Harley's example

Percentage Accurate: 91.5% → 96.6%
Time: 57.0s
Alternatives: 8
Speedup: 147.6×

Specification

?
\[0 < c\_p \land 0 < c\_n\]
\[\begin{array}{l} \\ \begin{array}{l} t_1 := \frac{1}{1 + e^{-t}}\\ t_2 := \frac{1}{1 + e^{-s}}\\ \frac{{t\_2}^{c\_p} \cdot {\left(1 - t\_2\right)}^{c\_n}}{{t\_1}^{c\_p} \cdot {\left(1 - t\_1\right)}^{c\_n}} \end{array} \end{array} \]
(FPCore (c_p c_n t s)
 :precision binary64
 (let* ((t_1 (/ 1.0 (+ 1.0 (exp (- t))))) (t_2 (/ 1.0 (+ 1.0 (exp (- s))))))
   (/
    (* (pow t_2 c_p) (pow (- 1.0 t_2) c_n))
    (* (pow t_1 c_p) (pow (- 1.0 t_1) c_n)))))
double code(double c_p, double c_n, double t, double s) {
	double t_1 = 1.0 / (1.0 + exp(-t));
	double t_2 = 1.0 / (1.0 + exp(-s));
	return (pow(t_2, c_p) * pow((1.0 - t_2), c_n)) / (pow(t_1, c_p) * pow((1.0 - t_1), c_n));
}
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(c_p, c_n, t, s)
use fmin_fmax_functions
    real(8), intent (in) :: c_p
    real(8), intent (in) :: c_n
    real(8), intent (in) :: t
    real(8), intent (in) :: s
    real(8) :: t_1
    real(8) :: t_2
    t_1 = 1.0d0 / (1.0d0 + exp(-t))
    t_2 = 1.0d0 / (1.0d0 + exp(-s))
    code = ((t_2 ** c_p) * ((1.0d0 - t_2) ** c_n)) / ((t_1 ** c_p) * ((1.0d0 - t_1) ** c_n))
end function
public static double code(double c_p, double c_n, double t, double s) {
	double t_1 = 1.0 / (1.0 + Math.exp(-t));
	double t_2 = 1.0 / (1.0 + Math.exp(-s));
	return (Math.pow(t_2, c_p) * Math.pow((1.0 - t_2), c_n)) / (Math.pow(t_1, c_p) * Math.pow((1.0 - t_1), c_n));
}
def code(c_p, c_n, t, s):
	t_1 = 1.0 / (1.0 + math.exp(-t))
	t_2 = 1.0 / (1.0 + math.exp(-s))
	return (math.pow(t_2, c_p) * math.pow((1.0 - t_2), c_n)) / (math.pow(t_1, c_p) * math.pow((1.0 - t_1), c_n))
function code(c_p, c_n, t, s)
	t_1 = Float64(1.0 / Float64(1.0 + exp(Float64(-t))))
	t_2 = Float64(1.0 / Float64(1.0 + exp(Float64(-s))))
	return Float64(Float64((t_2 ^ c_p) * (Float64(1.0 - t_2) ^ c_n)) / Float64((t_1 ^ c_p) * (Float64(1.0 - t_1) ^ c_n)))
end
function tmp = code(c_p, c_n, t, s)
	t_1 = 1.0 / (1.0 + exp(-t));
	t_2 = 1.0 / (1.0 + exp(-s));
	tmp = ((t_2 ^ c_p) * ((1.0 - t_2) ^ c_n)) / ((t_1 ^ c_p) * ((1.0 - t_1) ^ c_n));
end
code[c$95$p_, c$95$n_, t_, s_] := Block[{t$95$1 = N[(1.0 / N[(1.0 + N[Exp[(-t)], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]}, Block[{t$95$2 = N[(1.0 / N[(1.0 + N[Exp[(-s)], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]}, N[(N[(N[Power[t$95$2, c$95$p], $MachinePrecision] * N[Power[N[(1.0 - t$95$2), $MachinePrecision], c$95$n], $MachinePrecision]), $MachinePrecision] / N[(N[Power[t$95$1, c$95$p], $MachinePrecision] * N[Power[N[(1.0 - t$95$1), $MachinePrecision], c$95$n], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
t_1 := \frac{1}{1 + e^{-t}}\\
t_2 := \frac{1}{1 + e^{-s}}\\
\frac{{t\_2}^{c\_p} \cdot {\left(1 - t\_2\right)}^{c\_n}}{{t\_1}^{c\_p} \cdot {\left(1 - t\_1\right)}^{c\_n}}
\end{array}
\end{array}

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: 91.5% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_1 := \frac{1}{1 + e^{-t}}\\ t_2 := \frac{1}{1 + e^{-s}}\\ \frac{{t\_2}^{c\_p} \cdot {\left(1 - t\_2\right)}^{c\_n}}{{t\_1}^{c\_p} \cdot {\left(1 - t\_1\right)}^{c\_n}} \end{array} \end{array} \]
(FPCore (c_p c_n t s)
 :precision binary64
 (let* ((t_1 (/ 1.0 (+ 1.0 (exp (- t))))) (t_2 (/ 1.0 (+ 1.0 (exp (- s))))))
   (/
    (* (pow t_2 c_p) (pow (- 1.0 t_2) c_n))
    (* (pow t_1 c_p) (pow (- 1.0 t_1) c_n)))))
double code(double c_p, double c_n, double t, double s) {
	double t_1 = 1.0 / (1.0 + exp(-t));
	double t_2 = 1.0 / (1.0 + exp(-s));
	return (pow(t_2, c_p) * pow((1.0 - t_2), c_n)) / (pow(t_1, c_p) * pow((1.0 - t_1), c_n));
}
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(c_p, c_n, t, s)
use fmin_fmax_functions
    real(8), intent (in) :: c_p
    real(8), intent (in) :: c_n
    real(8), intent (in) :: t
    real(8), intent (in) :: s
    real(8) :: t_1
    real(8) :: t_2
    t_1 = 1.0d0 / (1.0d0 + exp(-t))
    t_2 = 1.0d0 / (1.0d0 + exp(-s))
    code = ((t_2 ** c_p) * ((1.0d0 - t_2) ** c_n)) / ((t_1 ** c_p) * ((1.0d0 - t_1) ** c_n))
end function
public static double code(double c_p, double c_n, double t, double s) {
	double t_1 = 1.0 / (1.0 + Math.exp(-t));
	double t_2 = 1.0 / (1.0 + Math.exp(-s));
	return (Math.pow(t_2, c_p) * Math.pow((1.0 - t_2), c_n)) / (Math.pow(t_1, c_p) * Math.pow((1.0 - t_1), c_n));
}
def code(c_p, c_n, t, s):
	t_1 = 1.0 / (1.0 + math.exp(-t))
	t_2 = 1.0 / (1.0 + math.exp(-s))
	return (math.pow(t_2, c_p) * math.pow((1.0 - t_2), c_n)) / (math.pow(t_1, c_p) * math.pow((1.0 - t_1), c_n))
function code(c_p, c_n, t, s)
	t_1 = Float64(1.0 / Float64(1.0 + exp(Float64(-t))))
	t_2 = Float64(1.0 / Float64(1.0 + exp(Float64(-s))))
	return Float64(Float64((t_2 ^ c_p) * (Float64(1.0 - t_2) ^ c_n)) / Float64((t_1 ^ c_p) * (Float64(1.0 - t_1) ^ c_n)))
end
function tmp = code(c_p, c_n, t, s)
	t_1 = 1.0 / (1.0 + exp(-t));
	t_2 = 1.0 / (1.0 + exp(-s));
	tmp = ((t_2 ^ c_p) * ((1.0 - t_2) ^ c_n)) / ((t_1 ^ c_p) * ((1.0 - t_1) ^ c_n));
end
code[c$95$p_, c$95$n_, t_, s_] := Block[{t$95$1 = N[(1.0 / N[(1.0 + N[Exp[(-t)], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]}, Block[{t$95$2 = N[(1.0 / N[(1.0 + N[Exp[(-s)], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]}, N[(N[(N[Power[t$95$2, c$95$p], $MachinePrecision] * N[Power[N[(1.0 - t$95$2), $MachinePrecision], c$95$n], $MachinePrecision]), $MachinePrecision] / N[(N[Power[t$95$1, c$95$p], $MachinePrecision] * N[Power[N[(1.0 - t$95$1), $MachinePrecision], c$95$n], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
t_1 := \frac{1}{1 + e^{-t}}\\
t_2 := \frac{1}{1 + e^{-s}}\\
\frac{{t\_2}^{c\_p} \cdot {\left(1 - t\_2\right)}^{c\_n}}{{t\_1}^{c\_p} \cdot {\left(1 - t\_1\right)}^{c\_n}}
\end{array}
\end{array}

