Harley's example

Percentage Accurate: 90.6% → 98.4%
Time: 2.4min
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: 90.6% 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: 98.4% accurate, 0.8× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_1 := 1 + e^{t}\\ \mathbf{if}\;c\_p \leq 5 \cdot 10^{-85}:\\ \;\;\;\;\frac{e^{\mathsf{fma}\left(\mathsf{log1p}\left(\frac{1}{1 + e^{s}}\right), c\_n, \mathsf{log1p}\left(e^{s}\right) \cdot \left(-c\_p\right) - c\_n \cdot \mathsf{log1p}\left(\frac{1}{t\_1}\right)\right)}}{{t\_1}^{\left(-c\_p\right)}}\\ \mathbf{else}:\\ \;\;\;\;{\left({e}^{c\_p}\right)}^{\left(\mathsf{log1p}\left(e^{-t}\right) + \left(s \cdot \left(0.5 + s \cdot -0.125\right) - \log 2\right)\right)}\\ \end{array} \end{array} \]
(FPCore (c_p c_n t s)
 :precision binary64
 (let* ((t_1 (+ 1.0 (exp t))))
   (if (<= c_p 5e-85)
     (/
      (exp
       (fma
        (log1p (/ 1.0 (+ 1.0 (exp s))))
        c_n
        (- (* (log1p (exp s)) (- c_p)) (* c_n (log1p (/ 1.0 t_1))))))
      (pow t_1 (- c_p)))
     (pow
      (pow E c_p)
      (+ (log1p (exp (- t))) (- (* s (+ 0.5 (* s -0.125))) (log 2.0)))))))
double code(double c_p, double c_n, double t, double s) {
	double t_1 = 1.0 + exp(t);
	double tmp;
	if (c_p <= 5e-85) {
		tmp = exp(fma(log1p((1.0 / (1.0 + exp(s)))), c_n, ((log1p(exp(s)) * -c_p) - (c_n * log1p((1.0 / t_1)))))) / pow(t_1, -c_p);
	} else {
		tmp = pow(pow(((double) M_E), c_p), (log1p(exp(-t)) + ((s * (0.5 + (s * -0.125))) - log(2.0))));
	}
	return tmp;
}
function code(c_p, c_n, t, s)
	t_1 = Float64(1.0 + exp(t))
	tmp = 0.0
	if (c_p <= 5e-85)
		tmp = Float64(exp(fma(log1p(Float64(1.0 / Float64(1.0 + exp(s)))), c_n, Float64(Float64(log1p(exp(s)) * Float64(-c_p)) - Float64(c_n * log1p(Float64(1.0 / t_1)))))) / (t_1 ^ Float64(-c_p)));
	else
		tmp = (exp(1) ^ c_p) ^ Float64(log1p(exp(Float64(-t))) + Float64(Float64(s * Float64(0.5 + Float64(s * -0.125))) - log(2.0)));
	end
	return tmp
end
code[c$95$p_, c$95$n_, t_, s_] := Block[{t$95$1 = N[(1.0 + N[Exp[t], $MachinePrecision]), $MachinePrecision]}, If[LessEqual[c$95$p, 5e-85], N[(N[Exp[N[(N[Log[1 + N[(1.0 / N[(1.0 + N[Exp[s], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] * c$95$n + N[(N[(N[Log[1 + N[Exp[s], $MachinePrecision]], $MachinePrecision] * (-c$95$p)), $MachinePrecision] - N[(c$95$n * N[Log[1 + N[(1.0 / t$95$1), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] / N[Power[t$95$1, (-c$95$p)], $MachinePrecision]), $MachinePrecision], N[Power[N[Power[E, c$95$p], $MachinePrecision], N[(N[Log[1 + N[Exp[(-t)], $MachinePrecision]], $MachinePrecision] + N[(N[(s * N[(0.5 + N[(s * -0.125), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - N[Log[2.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
t_1 := 1 + e^{t}\\
\mathbf{if}\;c\_p \leq 5 \cdot 10^{-85}:\\
\;\;\;\;\frac{e^{\mathsf{fma}\left(\mathsf{log1p}\left(\frac{1}{1 + e^{s}}\right), c\_n, \mathsf{log1p}\left(e^{s}\right) \cdot \left(-c\_p\right) - c\_n \cdot \mathsf{log1p}\left(\frac{1}{t\_1}\right)\right)}}{{t\_1}^{\left(-c\_p\right)}}\\

\mathbf{else}:\\
\;\;\;\;{\left({e}^{c\_p}\right)}^{\left(\mathsf{log1p}\left(e^{-t}\right) + \left(s \cdot \left(0.5 + s \cdot -0.125\right) - \log 2\right)\right)}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if c_p < 5.0000000000000002e-85

