Harley's example

Percentage Accurate: 90.9% → 96.7%
Time: 1.3min
Alternatives: 7
Speedup: 835.0×

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));
}
real(8) function code(c_p, c_n, t, s)
    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}

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 7 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: 90.9% 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));
}
real(8) function code(c_p, c_n, t, s)
    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: 96.7% accurate, 2.6× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;-s \leq -2 \cdot 10^{+113} \lor \neg \left(-s \leq 2 \cdot 10^{-100}\right):\\ \;\;\;\;{\left(\frac{1}{2 + s \cdot \left(s \cdot \left(0.5 + s \cdot -0.16666666666666666\right) + -1\right)}\right)}^{c\_p}\\ \mathbf{else}:\\ \;\;\;\;1 - {\left(\sqrt[3]{t \cdot \mathsf{fma}\left(-0.5, c\_n, c\_p \cdot 0.5\right)}\right)}^{3}\\ \end{array} \end{array} \]
(FPCore (c_p c_n t s)
 :precision binary64
 (if (or (<= (- s) -2e+113) (not (<= (- s) 2e-100)))
   (pow
    (/ 1.0 (+ 2.0 (* s (+ (* s (+ 0.5 (* s -0.16666666666666666))) -1.0))))
    c_p)
   (- 1.0 (pow (cbrt (* t (fma -0.5 c_n (* c_p 0.5)))) 3.0))))
double code(double c_p, double c_n, double t, double s) {
	double tmp;
	if ((-s <= -2e+113) || !(-s <= 2e-100)) {
		tmp = pow((1.0 / (2.0 + (s * ((s * (0.5 + (s * -0.16666666666666666))) + -1.0)))), c_p);
	} else {
		tmp = 1.0 - pow(cbrt((t * fma(-0.5, c_n, (c_p * 0.5)))), 3.0);
	}
	return tmp;
}
function code(c_p, c_n, t, s)
	tmp = 0.0
	if ((Float64(-s) <= -2e+113) || !(Float64(-s) <= 2e-100))
		tmp = Float64(1.0 / Float64(2.0 + Float64(s * Float64(Float64(s * Float64(0.5 + Float64(s * -0.16666666666666666))) + -1.0)))) ^ c_p;
	else
		tmp = Float64(1.0 - (cbrt(Float64(t * fma(-0.5, c_n, Float64(c_p * 0.5)))) ^ 3.0));
	end
	return tmp
end
code[c$95$p_, c$95$n_, t_, s_] := If[Or[LessEqual[(-s), -2e+113], N[Not[LessEqual[(-s), 2e-100]], $MachinePrecision]], N[Power[N[(1.0 / N[(2.0 + N[(s * N[(N[(s * N[(0.5 + N[(s * -0.16666666666666666), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + -1.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], c$95$p], $MachinePrecision], N[(1.0 - N[Power[N[Power[N[(t * N[(-0.5 * c$95$n + N[(c$95$p * 0.5), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], 1/3], $MachinePrecision], 3.0], $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;-s \leq -2 \cdot 10^{+113} \lor \neg \left(-s \leq 2 \cdot 10^{-100}\right):\\
\;\;\;\;{\left(\frac{1}{2 + s \cdot \left(s \cdot \left(0.5 + s \cdot -0.16666666666666666\right) + -1\right)}\right)}^{c\_p}\\

\mathbf{else}:\\
\;\;\;\;1 - {\left(\sqrt[3]{t \cdot \mathsf{fma}\left(-0.5, c\_n, c\_p \cdot 0.5\right)}\right)}^{3}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if (neg.f64 s) < -2e113 or 2e-100 < (neg.f64 s)

    1. Initial program 83.5%

      \[\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}} \]
    2. Step-by-step derivation
      1. associate-/l/83.5%

        \[\leadsto \color{blue}{\frac{\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}}} \]
    3. Simplified83.5%

      \[\leadsto \color{blue}{\frac{\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 + \frac{1}{-1 - e^{-s}}\right)}^{c\_n}}{{\left(1 + \frac{1}{-1 - e^{-t}}\right)}^{c\_n}}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}}} \]
    4. Add Preprocessing
    5. Taylor expanded in c_n around 0 79.7%

      \[\leadsto \frac{\color{blue}{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p}}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}} \]
    6. Taylor expanded in s around 0 93.8%

      \[\leadsto \frac{{\left(\frac{1}{\color{blue}{2 + s \cdot \left(s \cdot \left(0.5 + -0.16666666666666666 \cdot s\right) - 1\right)}}\right)}^{c\_p}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}} \]
    7. Taylor expanded in c_p around 0 100.0%

      \[\leadsto \frac{{\left(\frac{1}{2 + s \cdot \left(s \cdot \left(0.5 + -0.16666666666666666 \cdot s\right) - 1\right)}\right)}^{c\_p}}{\color{blue}{1}} \]

    if -2e113 < (neg.f64 s) < 2e-100

    1. Initial program 96.1%

      \[\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}} \]
    2. Step-by-step derivation
      1. associate-/l/96.1%

        \[\leadsto \color{blue}{\frac{\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}}} \]
    3. Simplified96.1%

      \[\leadsto \color{blue}{\frac{\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 + \frac{1}{-1 - e^{-s}}\right)}^{c\_n}}{{\left(1 + \frac{1}{-1 - e^{-t}}\right)}^{c\_n}}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}}} \]
    4. Add Preprocessing
    5. Taylor expanded in s around 0 97.1%

      \[\leadsto \frac{\color{blue}{\frac{{0.5}^{c\_n} \cdot {0.5}^{c\_p}}{{\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}}}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}} \]
    6. Taylor expanded in t around 0 99.2%

