Hyperbolic secant

Percentage Accurate: 100.0% → 100.0%
Time: 4.2s
Alternatives: 8
Speedup: 1.1×

Specification

?
\[\begin{array}{l} \\ \frac{2}{e^{x} + e^{-x}} \end{array} \]
(FPCore (x) :precision binary64 (/ 2.0 (+ (exp x) (exp (- x)))))
double code(double x) {
	return 2.0 / (exp(x) + exp(-x));
}
module fmin_fmax_functions
    implicit none
    private
    public fmax
    public fmin

    interface fmax
        module procedure fmax88
        module procedure fmax44
        module procedure fmax84
        module procedure fmax48
    end interface
    interface fmin
        module procedure fmin88
        module procedure fmin44
        module procedure fmin84
        module procedure fmin48
    end interface
contains
    real(8) function fmax88(x, y) result (res)
        real(8), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(x, max(x, y), y /= y), x /= x)
    end function
    real(4) function fmax44(x, y) result (res)
        real(4), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(y, merge(x, max(x, y), y /= y), x /= x)
    end function
    real(8) function fmax84(x, y) result(res)
        real(8), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(dble(y), merge(x, max(x, dble(y)), y /= y), x /= x)
    end function
    real(8) function fmax48(x, y) result(res)
        real(4), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(dble(x), max(dble(x), y), y /= y), x /= x)
    end function
    real(8) function fmin88(x, y) result (res)
        real(8), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(x, min(x, y), y /= y), x /= x)
    end function
    real(4) function fmin44(x, y) result (res)
        real(4), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(y, merge(x, min(x, y), y /= y), x /= x)
    end function
    real(8) function fmin84(x, y) result(res)
        real(8), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(dble(y), merge(x, min(x, dble(y)), y /= y), x /= x)
    end function
    real(8) function fmin48(x, y) result(res)
        real(4), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(dble(x), min(dble(x), y), y /= y), x /= x)
    end function
end module

real(8) function code(x)
use fmin_fmax_functions
    real(8), intent (in) :: x
    code = 2.0d0 / (exp(x) + exp(-x))
end function
public static double code(double x) {
	return 2.0 / (Math.exp(x) + Math.exp(-x));
}
def code(x):
	return 2.0 / (math.exp(x) + math.exp(-x))
function code(x)
	return Float64(2.0 / Float64(exp(x) + exp(Float64(-x))))
end
function tmp = code(x)
	tmp = 2.0 / (exp(x) + exp(-x));
end
code[x_] := N[(2.0 / N[(N[Exp[x], $MachinePrecision] + N[Exp[(-x)], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{2}{e^{x} + e^{-x}}
\end{array}

Sampling outcomes in binary64 precision:

Local Percentage Accuracy vs ?

The average percentage accuracy by input value. Horizontal axis shows value of an input variable; the variable is choosen in the title. Vertical axis is accuracy; higher is better. Red represent the original program, while blue represents Herbie's suggestion. These can be toggled with buttons below the plot. The line is an average while dots represent individual samples.

Accuracy vs Speed?

Herbie found 8 alternatives:

AlternativeAccuracySpeedup
The accuracy (vertical axis) and speed (horizontal axis) of each alternatives. Up and to the right is better. The red square shows the initial program, and each blue circle shows an alternative.The line shows the best available speed-accuracy tradeoffs.

Initial Program: 100.0% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \frac{2}{e^{x} + e^{-x}} \end{array} \]
(FPCore (x) :precision binary64 (/ 2.0 (+ (exp x) (exp (- x)))))
double code(double x) {
	return 2.0 / (exp(x) + exp(-x));
}
module fmin_fmax_functions
    implicit none
    private
    public fmax
    public fmin

    interface fmax
        module procedure fmax88
        module procedure fmax44
        module procedure fmax84
        module procedure fmax48
    end interface
    interface fmin
        module procedure fmin88
        module procedure fmin44
        module procedure fmin84
        module procedure fmin48
    end interface
contains
    real(8) function fmax88(x, y) result (res)
        real(8), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(x, max(x, y), y /= y), x /= x)
    end function
    real(4) function fmax44(x, y) result (res)
        real(4), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(y, merge(x, max(x, y), y /= y), x /= x)
    end function
    real(8) function fmax84(x, y) result(res)
        real(8), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(dble(y), merge(x, max(x, dble(y)), y /= y), x /= x)
    end function
    real(8) function fmax48(x, y) result(res)
        real(4), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(dble(x), max(dble(x), y), y /= y), x /= x)
    end function
    real(8) function fmin88(x, y) result (res)
        real(8), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(x, min(x, y), y /= y), x /= x)
    end function
    real(4) function fmin44(x, y) result (res)
        real(4), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(y, merge(x, min(x, y), y /= y), x /= x)
    end function
    real(8) function fmin84(x, y) result(res)
        real(8), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(dble(y), merge(x, min(x, dble(y)), y /= y), x /= x)
    end function
    real(8) function fmin48(x, y) result(res)
        real(4), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(dble(x), min(dble(x), y), y /= y), x /= x)
    end function
end module

real(8) function code(x)
use fmin_fmax_functions
    real(8), intent (in) :: x
    code = 2.0d0 / (exp(x) + exp(-x))
end function
public static double code(double x) {
	return 2.0 / (Math.exp(x) + Math.exp(-x));
}
def code(x):
	return 2.0 / (math.exp(x) + math.exp(-x))
function code(x)
	return Float64(2.0 / Float64(exp(x) + exp(Float64(-x))))
end
function tmp = code(x)
	tmp = 2.0 / (exp(x) + exp(-x));
end
code[x_] := N[(2.0 / N[(N[Exp[x], $MachinePrecision] + N[Exp[(-x)], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{2}{e^{x} + e^{-x}}
\end{array}

Alternative 1: 100.0% accurate, 0.7× speedup?