Alternative 1: 96.6% accurate, 1.7× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;c\_p \leq 5 \cdot 10^{-41}:\\ \;\;\;\;\frac{\mathsf{fma}\left(-0.5, c\_n \cdot \left(s \cdot {0.5}^{c\_n}\right), {0.5}^{c\_n}\right)}{{\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}}\\ \mathbf{else}:\\ \;\;\;\;\frac{\left(1 + s\right) + 1}{\left(1 + s\right) \cdot \left(1 + e^{-s}\right)}\\ \end{array} \end{array} \]
(FPCore (c_p c_n t s)
 :precision binary64
 (if (<= c_p 5e-41)
   (/
    (fma -0.5 (* c_n (* s (pow 0.5 c_n))) (pow 0.5 c_n))
    (pow (- 1.0 (/ 1.0 (+ 1.0 (exp (- t))))) c_n))
   (/ (+ (+ 1.0 s) 1.0) (* (+ 1.0 s) (+ 1.0 (exp (- s)))))))
double code(double c_p, double c_n, double t, double s) {
	double tmp;
	if (c_p <= 5e-41) {
		tmp = fma(-0.5, (c_n * (s * pow(0.5, c_n))), pow(0.5, c_n)) / pow((1.0 - (1.0 / (1.0 + exp(-t)))), c_n);
	} else {
		tmp = ((1.0 + s) + 1.0) / ((1.0 + s) * (1.0 + exp(-s)));
	}
	return tmp;
}
function code(c_p, c_n, t, s)
	tmp = 0.0
	if (c_p <= 5e-41)
		tmp = Float64(fma(-0.5, Float64(c_n * Float64(s * (0.5 ^ c_n))), (0.5 ^ c_n)) / (Float64(1.0 - Float64(1.0 / Float64(1.0 + exp(Float64(-t))))) ^ c_n));
	else
		tmp = Float64(Float64(Float64(1.0 + s) + 1.0) / Float64(Float64(1.0 + s) * Float64(1.0 + exp(Float64(-s)))));
	end
	return tmp
end
code[c$95$p_, c$95$n_, t_, s_] := If[LessEqual[c$95$p, 5e-41], N[(N[(-0.5 * N[(c$95$n * N[(s * N[Power[0.5, c$95$n], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[Power[0.5, c$95$n], $MachinePrecision]), $MachinePrecision] / N[Power[N[(1.0 - N[(1.0 / N[(1.0 + N[Exp[(-t)], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], c$95$n], $MachinePrecision]), $MachinePrecision], N[(N[(N[(1.0 + s), $MachinePrecision] + 1.0), $MachinePrecision] / N[(N[(1.0 + s), $MachinePrecision] * N[(1.0 + N[Exp[(-s)], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;c\_p \leq 5 \cdot 10^{-41}:\\
\;\;\;\;\frac{\mathsf{fma}\left(-0.5, c\_n \cdot \left(s \cdot {0.5}^{c\_n}\right), {0.5}^{c\_n}\right)}{{\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}}\\

\mathbf{else}:\\
\;\;\;\;\frac{\left(1 + s\right) + 1}{\left(1 + s\right) \cdot \left(1 + e^{-s}\right)}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if c_p < 4.9999999999999996e-41

    1. Initial program 91.5%

      \[\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}} \]
    2. Taylor expanded in c_p around 0

      \[\leadsto \color{blue}{\frac{{\left(1 - \frac{1}{1 + e^{\mathsf{neg}\left(s\right)}}\right)}^{c\_n}}{{\left(1 - \frac{1}{1 + e^{\mathsf{neg}\left(t\right)}}\right)}^{c\_n}}} \]
    3. Applied rewrites94.5%

      \[\leadsto \color{blue}{\frac{{\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}}} \]
    4. Taylor expanded in s around 0

      \[\leadsto \frac{\frac{-1}{2} \cdot \left(c\_n \cdot \left(s \cdot {\frac{1}{2}}^{c\_n}\right)\right) + {\frac{1}{2}}^{c\_n}}{{\color{blue}{\left(1 - \frac{1}{1 + e^{-t}}\right)}}^{c\_n}} \]
    5. Applied rewrites94.2%

      \[\leadsto \frac{\mathsf{fma}\left(-0.5, c\_n \cdot \left(s \cdot {0.5}^{c\_n}\right), {0.5}^{c\_n}\right)}{{\color{blue}{\left(1 - \frac{1}{1 + e^{-t}}\right)}}^{c\_n}} \]

    if 4.9999999999999996e-41 < c_p

    1. Initial program 91.5%

      \[\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}} \]
    2. Taylor expanded in c_n around 0

      \[\leadsto \color{blue}{\frac{{\left(\frac{1}{1 + e^{\mathsf{neg}\left(s\right)}}\right)}^{c\_p}}{{\left(\frac{1}{1 + e^{\mathsf{neg}\left(t\right)}}\right)}^{c\_p}}} \]
    3. Applied rewrites93.3%

      \[\leadsto \color{blue}{\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}}} \]
    4. Taylor expanded in c_p around 0

      \[\leadsto 1 \]
    5. Applied rewrites94.7%

      \[\leadsto 1 \]
    6. Applied rewrites93.7%

      \[\leadsto \frac{e^{s} + 1}{e^{s} \cdot \color{blue}{\left(1 + e^{-s}\right)}} \]
    7. Taylor expanded in s around 0

      \[\leadsto \frac{\left(1 + s\right) + 1}{e^{s} \cdot \left(1 + e^{-s}\right)} \]
    8. Applied rewrites93.8%

      \[\leadsto \frac{\left(1 + s\right) + 1}{e^{s} \cdot \left(1 + e^{-s}\right)} \]
    9. Taylor expanded in s around 0

      \[\leadsto \frac{\left(1 + s\right) + 1}{\left(1 + s\right) \cdot \left(1 + e^{\color{blue}{-s}}\right)} \]
    10. Applied rewrites94.4%

      \[\leadsto \frac{\left(1 + s\right) + 1}{\left(1 + s\right) \cdot \left(1 + e^{\color{blue}{-s}}\right)} \]
  3. Recombined 2 regimes into one program.
  4. Add Preprocessing