      \[\leadsto \color{blue}{1 + -1 \cdot \left(t \cdot \left(-0.5 \cdot c\_n + 0.5 \cdot c\_p\right)\right)} \]
    7. Step-by-step derivation
      1. add-cube-cbrt99.2%

        \[\leadsto 1 + -1 \cdot \color{blue}{\left(\left(\sqrt[3]{t \cdot \left(-0.5 \cdot c\_n + 0.5 \cdot c\_p\right)} \cdot \sqrt[3]{t \cdot \left(-0.5 \cdot c\_n + 0.5 \cdot c\_p\right)}\right) \cdot \sqrt[3]{t \cdot \left(-0.5 \cdot c\_n + 0.5 \cdot c\_p\right)}\right)} \]
      2. pow399.2%

        \[\leadsto 1 + -1 \cdot \color{blue}{{\left(\sqrt[3]{t \cdot \left(-0.5 \cdot c\_n + 0.5 \cdot c\_p\right)}\right)}^{3}} \]
      3. fma-define99.2%

        \[\leadsto 1 + -1 \cdot {\left(\sqrt[3]{t \cdot \color{blue}{\mathsf{fma}\left(-0.5, c\_n, 0.5 \cdot c\_p\right)}}\right)}^{3} \]
      4. *-commutative99.2%

        \[\leadsto 1 + -1 \cdot {\left(\sqrt[3]{t \cdot \mathsf{fma}\left(-0.5, c\_n, \color{blue}{c\_p \cdot 0.5}\right)}\right)}^{3} \]
    8. Applied egg-rr99.2%

      \[\leadsto 1 + -1 \cdot \color{blue}{{\left(\sqrt[3]{t \cdot \mathsf{fma}\left(-0.5, c\_n, c\_p \cdot 0.5\right)}\right)}^{3}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification99.3%

    \[\leadsto \begin{array}{l} \mathbf{if}\;-s \leq -2 \cdot 10^{+113} \lor \neg \left(-s \leq 2 \cdot 10^{-100}\right):\\ \;\;\;\;{\left(\frac{1}{2 + s \cdot \left(s \cdot \left(0.5 + s \cdot -0.16666666666666666\right) + -1\right)}\right)}^{c\_p}\\ \mathbf{else}:\\ \;\;\;\;1 - {\left(\sqrt[3]{t \cdot \mathsf{fma}\left(-0.5, c\_n, c\_p \cdot 0.5\right)}\right)}^{3}\\ \end{array} \]
  5. Add Preprocessing

Alternative 2: 97.8% accurate, 0.9× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;-s \leq 2 \cdot 10^{-100}:\\ \;\;\;\;e^{\left(c\_n \cdot \left(\mathsf{log1p}\left(\frac{1}{e^{s} + 1}\right) - \mathsf{log1p}\left(\frac{1}{1 + e^{t}}\right)\right) - c\_p \cdot \mathsf{log1p}\left(e^{s}\right)\right) + c\_p \cdot \mathsf{log1p}\left(e^{t}\right)}\\ \mathbf{else}:\\ \;\;\;\;{\left(\frac{1}{2 + s \cdot \left(s \cdot \left(0.5 + s \cdot -0.16666666666666666\right) + -1\right)}\right)}^{c\_p}\\ \end{array} \end{array} \]
(FPCore (c_p c_n t s)
 :precision binary64
 (if (<= (- s) 2e-100)
   (exp
    (+
     (-
      (*
       c_n
       (- (log1p (/ 1.0 (+ (exp s) 1.0))) (log1p (/ 1.0 (+ 1.0 (exp t))))))
      (* c_p (log1p (exp s))))
     (* c_p (log1p (exp t)))))
   (pow
    (/ 1.0 (+ 2.0 (* s (+ (* s (+ 0.5 (* s -0.16666666666666666))) -1.0))))
    c_p)))
double code(double c_p, double c_n, double t, double s) {
	double tmp;
	if (-s <= 2e-100) {
		tmp = exp((((c_n * (log1p((1.0 / (exp(s) + 1.0))) - log1p((1.0 / (1.0 + exp(t)))))) - (c_p * log1p(exp(s)))) + (c_p * log1p(exp(t)))));
	} else {
		tmp = pow((1.0 / (2.0 + (s * ((s * (0.5 + (s * -0.16666666666666666))) + -1.0)))), c_p);
	}
	return tmp;
}
public static double code(double c_p, double c_n, double t, double s) {
	double tmp;
	if (-s <= 2e-100) {
		tmp = Math.exp((((c_n * (Math.log1p((1.0 / (Math.exp(s) + 1.0))) - Math.log1p((1.0 / (1.0 + Math.exp(t)))))) - (c_p * Math.log1p(Math.exp(s)))) + (c_p * Math.log1p(Math.exp(t)))));
	} else {
		tmp = Math.pow((1.0 / (2.0 + (s * ((s * (0.5 + (s * -0.16666666666666666))) + -1.0)))), c_p);
	}
	return tmp;
}
def code(c_p, c_n, t, s):
	tmp = 0
	if -s <= 2e-100:
		tmp = math.exp((((c_n * (math.log1p((1.0 / (math.exp(s) + 1.0))) - math.log1p((1.0 / (1.0 + math.exp(t)))))) - (c_p * math.log1p(math.exp(s)))) + (c_p * math.log1p(math.exp(t)))))
	else:
		tmp = math.pow((1.0 / (2.0 + (s * ((s * (0.5 + (s * -0.16666666666666666))) + -1.0)))), c_p)
	return tmp
function code(c_p, c_n, t, s)
	tmp = 0.0
	if (Float64(-s) <= 2e-100)
		tmp = exp(Float64(Float64(Float64(c_n * Float64(log1p(Float64(1.0 / Float64(exp(s) + 1.0))) - log1p(Float64(1.0 / Float64(1.0 + exp(t)))))) - Float64(c_p * log1p(exp(s)))) + Float64(c_p * log1p(exp(t)))));
	else
		tmp = Float64(1.0 / Float64(2.0 + Float64(s * Float64(Float64(s * Float64(0.5 + Float64(s * -0.16666666666666666))) + -1.0)))) ^ c_p;
	end
	return tmp
end
code[c$95$p_, c$95$n_, t_, s_] := If[LessEqual[(-s), 2e-100], N[Exp[N[(N[(N[(c$95$n * N[(N[Log[1 + N[(1.0 / N[(N[Exp[s], $MachinePrecision] + 1.0), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] - N[Log[1 + N[(1.0 / N[(1.0 + N[Exp[t], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - N[(c$95$p * N[Log[1 + N[Exp[s], $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[(c$95$p * N[Log[1 + N[Exp[t], $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision], N[Power[N[(1.0 / N[(2.0 + N[(s * N[(N[(s * N[(0.5 + N[(s * -0.16666666666666666), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + -1.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], c$95$p], $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;-s \leq 2 \cdot 10^{-100}:\\
\;\;\;\;e^{\left(c\_n \cdot \left(\mathsf{log1p}\left(\frac{1}{e^{s} + 1}\right) - \mathsf{log1p}\left(\frac{1}{1 + e^{t}}\right)\right) - c\_p \cdot \mathsf{log1p}\left(e^{s}\right)\right) + c\_p \cdot \mathsf{log1p}\left(e^{t}\right)}\\

