666666666666664), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]

Derivation

1. Split input into 2 regimes

2. if (/.f64 (-.f64 (exp.f64 x) #s(literal 1 binary64)) x) < 2

   1. Initial program 37.2%

      \[\frac{e^{x} - 1}{x} \]
   2. Add Preprocessing

   3. Taylor expanded in x around 0

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

   5. Simplified 67.2%

      \[\leadsto \color{blue}{1} \]

   if 2 < (/.f64 (-.f64 (exp.f64 x) #s(literal 1 binary64)) x)

   1. Initial program 100.0%

      \[\frac{e^{x} - 1}{x} \]
   2. Add Preprocessing
   3. Step-by-step derivation

      1. accelerator-lowering-expm1.f64 100.0

         \[\leadsto \frac{\color{blue}{\mathsf{expm1}\left(x\right)}}{x} \]

   4. Applied egg-rr 100.0%

      \[\leadsto \frac{\color{blue}{\mathsf{expm1}\left(x\right)}}{x} \]

   5. Taylor expanded in x around 0

      \[\leadsto \frac{\color{blue}{x \cdot \left(1 + x \cdot \left(\frac{1}{2} + x \cdot \left(\frac{1}{6} + \frac{1}{24} \cdot x\right)\right)\right)}}{x} \]
   6. Step-by-step derivation

      1. *-lowering-*.f64 N/A

         \[\leadsto \frac{\color{blue}{x \cdot \left(1 + x \cdot \left(\frac{1}{2} + x \cdot \left(\frac{1}{6} + \frac{1}{24} \cdot x\right)\right)\right)}}{x} \]

      2. +-commutative N/A

         \[\leadsto \frac{x \cdot \color{blue}{\left(x \cdot \left(\frac{1}{2} + x \cdot \left(\frac{1}{6} + \frac{1}{24} \cdot x\right)\right) + 1\right)}}{x} \]

      3. accelerator-lowering-fma.f64 N/A

         \[\leadsto \frac{x \cdot \color{blue}{\mathsf{fma}\left(x, \frac{1}{2} + x \cdot \left(\frac{1}{6} + \frac{1}{24} \cdot x\right), 1\right)}}{x} \]

      4. +-commutative N/A

         \[\leadsto \frac{x \cdot \mathsf{fma}\left(x, \color{blue}{x \cdot \left(\frac{1}{6} + \frac{1}{24} \cdot x\right) + \frac{1}{2}}, 1\right)}{x} \]

      5. accelerator-lowering-fma.f64 N/A

         \[\leadsto \frac{x \cdot \mathsf{fma}\left(x, \color{blue}{\mathsf{fma}\left(x, \frac{1}{6} + \frac{1}{24} \cdot x, \frac{1}{2}\right)}, 1\right)}{x} \]

      6. +-commutative N/A

         \[\leadsto \frac{x \cdot \mathsf{fma}\left(x, \mathsf{fma}\left(x, \color{blue}{\frac{1}{24} \cdot x + \frac{1}{6}}, \frac{1}{2}\right), 1\right)}{x} \]

      7. *-commutative N/A

         \[\leadsto \frac{x \cdot \mathsf{fma}\left(x, \mathsf{fma}\left(x, \color{blue}{x \cdot \frac{1}{24}} + \frac{1}{6}, \frac{1}{2}\right), 1\right)}{x} \]

      8. accelerator-lowering-fma.f64 82.4

         \[\leadsto \frac{x \cdot \mathsf{fma}\left(x, \mathsf{fma}\left(x, \color{blue}{\mathsf{fma}\left(x, 0.041666666666666664, 0.16666666666666666\right)}, 0.5\right), 1\right)}{x} \]

   7. Simplified 82.4%

      \[\leadsto \frac{\color{blue}{x \cdot \mathsf{fma}\left(x, \mathsf{fma}\left(x, \mathsf{fma}\left(x, 0.041666666666666664, 0.16666666666666666\right), 0.5\right), 1\right)}}{x} \]

   8. Taylor expanded in x around inf

      \[\leadsto \color{blue}{\frac{1}{24} \cdot {x}^{3}} \]
   9. Step-by-step derivation

      1. unpow3 N/A

         \[\leadsto \frac{1}{24} \cdot \color{blue}{\left(\left(x \cdot x\right) \cdot x\right)} \]