Alternative 2: 96.2% accurate, 1.9× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_1 := 1 + e^{-s}\\ \mathbf{if}\;c\_p \leq 5 \cdot 10^{-41}:\\ \;\;\;\;\frac{{\left(1 - \frac{1}{t\_1}\right)}^{c\_n}}{{\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}}\\ \mathbf{else}:\\ \;\;\;\;\frac{\left(1 + s\right) + 1}{\left(1 + s\right) \cdot t\_1}\\ \end{array} \end{array} \]
(FPCore (c_p c_n t s)
 :precision binary64
 (let* ((t_1 (+ 1.0 (exp (- s)))))
   (if (<= c_p 5e-41)
     (/
      (pow (- 1.0 (/ 1.0 t_1)) c_n)
      (pow (- 1.0 (/ 1.0 (+ 1.0 (exp (- t))))) c_n))
     (/ (+ (+ 1.0 s) 1.0) (* (+ 1.0 s) t_1)))))
double code(double c_p, double c_n, double t, double s) {
	double t_1 = 1.0 + exp(-s);
	double tmp;
	if (c_p <= 5e-41) {
		tmp = pow((1.0 - (1.0 / t_1)), c_n) / pow((1.0 - (1.0 / (1.0 + exp(-t)))), c_n);
	} else {
		tmp = ((1.0 + s) + 1.0) / ((1.0 + s) * t_1);
	}
	return tmp;
}
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(c_p, c_n, t, s)
use fmin_fmax_functions
    real(8), intent (in) :: c_p
    real(8), intent (in) :: c_n
    real(8), intent (in) :: t
    real(8), intent (in) :: s
    real(8) :: t_1
    real(8) :: tmp
    t_1 = 1.0d0 + exp(-s)
    if (c_p <= 5d-41) then
        tmp = ((1.0d0 - (1.0d0 / t_1)) ** c_n) / ((1.0d0 - (1.0d0 / (1.0d0 + exp(-t)))) ** c_n)
    else
        tmp = ((1.0d0 + s) + 1.0d0) / ((1.0d0 + s) * t_1)
    end if
    code = tmp
end function
public static double code(double c_p, double c_n, double t, double s) {
	double t_1 = 1.0 + Math.exp(-s);
	double tmp;
	if (c_p <= 5e-41) {
		tmp = Math.pow((1.0 - (1.0 / t_1)), c_n) / Math.pow((1.0 - (1.0 / (1.0 + Math.exp(-t)))), c_n);
	} else {
		tmp = ((1.0 + s) + 1.0) / ((1.0 + s) * t_1);
	}
	return tmp;
}
def code(c_p, c_n, t, s):
	t_1 = 1.0 + math.exp(-s)
	tmp = 0
	if c_p <= 5e-41:
		tmp = math.pow((1.0 - (1.0 / t_1)), c_n) / math.pow((1.0 - (1.0 / (1.0 + math.exp(-t)))), c_n)
	else:
		tmp = ((1.0 + s) + 1.0) / ((1.0 + s) * t_1)
	return tmp
function code(c_p, c_n, t, s)
	t_1 = Float64(1.0 + exp(Float64(-s)))
	tmp = 0.0
	if (c_p <= 5e-41)
		tmp = Float64((Float64(1.0 - Float64(1.0 / t_1)) ^ c_n) / (Float64(1.0 - Float64(1.0 / Float64(1.0 + exp(Float64(-t))))) ^ c_n));
	else
		tmp = Float64(Float64(Float64(1.0 + s) + 1.0) / Float64(Float64(1.0 + s) * t_1));
	end
	return tmp
end
function tmp_2 = code(c_p, c_n, t, s)
	t_1 = 1.0 + exp(-s);
	tmp = 0.0;
	if (c_p <= 5e-41)
		tmp = ((1.0 - (1.0 / t_1)) ^ c_n) / ((1.0 - (1.0 / (1.0 + exp(-t)))) ^ c_n);
	else
		tmp = ((1.0 + s) + 1.0) / ((1.0 + s) * t_1);
	end
	tmp_2 = tmp;
end
code[c$95$p_, c$95$n_, t_, s_] := Block[{t$95$1 = N[(1.0 + N[Exp[(-s)], $MachinePrecision]), $MachinePrecision]}, If[LessEqual[c$95$p, 5e-41], N[(N[Power[N[(1.0 - N[(1.0 / t$95$1), $MachinePrecision]), $MachinePrecision], c$95$n], $MachinePrecision] / N[Power[N[(1.0 - N[(1.0 / N[(1.0 + N[Exp[(-t)], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], c$95$n], $MachinePrecision]), $MachinePrecision], N[(N[(N[(1.0 + s), $MachinePrecision] + 1.0), $MachinePrecision] / N[(N[(1.0 + s), $MachinePrecision] * t$95$1), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
t_1 := 1 + e^{-s}\\
\mathbf{if}\;c\_p \leq 5 \cdot 10^{-41}:\\
\;\;\;\;\frac{{\left(1 - \frac{1}{t\_1}\right)}^{c\_n}}{{\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}}\\

\mathbf{else}:\\
\;\;\;\;\frac{\left(1 + s\right) + 1}{\left(1 + s\right) \cdot t\_1}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if c_p < 4.9999999999999996e-41

    1. Initial program 91.5%

      \[\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}} \]
    2. Taylor expanded in c_p around 0

      \[\leadsto \color{blue}{\frac{{\left(1 - \frac{1}{1 + e^{\mathsf{neg}\left(s\right)}}\right)}^{c\_n}}{{\left(1 - \frac{1}{1 + e^{\mathsf{neg}\left(t\right)}}\right)}^{c\_n}}} \]
    3. Applied rewrites94.5%

      \[\leadsto \color{blue}{\frac{{\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}}} \]

    if 4.9999999999999996e-41 < c_p

    1. Initial program 91.5%

      \[\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}} \]
    2. Taylor expanded in c_n around 0

      \[\leadsto \color{blue}{\frac{{\left(\frac{1}{1 + e^{\mathsf{neg}\left(s\right)}}\right)}^{c\_p}}{{\left(\frac{1}{1 + e^{\mathsf{neg}\left(t\right)}}\right)}^{c\_p}}} \]
    3. Applied rewrites93.3%

      \[\leadsto \color{blue}{\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}}} \]
    4. Taylor expanded in c_p around 0

      \[\leadsto 1 \]
    5. Applied rewrites94.7%

      \[\leadsto 1 \]
    6. Applied rewrites93.7%

      \[\leadsto \frac{e^{s} + 1}{e^{s} \cdot \color{blue}{\left(1 + e^{-s}\right)}} \]
    7. Taylor expanded in s around 0

      \[\leadsto \frac{\left(1 + s\right) + 1}{e^{s} \cdot \left(1 + e^{-s}\right)} \]
    8. Applied rewrites93.8%

      \[\leadsto \frac{\left(1 + s\right) + 1}{e^{s} \cdot \left(1 + e^{-s}\right)} \]
    9. Taylor expanded in s around 0

      \[\leadsto \frac{\left(1 + s\right) + 1}{\left(1 + s\right) \cdot \left(1 + e^{\color{blue}{-s}}\right)} \]
    10. Applied rewrites94.4%

      \[\leadsto \frac{\left(1 + s\right) + 1}{\left(1 + s\right) \cdot \left(1 + e^{\color{blue}{-s}}\right)} \]
  3. Recombined 2 regimes into one program.
  4. Add Preprocessing