\mathbf{else}:\\
\;\;\;\;{\left(\frac{1}{2 + s \cdot \left(s \cdot \left(0.5 + s \cdot -0.16666666666666666\right) + -1\right)}\right)}^{c\_p}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if (neg.f64 s) < 2e-100

    1. Initial program 94.4%

      \[\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}} \]
    2. Step-by-step derivation
      1. associate-/l/94.4%

        \[\leadsto \color{blue}{\frac{\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}}} \]
    3. Simplified94.4%

      \[\leadsto \color{blue}{\frac{\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 + \frac{1}{-1 - e^{-s}}\right)}^{c\_n}}{{\left(1 + \frac{1}{-1 - e^{-t}}\right)}^{c\_n}}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}}} \]
    4. Add Preprocessing
    5. Applied egg-rr98.7%

      \[\leadsto \color{blue}{1 \cdot e^{\left(\left(c\_p \cdot \left(-\mathsf{log1p}\left(e^{s}\right)\right) + c\_n \cdot \mathsf{log1p}\left(\frac{1}{1 + e^{s}}\right)\right) - c\_n \cdot \mathsf{log1p}\left(\frac{1}{1 + e^{t}}\right)\right) - c\_p \cdot \left(-\mathsf{log1p}\left(e^{t}\right)\right)}} \]
    6. Step-by-step derivation
      1. *-lft-identity98.7%

        \[\leadsto \color{blue}{e^{\left(\left(c\_p \cdot \left(-\mathsf{log1p}\left(e^{s}\right)\right) + c\_n \cdot \mathsf{log1p}\left(\frac{1}{1 + e^{s}}\right)\right) - c\_n \cdot \mathsf{log1p}\left(\frac{1}{1 + e^{t}}\right)\right) - c\_p \cdot \left(-\mathsf{log1p}\left(e^{t}\right)\right)}} \]
      2. associate--l+98.7%

        \[\leadsto e^{\color{blue}{\left(c\_p \cdot \left(-\mathsf{log1p}\left(e^{s}\right)\right) + \left(c\_n \cdot \mathsf{log1p}\left(\frac{1}{1 + e^{s}}\right) - c\_n \cdot \mathsf{log1p}\left(\frac{1}{1 + e^{t}}\right)\right)\right)} - c\_p \cdot \left(-\mathsf{log1p}\left(e^{t}\right)\right)} \]
      3. distribute-lft-out--98.7%

        \[\leadsto e^{\left(c\_p \cdot \left(-\mathsf{log1p}\left(e^{s}\right)\right) + \color{blue}{c\_n \cdot \left(\mathsf{log1p}\left(\frac{1}{1 + e^{s}}\right) - \mathsf{log1p}\left(\frac{1}{1 + e^{t}}\right)\right)}\right) - c\_p \cdot \left(-\mathsf{log1p}\left(e^{t}\right)\right)} \]
    7. Simplified98.7%

      \[\leadsto \color{blue}{e^{\left(c\_p \cdot \left(-\mathsf{log1p}\left(e^{s}\right)\right) + c\_n \cdot \left(\mathsf{log1p}\left(\frac{1}{1 + e^{s}}\right) - \mathsf{log1p}\left(\frac{1}{1 + e^{t}}\right)\right)\right) - c\_p \cdot \left(-\mathsf{log1p}\left(e^{t}\right)\right)}} \]

    if 2e-100 < (neg.f64 s)