      2. unpow2 N/A

         \[\leadsto \frac{1}{24} \cdot \left(\color{blue}{{x}^{2}} \cdot x\right) \]

      3. associate-*r* N/A

         \[\leadsto \color{blue}{\left(\frac{1}{24} \cdot {x}^{2}\right) \cdot x} \]

      4. *-commutative N/A

         \[\leadsto \color{blue}{x \cdot \left(\frac{1}{24} \cdot {x}^{2}\right)} \]

      5. *-lowering-*.f64 N/A

         \[\leadsto \color{blue}{x \cdot \left(\frac{1}{24} \cdot {x}^{2}\right)} \]

      6. unpow2 N/A

         \[\leadsto x \cdot \left(\frac{1}{24} \cdot \color{blue}{\left(x \cdot x\right)}\right) \]

      7. associate-*r* N/A

         \[\leadsto x \cdot \color{blue}{\left(\left(\frac{1}{24} \cdot x\right) \cdot x\right)} \]

      8. *-commutative N/A

         \[\leadsto x \cdot \color{blue}{\left(x \cdot \left(\frac{1}{24} \cdot x\right)\right)} \]

      9. *-lowering-*.f64 N/A

         \[\leadsto x \cdot \color{blue}{\left(x \cdot \left(\frac{1}{24} \cdot x\right)\right)} \]

      10. *-commutative N/A

          \[\leadsto x \cdot \left(x \cdot \color{blue}{\left(x \cdot \frac{1}{24}\right)}\right) \]

      11. *-lowering-*.f64 76.3

          \[\leadsto x \cdot \left(x \cdot \color{blue}{\left(x \cdot 0.041666666666666664\right)}\right) \]

   10. Simplified 76.3%

       \[\leadsto \color{blue}{x \cdot \left(x \cdot \left(x \cdot 0.041666666666666664\right)\right)} \]
3. Recombined 2 regimes into one program.

4. Final simplification 69.3%

   \[\leadsto \begin{array}{l} \mathbf{if}\;\frac{e^{x} + -1}{x} \leq 2:\\ \;\;\;\;1\\ \mathbf{else}:\\ \;\;\;\;x \cdot \left(x \cdot \left(x \cdot 0.041666666666666664\right)\right)\\ \end{array} \]
5. Add Preprocessing

Alternative 7: 63.6% accurate, 0.9× speedup

Math

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\frac{e^{x} + -1}{x} \leq 2:\\ \;\;\;\;1\\ \mathbf{else}:\\ \;\;\;\;x \cdot \mathsf{fma}\left(x, 0.16666666666666666, 0.5\right)\\ \end{array} \end{array} \]

FPCore

(FPCore (x)
 :precision binary64
 (if (<= (/ (+ (exp x) -1.0) x) 2.0)
   1.0
   (* x (fma x 0.16666666666666666 0.5))))

C

double code(double x) {
	double tmp;
	if (((exp(x) + -1.0) / x) <= 2.0) {
		tmp = 1.0;
	} else {
		tmp = x * fma(x, 0.16666666666666666, 0.5);
	}
	return tmp;
}

Julia

function code(x)
	tmp = 0.0
	if (Float64(Float64(exp(x) + -1.0) / x) <= 2.0)
		tmp = 1.0;
	else
		tmp = Float64(x * fma(x, 0.16666666666666666, 0.5));
	end
	return tmp
end

Wolfram

code[x_] := If[LessEqual[N[(N[(N[Exp[x], $MachinePrecision] + -1.0), $MachinePrecision] / x), $MachinePrecision], 2.0], 1.0, N[(x * N[(x * 0.16666666666666666 + 0.5), $MachinePrecision]), $MachinePrecision]]

Derivation

1. Split input into 2 regimes

2. if (/.f64 (-.f64 (exp.f64 x) #s(literal 1 binary64)) x) < 2

   1. Initial program 37.2%

      \[\frac{e^{x} - 1}{x} \]
   2. Add Preprocessing

   3. Taylor expanded in x around 0

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

   5. Simplified 67.2%

      \[\leadsto \color{blue}{1} \]

   if 2 < (/.f64 (-.f64 (exp.f64 x) #s(literal 1 binary64)) x)