\[\begin{array}{l} x_m = \left|x\right| \\ \begin{array}{l} t_0 := e^{-x\_m}\\ \frac{2}{{t\_0}^{-1} + t\_0} \end{array} \end{array} \]
x_m = (fabs.f64 x)
(FPCore (x_m)
 :precision binary64
 (let* ((t_0 (exp (- x_m)))) (/ 2.0 (+ (pow t_0 -1.0) t_0))))
x_m = fabs(x);
double code(double x_m) {
	double t_0 = exp(-x_m);
	return 2.0 / (pow(t_0, -1.0) + t_0);
}
x_m =     private
module fmin_fmax_functions
    implicit none
    private
    public fmax
    public fmin

    interface fmax
        module procedure fmax88
        module procedure fmax44
        module procedure fmax84
        module procedure fmax48
    end interface
    interface fmin
        module procedure fmin88
        module procedure fmin44
        module procedure fmin84
        module procedure fmin48
    end interface
contains
    real(8) function fmax88(x, y) result (res)
        real(8), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(x, max(x, y), y /= y), x /= x)
    end function
    real(4) function fmax44(x, y) result (res)
        real(4), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(y, merge(x, max(x, y), y /= y), x /= x)
    end function
    real(8) function fmax84(x, y) result(res)
        real(8), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(dble(y), merge(x, max(x, dble(y)), y /= y), x /= x)
    end function
    real(8) function fmax48(x, y) result(res)
        real(4), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(dble(x), max(dble(x), y), y /= y), x /= x)
    end function
    real(8) function fmin88(x, y) result (res)
        real(8), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(x, min(x, y), y /= y), x /= x)
    end function
    real(4) function fmin44(x, y) result (res)
        real(4), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(y, merge(x, min(x, y), y /= y), x /= x)
    end function
    real(8) function fmin84(x, y) result(res)
        real(8), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(dble(y), merge(x, min(x, dble(y)), y /= y), x /= x)
    end function
    real(8) function fmin48(x, y) result(res)
        real(4), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(dble(x), min(dble(x), y), y /= y), x /= x)
    end function
end module

real(8) function code(x_m)
use fmin_fmax_functions
    real(8), intent (in) :: x_m
    real(8) :: t_0
    t_0 = exp(-x_m)
    code = 2.0d0 / ((t_0 ** (-1.0d0)) + t_0)
end function
x_m = Math.abs(x);
public static double code(double x_m) {
	double t_0 = Math.exp(-x_m);
	return 2.0 / (Math.pow(t_0, -1.0) + t_0);
}
x_m = math.fabs(x)
def code(x_m):
	t_0 = math.exp(-x_m)
	return 2.0 / (math.pow(t_0, -1.0) + t_0)
x_m = abs(x)
function code(x_m)
	t_0 = exp(Float64(-x_m))
	return Float64(2.0 / Float64((t_0 ^ -1.0) + t_0))
end
x_m = abs(x);
function tmp = code(x_m)
	t_0 = exp(-x_m);
	tmp = 2.0 / ((t_0 ^ -1.0) + t_0);
end
x_m = N[Abs[x], $MachinePrecision]
code[x$95$m_] := Block[{t$95$0 = N[Exp[(-x$95$m)], $MachinePrecision]}, N[(2.0 / N[(N[Power[t$95$0, -1.0], $MachinePrecision] + t$95$0), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
x_m = \left|x\right|

\\
\begin{array}{l}
t_0 := e^{-x\_m}\\
\frac{2}{{t\_0}^{-1} + t\_0}
\end{array}
\end{array}
Derivation
  1. Initial program 100.0%

    \[\frac{2}{e^{x} + e^{-x}} \]
  2. Add Preprocessing
  3. Step-by-step derivation
    1. remove-double-divN/A

      \[\leadsto \frac{2}{\color{blue}{\frac{1}{\frac{1}{e^{x}}}} + e^{-x}} \]
    2. lift-exp.f64N/A

      \[\leadsto \frac{2}{\frac{1}{\frac{1}{\color{blue}{e^{x}}}} + e^{-x}} \]
    3. exp-negN/A

      \[\leadsto \frac{2}{\frac{1}{\color{blue}{e^{\mathsf{neg}\left(x\right)}}} + e^{-x}} \]
    4. lift-neg.f64N/A

      \[\leadsto \frac{2}{\frac{1}{e^{\color{blue}{-x}}} + e^{-x}} \]
    5. lift-exp.f64N/A

      \[\leadsto \frac{2}{\frac{1}{\color{blue}{e^{-x}}} + e^{-x}} \]
    6. lower-/.f64100.0

      \[\leadsto \frac{2}{\color{blue}{\frac{1}{e^{-x}}} + e^{-x}} \]
  4. Applied rewrites100.0%

    \[\leadsto \frac{2}{\color{blue}{\frac{1}{e^{-x}}} + e^{-x}} \]
  5. Final simplification100.0%

    \[\leadsto \frac{2}{{\left(e^{-x}\right)}^{-1} + e^{-x}} \]
  6. Add Preprocessing

Alternative 2: 100.0% accurate, 1.1× speedup?

\[\begin{array}{l} x_m = \left|x\right| \\ {\cosh x\_m}^{-1} \end{array} \]
x_m = (fabs.f64 x)
(FPCore (x_m) :precision binary64 (pow (cosh x_m) -1.0))
x_m = fabs(x);
double code(double x_m) {
	return pow(cosh(x_m), -1.0);
}
x_m =     private
module fmin_fmax_functions
    implicit none
    private
    public fmax
    public fmin

    interface fmax
        module procedure fmax88
        module procedure fmax44
        module procedure fmax84
        module procedure fmax48
    end interface
    interface fmin
        module procedure fmin88
        module procedure fmin44
        module procedure fmin84
        module procedure fmin48
    end interface
contains
    real(8) function fmax88(x, y) result (res)
        real(8), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(x, max(x, y), y /= y), x /= x)
    end function
    real(4) function fmax44(x, y) result (res)
        real(4), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(y, merge(x, max(x, y), y /= y), x /= x)
    end function
    real(8) function fmax84(x, y) result(res)
        real(8), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(dble(y), merge(x, max(x, dble(y)), y /= y), x /= x)
    end function
    real(8) function fmax48(x, y) result(res)
        real(4), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(dble(x), max(dble(x), y), y /= y), x /= x)
    end function
    real(8) function fmin88(x, y) result (res)
        real(8), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(x, min(x, y), y /= y), x /= x)
    end function
    real(4) function fmin44(x, y) result (res)
        real(4), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(y, merge(x, min(x, y), y /= y), x /= x)
    end function
    real(8) function fmin84(x, y) result(res)
        real(8), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(dble(y), merge(x, min(x, dble(y)), y /= y), x /= x)
    end function
    real(8) function fmin48(x, y) result(res)
        real(4), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(dble(x), min(dble(x), y), y /= y), x /= x)
    end function
end module