    1. Initial program 90.4%

      \[\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}} \]
    2. Step-by-step derivation
      1. associate-/l/90.4%

        \[\leadsto \color{blue}{\frac{\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}}} \]
    3. Simplified90.4%

      \[\leadsto \color{blue}{\frac{\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 + \frac{1}{-1 - e^{-s}}\right)}^{c\_n}}{{\left(1 + \frac{1}{-1 - e^{-t}}\right)}^{c\_n}}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}}} \]
    4. Add Preprocessing
    5. Taylor expanded in c_n around 0 92.8%

      \[\leadsto \frac{\color{blue}{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p}}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}} \]
    6. Taylor expanded in s around 0 95.2%

      \[\leadsto \frac{{\left(\frac{1}{\color{blue}{2 + s \cdot \left(s \cdot \left(0.5 + -0.16666666666666666 \cdot s\right) - 1\right)}}\right)}^{c\_p}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}} \]
    7. Taylor expanded in c_p around 0 100.0%

      \[\leadsto \frac{{\left(\frac{1}{2 + s \cdot \left(s \cdot \left(0.5 + -0.16666666666666666 \cdot s\right) - 1\right)}\right)}^{c\_p}}{\color{blue}{1}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification99.0%

    \[\leadsto \begin{array}{l} \mathbf{if}\;-s \leq 2 \cdot 10^{-100}:\\ \;\;\;\;e^{\left(c\_n \cdot \left(\mathsf{log1p}\left(\frac{1}{e^{s} + 1}\right) - \mathsf{log1p}\left(\frac{1}{1 + e^{t}}\right)\right) - c\_p \cdot \mathsf{log1p}\left(e^{s}\right)\right) + c\_p \cdot \mathsf{log1p}\left(e^{t}\right)}\\ \mathbf{else}:\\ \;\;\;\;{\left(\frac{1}{2 + s \cdot \left(s \cdot \left(0.5 + s \cdot -0.16666666666666666\right) + -1\right)}\right)}^{c\_p}\\ \end{array} \]
  5. Add Preprocessing

Alternative 3: 95.7% accurate, 2.5× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_1 := e^{-t}\\ \mathbf{if}\;-t \leq 10^{-38}:\\ \;\;\;\;\frac{{\left(\frac{1}{2 + s \cdot \left(s \cdot \left(0.5 + s \cdot -0.16666666666666666\right) + -1\right)}\right)}^{c\_p}}{{\left(\frac{1}{1 + t\_1}\right)}^{c\_p}}\\ \mathbf{else}:\\ \;\;\;\;\frac{{0.5}^{c\_n}}{{\left(1 + \frac{1}{-1 - t\_1}\right)}^{c\_n}}\\ \end{array} \end{array} \]
(FPCore (c_p c_n t s)
 :precision binary64
 (let* ((t_1 (exp (- t))))
   (if (<= (- t) 1e-38)
     (/
      (pow
       (/ 1.0 (+ 2.0 (* s (+ (* s (+ 0.5 (* s -0.16666666666666666))) -1.0))))
       c_p)
      (pow (/ 1.0 (+ 1.0 t_1)) c_p))
     (/ (pow 0.5 c_n) (pow (+ 1.0 (/ 1.0 (- -1.0 t_1))) c_n)))))
double code(double c_p, double c_n, double t, double s) {
	double t_1 = exp(-t);
	double tmp;
	if (-t <= 1e-38) {
		tmp = pow((1.0 / (2.0 + (s * ((s * (0.5 + (s * -0.16666666666666666))) + -1.0)))), c_p) / pow((1.0 / (1.0 + t_1)), c_p);
	} else {
		tmp = pow(0.5, c_n) / pow((1.0 + (1.0 / (-1.0 - t_1))), c_n);
	}
	return tmp;
}
real(8) function code(c_p, c_n, t, s)
    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 = exp(-t)
    if (-t <= 1d-38) then
        tmp = ((1.0d0 / (2.0d0 + (s * ((s * (0.5d0 + (s * (-0.16666666666666666d0)))) + (-1.0d0))))) ** c_p) / ((1.0d0 / (1.0d0 + t_1)) ** c_p)
    else
        tmp = (0.5d0 ** c_n) / ((1.0d0 + (1.0d0 / ((-1.0d0) - t_1))) ** c_n)
    end if
    code = tmp
end function
public static double code(double c_p, double c_n, double t, double s) {
	double t_1 = Math.exp(-t);
	double tmp;
	if (-t <= 1e-38) {
		tmp = Math.pow((1.0 / (2.0 + (s * ((s * (0.5 + (s * -0.16666666666666666))) + -1.0)))), c_p) / Math.pow((1.0 / (1.0 + t_1)), c_p);
	} else {
		tmp = Math.pow(0.5, c_n) / Math.pow((1.0 + (1.0 / (-1.0 - t_1))), c_n);
	}
	return tmp;
}
def code(c_p, c_n, t, s):
	t_1 = math.exp(-t)
	tmp = 0
	if -t <= 1e-38:
		tmp = math.pow((1.0 / (2.0 + (s * ((s * (0.5 + (s * -0.16666666666666666))) + -1.0)))), c_p) / math.pow((1.0 / (1.0 + t_1)), c_p)
	else:
		tmp = math.pow(0.5, c_n) / math.pow((1.0 + (1.0 / (-1.0 - t_1))), c_n)
	return tmp
function code(c_p, c_n, t, s)
	t_1 = exp(Float64(-t))
	tmp = 0.0
	if (Float64(-t) <= 1e-38)
		tmp = Float64((Float64(1.0 / Float64(2.0 + Float64(s * Float64(Float64(s * Float64(0.5 + Float64(s * -0.16666666666666666))) + -1.0)))) ^ c_p) / (Float64(1.0 / Float64(1.0 + t_1)) ^ c_p));
	else
		tmp = Float64((0.5 ^ c_n) / (Float64(1.0 + Float64(1.0 / Float64(-1.0 - t_1))) ^ c_n));
	end
	return tmp
end
function tmp_2 = code(c_p, c_n, t, s)
	t_1 = exp(-t);
	tmp = 0.0;
	if (-t <= 1e-38)
		tmp = ((1.0 / (2.0 + (s * ((s * (0.5 + (s * -0.16666666666666666))) + -1.0)))) ^ c_p) / ((1.0 / (1.0 + t_1)) ^ c_p);
	else
		tmp = (0.5 ^ c_n) / ((1.0 + (1.0 / (-1.0 - t_1))) ^ c_n);
	end
	tmp_2 = tmp;
end
code[c$95$p_, c$95$n_, t_, s_] := Block[{t$95$1 = N[Exp[(-t)], $MachinePrecision]}, If[LessEqual[(-t), 1e-38], N[(N[Power[N[(1.0 / N[(2.0 + N[(s * N[(N[(s * N[(0.5 + N[(s * -0.16666666666666666), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + -1.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], c$95$p], $MachinePrecision] / N[Power[N[(1.0 / N[(1.0 + t$95$1), $MachinePrecision]), $MachinePrecision], c$95$p], $MachinePrecision]), $MachinePrecision], N[(N[Power[0.5, c$95$n], $MachinePrecision] / N[Power[N[(1.0 + N[(1.0 / N[(-1.0 - t$95$1), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], c$95$n], $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
t_1 := e^{-t}\\
\mathbf{if}\;-t \leq 10^{-38}:\\
\;\;\;\;\frac{{\left(\frac{1}{2 + s \cdot \left(s \cdot \left(0.5 + s \cdot -0.16666666666666666\right) + -1\right)}\right)}^{c\_p}}{{\left(\frac{1}{1 + t\_1}\right)}^{c\_p}}\\