   1. Initial program 100.0%

      \[\frac{e^{x} - 1}{x} \]
   2. Add Preprocessing

   3. Taylor expanded in x around 0

      \[\leadsto \color{blue}{1 + x \cdot \left(\frac{1}{2} + \frac{1}{6} \cdot x\right)} \]
   4. Step-by-step derivation

      1. +-commutative N/A

         \[\leadsto \color{blue}{x \cdot \left(\frac{1}{2} + \frac{1}{6} \cdot x\right) + 1} \]

      2. accelerator-lowering-fma.f64 N/A

         \[\leadsto \color{blue}{\mathsf{fma}\left(x, \frac{1}{2} + \frac{1}{6} \cdot x, 1\right)} \]

      3. +-commutative N/A

         \[\leadsto \mathsf{fma}\left(x, \color{blue}{\frac{1}{6} \cdot x + \frac{1}{2}}, 1\right) \]

      4. *-commutative N/A

         \[\leadsto \mathsf{fma}\left(x, \color{blue}{x \cdot \frac{1}{6}} + \frac{1}{2}, 1\right) \]

      5. accelerator-lowering-fma.f64 65.3

         \[\leadsto \mathsf{fma}\left(x, \color{blue}{\mathsf{fma}\left(x, 0.16666666666666666, 0.5\right)}, 1\right) \]

   5. Simplified 65.3%

      \[\leadsto \color{blue}{\mathsf{fma}\left(x, \mathsf{fma}\left(x, 0.16666666666666666, 0.5\right), 1\right)} \]

   6. Taylor expanded in x around inf

      \[\leadsto \color{blue}{{x}^{2} \cdot \left(\frac{1}{6} + \frac{1}{2} \cdot \frac{1}{x}\right)} \]
   7. Step-by-step derivation

      1. unpow2 N/A

         \[\leadsto \color{blue}{\left(x \cdot x\right)} \cdot \left(\frac{1}{6} + \frac{1}{2} \cdot \frac{1}{x}\right) \]

      2. associate-*l* N/A

         \[\leadsto \color{blue}{x \cdot \left(x \cdot \left(\frac{1}{6} + \frac{1}{2} \cdot \frac{1}{x}\right)\right)} \]

      3. +-commutative N/A

         \[\leadsto x \cdot \left(x \cdot \color{blue}{\left(\frac{1}{2} \cdot \frac{1}{x} + \frac{1}{6}\right)}\right) \]

      4. distribute-rgt-in N/A

         \[\leadsto x \cdot \color{blue}{\left(\left(\frac{1}{2} \cdot \frac{1}{x}\right) \cdot x + \frac{1}{6} \cdot x\right)} \]

      5. associate-*l* N/A

         \[\leadsto x \cdot \left(\color{blue}{\frac{1}{2} \cdot \left(\frac{1}{x} \cdot x\right)} + \frac{1}{6} \cdot x\right) \]

      6. lft-mult-inverse N/A

         \[\leadsto x \cdot \left(\frac{1}{2} \cdot \color{blue}{1} + \frac{1}{6} \cdot x\right) \]

      7. metadata-eval N/A

         \[\leadsto x \cdot \left(\color{blue}{\frac{1}{2}} + \frac{1}{6} \cdot x\right) \]

      8. *-lowering-*.f64 N/A

         \[\leadsto \color{blue}{x \cdot \left(\frac{1}{2} + \frac{1}{6} \cdot x\right)} \]

      9. +-commutative N/A

         \[\leadsto x \cdot \color{blue}{\left(\frac{1}{6} \cdot x + \frac{1}{2}\right)} \]

      10. *-commutative N/A

          \[\leadsto x \cdot \left(\color{blue}{x \cdot \frac{1}{6}} + \frac{1}{2}\right) \]

      11. accelerator-lowering-fma.f64 65.3

          \[\leadsto x \cdot \color{blue}{\mathsf{fma}\left(x, 0.16666666666666666, 0.5\right)} \]

   8. Simplified 65.3%

      \[\leadsto \color{blue}{x \cdot \mathsf{fma}\left(x, 0.16666666666666666, 0.5\right)} \]
3. Recombined 2 regimes into one program.