real(8) function code(x_m)
use fmin_fmax_functions
    real(8), intent (in) :: x_m
    code = cosh(x_m) ** (-1.0d0)
end function
x_m = Math.abs(x);
public static double code(double x_m) {
	return Math.pow(Math.cosh(x_m), -1.0);
}
x_m = math.fabs(x)
def code(x_m):
	return math.pow(math.cosh(x_m), -1.0)
x_m = abs(x)
function code(x_m)
	return cosh(x_m) ^ -1.0
end
x_m = abs(x);
function tmp = code(x_m)
	tmp = cosh(x_m) ^ -1.0;
end
x_m = N[Abs[x], $MachinePrecision]
code[x$95$m_] := N[Power[N[Cosh[x$95$m], $MachinePrecision], -1.0], $MachinePrecision]
\begin{array}{l}
x_m = \left|x\right|

\\
{\cosh x\_m}^{-1}
\end{array}
Derivation
  1. Initial program 100.0%

    \[\frac{2}{e^{x} + e^{-x}} \]
  2. Add Preprocessing
  3. Step-by-step derivation
    1. lift-/.f64N/A

      \[\leadsto \color{blue}{\frac{2}{e^{x} + e^{-x}}} \]
    2. lift-+.f64N/A

      \[\leadsto \frac{2}{\color{blue}{e^{x} + e^{-x}}} \]
    3. lift-exp.f64N/A

      \[\leadsto \frac{2}{\color{blue}{e^{x}} + e^{-x}} \]
    4. lift-exp.f64N/A

      \[\leadsto \frac{2}{e^{x} + \color{blue}{e^{-x}}} \]
    5. lift-neg.f64N/A

      \[\leadsto \frac{2}{e^{x} + e^{\color{blue}{\mathsf{neg}\left(x\right)}}} \]
    6. cosh-undefN/A

      \[\leadsto \frac{2}{\color{blue}{2 \cdot \cosh x}} \]
    7. associate-/r*N/A

      \[\leadsto \color{blue}{\frac{\frac{2}{2}}{\cosh x}} \]
    8. metadata-evalN/A

      \[\leadsto \frac{\color{blue}{1}}{\cosh x} \]
    9. lower-/.f64N/A

      \[\leadsto \color{blue}{\frac{1}{\cosh x}} \]
    10. lower-cosh.f64100.0

      \[\leadsto \frac{1}{\color{blue}{\cosh x}} \]
  4. Applied rewrites100.0%

    \[\leadsto \color{blue}{\frac{1}{\cosh x}} \]
  5. Final simplification100.0%

    \[\leadsto {\cosh x}^{-1} \]
  6. Add Preprocessing

Alternative 3: 91.9% accurate, 1.6× speedup?

\[\begin{array}{l} x_m = \left|x\right| \\ {\left(\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(0.001388888888888889, x\_m \cdot x\_m, 0.041666666666666664\right), x\_m \cdot x\_m, 0.5\right) \cdot x\_m, x\_m, 1\right)\right)}^{-1} \end{array} \]
x_m = (fabs.f64 x)
(FPCore (x_m)
 :precision binary64
 (pow
  (fma
   (*
    (fma
     (fma 0.001388888888888889 (* x_m x_m) 0.041666666666666664)
     (* x_m x_m)
     0.5)
    x_m)
   x_m
   1.0)
  -1.0))
x_m = fabs(x);
double code(double x_m) {
	return pow(fma((fma(fma(0.001388888888888889, (x_m * x_m), 0.041666666666666664), (x_m * x_m), 0.5) * x_m), x_m, 1.0), -1.0);
}
x_m = abs(x)
function code(x_m)
	return fma(Float64(fma(fma(0.001388888888888889, Float64(x_m * x_m), 0.041666666666666664), Float64(x_m * x_m), 0.5) * x_m), x_m, 1.0) ^ -1.0
end
x_m = N[Abs[x], $MachinePrecision]
code[x$95$m_] := N[Power[N[(N[(N[(N[(0.001388888888888889 * N[(x$95$m * x$95$m), $MachinePrecision] + 0.041666666666666664), $MachinePrecision] * N[(x$95$m * x$95$m), $MachinePrecision] + 0.5), $MachinePrecision] * x$95$m), $MachinePrecision] * x$95$m + 1.0), $MachinePrecision], -1.0], $MachinePrecision]
\begin{array}{l}
x_m = \left|x\right|

\\
{\left(\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(0.001388888888888889, x\_m \cdot x\_m, 0.041666666666666664\right), x\_m \cdot x\_m, 0.5\right) \cdot x\_m, x\_m, 1\right)\right)}^{-1}
\end{array}
Derivation
  1. Initial program 100.0%

    \[\frac{2}{e^{x} + e^{-x}} \]
  2. Add Preprocessing
  3. Step-by-step derivation
    1. lift-/.f64N/A

      \[\leadsto \color{blue}{\frac{2}{e^{x} + e^{-x}}} \]
    2. lift-+.f64N/A

      \[\leadsto \frac{2}{\color{blue}{e^{x} + e^{-x}}} \]
    3. lift-exp.f64N/A

      \[\leadsto \frac{2}{\color{blue}{e^{x}} + e^{-x}} \]
    4. lift-exp.f64N/A

      \[\leadsto \frac{2}{e^{x} + \color{blue}{e^{-x}}} \]
    5. lift-neg.f64N/A

      \[\leadsto \frac{2}{e^{x} + e^{\color{blue}{\mathsf{neg}\left(x\right)}}} \]
    6. cosh-undefN/A