\mathbf{else}:\\
\;\;\;\;\frac{{0.5}^{c\_n}}{{\left(1 + \frac{1}{-1 - t\_1}\right)}^{c\_n}}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if (neg.f64 t) < 9.9999999999999996e-39

    1. Initial program 95.3%

      \[\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}} \]
    2. Step-by-step derivation
      1. associate-/l/95.3%

        \[\leadsto \color{blue}{\frac{\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}}} \]
    3. Simplified95.3%

      \[\leadsto \color{blue}{\frac{\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 + \frac{1}{-1 - e^{-s}}\right)}^{c\_n}}{{\left(1 + \frac{1}{-1 - e^{-t}}\right)}^{c\_n}}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}}} \]
    4. Add Preprocessing
    5. Taylor expanded in c_n around 0 95.5%

      \[\leadsto \frac{\color{blue}{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p}}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}} \]
    6. Taylor expanded in s around 0 98.0%

      \[\leadsto \frac{{\left(\frac{1}{\color{blue}{2 + s \cdot \left(s \cdot \left(0.5 + -0.16666666666666666 \cdot s\right) - 1\right)}}\right)}^{c\_p}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}} \]

    if 9.9999999999999996e-39 < (neg.f64 t)

    1. Initial program 76.6%

      \[\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}} \]
    2. Step-by-step derivation
      1. associate-/l/76.6%

        \[\leadsto \color{blue}{\frac{\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}}} \]
    3. Simplified76.6%

      \[\leadsto \color{blue}{\frac{\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 + \frac{1}{-1 - e^{-s}}\right)}^{c\_n}}{{\left(1 + \frac{1}{-1 - e^{-t}}\right)}^{c\_n}}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}}} \]
    4. Add Preprocessing
    5. Taylor expanded in s around 0 81.3%

      \[\leadsto \frac{\color{blue}{\frac{{0.5}^{c\_n} \cdot {0.5}^{c\_p}}{{\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}}}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}} \]
    6. Taylor expanded in c_p around 0 100.0%

      \[\leadsto \frac{\frac{{0.5}^{c\_n} \cdot {0.5}^{c\_p}}{{\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}}}{\color{blue}{1}} \]
    7. Taylor expanded in c_p around 0 100.0%

      \[\leadsto \frac{\color{blue}{\frac{{0.5}^{c\_n}}{{\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}}}}{1} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification98.1%

    \[\leadsto \begin{array}{l} \mathbf{if}\;-t \leq 10^{-38}:\\ \;\;\;\;\frac{{\left(\frac{1}{2 + s \cdot \left(s \cdot \left(0.5 + s \cdot -0.16666666666666666\right) + -1\right)}\right)}^{c\_p}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}}\\ \mathbf{else}:\\ \;\;\;\;\frac{{0.5}^{c\_n}}{{\left(1 + \frac{1}{-1 - e^{-t}}\right)}^{c\_n}}\\ \end{array} \]
  5. Add Preprocessing