4. Final simplification 66.8%

   \[\leadsto \begin{array}{l} \mathbf{if}\;\frac{e^{x} + -1}{x} \leq 2:\\ \;\;\;\;1\\ \mathbf{else}:\\ \;\;\;\;x \cdot \mathsf{fma}\left(x, 0.16666666666666666, 0.5\right)\\ \end{array} \]
5. Add Preprocessing

Alternative 8: 63.6% accurate, 0.9× speedup

Math

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\frac{e^{x} + -1}{x} \leq 2:\\ \;\;\;\;1\\ \mathbf{else}:\\ \;\;\;\;x \cdot \left(x \cdot 0.16666666666666666\right)\\ \end{array} \end{array} \]

FPCore

(FPCore (x)
 :precision binary64
 (if (<= (/ (+ (exp x) -1.0) x) 2.0) 1.0 (* x (* x 0.16666666666666666))))

C

double code(double x) {
	double tmp;
	if (((exp(x) + -1.0) / x) <= 2.0) {
		tmp = 1.0;
	} else {
		tmp = x * (x * 0.16666666666666666);
	}
	return tmp;
}

Fortran

real(8) function code(x)
    real(8), intent (in) :: x
    real(8) :: tmp
    if (((exp(x) + (-1.0d0)) / x) <= 2.0d0) then
        tmp = 1.0d0
    else
        tmp = x * (x * 0.16666666666666666d0)
    end if
    code = tmp
end function

Java

public static double code(double x) {
	double tmp;
	if (((Math.exp(x) + -1.0) / x) <= 2.0) {
		tmp = 1.0;
	} else {
		tmp = x * (x * 0.16666666666666666);
	}
	return tmp;
}

Python

def code(x):
	tmp = 0
	if ((math.exp(x) + -1.0) / x) <= 2.0:
		tmp = 1.0
	else:
		tmp = x * (x * 0.16666666666666666)
	return tmp

Julia

function code(x)
	tmp = 0.0
	if (Float64(Float64(exp(x) + -1.0) / x) <= 2.0)
		tmp = 1.0;
	else
		tmp = Float64(x * Float64(x * 0.16666666666666666));
	end
	return tmp
end

MATLAB

function tmp_2 = code(x)
	tmp = 0.0;
	if (((exp(x) + -1.0) / x) <= 2.0)
		tmp = 1.0;
	else
		tmp = x * (x * 0.16666666666666666);
	end
	tmp_2 = tmp;
end

Wolfram

code[x_] := If[LessEqual[N[(N[(N[Exp[x], $MachinePrecision] + -1.0), $MachinePrecision] / x), $MachinePrecision], 2.0], 1.0, N[(x * N[(x * 0.16666666666666666), $MachinePrecision]), $MachinePrecision]]

Derivation

1. Split input into 2 regimes

2. if (/.f64 (-.f64 (exp.f64 x) #s(literal 1 binary64)) x) < 2

   1. Initial program 37.2%

      \[\frac{e^{x} - 1}{x} \]
   2. Add Preprocessing

   3. Taylor expanded in x around 0

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

   5. Simplified 67.2%

      \[\leadsto \color{blue}{1} \]

   if 2 < (/.f64 (-.f64 (exp.f64 x) #s(literal 1 binary64)) x)

   1. Initial program 100.0%

      \[\frac{e^{x} - 1}{x} \]
   2. Add Preprocessing

   3. Taylor expanded in x around 0

      \[\leadsto \color{blue}{1 + x \cdot \left(\frac{1}{2} + \frac{1}{6} \cdot x\right)} \]
   4. Step-by-step derivation

      1. +-commutative N/A

         \[\leadsto \color{blue}{x \cdot \left(\frac{1}{2} + \frac{1}{6} \cdot x\right) + 1} \]

      2. accelerator-lowering-fma.f64 N/A

         \[\leadsto \color{blue}{\mathsf{fma}\left(x, \frac{1}{2} + \frac{1}{6} \cdot x, 1\right)} \]

      3. +-commutative N/A

         \[\leadsto \mathsf{fma}\left(x, \color{blue}{\frac{1}{6} \cdot x + \frac{1}{2}}, 1\right) \]

      4. *-commutative N/A

         \[\leadsto \mathsf{fma}\left(x, \color{blue}{x \cdot \frac{1}{6}} + \frac{1}{2}, 1\right) \]

      5. accelerator-lowering-fma.f64 65.3

         \[\leadsto \mathsf{fma}\left(x, \color{blue}{\mathsf{fma}\left(x, 0.16666666666666666, 0.5\right)}, 1\right) \]