      \[\leadsto \frac{2}{\color{blue}{2 \cdot \cosh x}} \]
    7. associate-/r*N/A

      \[\leadsto \color{blue}{\frac{\frac{2}{2}}{\cosh x}} \]
    8. metadata-evalN/A

      \[\leadsto \frac{\color{blue}{1}}{\cosh x} \]
    9. lower-/.f64N/A

      \[\leadsto \color{blue}{\frac{1}{\cosh x}} \]
    10. lower-cosh.f64100.0

      \[\leadsto \frac{1}{\color{blue}{\cosh x}} \]
  4. Applied rewrites100.0%

    \[\leadsto \color{blue}{\frac{1}{\cosh x}} \]
  5. Taylor expanded in x around 0

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

      \[\leadsto \frac{1}{\color{blue}{{x}^{2} \cdot \left(\frac{1}{2} + \frac{1}{24} \cdot {x}^{2}\right) + 1}} \]
    2. *-commutativeN/A

      \[\leadsto \frac{1}{\color{blue}{\left(\frac{1}{2} + \frac{1}{24} \cdot {x}^{2}\right) \cdot {x}^{2}} + 1} \]
    3. lower-fma.f64N/A

      \[\leadsto \frac{1}{\color{blue}{\mathsf{fma}\left(\frac{1}{2} + \frac{1}{24} \cdot {x}^{2}, {x}^{2}, 1\right)}} \]
    4. +-commutativeN/A

      \[\leadsto \frac{1}{\mathsf{fma}\left(\color{blue}{\frac{1}{24} \cdot {x}^{2} + \frac{1}{2}}, {x}^{2}, 1\right)} \]
    5. lower-fma.f64N/A

      \[\leadsto \frac{1}{\mathsf{fma}\left(\color{blue}{\mathsf{fma}\left(\frac{1}{24}, {x}^{2}, \frac{1}{2}\right)}, {x}^{2}, 1\right)} \]
    6. unpow2N/A

      \[\leadsto \frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(\frac{1}{24}, \color{blue}{x \cdot x}, \frac{1}{2}\right), {x}^{2}, 1\right)} \]
    7. lower-*.f64N/A

      \[\leadsto \frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(\frac{1}{24}, \color{blue}{x \cdot x}, \frac{1}{2}\right), {x}^{2}, 1\right)} \]
    8. unpow2N/A

      \[\leadsto \frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(\frac{1}{24}, x \cdot x, \frac{1}{2}\right), \color{blue}{x \cdot x}, 1\right)} \]
    9. lower-*.f6485.3

      \[\leadsto \frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(0.041666666666666664, x \cdot x, 0.5\right), \color{blue}{x \cdot x}, 1\right)} \]
  7. Applied rewrites85.3%

    \[\leadsto \frac{1}{\color{blue}{\mathsf{fma}\left(\mathsf{fma}\left(0.041666666666666664, x \cdot x, 0.5\right), x \cdot x, 1\right)}} \]
  8. Taylor expanded in x around 0

    \[\leadsto \frac{1}{\color{blue}{1 + {x}^{2} \cdot \left(\frac{1}{2} + {x}^{2} \cdot \left(\frac{1}{24} + \frac{1}{720} \cdot {x}^{2}\right)\right)}} \]
  9. Step-by-step derivation
    1. +-commutativeN/A

      \[\leadsto \frac{1}{\color{blue}{{x}^{2} \cdot \left(\frac{1}{2} + {x}^{2} \cdot \left(\frac{1}{24} + \frac{1}{720} \cdot {x}^{2}\right)\right) + 1}} \]
    2. unpow2N/A

      \[\leadsto \frac{1}{\color{blue}{\left(x \cdot x\right)} \cdot \left(\frac{1}{2} + {x}^{2} \cdot \left(\frac{1}{24} + \frac{1}{720} \cdot {x}^{2}\right)\right) + 1} \]
    3. associate-*l*N/A

      \[\leadsto \frac{1}{\color{blue}{x \cdot \left(x \cdot \left(\frac{1}{2} + {x}^{2} \cdot \left(\frac{1}{24} + \frac{1}{720} \cdot {x}^{2}\right)\right)\right)} + 1} \]
    4. *-commutativeN/A

      \[\leadsto \frac{1}{\color{blue}{\left(x \cdot \left(\frac{1}{2} + {x}^{2} \cdot \left(\frac{1}{24} + \frac{1}{720} \cdot {x}^{2}\right)\right)\right) \cdot x} + 1} \]
    5. lower-fma.f64N/A

      \[\leadsto \frac{1}{\color{blue}{\mathsf{fma}\left(x \cdot \left(\frac{1}{2} + {x}^{2} \cdot \left(\frac{1}{24} + \frac{1}{720} \cdot {x}^{2}\right)\right), x, 1\right)}} \]
  10. Applied rewrites89.1%

    \[\leadsto \frac{1}{\color{blue}{\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(0.001388888888888889, x \cdot x, 0.041666666666666664\right), x \cdot x, 0.5\right) \cdot x, x, 1\right)}} \]
  11. Final simplification89.1%

    \[\leadsto {\left(\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(0.001388888888888889, x \cdot x, 0.041666666666666664\right), x \cdot x, 0.5\right) \cdot x, x, 1\right)\right)}^{-1} \]
  12. Add Preprocessing

Alternative 4: 91.7% accurate, 1.6× speedup?

\[\begin{array}{l} x_m = \left|x\right| \\ {\left(\mathsf{fma}\left(\mathsf{fma}\left(0.001388888888888889 \cdot \left(x\_m \cdot x\_m\right), x\_m \cdot x\_m, 0.5\right), x\_m \cdot x\_m, 1\right)\right)}^{-1} \end{array} \]
x_m = (fabs.f64 x)
(FPCore (x_m)
 :precision binary64
 (pow
  (fma
   (fma (* 0.001388888888888889 (* x_m x_m)) (* x_m x_m) 0.5)
   (* x_m x_m)
   1.0)
  -1.0))
x_m = fabs(x);
double code(double x_m) {
	return pow(fma(fma((0.001388888888888889 * (x_m * x_m)), (x_m * x_m), 0.5), (x_m * x_m), 1.0), -1.0);
}
x_m = abs(x)
function code(x_m)
	return fma(fma(Float64(0.001388888888888889 * Float64(x_m * x_m)), Float64(x_m * x_m), 0.5), Float64(x_m * x_m), 1.0) ^ -1.0
end
x_m = N[Abs[x], $MachinePrecision]
code[x$95$m_] := N[Power[N[(N[(N[(0.001388888888888889 * N[(x$95$m * x$95$m), $MachinePrecision]), $MachinePrecision] * N[(x$95$m * x$95$m), $MachinePrecision] + 0.5), $MachinePrecision] * N[(x$95$m * x$95$m), $MachinePrecision] + 1.0), $MachinePrecision], -1.0], $MachinePrecision]
\begin{array}{l}
x_m = \left|x\right|