Alternative 4: 96.7% accurate, 6.5× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;-s \leq -2 \cdot 10^{+113} \lor \neg \left(-s \leq 2 \cdot 10^{-100}\right):\\ \;\;\;\;{\left(\frac{1}{2 + s \cdot \left(s \cdot \left(0.5 + s \cdot -0.16666666666666666\right) + -1\right)}\right)}^{c\_p}\\ \mathbf{else}:\\ \;\;\;\;1 - t \cdot \left(c\_n \cdot -0.5\right)\\ \end{array} \end{array} \]
(FPCore (c_p c_n t s)
 :precision binary64
 (if (or (<= (- s) -2e+113) (not (<= (- s) 2e-100)))
   (pow
    (/ 1.0 (+ 2.0 (* s (+ (* s (+ 0.5 (* s -0.16666666666666666))) -1.0))))
    c_p)
   (- 1.0 (* t (* c_n -0.5)))))
double code(double c_p, double c_n, double t, double s) {
	double tmp;
	if ((-s <= -2e+113) || !(-s <= 2e-100)) {
		tmp = pow((1.0 / (2.0 + (s * ((s * (0.5 + (s * -0.16666666666666666))) + -1.0)))), c_p);
	} else {
		tmp = 1.0 - (t * (c_n * -0.5));
	}
	return tmp;
}
real(8) function code(c_p, c_n, t, s)
    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 ((-s <= (-2d+113)) .or. (.not. (-s <= 2d-100))) then
        tmp = (1.0d0 / (2.0d0 + (s * ((s * (0.5d0 + (s * (-0.16666666666666666d0)))) + (-1.0d0))))) ** c_p
    else
        tmp = 1.0d0 - (t * (c_n * (-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 ((-s <= -2e+113) || !(-s <= 2e-100)) {
		tmp = Math.pow((1.0 / (2.0 + (s * ((s * (0.5 + (s * -0.16666666666666666))) + -1.0)))), c_p);
	} else {
		tmp = 1.0 - (t * (c_n * -0.5));
	}
	return tmp;
}
def code(c_p, c_n, t, s):
	tmp = 0
	if (-s <= -2e+113) or not (-s <= 2e-100):
		tmp = math.pow((1.0 / (2.0 + (s * ((s * (0.5 + (s * -0.16666666666666666))) + -1.0)))), c_p)
	else:
		tmp = 1.0 - (t * (c_n * -0.5))
	return tmp
function code(c_p, c_n, t, s)
	tmp = 0.0
	if ((Float64(-s) <= -2e+113) || !(Float64(-s) <= 2e-100))
		tmp = Float64(1.0 / Float64(2.0 + Float64(s * Float64(Float64(s * Float64(0.5 + Float64(s * -0.16666666666666666))) + -1.0)))) ^ c_p;
	else
		tmp = Float64(1.0 - Float64(t * Float64(c_n * -0.5)));
	end
	return tmp
end
function tmp_2 = code(c_p, c_n, t, s)
	tmp = 0.0;
	if ((-s <= -2e+113) || ~((-s <= 2e-100)))
		tmp = (1.0 / (2.0 + (s * ((s * (0.5 + (s * -0.16666666666666666))) + -1.0)))) ^ c_p;
	else
		tmp = 1.0 - (t * (c_n * -0.5));
	end
	tmp_2 = tmp;
end
code[c$95$p_, c$95$n_, t_, s_] := If[Or[LessEqual[(-s), -2e+113], N[Not[LessEqual[(-s), 2e-100]], $MachinePrecision]], N[Power[N[(1.0 / N[(2.0 + N[(s * N[(N[(s * N[(0.5 + N[(s * -0.16666666666666666), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + -1.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], c$95$p], $MachinePrecision], N[(1.0 - N[(t * N[(c$95$n * -0.5), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;-s \leq -2 \cdot 10^{+113} \lor \neg \left(-s \leq 2 \cdot 10^{-100}\right):\\
\;\;\;\;{\left(\frac{1}{2 + s \cdot \left(s \cdot \left(0.5 + s \cdot -0.16666666666666666\right) + -1\right)}\right)}^{c\_p}\\

\mathbf{else}:\\
\;\;\;\;1 - t \cdot \left(c\_n \cdot -0.5\right)\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if (neg.f64 s) < -2e113 or 2e-100 < (neg.f64 s)

    1. Initial program 83.5%

      \[\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}} \]
    2. Step-by-step derivation
      1. associate-/l/83.5%

        \[\leadsto \color{blue}{\frac{\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}}} \]
    3. Simplified83.5%

      \[\leadsto \color{blue}{\frac{\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 + \frac{1}{-1 - e^{-s}}\right)}^{c\_n}}{{\left(1 + \frac{1}{-1 - e^{-t}}\right)}^{c\_n}}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}}} \]
    4. Add Preprocessing
    5. Taylor expanded in c_n around 0 79.7%

      \[\leadsto \frac{\color{blue}{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p}}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}} \]
    6. Taylor expanded in s around 0 93.8%

      \[\leadsto \frac{{\left(\frac{1}{\color{blue}{2 + s \cdot \left(s \cdot \left(0.5 + -0.16666666666666666 \cdot s\right) - 1\right)}}\right)}^{c\_p}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}} \]
    7. Taylor expanded in c_p around 0 100.0%

      \[\leadsto \frac{{\left(\frac{1}{2 + s \cdot \left(s \cdot \left(0.5 + -0.16666666666666666 \cdot s\right) - 1\right)}\right)}^{c\_p}}{\color{blue}{1}} \]

    if -2e113 < (neg.f64 s) < 2e-100

    1. Initial program 96.1%

      \[\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}} \]
    2. Step-by-step derivation
      1. associate-/l/96.1%

        \[\leadsto \color{blue}{\frac{\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}}} \]
    3. Simplified96.1%

      \[\leadsto \color{blue}{\frac{\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 + \frac{1}{-1 - e^{-s}}\right)}^{c\_n}}{{\left(1 + \frac{1}{-1 - e^{-t}}\right)}^{c\_n}}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}}} \]
    4. Add Preprocessing
    5. Taylor expanded in s around 0 97.1%

      \[\leadsto \frac{\color{blue}{\frac{{0.5}^{c\_n} \cdot {0.5}^{c\_p}}{{\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}}}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}} \]
    6. Taylor expanded in t around 0 99.2%

      \[\leadsto \color{blue}{1 + -1 \cdot \left(t \cdot \left(-0.5 \cdot c\_n + 0.5 \cdot c\_p\right)\right)} \]
    7. Taylor expanded in c_n around inf 99.2%

      \[\leadsto 1 + -1 \cdot \color{blue}{\left(-0.5 \cdot \left(c\_n \cdot t\right)\right)} \]
    8. Step-by-step derivation
      1. associate-*r*99.2%

        \[\leadsto 1 + -1 \cdot \color{blue}{\left(\left(-0.5 \cdot c\_n\right) \cdot t\right)} \]
      2. *-commutative99.2%

        \[\leadsto 1 + -1 \cdot \color{blue}{\left(t \cdot \left(-0.5 \cdot c\_n\right)\right)} \]
    9. Simplified99.2%

      \[\leadsto 1 + -1 \cdot \color{blue}{\left(t \cdot \left(-0.5 \cdot c\_n\right)\right)} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification99.3%

    \[\leadsto \begin{array}{l} \mathbf{if}\;-s \leq -2 \cdot 10^{+113} \lor \neg \left(-s \leq 2 \cdot 10^{-100}\right):\\ \;\;\;\;{\left(\frac{1}{2 + s \cdot \left(s \cdot \left(0.5 + s \cdot -0.16666666666666666\right) + -1\right)}\right)}^{c\_p}\\ \mathbf{else}:\\ \;\;\;\;1 - t \cdot \left(c\_n \cdot -0.5\right)\\ \end{array} \]
  5. Add Preprocessing