   5. Simplified 65.3%

      \[\leadsto \color{blue}{\mathsf{fma}\left(x, \mathsf{fma}\left(x, 0.16666666666666666, 0.5\right), 1\right)} \]

   6. Taylor expanded in x around inf

      \[\leadsto \color{blue}{\frac{1}{6} \cdot {x}^{2}} \]
   7. Step-by-step derivation

      1. unpow2 N/A

         \[\leadsto \frac{1}{6} \cdot \color{blue}{\left(x \cdot x\right)} \]

      2. associate-*r* N/A

         \[\leadsto \color{blue}{\left(\frac{1}{6} \cdot x\right) \cdot x} \]

      3. *-commutative N/A

         \[\leadsto \color{blue}{x \cdot \left(\frac{1}{6} \cdot x\right)} \]

      4. *-lowering-*.f64 N/A

         \[\leadsto \color{blue}{x \cdot \left(\frac{1}{6} \cdot x\right)} \]

      5. *-commutative N/A

         \[\leadsto x \cdot \color{blue}{\left(x \cdot \frac{1}{6}\right)} \]

      6. *-lowering-*.f64 65.3

         \[\leadsto x \cdot \color{blue}{\left(x \cdot 0.16666666666666666\right)} \]

   8. Simplified 65.3%

      \[\leadsto \color{blue}{x \cdot \left(x \cdot 0.16666666666666666\right)} \]
3. Recombined 2 regimes into one program.

4. Final simplification 66.8%

   \[\leadsto \begin{array}{l} \mathbf{if}\;\frac{e^{x} + -1}{x} \leq 2:\\ \;\;\;\;1\\ \mathbf{else}:\\ \;\;\;\;x \cdot \left(x \cdot 0.16666666666666666\right)\\ \end{array} \]
5. Add Preprocessing

Alternative 9: 69.8% accurate, 3.3× speedup

Math

\[\begin{array}{l} \\ \frac{x \cdot \mathsf{fma}\left(x, \mathsf{fma}\left(x, \mathsf{fma}\left(x, 0.041666666666666664, 0.16666666666666666\right), 0.5\right), 1\right)}{x} \end{array} \]

FPCore

(FPCore (x)
 :precision binary64
 (/
  (*
   x
   (fma x (fma x (fma x 0.041666666666666664 0.16666666666666666) 0.5) 1.0))
  x))

C

double code(double x) {
	return (x * fma(x, fma(x, fma(x, 0.041666666666666664, 0.16666666666666666), 0.5), 1.0)) / x;
}

Julia

function code(x)
	return Float64(Float64(x * fma(x, fma(x, fma(x, 0.041666666666666664, 0.16666666666666666), 0.5), 1.0)) / x)
end

Wolfram

code[x_] := N[(N[(x * N[(x * N[(x * N[(x * 0.041666666666666664 + 0.16666666666666666), $MachinePrecision] + 0.5), $MachinePrecision] + 1.0), $MachinePrecision]), $MachinePrecision] / x), $MachinePrecision]

Derivation

1. Initial program 51.9%

   \[\frac{e^{x} - 1}{x} \]
2. Add Preprocessing
3. Step-by-step derivation

   1. accelerator-lowering-expm1.f64 100.0

      \[\leadsto \frac{\color{blue}{\mathsf{expm1}\left(x\right)}}{x} \]

4. Applied egg-rr 100.0%

   \[\leadsto \frac{\color{blue}{\mathsf{expm1}\left(x\right)}}{x} \]

5. Taylor expanded in x around 0

   \[\leadsto \frac{\color{blue}{x \cdot \left(1 + x \cdot \left(\frac{1}{2} + x \cdot \left(\frac{1}{6} + \frac{1}{24} \cdot x\right)\right)\right)}}{x} \]
6. Step-by-step derivation

   1. *-lowering-*.f64 N/A

      \[\leadsto \frac{\color{blue}{x \cdot \left(1 + x \cdot \left(\frac{1}{2} + x \cdot \left(\frac{1}{6} + \frac{1}{24} \cdot x\right)\right)\right)}}{x} \]

   2. +-commutative N/A

      \[\leadsto \frac{x \cdot \color{blue}{\left(x \cdot \left(\frac{1}{2} + x \cdot \left(\frac{1}{6} + \frac{1}{24} \cdot x\right)\right) + 1\right)}}{x} \]