\\
{\left(\mathsf{fma}\left(\mathsf{fma}\left(0.001388888888888889 \cdot \left(x\_m \cdot x\_m\right), x\_m \cdot x\_m, 0.5\right), x\_m \cdot x\_m, 1\right)\right)}^{-1}
\end{array}
Derivation
  1. Initial program 100.0%

    \[\frac{2}{e^{x} + e^{-x}} \]
  2. Add Preprocessing
  3. Step-by-step derivation
    1. lift-/.f64N/A

      \[\leadsto \color{blue}{\frac{2}{e^{x} + e^{-x}}} \]
    2. lift-+.f64N/A

      \[\leadsto \frac{2}{\color{blue}{e^{x} + e^{-x}}} \]
    3. lift-exp.f64N/A

      \[\leadsto \frac{2}{\color{blue}{e^{x}} + e^{-x}} \]
    4. lift-exp.f64N/A

      \[\leadsto \frac{2}{e^{x} + \color{blue}{e^{-x}}} \]
    5. lift-neg.f64N/A

      \[\leadsto \frac{2}{e^{x} + e^{\color{blue}{\mathsf{neg}\left(x\right)}}} \]
    6. cosh-undefN/A

      \[\leadsto \frac{2}{\color{blue}{2 \cdot \cosh x}} \]
    7. associate-/r*N/A

      \[\leadsto \color{blue}{\frac{\frac{2}{2}}{\cosh x}} \]
    8. metadata-evalN/A

      \[\leadsto \frac{\color{blue}{1}}{\cosh x} \]
    9. lower-/.f64N/A

      \[\leadsto \color{blue}{\frac{1}{\cosh x}} \]
    10. lower-cosh.f64100.0

      \[\leadsto \frac{1}{\color{blue}{\cosh x}} \]
  4. Applied rewrites100.0%

    \[\leadsto \color{blue}{\frac{1}{\cosh x}} \]
  5. Taylor expanded in x around 0

    \[\leadsto \frac{1}{\color{blue}{1 + {x}^{2} \cdot \left(\frac{1}{2} + {x}^{2} \cdot \left(\frac{1}{24} + \frac{1}{720} \cdot {x}^{2}\right)\right)}} \]
  6. Step-by-step derivation
    1. +-commutativeN/A

      \[\leadsto \frac{1}{\color{blue}{{x}^{2} \cdot \left(\frac{1}{2} + {x}^{2} \cdot \left(\frac{1}{24} + \frac{1}{720} \cdot {x}^{2}\right)\right) + 1}} \]
    2. *-commutativeN/A

      \[\leadsto \frac{1}{\color{blue}{\left(\frac{1}{2} + {x}^{2} \cdot \left(\frac{1}{24} + \frac{1}{720} \cdot {x}^{2}\right)\right) \cdot {x}^{2}} + 1} \]
    3. lower-fma.f64N/A

      \[\leadsto \frac{1}{\color{blue}{\mathsf{fma}\left(\frac{1}{2} + {x}^{2} \cdot \left(\frac{1}{24} + \frac{1}{720} \cdot {x}^{2}\right), {x}^{2}, 1\right)}} \]
    4. +-commutativeN/A

      \[\leadsto \frac{1}{\mathsf{fma}\left(\color{blue}{{x}^{2} \cdot \left(\frac{1}{24} + \frac{1}{720} \cdot {x}^{2}\right) + \frac{1}{2}}, {x}^{2}, 1\right)} \]
    5. *-commutativeN/A

      \[\leadsto \frac{1}{\mathsf{fma}\left(\color{blue}{\left(\frac{1}{24} + \frac{1}{720} \cdot {x}^{2}\right) \cdot {x}^{2}} + \frac{1}{2}, {x}^{2}, 1\right)} \]
    6. lower-fma.f64N/A

      \[\leadsto \frac{1}{\mathsf{fma}\left(\color{blue}{\mathsf{fma}\left(\frac{1}{24} + \frac{1}{720} \cdot {x}^{2}, {x}^{2}, \frac{1}{2}\right)}, {x}^{2}, 1\right)} \]
    7. +-commutativeN/A

      \[\leadsto \frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(\color{blue}{\frac{1}{720} \cdot {x}^{2} + \frac{1}{24}}, {x}^{2}, \frac{1}{2}\right), {x}^{2}, 1\right)} \]
    8. lower-fma.f64N/A

      \[\leadsto \frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(\color{blue}{\mathsf{fma}\left(\frac{1}{720}, {x}^{2}, \frac{1}{24}\right)}, {x}^{2}, \frac{1}{2}\right), {x}^{2}, 1\right)} \]
    9. unpow2N/A

      \[\leadsto \frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(\frac{1}{720}, \color{blue}{x \cdot x}, \frac{1}{24}\right), {x}^{2}, \frac{1}{2}\right), {x}^{2}, 1\right)} \]
    10. lower-*.f64N/A

      \[\leadsto \frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(\frac{1}{720}, \color{blue}{x \cdot x}, \frac{1}{24}\right), {x}^{2}, \frac{1}{2}\right), {x}^{2}, 1\right)} \]
    11. unpow2N/A

      \[\leadsto \frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(\frac{1}{720}, x \cdot x, \frac{1}{24}\right), \color{blue}{x \cdot x}, \frac{1}{2}\right), {x}^{2}, 1\right)} \]
    12. lower-*.f64N/A

      \[\leadsto \frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(\frac{1}{720}, x \cdot x, \frac{1}{24}\right), \color{blue}{x \cdot x}, \frac{1}{2}\right), {x}^{2}, 1\right)} \]
    13. unpow2N/A

      \[\leadsto \frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(\frac{1}{720}, x \cdot x, \frac{1}{24}\right), x \cdot x, \frac{1}{2}\right), \color{blue}{x \cdot x}, 1\right)} \]
    14. lower-*.f6489.1

      \[\leadsto \frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(0.001388888888888889, x \cdot x, 0.041666666666666664\right), x \cdot x, 0.5\right), \color{blue}{x \cdot x}, 1\right)} \]
  7. Applied rewrites89.1%