Alternative 3: 96.0% accurate, 0.7× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_1 := \frac{1}{1 + e^{-t}}\\ t_2 := {t\_1}^{c\_p}\\ t_3 := \frac{1}{1 + e^{-s}}\\ t_4 := 1 - t\_1\\ \mathbf{if}\;\frac{{t\_3}^{c\_p} \cdot {\left(1 - t\_3\right)}^{c\_n}}{t\_2 \cdot {t\_4}^{c\_n}} \leq 2:\\ \;\;\;\;\frac{{\left(\frac{1}{2 + s \cdot \left(0.5 \cdot s - 1\right)}\right)}^{c\_p}}{t\_2}\\ \mathbf{else}:\\ \;\;\;\;\frac{{0.5}^{c\_n}}{1 + c\_n \cdot \log t\_4}\\ \end{array} \end{array} \]
(FPCore (c_p c_n t s)
 :precision binary64
 (let* ((t_1 (/ 1.0 (+ 1.0 (exp (- t)))))
        (t_2 (pow t_1 c_p))
        (t_3 (/ 1.0 (+ 1.0 (exp (- s)))))
        (t_4 (- 1.0 t_1)))
   (if (<=
        (/ (* (pow t_3 c_p) (pow (- 1.0 t_3) c_n)) (* t_2 (pow t_4 c_n)))
        2.0)
     (/ (pow (/ 1.0 (+ 2.0 (* s (- (* 0.5 s) 1.0)))) c_p) t_2)
     (/ (pow 0.5 c_n) (+ 1.0 (* c_n (log t_4)))))))
double code(double c_p, double c_n, double t, double s) {
	double t_1 = 1.0 / (1.0 + exp(-t));
	double t_2 = pow(t_1, c_p);
	double t_3 = 1.0 / (1.0 + exp(-s));
	double t_4 = 1.0 - t_1;
	double tmp;
	if (((pow(t_3, c_p) * pow((1.0 - t_3), c_n)) / (t_2 * pow(t_4, c_n))) <= 2.0) {
		tmp = pow((1.0 / (2.0 + (s * ((0.5 * s) - 1.0)))), c_p) / t_2;
	} else {
		tmp = pow(0.5, c_n) / (1.0 + (c_n * log(t_4)));
	}
	return tmp;
}
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(c_p, c_n, t, s)
use fmin_fmax_functions
    real(8), intent (in) :: c_p
    real(8), intent (in) :: c_n
    real(8), intent (in) :: t
    real(8), intent (in) :: s
    real(8) :: t_1
    real(8) :: t_2
    real(8) :: t_3
    real(8) :: t_4
    real(8) :: tmp
    t_1 = 1.0d0 / (1.0d0 + exp(-t))
    t_2 = t_1 ** c_p
    t_3 = 1.0d0 / (1.0d0 + exp(-s))
    t_4 = 1.0d0 - t_1
    if ((((t_3 ** c_p) * ((1.0d0 - t_3) ** c_n)) / (t_2 * (t_4 ** c_n))) <= 2.0d0) then
        tmp = ((1.0d0 / (2.0d0 + (s * ((0.5d0 * s) - 1.0d0)))) ** c_p) / t_2
    else
        tmp = (0.5d0 ** c_n) / (1.0d0 + (c_n * log(t_4)))
    end if
    code = tmp
end function
public static double code(double c_p, double c_n, double t, double s) {
	double t_1 = 1.0 / (1.0 + Math.exp(-t));
	double t_2 = Math.pow(t_1, c_p);
	double t_3 = 1.0 / (1.0 + Math.exp(-s));
	double t_4 = 1.0 - t_1;
	double tmp;
	if (((Math.pow(t_3, c_p) * Math.pow((1.0 - t_3), c_n)) / (t_2 * Math.pow(t_4, c_n))) <= 2.0) {
		tmp = Math.pow((1.0 / (2.0 + (s * ((0.5 * s) - 1.0)))), c_p) / t_2;
	} else {
		tmp = Math.pow(0.5, c_n) / (1.0 + (c_n * Math.log(t_4)));
	}
	return tmp;
}
def code(c_p, c_n, t, s):
	t_1 = 1.0 / (1.0 + math.exp(-t))
	t_2 = math.pow(t_1, c_p)
	t_3 = 1.0 / (1.0 + math.exp(-s))
	t_4 = 1.0 - t_1
	tmp = 0
	if ((math.pow(t_3, c_p) * math.pow((1.0 - t_3), c_n)) / (t_2 * math.pow(t_4, c_n))) <= 2.0:
		tmp = math.pow((1.0 / (2.0 + (s * ((0.5 * s) - 1.0)))), c_p) / t_2
	else:
		tmp = math.pow(0.5, c_n) / (1.0 + (c_n * math.log(t_4)))
	return tmp
function code(c_p, c_n, t, s)
	t_1 = Float64(1.0 / Float64(1.0 + exp(Float64(-t))))
	t_2 = t_1 ^ c_p
	t_3 = Float64(1.0 / Float64(1.0 + exp(Float64(-s))))
	t_4 = Float64(1.0 - t_1)
	tmp = 0.0
	if (Float64(Float64((t_3 ^ c_p) * (Float64(1.0 - t_3) ^ c_n)) / Float64(t_2 * (t_4 ^ c_n))) <= 2.0)
		tmp = Float64((Float64(1.0 / Float64(2.0 + Float64(s * Float64(Float64(0.5 * s) - 1.0)))) ^ c_p) / t_2);
	else
		tmp = Float64((0.5 ^ c_n) / Float64(1.0 + Float64(c_n * log(t_4))));
	end
	return tmp
end
function tmp_2 = code(c_p, c_n, t, s)
	t_1 = 1.0 / (1.0 + exp(-t));
	t_2 = t_1 ^ c_p;
	t_3 = 1.0 / (1.0 + exp(-s));
	t_4 = 1.0 - t_1;
	tmp = 0.0;
	if ((((t_3 ^ c_p) * ((1.0 - t_3) ^ c_n)) / (t_2 * (t_4 ^ c_n))) <= 2.0)
		tmp = ((1.0 / (2.0 + (s * ((0.5 * s) - 1.0)))) ^ c_p) / t_2;
	else
		tmp = (0.5 ^ c_n) / (1.0 + (c_n * log(t_4)));
	end
	tmp_2 = tmp;
end
code[c$95$p_, c$95$n_, t_, s_] := Block[{t$95$1 = N[(1.0 / N[(1.0 + N[Exp[(-t)], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]}, Block[{t$95$2 = N[Power[t$95$1, c$95$p], $MachinePrecision]}, Block[{t$95$3 = N[(1.0 / N[(1.0 + N[Exp[(-s)], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]}, Block[{t$95$4 = N[(1.0 - t$95$1), $MachinePrecision]}, If[LessEqual[N[(N[(N[Power[t$95$3, c$95$p], $MachinePrecision] * N[Power[N[(1.0 - t$95$3), $MachinePrecision], c$95$n], $MachinePrecision]), $MachinePrecision] / N[(t$95$2 * N[Power[t$95$4, c$95$n], $MachinePrecision]), $MachinePrecision]), $MachinePrecision], 2.0], N[(N[Power[N[(1.0 / N[(2.0 + N[(s * N[(N[(0.5 * s), $MachinePrecision] - 1.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], c$95$p], $MachinePrecision] / t$95$2), $MachinePrecision], N[(N[Power[0.5, c$95$n], $MachinePrecision] / N[(1.0 + N[(c$95$n * N[Log[t$95$4], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]]]]]
\begin{array}{l}

\\
\begin{array}{l}
t_1 := \frac{1}{1 + e^{-t}}\\
t_2 := {t\_1}^{c\_p}\\
t_3 := \frac{1}{1 + e^{-s}}\\
t_4 := 1 - t\_1\\
\mathbf{if}\;\frac{{t\_3}^{c\_p} \cdot {\left(1 - t\_3\right)}^{c\_n}}{t\_2 \cdot {t\_4}^{c\_n}} \leq 2:\\
\;\;\;\;\frac{{\left(\frac{1}{2 + s \cdot \left(0.5 \cdot s - 1\right)}\right)}^{c\_p}}{t\_2}\\

\mathbf{else}:\\
\;\;\;\;\frac{{0.5}^{c\_n}}{1 + c\_n \cdot \log t\_4}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if (/.f64 (*.f64 (pow.f64 (/.f64 #s(literal 1 binary64) (+.f64 #s(literal 1 binary64) (exp.f64 (neg.f64 s)))) c_p) (pow.f64 (-.f64 #s(literal 1 binary64) (/.f64 #s(literal 1 binary64) (+.f64 #s(literal 1 binary64) (exp.f64 (neg.f64 s))))) c_n)) (*.f64 (pow.f64 (/.f64 #s(literal 1 binary64) (+.f64 #s(literal 1 binary64) (exp.f64 (neg.f64 t)))) c_p) (pow.f64 (-.f64 #s(literal 1 binary64) (/.f64 #s(literal 1 binary64) (+.f64 #s(literal 1 binary64) (exp.f64 (neg.f64 t))))) c_n))) < 2