Alternative 5: 95.1% accurate, 7.1× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;s \leq 5 \cdot 10^{+113}:\\ \;\;\;\;1 - t \cdot \left(c\_n \cdot -0.5\right)\\ \mathbf{else}:\\ \;\;\;\;{\left(\frac{1}{2 + s \cdot \left(-1 + s \cdot 0.5\right)}\right)}^{c\_p}\\ \end{array} \end{array} \]
(FPCore (c_p c_n t s)
 :precision binary64
 (if (<= s 5e+113)
   (- 1.0 (* t (* c_n -0.5)))
   (pow (/ 1.0 (+ 2.0 (* s (+ -1.0 (* s 0.5))))) c_p)))
double code(double c_p, double c_n, double t, double s) {
	double tmp;
	if (s <= 5e+113) {
		tmp = 1.0 - (t * (c_n * -0.5));
	} else {
		tmp = pow((1.0 / (2.0 + (s * (-1.0 + (s * 0.5))))), c_p);
	}
	return tmp;
}
real(8) function code(c_p, c_n, t, s)
    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 (s <= 5d+113) then
        tmp = 1.0d0 - (t * (c_n * (-0.5d0)))
    else
        tmp = (1.0d0 / (2.0d0 + (s * ((-1.0d0) + (s * 0.5d0))))) ** c_p
    end if
    code = tmp
end function
public static double code(double c_p, double c_n, double t, double s) {
	double tmp;
	if (s <= 5e+113) {
		tmp = 1.0 - (t * (c_n * -0.5));
	} else {
		tmp = Math.pow((1.0 / (2.0 + (s * (-1.0 + (s * 0.5))))), c_p);
	}
	return tmp;
}
def code(c_p, c_n, t, s):
	tmp = 0
	if s <= 5e+113:
		tmp = 1.0 - (t * (c_n * -0.5))
	else:
		tmp = math.pow((1.0 / (2.0 + (s * (-1.0 + (s * 0.5))))), c_p)
	return tmp
function code(c_p, c_n, t, s)
	tmp = 0.0
	if (s <= 5e+113)
		tmp = Float64(1.0 - Float64(t * Float64(c_n * -0.5)));
	else
		tmp = Float64(1.0 / Float64(2.0 + Float64(s * Float64(-1.0 + Float64(s * 0.5))))) ^ c_p;
	end
	return tmp
end
function tmp_2 = code(c_p, c_n, t, s)
	tmp = 0.0;
	if (s <= 5e+113)
		tmp = 1.0 - (t * (c_n * -0.5));
	else
		tmp = (1.0 / (2.0 + (s * (-1.0 + (s * 0.5))))) ^ c_p;
	end
	tmp_2 = tmp;
end
code[c$95$p_, c$95$n_, t_, s_] := If[LessEqual[s, 5e+113], N[(1.0 - N[(t * N[(c$95$n * -0.5), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[Power[N[(1.0 / N[(2.0 + N[(s * N[(-1.0 + N[(s * 0.5), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], c$95$p], $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;s \leq 5 \cdot 10^{+113}:\\
\;\;\;\;1 - t \cdot \left(c\_n \cdot -0.5\right)\\

\mathbf{else}:\\
\;\;\;\;{\left(\frac{1}{2 + s \cdot \left(-1 + s \cdot 0.5\right)}\right)}^{c\_p}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if s < 5e113

    1. Initial program 95.2%

      \[\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}} \]
    2. Step-by-step derivation
      1. associate-/l/95.2%

        \[\leadsto \color{blue}{\frac{\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}}} \]
    3. Simplified95.2%

      \[\leadsto \color{blue}{\frac{\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 + \frac{1}{-1 - e^{-s}}\right)}^{c\_n}}{{\left(1 + \frac{1}{-1 - e^{-t}}\right)}^{c\_n}}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}}} \]
    4. Add Preprocessing
    5. Taylor expanded in s around 0 94.4%

      \[\leadsto \frac{\color{blue}{\frac{{0.5}^{c\_n} \cdot {0.5}^{c\_p}}{{\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}}}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}} \]
    6. Taylor expanded in t around 0 97.0%

      \[\leadsto \color{blue}{1 + -1 \cdot \left(t \cdot \left(-0.5 \cdot c\_n + 0.5 \cdot c\_p\right)\right)} \]
    7. Taylor expanded in c_n around inf 97.0%

      \[\leadsto 1 + -1 \cdot \color{blue}{\left(-0.5 \cdot \left(c\_n \cdot t\right)\right)} \]
    8. Step-by-step derivation
      1. associate-*r*97.0%

        \[\leadsto 1 + -1 \cdot \color{blue}{\left(\left(-0.5 \cdot c\_n\right) \cdot t\right)} \]
      2. *-commutative97.0%

        \[\leadsto 1 + -1 \cdot \color{blue}{\left(t \cdot \left(-0.5 \cdot c\_n\right)\right)} \]
    9. Simplified97.0%