    \[\leadsto \frac{1}{\color{blue}{\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(0.001388888888888889, x \cdot x, 0.041666666666666664\right), x \cdot x, 0.5\right), x \cdot x, 1\right)}} \]
  8. Taylor expanded in x around inf

    \[\leadsto \frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(\frac{1}{720} \cdot {x}^{2}, x \cdot x, \frac{1}{2}\right), x \cdot x, 1\right)} \]
  9. Step-by-step derivation
    1. Applied rewrites89.0%

      \[\leadsto \frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(0.001388888888888889 \cdot \left(x \cdot x\right), x \cdot x, 0.5\right), x \cdot x, 1\right)} \]
    2. Final simplification89.0%

      \[\leadsto {\left(\mathsf{fma}\left(\mathsf{fma}\left(0.001388888888888889 \cdot \left(x \cdot x\right), x \cdot x, 0.5\right), x \cdot x, 1\right)\right)}^{-1} \]
    3. Add Preprocessing

    Alternative 5: 87.9% accurate, 1.8× speedup?

    \[\begin{array}{l} x_m = \left|x\right| \\ {\left(\mathsf{fma}\left(\mathsf{fma}\left(x\_m \cdot x\_m, 0.041666666666666664, 0.5\right) \cdot x\_m, x\_m, 1\right)\right)}^{-1} \end{array} \]
    x_m = (fabs.f64 x)
    (FPCore (x_m)
     :precision binary64
     (pow (fma (* (fma (* x_m x_m) 0.041666666666666664 0.5) x_m) x_m 1.0) -1.0))
    x_m = fabs(x);
    double code(double x_m) {
    	return pow(fma((fma((x_m * x_m), 0.041666666666666664, 0.5) * x_m), x_m, 1.0), -1.0);
    }
    
    x_m = abs(x)
    function code(x_m)
    	return fma(Float64(fma(Float64(x_m * x_m), 0.041666666666666664, 0.5) * x_m), x_m, 1.0) ^ -1.0
    end
    
    x_m = N[Abs[x], $MachinePrecision]
    code[x$95$m_] := N[Power[N[(N[(N[(N[(x$95$m * x$95$m), $MachinePrecision] * 0.041666666666666664 + 0.5), $MachinePrecision] * x$95$m), $MachinePrecision] * x$95$m + 1.0), $MachinePrecision], -1.0], $MachinePrecision]
    
    \begin{array}{l}
    x_m = \left|x\right|
    
    \\
    {\left(\mathsf{fma}\left(\mathsf{fma}\left(x\_m \cdot x\_m, 0.041666666666666664, 0.5\right) \cdot x\_m, x\_m, 1\right)\right)}^{-1}
    \end{array}
    
    Derivation
    1. Initial program 100.0%

      \[\frac{2}{e^{x} + e^{-x}} \]
    2. Add Preprocessing
    3. Step-by-step derivation
      1. lift-/.f64N/A

        \[\leadsto \color{blue}{\frac{2}{e^{x} + e^{-x}}} \]
      2. lift-+.f64N/A

        \[\leadsto \frac{2}{\color{blue}{e^{x} + e^{-x}}} \]
      3. lift-exp.f64N/A

        \[\leadsto \frac{2}{\color{blue}{e^{x}} + e^{-x}} \]
      4. lift-exp.f64N/A

        \[\leadsto \frac{2}{e^{x} + \color{blue}{e^{-x}}} \]
      5. lift-neg.f64N/A

        \[\leadsto \frac{2}{e^{x} + e^{\color{blue}{\mathsf{neg}\left(x\right)}}} \]
      6. cosh-undefN/A

        \[\leadsto \frac{2}{\color{blue}{2 \cdot \cosh x}} \]
      7. associate-/r*N/A

        \[\leadsto \color{blue}{\frac{\frac{2}{2}}{\cosh x}} \]
      8. metadata-evalN/A

        \[\leadsto \frac{\color{blue}{1}}{\cosh x} \]
      9. lower-/.f64N/A

        \[\leadsto \color{blue}{\frac{1}{\cosh x}} \]
      10. lower-cosh.f64100.0

        \[\leadsto \frac{1}{\color{blue}{\cosh x}} \]
    4. Applied rewrites100.0%

      \[\leadsto \color{blue}{\frac{1}{\cosh x}} \]
    5. Taylor expanded in x around 0

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

        \[\leadsto \frac{1}{\color{blue}{{x}^{2} \cdot \left(\frac{1}{2} + \frac{1}{24} \cdot {x}^{2}\right) + 1}} \]
      2. *-commutativeN/A

        \[\leadsto \frac{1}{\color{blue}{\left(\frac{1}{2} + \frac{1}{24} \cdot {x}^{2}\right) \cdot {x}^{2}} + 1} \]
      3. lower-fma.f64N/A

        \[\leadsto \frac{1}{\color{blue}{\mathsf{fma}\left(\frac{1}{2} + \frac{1}{24} \cdot {x}^{2}, {x}^{2}, 1\right)}} \]
      4. +-commutativeN/A

        \[\leadsto \frac{1}{\mathsf{fma}\left(\color{blue}{\frac{1}{24} \cdot {x}^{2} + \frac{1}{2}}, {x}^{2}, 1\right)} \]
      5. lower-fma.f64N/A

        \[\leadsto \frac{1}{\mathsf{fma}\left(\color{blue}{\mathsf{fma}\left(\frac{1}{24}, {x}^{2}, \frac{1}{2}\right)}, {x}^{2}, 1\right)} \]
      6. unpow2N/A

        \[\leadsto \frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(\frac{1}{24}, \color{blue}{x \cdot x}, \frac{1}{2}\right), {x}^{2}, 1\right)} \]
      7. lower-*.f64N/A

        \[\leadsto \frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(\frac{1}{24}, \color{blue}{x \cdot x}, \frac{1}{2}\right), {x}^{2}, 1\right)} \]
      8. unpow2N/A

        \[\leadsto \frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(\frac{1}{24}, x \cdot x, \frac{1}{2}\right), \color{blue}{x \cdot x}, 1\right)} \]
      9. lower-*.f6485.3

        \[\leadsto \frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(0.041666666666666664, x \cdot x, 0.5\right), \color{blue}{x \cdot x}, 1\right)} \]
    7. Applied rewrites85.3%

      \[\leadsto \frac{1}{\color{blue}{\mathsf{fma}\left(\mathsf{fma}\left(0.041666666666666664, x \cdot x, 0.5\right), x \cdot x, 1\right)}} \]
    8. Step-by-step derivation
      1. Applied rewrites85.3%

        \[\leadsto \frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(x \cdot x, 0.041666666666666664, 0.5\right) \cdot x, \color{blue}{x}, 1\right)} \]
      2. Final simplification85.3%

        \[\leadsto {\left(\mathsf{fma}\left(\mathsf{fma}\left(x \cdot x, 0.041666666666666664, 0.5\right) \cdot x, x, 1\right)\right)}^{-1} \]
      3. Add Preprocessing