    1. Initial program 91.5%

      \[\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}} \]
    2. Taylor expanded in c_n around 0

      \[\leadsto \color{blue}{\frac{{\left(\frac{1}{1 + e^{\mathsf{neg}\left(s\right)}}\right)}^{c\_p}}{{\left(\frac{1}{1 + e^{\mathsf{neg}\left(t\right)}}\right)}^{c\_p}}} \]
    3. Applied rewrites93.3%

      \[\leadsto \color{blue}{\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}}} \]
    4. Taylor expanded in s around 0

      \[\leadsto \frac{{\left(\frac{1}{2 + s \cdot \left(\frac{1}{2} \cdot s - 1\right)}\right)}^{c\_p}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}} \]
    5. Applied rewrites94.0%

      \[\leadsto \frac{{\left(\frac{1}{2 + s \cdot \left(0.5 \cdot s - 1\right)}\right)}^{c\_p}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}} \]

    if 2 < (/.f64 (*.f64 (pow.f64 (/.f64 #s(literal 1 binary64) (+.f64 #s(literal 1 binary64) (exp.f64 (neg.f64 s)))) c_p) (pow.f64 (-.f64 #s(literal 1 binary64) (/.f64 #s(literal 1 binary64) (+.f64 #s(literal 1 binary64) (exp.f64 (neg.f64 s))))) c_n)) (*.f64 (pow.f64 (/.f64 #s(literal 1 binary64) (+.f64 #s(literal 1 binary64) (exp.f64 (neg.f64 t)))) c_p) (pow.f64 (-.f64 #s(literal 1 binary64) (/.f64 #s(literal 1 binary64) (+.f64 #s(literal 1 binary64) (exp.f64 (neg.f64 t))))) c_n)))

    1. Initial program 91.5%

      \[\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}} \]
    2. Taylor expanded in c_p around 0

      \[\leadsto \color{blue}{\frac{{\left(1 - \frac{1}{1 + e^{\mathsf{neg}\left(s\right)}}\right)}^{c\_n}}{{\left(1 - \frac{1}{1 + e^{\mathsf{neg}\left(t\right)}}\right)}^{c\_n}}} \]
    3. Applied rewrites94.5%

      \[\leadsto \color{blue}{\frac{{\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}}} \]
    4. Taylor expanded in s around 0

      \[\leadsto \frac{{\frac{1}{2}}^{c\_n}}{\color{blue}{{\left(1 - \frac{1}{1 + e^{\mathsf{neg}\left(t\right)}}\right)}^{c\_n}}} \]
    5. Applied rewrites94.2%

      \[\leadsto \frac{{0.5}^{c\_n}}{\color{blue}{{\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}}} \]
    6. Taylor expanded in c_n around 0

      \[\leadsto \frac{{\frac{1}{2}}^{c\_n}}{1 + c\_n \cdot \color{blue}{\log \left(1 - \frac{1}{1 + e^{\mathsf{neg}\left(t\right)}}\right)}} \]
    7. Applied rewrites93.6%

      \[\leadsto \frac{{0.5}^{c\_n}}{1 + c\_n \cdot \color{blue}{\log \left(1 - \frac{1}{1 + e^{-t}}\right)}} \]
  3. Recombined 2 regimes into one program.
  4. Add Preprocessing

Alternative 4: 95.9% accurate, 2.5× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;c\_p \leq 5 \cdot 10^{-41}:\\ \;\;\;\;\frac{{0.5}^{c\_n}}{{\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}}\\ \mathbf{else}:\\ \;\;\;\;\frac{\left(1 + s\right) + 1}{\left(1 + s\right) \cdot \left(1 + e^{-s}\right)}\\ \end{array} \end{array} \]
(FPCore (c_p c_n t s)
 :precision binary64
 (if (<= c_p 5e-41)
   (/ (pow 0.5 c_n) (pow (- 1.0 (/ 1.0 (+ 1.0 (exp (- t))))) c_n))
   (/ (+ (+ 1.0 s) 1.0) (* (+ 1.0 s) (+ 1.0 (exp (- s)))))))
double code(double c_p, double c_n, double t, double s) {
	double tmp;
	if (c_p <= 5e-41) {
		tmp = pow(0.5, c_n) / pow((1.0 - (1.0 / (1.0 + exp(-t)))), c_n);
	} else {
		tmp = ((1.0 + s) + 1.0) / ((1.0 + s) * (1.0 + exp(-s)));
	}
	return tmp;
}
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(c_p, c_n, t, s)
use fmin_fmax_functions
    real(8), intent (in) :: c_p
    real(8), intent (in) :: c_n
    real(8), intent (in) :: t
    real(8), intent (in) :: s
    real(8) :: tmp
    if (c_p <= 5d-41) then
        tmp = (0.5d0 ** c_n) / ((1.0d0 - (1.0d0 / (1.0d0 + exp(-t)))) ** c_n)
    else
        tmp = ((1.0d0 + s) + 1.0d0) / ((1.0d0 + s) * (1.0d0 + exp(-s)))
    end if
    code = tmp
end function
public static double code(double c_p, double c_n, double t, double s) {
	double tmp;
	if (c_p <= 5e-41) {
		tmp = Math.pow(0.5, c_n) / Math.pow((1.0 - (1.0 / (1.0 + Math.exp(-t)))), c_n);
	} else {
		tmp = ((1.0 + s) + 1.0) / ((1.0 + s) * (1.0 + Math.exp(-s)));
	}
	return tmp;
}
def code(c_p, c_n, t, s):
	tmp = 0
	if c_p <= 5e-41:
		tmp = math.pow(0.5, c_n) / math.pow((1.0 - (1.0 / (1.0 + math.exp(-t)))), c_n)
	else:
		tmp = ((1.0 + s) + 1.0) / ((1.0 + s) * (1.0 + math.exp(-s)))
	return tmp
function code(c_p, c_n, t, s)
	tmp = 0.0
	if (c_p <= 5e-41)
		tmp = Float64((0.5 ^ c_n) / (Float64(1.0 - Float64(1.0 / Float64(1.0 + exp(Float64(-t))))) ^ c_n));
	else
		tmp = Float64(Float64(Float64(1.0 + s) + 1.0) / Float64(Float64(1.0 + s) * Float64(1.0 + exp(Float64(-s)))));
	end
	return tmp
end
function tmp_2 = code(c_p, c_n, t, s)
	tmp = 0.0;
	if (c_p <= 5e-41)
		tmp = (0.5 ^ c_n) / ((1.0 - (1.0 / (1.0 + exp(-t)))) ^ c_n);
	else
		tmp = ((1.0 + s) + 1.0) / ((1.0 + s) * (1.0 + exp(-s)));
	end
	tmp_2 = tmp;
end
code[c$95$p_, c$95$n_, t_, s_] := If[LessEqual[c$95$p, 5e-41], N[(N[Power[0.5, c$95$n], $MachinePrecision] / N[Power[N[(1.0 - N[(1.0 / N[(1.0 + N[Exp[(-t)], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], c$95$n], $MachinePrecision]), $MachinePrecision], N[(N[(N[(1.0 + s), $MachinePrecision] + 1.0), $MachinePrecision] / N[(N[(1.0 + s), $MachinePrecision] * N[(1.0 + N[Exp[(-s)], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;c\_p \leq 5 \cdot 10^{-41}:\\
\;\;\;\;\frac{{0.5}^{c\_n}}{{\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}}\\