   3. accelerator-lowering-fma.f64 N/A

      \[\leadsto \frac{x \cdot \color{blue}{\mathsf{fma}\left(x, \frac{1}{2} + x \cdot \left(\frac{1}{6} + \frac{1}{24} \cdot x\right), 1\right)}}{x} \]

   4. +-commutative N/A

      \[\leadsto \frac{x \cdot \mathsf{fma}\left(x, \color{blue}{x \cdot \left(\frac{1}{6} + \frac{1}{24} \cdot x\right) + \frac{1}{2}}, 1\right)}{x} \]

   5. accelerator-lowering-fma.f64 N/A

      \[\leadsto \frac{x \cdot \mathsf{fma}\left(x, \color{blue}{\mathsf{fma}\left(x, \frac{1}{6} + \frac{1}{24} \cdot x, \frac{1}{2}\right)}, 1\right)}{x} \]

   6. +-commutative N/A

      \[\leadsto \frac{x \cdot \mathsf{fma}\left(x, \mathsf{fma}\left(x, \color{blue}{\frac{1}{24} \cdot x + \frac{1}{6}}, \frac{1}{2}\right), 1\right)}{x} \]

   7. *-commutative N/A

      \[\leadsto \frac{x \cdot \mathsf{fma}\left(x, \mathsf{fma}\left(x, \color{blue}{x \cdot \frac{1}{24}} + \frac{1}{6}, \frac{1}{2}\right), 1\right)}{x} \]

   8. accelerator-lowering-fma.f64 70.1

      \[\leadsto \frac{x \cdot \mathsf{fma}\left(x, \mathsf{fma}\left(x, \color{blue}{\mathsf{fma}\left(x, 0.041666666666666664, 0.16666666666666666\right)}, 0.5\right), 1\right)}{x} \]

7. Simplified 70.1%

   \[\leadsto \frac{\color{blue}{x \cdot \mathsf{fma}\left(x, \mathsf{fma}\left(x, \mathsf{fma}\left(x, 0.041666666666666664, 0.16666666666666666\right), 0.5\right), 1\right)}}{x} \]
8. Add Preprocessing

Alternative 10: 67.7% accurate, 6.1× speedup

Math

\[\begin{array}{l} \\ \mathsf{fma}\left(x, \mathsf{fma}\left(x, \mathsf{fma}\left(x, 0.041666666666666664, 0.16666666666666666\right), 0.5\right), 1\right) \end{array} \]

FPCore

(FPCore (x)
 :precision binary64
 (fma x (fma x (fma x 0.041666666666666664 0.16666666666666666) 0.5) 1.0))

C

double code(double x) {
	return fma(x, fma(x, fma(x, 0.041666666666666664, 0.16666666666666666), 0.5), 1.0);
}

Julia

function code(x)
	return fma(x, fma(x, fma(x, 0.041666666666666664, 0.16666666666666666), 0.5), 1.0)
end

Wolfram

code[x_] := N[(x * N[(x * N[(x * 0.041666666666666664 + 0.16666666666666666), $MachinePrecision] + 0.5), $MachinePrecision] + 1.0), $MachinePrecision]

Derivation

1. Initial program 51.9%

   \[\frac{e^{x} - 1}{x} \]
2. Add Preprocessing

3. Taylor expanded in x around 0

   \[\leadsto \color{blue}{1 + x \cdot \left(\frac{1}{2} + x \cdot \left(\frac{1}{6} + \frac{1}{24} \cdot x\right)\right)} \]
4. Step-by-step derivation

   1. +-commutative N/A

      \[\leadsto \color{blue}{x \cdot \left(\frac{1}{2} + x \cdot \left(\frac{1}{6} + \frac{1}{24} \cdot x\right)\right) + 1} \]

   2. accelerator-lowering-fma.f64 N/A

      \[\leadsto \color{blue}{\mathsf{fma}\left(x, \frac{1}{2} + x \cdot \left(\frac{1}{6} + \frac{1}{24} \cdot x\right), 1\right)} \]

   3. +-commutative N/A

      \[\leadsto \mathsf{fma}\left(x, \color{blue}{x \cdot \left(\frac{1}{6} + \frac{1}{24} \cdot x\right) + \frac{1}{2}}, 1\right) \]