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

    if 5e113 < s

    1. Initial program 33.3%

      \[\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}} \]
    2. Step-by-step derivation
      1. associate-/l/33.3%

        \[\leadsto \color{blue}{\frac{\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}}} \]
    3. Simplified33.3%

      \[\leadsto \color{blue}{\frac{\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 + \frac{1}{-1 - e^{-s}}\right)}^{c\_n}}{{\left(1 + \frac{1}{-1 - e^{-t}}\right)}^{c\_n}}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}}} \]
    4. Add Preprocessing
    5. Taylor expanded in c_n around 0 2.9%

      \[\leadsto \frac{\color{blue}{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p}}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}} \]
    6. Taylor expanded in s around 0 67.2%

      \[\leadsto \frac{{\left(\frac{1}{\color{blue}{2 + s \cdot \left(0.5 \cdot s - 1\right)}}\right)}^{c\_p}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}} \]
    7. Taylor expanded in c_p around 0 83.9%

      \[\leadsto \frac{{\left(\frac{1}{2 + s \cdot \left(0.5 \cdot s - 1\right)}\right)}^{c\_p}}{\color{blue}{1}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification96.7%

    \[\leadsto \begin{array}{l} \mathbf{if}\;s \leq 5 \cdot 10^{+113}:\\ \;\;\;\;1 - t \cdot \left(c\_n \cdot -0.5\right)\\ \mathbf{else}:\\ \;\;\;\;{\left(\frac{1}{2 + s \cdot \left(-1 + s \cdot 0.5\right)}\right)}^{c\_p}\\ \end{array} \]
  5. Add Preprocessing

Alternative 6: 94.3% accurate, 119.3× speedup?

\[\begin{array}{l} \\ 1 - t \cdot \left(c\_n \cdot -0.5\right) \end{array} \]
(FPCore (c_p c_n t s) :precision binary64 (- 1.0 (* t (* c_n -0.5))))
double code(double c_p, double c_n, double t, double s) {
	return 1.0 - (t * (c_n * -0.5));
}
real(8) function code(c_p, c_n, t, s)
    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 - (t * (c_n * (-0.5d0)))
end function
public static double code(double c_p, double c_n, double t, double s) {
	return 1.0 - (t * (c_n * -0.5));
}
def code(c_p, c_n, t, s):
	return 1.0 - (t * (c_n * -0.5))
function code(c_p, c_n, t, s)
	return Float64(1.0 - Float64(t * Float64(c_n * -0.5)))
end
function tmp = code(c_p, c_n, t, s)
	tmp = 1.0 - (t * (c_n * -0.5));
end
code[c$95$p_, c$95$n_, t_, s_] := N[(1.0 - N[(t * N[(c$95$n * -0.5), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
1 - t \cdot \left(c\_n \cdot -0.5\right)
\end{array}
Derivation
  1. Initial program 93.8%

    \[\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}} \]
  2. Step-by-step derivation
    1. associate-/l/93.8%

      \[\leadsto \color{blue}{\frac{\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}}} \]
  3. Simplified93.8%

    \[\leadsto \color{blue}{\frac{\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 + \frac{1}{-1 - e^{-s}}\right)}^{c\_n}}{{\left(1 + \frac{1}{-1 - e^{-t}}\right)}^{c\_n}}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}}} \]
  4. Add Preprocessing
  5. Taylor expanded in s around 0 92.3%

    \[\leadsto \frac{\color{blue}{\frac{{0.5}^{c\_n} \cdot {0.5}^{c\_p}}{{\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}}}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}} \]
  6. Taylor expanded in t around 0 94.8%

    \[\leadsto \color{blue}{1 + -1 \cdot \left(t \cdot \left(-0.5 \cdot c\_n + 0.5 \cdot c\_p\right)\right)} \]
  7. Taylor expanded in c_n around inf 94.8%

    \[\leadsto 1 + -1 \cdot \color{blue}{\left(-0.5 \cdot \left(c\_n \cdot t\right)\right)} \]
  8. Step-by-step derivation
    1. associate-*r*94.8%

      \[\leadsto 1 + -1 \cdot \color{blue}{\left(\left(-0.5 \cdot c\_n\right) \cdot t\right)} \]
    2. *-commutative94.8%

      \[\leadsto 1 + -1 \cdot \color{blue}{\left(t \cdot \left(-0.5 \cdot c\_n\right)\right)} \]
  9. Simplified94.8%

    \[\leadsto 1 + -1 \cdot \color{blue}{\left(t \cdot \left(-0.5 \cdot c\_n\right)\right)} \]
  10. Final simplification94.8%

    \[\leadsto 1 - t \cdot \left(c\_n \cdot -0.5\right) \]
  11. Add Preprocessing

Alternative 7: 94.2% accurate, 835.0× 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;
}
real(8) function code(c_p, c_n, t, s)
    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 93.8%

    \[\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}} \]
  2. Step-by-step derivation
    1. associate-/l/93.8%

      \[\leadsto \color{blue}{\frac{\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}}} \]
  3. Simplified93.8%

    \[\leadsto \color{blue}{\frac{\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 + \frac{1}{-1 - e^{-s}}\right)}^{c\_n}}{{\left(1 + \frac{1}{-1 - e^{-t}}\right)}^{c\_n}}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}}} \]
  4. Add Preprocessing
  5. Taylor expanded in c_n around 0 94.4%

    \[\leadsto \frac{\color{blue}{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p}}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}} \]
  6. Taylor expanded in c_p around 0 94.8%

    \[\leadsto \color{blue}{1} \]
  7. Final simplification94.8%

    \[\leadsto 1 \]
  8. Add Preprocessing

Developer target: 96.5% accurate, 1.3× 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);
}
real(8) function code(c_p, c_n, t, s)
    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 2024073 
(FPCore (c_p c_n t s)
  :name "Harley's example"
  :precision binary64
  :pre (and (< 0.0 c_p) (< 0.0 c_n))

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