\mathbf{else}:\\
\;\;\;\;\frac{\left(1 + s\right) + 1}{\left(1 + s\right) \cdot \left(1 + e^{-s}\right)}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if c_p < 4.9999999999999996e-41

    1. Initial program 91.5%

      \[\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}} \]
    2. Taylor expanded in c_p around 0

      \[\leadsto \color{blue}{\frac{{\left(1 - \frac{1}{1 + e^{\mathsf{neg}\left(s\right)}}\right)}^{c\_n}}{{\left(1 - \frac{1}{1 + e^{\mathsf{neg}\left(t\right)}}\right)}^{c\_n}}} \]
    3. Applied rewrites94.5%

      \[\leadsto \color{blue}{\frac{{\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}}} \]
    4. Taylor expanded in s around 0

      \[\leadsto \frac{{\frac{1}{2}}^{c\_n}}{\color{blue}{{\left(1 - \frac{1}{1 + e^{\mathsf{neg}\left(t\right)}}\right)}^{c\_n}}} \]
    5. Applied rewrites94.2%

      \[\leadsto \frac{{0.5}^{c\_n}}{\color{blue}{{\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}}} \]

    if 4.9999999999999996e-41 < c_p

    1. Initial program 91.5%

      \[\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}} \]
    2. Taylor expanded in c_n around 0

      \[\leadsto \color{blue}{\frac{{\left(\frac{1}{1 + e^{\mathsf{neg}\left(s\right)}}\right)}^{c\_p}}{{\left(\frac{1}{1 + e^{\mathsf{neg}\left(t\right)}}\right)}^{c\_p}}} \]
    3. Applied rewrites93.3%

      \[\leadsto \color{blue}{\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}}} \]
    4. Taylor expanded in c_p around 0

      \[\leadsto 1 \]
    5. Applied rewrites94.7%

      \[\leadsto 1 \]
    6. Applied rewrites93.7%

      \[\leadsto \frac{e^{s} + 1}{e^{s} \cdot \color{blue}{\left(1 + e^{-s}\right)}} \]
    7. Taylor expanded in s around 0

      \[\leadsto \frac{\left(1 + s\right) + 1}{e^{s} \cdot \left(1 + e^{-s}\right)} \]
    8. Applied rewrites93.8%

      \[\leadsto \frac{\left(1 + s\right) + 1}{e^{s} \cdot \left(1 + e^{-s}\right)} \]
    9. Taylor expanded in s around 0

      \[\leadsto \frac{\left(1 + s\right) + 1}{\left(1 + s\right) \cdot \left(1 + e^{\color{blue}{-s}}\right)} \]
    10. Applied rewrites94.4%

      \[\leadsto \frac{\left(1 + s\right) + 1}{\left(1 + s\right) \cdot \left(1 + e^{\color{blue}{-s}}\right)} \]
  3. Recombined 2 regimes into one program.
  4. Add Preprocessing

Alternative 5: 95.9% accurate, 4.2× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;c\_n \leq 110000:\\ \;\;\;\;\frac{\left(1 + s\right) + 1}{\left(1 + s\right) \cdot \left(1 + e^{-s}\right)}\\ \mathbf{else}:\\ \;\;\;\;\frac{{0.5}^{c\_n}}{1 + c\_n \cdot \log 0.5}\\ \end{array} \end{array} \]
(FPCore (c_p c_n t s)
 :precision binary64
 (if (<= c_n 110000.0)
   (/ (+ (+ 1.0 s) 1.0) (* (+ 1.0 s) (+ 1.0 (exp (- s)))))
   (/ (pow 0.5 c_n) (+ 1.0 (* c_n (log 0.5))))))
double code(double c_p, double c_n, double t, double s) {
	double tmp;
	if (c_n <= 110000.0) {
		tmp = ((1.0 + s) + 1.0) / ((1.0 + s) * (1.0 + exp(-s)));
	} else {
		tmp = pow(0.5, c_n) / (1.0 + (c_n * log(0.5)));
	}
	return tmp;
}
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(c_p, c_n, t, s)
use fmin_fmax_functions
    real(8), intent (in) :: c_p
    real(8), intent (in) :: c_n
    real(8), intent (in) :: t
    real(8), intent (in) :: s
    real(8) :: tmp
    if (c_n <= 110000.0d0) then
        tmp = ((1.0d0 + s) + 1.0d0) / ((1.0d0 + s) * (1.0d0 + exp(-s)))
    else
        tmp = (0.5d0 ** c_n) / (1.0d0 + (c_n * log(0.5d0)))
    end if
    code = tmp
end function
public static double code(double c_p, double c_n, double t, double s) {
	double tmp;
	if (c_n <= 110000.0) {
		tmp = ((1.0 + s) + 1.0) / ((1.0 + s) * (1.0 + Math.exp(-s)));
	} else {
		tmp = Math.pow(0.5, c_n) / (1.0 + (c_n * Math.log(0.5)));
	}
	return tmp;
}
def code(c_p, c_n, t, s):
	tmp = 0
	if c_n <= 110000.0:
		tmp = ((1.0 + s) + 1.0) / ((1.0 + s) * (1.0 + math.exp(-s)))
	else:
		tmp = math.pow(0.5, c_n) / (1.0 + (c_n * math.log(0.5)))
	return tmp
function code(c_p, c_n, t, s)
	tmp = 0.0
	if (c_n <= 110000.0)
		tmp = Float64(Float64(Float64(1.0 + s) + 1.0) / Float64(Float64(1.0 + s) * Float64(1.0 + exp(Float64(-s)))));
	else
		tmp = Float64((0.5 ^ c_n) / Float64(1.0 + Float64(c_n * log(0.5))));
	end
	return tmp
end
function tmp_2 = code(c_p, c_n, t, s)
	tmp = 0.0;
	if (c_n <= 110000.0)
		tmp = ((1.0 + s) + 1.0) / ((1.0 + s) * (1.0 + exp(-s)));
	else
		tmp = (0.5 ^ c_n) / (1.0 + (c_n * log(0.5)));
	end
	tmp_2 = tmp;
end
code[c$95$p_, c$95$n_, t_, s_] := If[LessEqual[c$95$n, 110000.0], N[(N[(N[(1.0 + s), $MachinePrecision] + 1.0), $MachinePrecision] / N[(N[(1.0 + s), $MachinePrecision] * N[(1.0 + N[Exp[(-s)], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(N[Power[0.5, c$95$n], $MachinePrecision] / N[(1.0 + N[(c$95$n * N[Log[0.5], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;c\_n \leq 110000:\\
\;\;\;\;\frac{\left(1 + s\right) + 1}{\left(1 + s\right) \cdot \left(1 + e^{-s}\right)}\\

\mathbf{else}:\\
\;\;\;\;\frac{{0.5}^{c\_n}}{1 + c\_n \cdot \log 0.5}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if c_n < 1.1e5