   4. accelerator-lowering-fma.f64 N/A

      \[\leadsto \mathsf{fma}\left(x, \color{blue}{\mathsf{fma}\left(x, \frac{1}{6} + \frac{1}{24} \cdot x, \frac{1}{2}\right)}, 1\right) \]

   5. +-commutative N/A

      \[\leadsto \mathsf{fma}\left(x, \mathsf{fma}\left(x, \color{blue}{\frac{1}{24} \cdot x + \frac{1}{6}}, \frac{1}{2}\right), 1\right) \]

   6. *-commutative N/A

      \[\leadsto \mathsf{fma}\left(x, \mathsf{fma}\left(x, \color{blue}{x \cdot \frac{1}{24}} + \frac{1}{6}, \frac{1}{2}\right), 1\right) \]

   7. accelerator-lowering-fma.f64 68.7

      \[\leadsto \mathsf{fma}\left(x, \mathsf{fma}\left(x, \color{blue}{\mathsf{fma}\left(x, 0.041666666666666664, 0.16666666666666666\right)}, 0.5\right), 1\right) \]

5. Simplified 68.7%

   \[\leadsto \color{blue}{\mathsf{fma}\left(x, \mathsf{fma}\left(x, \mathsf{fma}\left(x, 0.041666666666666664, 0.16666666666666666\right), 0.5\right), 1\right)} \]
6. Add Preprocessing

Alternative 11: 63.9% accurate, 8.8× speedup

Math

\[\begin{array}{l} \\ \mathsf{fma}\left(x, \mathsf{fma}\left(x, 0.16666666666666666, 0.5\right), 1\right) \end{array} \]

FPCore

(FPCore (x) :precision binary64 (fma x (fma x 0.16666666666666666 0.5) 1.0))

C

double code(double x) {
	return fma(x, fma(x, 0.16666666666666666, 0.5), 1.0);
}

Julia

function code(x)
	return fma(x, fma(x, 0.16666666666666666, 0.5), 1.0)
end

Wolfram

code[x_] := N[(x * N[(x * 0.16666666666666666 + 0.5), $MachinePrecision] + 1.0), $MachinePrecision]

Derivation

1. Initial program 51.9%

   \[\frac{e^{x} - 1}{x} \]
2. Add Preprocessing

3. Taylor expanded in x around 0

   \[\leadsto \color{blue}{1 + x \cdot \left(\frac{1}{2} + \frac{1}{6} \cdot x\right)} \]
4. Step-by-step derivation

   1. +-commutative N/A

      \[\leadsto \color{blue}{x \cdot \left(\frac{1}{2} + \frac{1}{6} \cdot x\right) + 1} \]

   2. accelerator-lowering-fma.f64 N/A

      \[\leadsto \color{blue}{\mathsf{fma}\left(x, \frac{1}{2} + \frac{1}{6} \cdot x, 1\right)} \]

   3. +-commutative N/A

      \[\leadsto \mathsf{fma}\left(x, \color{blue}{\frac{1}{6} \cdot x + \frac{1}{2}}, 1\right) \]

   4. *-commutative N/A

      \[\leadsto \mathsf{fma}\left(x, \color{blue}{x \cdot \frac{1}{6}} + \frac{1}{2}, 1\right) \]

   5. accelerator-lowering-fma.f64 66.7

      \[\leadsto \mathsf{fma}\left(x, \color{blue}{\mathsf{fma}\left(x, 0.16666666666666666, 0.5\right)}, 1\right) \]

5. Simplified 66.7%

   \[\leadsto \color{blue}{\mathsf{fma}\left(x, \mathsf{fma}\left(x, 0.16666666666666666, 0.5\right), 1\right)} \]
6. Add Preprocessing

Alternative 12: 51.2% accurate, 115.0× speedup

Math

\[\begin{array}{l} \\ 1 \end{array} \]

FPCore

(FPCore (x) :precision binary64 1.0)

C

double code(double x) {
	return 1.0;
}

Fortran

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

Java

public static double code(double x) {
	return 1.0;
}

Python

def code(x):
	return 1.0

Julia

function code(x)
	return 1.0
end

MATLAB

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

Wolfram

code[x_] := 1.0

Derivation

1. Initial program 51.9%

   \[\frac{e^{x} - 1}{x} \]
2. Add Preprocessing

3. Taylor expanded in x around 0

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

5. Simplified 52.2%

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

Alternative 13: 3.3% accurate, 115.0× speedup

Math

\[\begin{array}{l} \\ 0 \end{array} \]