      Alternative 6: 87.5% accurate, 1.8× speedup?

      \[\begin{array}{l} x_m = \left|x\right| \\ {\left(\mathsf{fma}\left(0.041666666666666664 \cdot \left(x\_m \cdot x\_m\right), x\_m \cdot x\_m, 1\right)\right)}^{-1} \end{array} \]
      x_m = (fabs.f64 x)
      (FPCore (x_m)
       :precision binary64
       (pow (fma (* 0.041666666666666664 (* x_m x_m)) (* x_m x_m) 1.0) -1.0))
      x_m = fabs(x);
      double code(double x_m) {
      	return pow(fma((0.041666666666666664 * (x_m * x_m)), (x_m * x_m), 1.0), -1.0);
      }
      
      x_m = abs(x)
      function code(x_m)
      	return fma(Float64(0.041666666666666664 * Float64(x_m * x_m)), Float64(x_m * x_m), 1.0) ^ -1.0
      end
      
      x_m = N[Abs[x], $MachinePrecision]
      code[x$95$m_] := N[Power[N[(N[(0.041666666666666664 * N[(x$95$m * x$95$m), $MachinePrecision]), $MachinePrecision] * N[(x$95$m * x$95$m), $MachinePrecision] + 1.0), $MachinePrecision], -1.0], $MachinePrecision]
      
      \begin{array}{l}
      x_m = \left|x\right|
      
      \\
      {\left(\mathsf{fma}\left(0.041666666666666664 \cdot \left(x\_m \cdot x\_m\right), x\_m \cdot x\_m, 1\right)\right)}^{-1}
      \end{array}
      
      Derivation
      1. Initial program 100.0%

        \[\frac{2}{e^{x} + e^{-x}} \]
      2. Add Preprocessing
      3. Step-by-step derivation
        1. lift-/.f64N/A

          \[\leadsto \color{blue}{\frac{2}{e^{x} + e^{-x}}} \]
        2. lift-+.f64N/A

          \[\leadsto \frac{2}{\color{blue}{e^{x} + e^{-x}}} \]
        3. lift-exp.f64N/A

          \[\leadsto \frac{2}{\color{blue}{e^{x}} + e^{-x}} \]
        4. lift-exp.f64N/A

          \[\leadsto \frac{2}{e^{x} + \color{blue}{e^{-x}}} \]
        5. lift-neg.f64N/A

          \[\leadsto \frac{2}{e^{x} + e^{\color{blue}{\mathsf{neg}\left(x\right)}}} \]
        6. cosh-undefN/A

          \[\leadsto \frac{2}{\color{blue}{2 \cdot \cosh x}} \]
        7. associate-/r*N/A

          \[\leadsto \color{blue}{\frac{\frac{2}{2}}{\cosh x}} \]
        8. metadata-evalN/A

          \[\leadsto \frac{\color{blue}{1}}{\cosh x} \]
        9. lower-/.f64N/A

          \[\leadsto \color{blue}{\frac{1}{\cosh x}} \]
        10. lower-cosh.f64100.0

          \[\leadsto \frac{1}{\color{blue}{\cosh x}} \]
      4. Applied rewrites100.0%

        \[\leadsto \color{blue}{\frac{1}{\cosh x}} \]
      5. Taylor expanded in x around 0

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

          \[\leadsto \frac{1}{\color{blue}{{x}^{2} \cdot \left(\frac{1}{2} + \frac{1}{24} \cdot {x}^{2}\right) + 1}} \]
        2. *-commutativeN/A

          \[\leadsto \frac{1}{\color{blue}{\left(\frac{1}{2} + \frac{1}{24} \cdot {x}^{2}\right) \cdot {x}^{2}} + 1} \]
        3. lower-fma.f64N/A

          \[\leadsto \frac{1}{\color{blue}{\mathsf{fma}\left(\frac{1}{2} + \frac{1}{24} \cdot {x}^{2}, {x}^{2}, 1\right)}} \]
        4. +-commutativeN/A

          \[\leadsto \frac{1}{\mathsf{fma}\left(\color{blue}{\frac{1}{24} \cdot {x}^{2} + \frac{1}{2}}, {x}^{2}, 1\right)} \]
        5. lower-fma.f64N/A

          \[\leadsto \frac{1}{\mathsf{fma}\left(\color{blue}{\mathsf{fma}\left(\frac{1}{24}, {x}^{2}, \frac{1}{2}\right)}, {x}^{2}, 1\right)} \]
        6. unpow2N/A

          \[\leadsto \frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(\frac{1}{24}, \color{blue}{x \cdot x}, \frac{1}{2}\right), {x}^{2}, 1\right)} \]
        7. lower-*.f64N/A

          \[\leadsto \frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(\frac{1}{24}, \color{blue}{x \cdot x}, \frac{1}{2}\right), {x}^{2}, 1\right)} \]
        8. unpow2N/A

          \[\leadsto \frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(\frac{1}{24}, x \cdot x, \frac{1}{2}\right), \color{blue}{x \cdot x}, 1\right)} \]
        9. lower-*.f6485.3

          \[\leadsto \frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(0.041666666666666664, x \cdot x, 0.5\right), \color{blue}{x \cdot x}, 1\right)} \]
      7. Applied rewrites85.3%

        \[\leadsto \frac{1}{\color{blue}{\mathsf{fma}\left(\mathsf{fma}\left(0.041666666666666664, x \cdot x, 0.5\right), x \cdot x, 1\right)}} \]
      8. Taylor expanded in x around inf

        \[\leadsto \frac{1}{\mathsf{fma}\left(\frac{1}{24} \cdot {x}^{2}, \color{blue}{x} \cdot x, 1\right)} \]
      9. Step-by-step derivation
        1. Applied rewrites85.1%

          \[\leadsto \frac{1}{\mathsf{fma}\left(0.041666666666666664 \cdot \left(x \cdot x\right), \color{blue}{x} \cdot x, 1\right)} \]
        2. Final simplification85.1%

          \[\leadsto {\left(\mathsf{fma}\left(0.041666666666666664 \cdot \left(x \cdot x\right), x \cdot x, 1\right)\right)}^{-1} \]
        3. Add Preprocessing