    1. Initial program 91.5%

      \[\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}} \]
    2. Taylor expanded in c_n around 0

      \[\leadsto \color{blue}{\frac{{\left(\frac{1}{1 + e^{\mathsf{neg}\left(s\right)}}\right)}^{c\_p}}{{\left(\frac{1}{1 + e^{\mathsf{neg}\left(t\right)}}\right)}^{c\_p}}} \]
    3. Applied rewrites93.3%

      \[\leadsto \color{blue}{\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}}} \]
    4. Taylor expanded in c_p around 0

      \[\leadsto 1 \]
    5. Applied rewrites94.7%

      \[\leadsto 1 \]
    6. Applied rewrites93.7%

      \[\leadsto \frac{e^{s} + 1}{e^{s} \cdot \color{blue}{\left(1 + e^{-s}\right)}} \]
    7. Taylor expanded in s around 0

      \[\leadsto \frac{\left(1 + s\right) + 1}{e^{s} \cdot \left(1 + e^{-s}\right)} \]
    8. Applied rewrites93.8%

      \[\leadsto \frac{\left(1 + s\right) + 1}{e^{s} \cdot \left(1 + e^{-s}\right)} \]
    9. Taylor expanded in s around 0

      \[\leadsto \frac{\left(1 + s\right) + 1}{\left(1 + s\right) \cdot \left(1 + e^{\color{blue}{-s}}\right)} \]
    10. Applied rewrites94.4%

      \[\leadsto \frac{\left(1 + s\right) + 1}{\left(1 + s\right) \cdot \left(1 + e^{\color{blue}{-s}}\right)} \]

    if 1.1e5 < c_n

    1. Initial program 91.5%

      \[\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}} \]
    2. Taylor expanded in c_p around 0

      \[\leadsto \color{blue}{\frac{{\left(1 - \frac{1}{1 + e^{\mathsf{neg}\left(s\right)}}\right)}^{c\_n}}{{\left(1 - \frac{1}{1 + e^{\mathsf{neg}\left(t\right)}}\right)}^{c\_n}}} \]
    3. Applied rewrites94.5%

      \[\leadsto \color{blue}{\frac{{\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}}} \]
    4. Taylor expanded in s around 0

      \[\leadsto \frac{{\frac{1}{2}}^{c\_n}}{\color{blue}{{\left(1 - \frac{1}{1 + e^{\mathsf{neg}\left(t\right)}}\right)}^{c\_n}}} \]
    5. Applied rewrites94.2%

      \[\leadsto \frac{{0.5}^{c\_n}}{\color{blue}{{\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}}} \]
    6. Taylor expanded in c_n around 0

      \[\leadsto \frac{{\frac{1}{2}}^{c\_n}}{1 + c\_n \cdot \color{blue}{\log \left(1 - \frac{1}{1 + e^{\mathsf{neg}\left(t\right)}}\right)}} \]
    7. Applied rewrites93.6%

      \[\leadsto \frac{{0.5}^{c\_n}}{1 + c\_n \cdot \color{blue}{\log \left(1 - \frac{1}{1 + e^{-t}}\right)}} \]
    8. Taylor expanded in t around 0

      \[\leadsto \frac{{\frac{1}{2}}^{c\_n}}{1 + c\_n \cdot \log \frac{1}{2}} \]
    9. Applied rewrites93.5%

      \[\leadsto \frac{{0.5}^{c\_n}}{1 + c\_n \cdot \log 0.5} \]
  3. Recombined 2 regimes into one program.
  4. Add Preprocessing

Alternative 6: 95.0% accurate, 4.5× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;c\_p \leq 10^{-17}:\\ \;\;\;\;\mathsf{fma}\left(t \cdot 0.5, c\_n, 1\right)\\ \mathbf{else}:\\ \;\;\;\;\frac{\left(1 + s\right) + 1}{\left(1 + s\right) \cdot \left(1 + e^{-s}\right)}\\ \end{array} \end{array} \]
(FPCore (c_p c_n t s)
 :precision binary64
 (if (<= c_p 1e-17)
   (fma (* t 0.5) c_n 1.0)
   (/ (+ (+ 1.0 s) 1.0) (* (+ 1.0 s) (+ 1.0 (exp (- s)))))))
double code(double c_p, double c_n, double t, double s) {
	double tmp;
	if (c_p <= 1e-17) {
		tmp = fma((t * 0.5), c_n, 1.0);
	} else {
		tmp = ((1.0 + s) + 1.0) / ((1.0 + s) * (1.0 + exp(-s)));
	}
	return tmp;
}
function code(c_p, c_n, t, s)
	tmp = 0.0
	if (c_p <= 1e-17)
		tmp = fma(Float64(t * 0.5), c_n, 1.0);
	else
		tmp = Float64(Float64(Float64(1.0 + s) + 1.0) / Float64(Float64(1.0 + s) * Float64(1.0 + exp(Float64(-s)))));
	end
	return tmp
end
code[c$95$p_, c$95$n_, t_, s_] := If[LessEqual[c$95$p, 1e-17], N[(N[(t * 0.5), $MachinePrecision] * c$95$n + 1.0), $MachinePrecision], N[(N[(N[(1.0 + s), $MachinePrecision] + 1.0), $MachinePrecision] / N[(N[(1.0 + s), $MachinePrecision] * N[(1.0 + N[Exp[(-s)], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;c\_p \leq 10^{-17}:\\
\;\;\;\;\mathsf{fma}\left(t \cdot 0.5, c\_n, 1\right)\\

\mathbf{else}:\\
\;\;\;\;\frac{\left(1 + s\right) + 1}{\left(1 + s\right) \cdot \left(1 + e^{-s}\right)}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if c_p < 1.00000000000000007e-17

    1. Initial program 91.5%

      \[\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}} \]
    2. Taylor expanded in c_p around 0

      \[\leadsto \color{blue}{\frac{{\left(1 - \frac{1}{1 + e^{\mathsf{neg}\left(s\right)}}\right)}^{c\_n}}{{\left(1 - \frac{1}{1 + e^{\mathsf{neg}\left(t\right)}}\right)}^{c\_n}}} \]
    3. Applied rewrites94.5%

      \[\leadsto \color{blue}{\frac{{\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}}} \]
    4. Taylor expanded in s around 0

      \[\leadsto \frac{{\frac{1}{2}}^{c\_n}}{\color{blue}{{\left(1 - \frac{1}{1 + e^{\mathsf{neg}\left(t\right)}}\right)}^{c\_n}}} \]
    5. Applied rewrites94.2%

      \[\leadsto \frac{{0.5}^{c\_n}}{\color{blue}{{\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}}} \]
    6. Taylor expanded in t around 0

      \[\leadsto 1 + \frac{1}{2} \cdot \color{blue}{\left(c\_n \cdot t\right)} \]
    7. Applied rewrites94.7%

      \[\leadsto 1 + 0.5 \cdot \color{blue}{\left(c\_n \cdot t\right)} \]
    8. Applied rewrites94.7%

      \[\leadsto \mathsf{fma}\left(t \cdot 0.5, \color{blue}{c\_n}, 1\right) \]

    if 1.00000000000000007e-17 < c_p

    1. Initial program 91.5%

      \[\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}} \]
    2. Taylor expanded in c_n around 0

      \[\leadsto \color{blue}{\frac{{\left(\frac{1}{1 + e^{\mathsf{neg}\left(s\right)}}\right)}^{c\_p}}{{\left(\frac{1}{1 + e^{\mathsf{neg}\left(t\right)}}\right)}^{c\_p}}} \]
    3. Applied rewrites93.3%

      \[\leadsto \color{blue}{\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}}} \]
    4. Taylor expanded in c_p around 0

      \[\leadsto 1 \]
    5. Applied rewrites94.7%

      \[\leadsto 1 \]
    6. Applied rewrites93.7%

      \[\leadsto \frac{e^{s} + 1}{e^{s} \cdot \color{blue}{\left(1 + e^{-s}\right)}} \]
    7. Taylor expanded in s around 0

      \[\leadsto \frac{\left(1 + s\right) + 1}{e^{s} \cdot \left(1 + e^{-s}\right)} \]
    8. Applied rewrites93.8%

      \[\leadsto \frac{\left(1 + s\right) + 1}{e^{s} \cdot \left(1 + e^{-s}\right)} \]
    9. Taylor expanded in s around 0

      \[\leadsto \frac{\left(1 + s\right) + 1}{\left(1 + s\right) \cdot \left(1 + e^{\color{blue}{-s}}\right)} \]
    10. Applied rewrites94.4%

      \[\leadsto \frac{\left(1 + s\right) + 1}{\left(1 + s\right) \cdot \left(1 + e^{\color{blue}{-s}}\right)} \]
  3. Recombined 2 regimes into one program.
  4. Add Preprocessing