FPCore

(FPCore (x) :precision binary64 0.0)

C

double code(double x) {
	return 0.0;
}

Fortran

real(8) function code(x)
    real(8), intent (in) :: x
    code = 0.0d0
end function

Java

public static double code(double x) {
	return 0.0;
}

Python

def code(x):
	return 0.0

Julia

function code(x)
	return 0.0
end

MATLAB

function tmp = code(x)
	tmp = 0.0;
end

Wolfram

code[x_] := 0.0

Derivation

1. Initial program 51.9%

   \[\frac{e^{x} - 1}{x} \]
2. Add Preprocessing

3. Taylor expanded in x around 0

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

5. Simplified 3.3%

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

   1. metadata-eval N/A

      \[\leadsto \frac{\color{blue}{0}}{x} \]

   2. div0 3.3

      \[\leadsto \color{blue}{0} \]

7. Applied egg-rr 3.3%

   \[\leadsto \color{blue}{0} \]
8. Add Preprocessing

Developer Target 1: 52.8% accurate, 0.4× speedup

Math

\[\begin{array}{l} \\ \begin{array}{l} t_0 := e^{x} - 1\\ \mathbf{if}\;x < 1 \land x > -1:\\ \;\;\;\;\frac{t\_0}{\log \left(e^{x}\right)}\\ \mathbf{else}:\\ \;\;\;\;\frac{t\_0}{x}\\ \end{array} \end{array} \]

FPCore

(FPCore (x)
 :precision binary64
 (let* ((t_0 (- (exp x) 1.0)))
   (if (and (< x 1.0) (> x -1.0)) (/ t_0 (log (exp x))) (/ t_0 x))))

C

double code(double x) {
	double t_0 = exp(x) - 1.0;
	double tmp;
	if ((x < 1.0) && (x > -1.0)) {
		tmp = t_0 / log(exp(x));
	} else {
		tmp = t_0 / x;
	}
	return tmp;
}

Fortran

real(8) function code(x)
    real(8), intent (in) :: x
    real(8) :: t_0
    real(8) :: tmp
    t_0 = exp(x) - 1.0d0
    if ((x < 1.0d0) .and. (x > (-1.0d0))) then
        tmp = t_0 / log(exp(x))
    else
        tmp = t_0 / x
    end if
    code = tmp
end function

Java

public static double code(double x) {
	double t_0 = Math.exp(x) - 1.0;
	double tmp;
	if ((x < 1.0) && (x > -1.0)) {
		tmp = t_0 / Math.log(Math.exp(x));
	} else {
		tmp = t_0 / x;
	}
	return tmp;
}

Python

def code(x):
	t_0 = math.exp(x) - 1.0
	tmp = 0
	if (x < 1.0) and (x > -1.0):
		tmp = t_0 / math.log(math.exp(x))
	else:
		tmp = t_0 / x
	return tmp

Julia

function code(x)
	t_0 = Float64(exp(x) - 1.0)
	tmp = 0.0
	if ((x < 1.0) && (x > -1.0))
		tmp = Float64(t_0 / log(exp(x)));
	else
		tmp = Float64(t_0 / x);
	end
	return tmp
end

MATLAB

function tmp_2 = code(x)
	t_0 = exp(x) - 1.0;
	tmp = 0.0;
	if ((x < 1.0) && (x > -1.0))
		tmp = t_0 / log(exp(x));
	else
		tmp = t_0 / x;
	end
	tmp_2 = tmp;
end

Wolfram

code[x_] := Block[{t$95$0 = N[(N[Exp[x], $MachinePrecision] - 1.0), $MachinePrecision]}, If[And[Less[x, 1.0], Greater[x, -1.0]], N[(t$95$0 / N[Log[N[Exp[x], $MachinePrecision]], $MachinePrecision]), $MachinePrecision], N[(t$95$0 / x), $MachinePrecision]]]

Reproduce

herbie shell --seed 2024199 
(FPCore (x)
  :name "Kahan's exp quotient"
  :precision binary64

  :alt
  (! :herbie-platform default (if (and (< x 1) (> x -1)) (/ (- (exp x) 1) (log (exp x))) (/ (- (exp x) 1) x)))

  (/ (- (exp x) 1.0) x))