        Alternative 7: 76.1% accurate, 12.1× speedup?

        \[\begin{array}{l} x_m = \left|x\right| \\ \frac{2}{\mathsf{fma}\left(x\_m, x\_m, 2\right)} \end{array} \]
        x_m = (fabs.f64 x)
        (FPCore (x_m) :precision binary64 (/ 2.0 (fma x_m x_m 2.0)))
        x_m = fabs(x);
        double code(double x_m) {
        	return 2.0 / fma(x_m, x_m, 2.0);
        }
        
        x_m = abs(x)
        function code(x_m)
        	return Float64(2.0 / fma(x_m, x_m, 2.0))
        end
        
        x_m = N[Abs[x], $MachinePrecision]
        code[x$95$m_] := N[(2.0 / N[(x$95$m * x$95$m + 2.0), $MachinePrecision]), $MachinePrecision]
        
        \begin{array}{l}
        x_m = \left|x\right|
        
        \\
        \frac{2}{\mathsf{fma}\left(x\_m, x\_m, 2\right)}
        \end{array}
        
        Derivation
        1. Initial program 100.0%

          \[\frac{2}{e^{x} + e^{-x}} \]
        2. Add Preprocessing
        3. Taylor expanded in x around 0

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

            \[\leadsto \frac{2}{\color{blue}{{x}^{2} + 2}} \]
          2. unpow2N/A

            \[\leadsto \frac{2}{\color{blue}{x \cdot x} + 2} \]
          3. lower-fma.f6473.7

            \[\leadsto \frac{2}{\color{blue}{\mathsf{fma}\left(x, x, 2\right)}} \]
        5. Applied rewrites73.7%

          \[\leadsto \frac{2}{\color{blue}{\mathsf{fma}\left(x, x, 2\right)}} \]
        6. Add Preprocessing

        Alternative 8: 51.7% accurate, 217.0× speedup?

        \[\begin{array}{l} x_m = \left|x\right| \\ 1 \end{array} \]
        x_m = (fabs.f64 x)
        (FPCore (x_m) :precision binary64 1.0)
        x_m = fabs(x);
        double code(double x_m) {
        	return 1.0;
        }
        
        x_m =     private
        module fmin_fmax_functions
            implicit none
            private
            public fmax
            public fmin
        
            interface fmax
                module procedure fmax88
                module procedure fmax44
                module procedure fmax84
                module procedure fmax48
            end interface
            interface fmin
                module procedure fmin88
                module procedure fmin44
                module procedure fmin84
                module procedure fmin48
            end interface
        contains
            real(8) function fmax88(x, y) result (res)
                real(8), intent (in) :: x
                real(8), intent (in) :: y
                res = merge(y, merge(x, max(x, y), y /= y), x /= x)
            end function
            real(4) function fmax44(x, y) result (res)
                real(4), intent (in) :: x
                real(4), intent (in) :: y
                res = merge(y, merge(x, max(x, y), y /= y), x /= x)
            end function
            real(8) function fmax84(x, y) result(res)
                real(8), intent (in) :: x
                real(4), intent (in) :: y
                res = merge(dble(y), merge(x, max(x, dble(y)), y /= y), x /= x)
            end function
            real(8) function fmax48(x, y) result(res)
                real(4), intent (in) :: x
                real(8), intent (in) :: y
                res = merge(y, merge(dble(x), max(dble(x), y), y /= y), x /= x)
            end function
            real(8) function fmin88(x, y) result (res)
                real(8), intent (in) :: x
                real(8), intent (in) :: y
                res = merge(y, merge(x, min(x, y), y /= y), x /= x)
            end function
            real(4) function fmin44(x, y) result (res)
                real(4), intent (in) :: x
                real(4), intent (in) :: y
                res = merge(y, merge(x, min(x, y), y /= y), x /= x)
            end function
            real(8) function fmin84(x, y) result(res)
                real(8), intent (in) :: x
                real(4), intent (in) :: y
                res = merge(dble(y), merge(x, min(x, dble(y)), y /= y), x /= x)
            end function
            real(8) function fmin48(x, y) result(res)
                real(4), intent (in) :: x
                real(8), intent (in) :: y
                res = merge(y, merge(dble(x), min(dble(x), y), y /= y), x /= x)
            end function
        end module
        
        real(8) function code(x_m)
        use fmin_fmax_functions
            real(8), intent (in) :: x_m
            code = 1.0d0
        end function
        
        x_m = Math.abs(x);
        public static double code(double x_m) {
        	return 1.0;
        }
        
        x_m = math.fabs(x)
        def code(x_m):
        	return 1.0
        
        x_m = abs(x)
        function code(x_m)
        	return 1.0
        end
        
        x_m = abs(x);
        function tmp = code(x_m)
        	tmp = 1.0;
        end
        
        x_m = N[Abs[x], $MachinePrecision]
        code[x$95$m_] := 1.0
        
        \begin{array}{l}
        x_m = \left|x\right|
        
        \\
        1
        \end{array}
        
        Derivation
        1. Initial program 100.0%

          \[\frac{2}{e^{x} + e^{-x}} \]
        2. Add Preprocessing
        3. Taylor expanded in x around 0

          \[\leadsto \color{blue}{1} \]
        4. Step-by-step derivation
          1. Applied rewrites51.1%

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

          Reproduce

          ?
          herbie shell --seed 2024359 
          (FPCore (x)
            :name "Hyperbolic secant"
            :precision binary64
            (/ 2.0 (+ (exp x) (exp (- x)))))