Alternative 7: 94.7% accurate, 16.5× speedup?

\[\begin{array}{l} \\ \mathsf{fma}\left(t \cdot 0.5, c\_n, 1\right) \end{array} \]
(FPCore (c_p c_n t s) :precision binary64 (fma (* t 0.5) c_n 1.0))
double code(double c_p, double c_n, double t, double s) {
	return fma((t * 0.5), c_n, 1.0);
}
function code(c_p, c_n, t, s)
	return fma(Float64(t * 0.5), c_n, 1.0)
end
code[c$95$p_, c$95$n_, t_, s_] := N[(N[(t * 0.5), $MachinePrecision] * c$95$n + 1.0), $MachinePrecision]
\begin{array}{l}

\\
\mathsf{fma}\left(t \cdot 0.5, c\_n, 1\right)
\end{array}
Derivation
  1. Initial program 91.5%

    \[\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}} \]
  2. Taylor expanded in c_p around 0

    \[\leadsto \color{blue}{\frac{{\left(1 - \frac{1}{1 + e^{\mathsf{neg}\left(s\right)}}\right)}^{c\_n}}{{\left(1 - \frac{1}{1 + e^{\mathsf{neg}\left(t\right)}}\right)}^{c\_n}}} \]
  3. Applied rewrites94.5%

    \[\leadsto \color{blue}{\frac{{\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}}} \]
  4. Taylor expanded in s around 0

    \[\leadsto \frac{{\frac{1}{2}}^{c\_n}}{\color{blue}{{\left(1 - \frac{1}{1 + e^{\mathsf{neg}\left(t\right)}}\right)}^{c\_n}}} \]
  5. Applied rewrites94.2%

    \[\leadsto \frac{{0.5}^{c\_n}}{\color{blue}{{\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}}} \]
  6. Taylor expanded in t around 0

    \[\leadsto 1 + \frac{1}{2} \cdot \color{blue}{\left(c\_n \cdot t\right)} \]
  7. Applied rewrites94.7%

    \[\leadsto 1 + 0.5 \cdot \color{blue}{\left(c\_n \cdot t\right)} \]
  8. Applied rewrites94.7%

    \[\leadsto \mathsf{fma}\left(t \cdot 0.5, \color{blue}{c\_n}, 1\right) \]
  9. Add Preprocessing

Alternative 8: 94.7% accurate, 147.6× speedup?

\[\begin{array}{l} \\ 1 \end{array} \]
(FPCore (c_p c_n t s) :precision binary64 1.0)
double code(double c_p, double c_n, double t, double s) {
	return 1.0;
}
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(c_p, c_n, t, s)
use fmin_fmax_functions
    real(8), intent (in) :: c_p
    real(8), intent (in) :: c_n
    real(8), intent (in) :: t
    real(8), intent (in) :: s
    code = 1.0d0
end function
public static double code(double c_p, double c_n, double t, double s) {
	return 1.0;
}
def code(c_p, c_n, t, s):
	return 1.0
function code(c_p, c_n, t, s)
	return 1.0
end
function tmp = code(c_p, c_n, t, s)
	tmp = 1.0;
end
code[c$95$p_, c$95$n_, t_, s_] := 1.0
\begin{array}{l}

\\
1
\end{array}
Derivation
  1. Initial program 91.5%

    \[\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}} \]
  2. Taylor expanded in c_n around 0

    \[\leadsto \color{blue}{\frac{{\left(\frac{1}{1 + e^{\mathsf{neg}\left(s\right)}}\right)}^{c\_p}}{{\left(\frac{1}{1 + e^{\mathsf{neg}\left(t\right)}}\right)}^{c\_p}}} \]
  3. Applied rewrites93.3%

    \[\leadsto \color{blue}{\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}}} \]
  4. Taylor expanded in c_p around 0

    \[\leadsto 1 \]
  5. Applied rewrites94.7%

    \[\leadsto 1 \]
  6. Add Preprocessing

Developer Target 1: 96.6% accurate, 1.5× speedup?

\[\begin{array}{l} \\ {\left(\frac{1 + e^{-t}}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(\frac{1 + e^{t}}{1 + e^{s}}\right)}^{c\_n} \end{array} \]
(FPCore (c_p c_n t s)
 :precision binary64
 (*
  (pow (/ (+ 1.0 (exp (- t))) (+ 1.0 (exp (- s)))) c_p)
  (pow (/ (+ 1.0 (exp t)) (+ 1.0 (exp s))) c_n)))
double code(double c_p, double c_n, double t, double s) {
	return pow(((1.0 + exp(-t)) / (1.0 + exp(-s))), c_p) * pow(((1.0 + exp(t)) / (1.0 + exp(s))), c_n);
}
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(c_p, c_n, t, s)
use fmin_fmax_functions
    real(8), intent (in) :: c_p
    real(8), intent (in) :: c_n
    real(8), intent (in) :: t
    real(8), intent (in) :: s
    code = (((1.0d0 + exp(-t)) / (1.0d0 + exp(-s))) ** c_p) * (((1.0d0 + exp(t)) / (1.0d0 + exp(s))) ** c_n)
end function
public static double code(double c_p, double c_n, double t, double s) {
	return Math.pow(((1.0 + Math.exp(-t)) / (1.0 + Math.exp(-s))), c_p) * Math.pow(((1.0 + Math.exp(t)) / (1.0 + Math.exp(s))), c_n);
}
def code(c_p, c_n, t, s):
	return math.pow(((1.0 + math.exp(-t)) / (1.0 + math.exp(-s))), c_p) * math.pow(((1.0 + math.exp(t)) / (1.0 + math.exp(s))), c_n)
function code(c_p, c_n, t, s)
	return Float64((Float64(Float64(1.0 + exp(Float64(-t))) / Float64(1.0 + exp(Float64(-s)))) ^ c_p) * (Float64(Float64(1.0 + exp(t)) / Float64(1.0 + exp(s))) ^ c_n))
end
function tmp = code(c_p, c_n, t, s)
	tmp = (((1.0 + exp(-t)) / (1.0 + exp(-s))) ^ c_p) * (((1.0 + exp(t)) / (1.0 + exp(s))) ^ c_n);
end
code[c$95$p_, c$95$n_, t_, s_] := N[(N[Power[N[(N[(1.0 + N[Exp[(-t)], $MachinePrecision]), $MachinePrecision] / N[(1.0 + N[Exp[(-s)], $MachinePrecision]), $MachinePrecision]), $MachinePrecision], c$95$p], $MachinePrecision] * N[Power[N[(N[(1.0 + N[Exp[t], $MachinePrecision]), $MachinePrecision] / N[(1.0 + N[Exp[s], $MachinePrecision]), $MachinePrecision]), $MachinePrecision], c$95$n], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
{\left(\frac{1 + e^{-t}}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(\frac{1 + e^{t}}{1 + e^{s}}\right)}^{c\_n}
\end{array}

Reproduce

?
herbie shell --seed 2025153 
(FPCore (c_p c_n t s)
  :name "Harley's example"
  :precision binary64
  :pre (and (< 0.0 c_p) (< 0.0 c_n))

  :alt
  (! :herbie-platform c (* (pow (/ (+ 1 (exp (- t))) (+ 1 (exp (- s)))) c_p) (pow (/ (+ 1 (exp t)) (+ 1 (exp s))) c_n)))

  (/ (* (pow (/ 1.0 (+ 1.0 (exp (- s)))) c_p) (pow (- 1.0 (/ 1.0 (+ 1.0 (exp (- s))))) c_n)) (* (pow (/ 1.0 (+ 1.0 (exp (- t)))) c_p) (pow (- 1.0 (/ 1.0 (+ 1.0 (exp (- t))))) c_n))))