    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. Applied egg-rr98.3%

      \[\leadsto \color{blue}{\frac{{\left(1 + \frac{1}{1 + e^{s}}\right)}^{c\_n}}{{\left(1 + e^{t}\right)}^{\left(-1 \cdot c\_p\right)}} \cdot \frac{{\left(1 + e^{s}\right)}^{\left(-1 \cdot c\_p\right)}}{{\left(1 + \frac{1}{1 + e^{t}}\right)}^{c\_n}}} \]
    6. Step-by-step derivation
      1. associate-*l/98.3%

        \[\leadsto \color{blue}{\frac{{\left(1 + \frac{1}{1 + e^{s}}\right)}^{c\_n} \cdot \frac{{\left(1 + e^{s}\right)}^{\left(-1 \cdot c\_p\right)}}{{\left(1 + \frac{1}{1 + e^{t}}\right)}^{c\_n}}}{{\left(1 + e^{t}\right)}^{\left(-1 \cdot c\_p\right)}}} \]
    7. Applied egg-rr99.9%

      \[\leadsto \color{blue}{\frac{e^{\mathsf{log1p}\left(\frac{1}{1 + e^{s}}\right) \cdot c\_n + \left(c\_p \cdot \left(-\mathsf{log1p}\left(e^{s}\right)\right) - c\_n \cdot \mathsf{log1p}\left(\frac{1}{1 + e^{t}}\right)\right)}}{{\left(1 + e^{t}\right)}^{\left(-c\_p\right)}}} \]
    8. Step-by-step derivation
      1. fma-define99.9%

        \[\leadsto \frac{e^{\color{blue}{\mathsf{fma}\left(\mathsf{log1p}\left(\frac{1}{1 + e^{s}}\right), c\_n, c\_p \cdot \left(-\mathsf{log1p}\left(e^{s}\right)\right) - c\_n \cdot \mathsf{log1p}\left(\frac{1}{1 + e^{t}}\right)\right)}}}{{\left(1 + e^{t}\right)}^{\left(-c\_p\right)}} \]
    9. Simplified99.9%

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

    if 5.0000000000000002e-85 < c_p

    1. Initial program 85.1%

      \[\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}} \]
    2. Step-by-step derivation
      1. associate-/l/85.1%

        \[\leadsto \color{blue}{\frac{\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}}} \]
    3. Simplified85.1%

      \[\leadsto \color{blue}{\frac{\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 + \frac{1}{-1 - e^{-s}}\right)}^{c\_n}}{{\left(1 + \frac{1}{-1 - e^{-t}}\right)}^{c\_n}}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}}} \]
    4. Add Preprocessing
    5. Taylor expanded in c_n around 0 88.9%

      \[\leadsto \color{blue}{\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}}} \]
    6. Taylor expanded in s around -inf 88.9%

      \[\leadsto \color{blue}{\frac{{\left(\frac{1}{1 + e^{-1 \cdot s}}\right)}^{c\_p}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}}} \]
    7. Simplified97.4%

      \[\leadsto \color{blue}{{\left(e^{c\_p}\right)}^{\left(\left(-\mathsf{log1p}\left(e^{-s}\right)\right) - \left(-\mathsf{log1p}\left(e^{-t}\right)\right)\right)}} \]
    8. Step-by-step derivation
      1. *-un-lft-identity97.4%

        \[\leadsto {\left(e^{\color{blue}{1 \cdot c\_p}}\right)}^{\left(\left(-\mathsf{log1p}\left(e^{-s}\right)\right) - \left(-\mathsf{log1p}\left(e^{-t}\right)\right)\right)} \]
      2. exp-prod97.4%

        \[\leadsto {\color{blue}{\left({\left(e^{1}\right)}^{c\_p}\right)}}^{\left(\left(-\mathsf{log1p}\left(e^{-s}\right)\right) - \left(-\mathsf{log1p}\left(e^{-t}\right)\right)\right)} \]
    9. Applied egg-rr97.4%

      \[\leadsto {\color{blue}{\left({\left(e^{1}\right)}^{c\_p}\right)}}^{\left(\left(-\mathsf{log1p}\left(e^{-s}\right)\right) - \left(-\mathsf{log1p}\left(e^{-t}\right)\right)\right)} \]
    10. Step-by-step derivation
      1. exp-1-e97.4%

        \[\leadsto {\left({\color{blue}{e}}^{c\_p}\right)}^{\left(\left(-\mathsf{log1p}\left(e^{-s}\right)\right) - \left(-\mathsf{log1p}\left(e^{-t}\right)\right)\right)} \]
    11. Simplified97.4%

      \[\leadsto {\color{blue}{\left({e}^{c\_p}\right)}}^{\left(\left(-\mathsf{log1p}\left(e^{-s}\right)\right) - \left(-\mathsf{log1p}\left(e^{-t}\right)\right)\right)} \]
    12. Taylor expanded in s around 0 98.6%

      \[\leadsto {\left({e}^{c\_p}\right)}^{\color{blue}{\left(\left(\log \left(1 + e^{-t}\right) + s \cdot \left(0.5 + -0.125 \cdot s\right)\right) - \log 2\right)}} \]
    13. Step-by-step derivation
      1. associate--l+98.6%

        \[\leadsto {\left({e}^{c\_p}\right)}^{\color{blue}{\left(\log \left(1 + e^{-t}\right) + \left(s \cdot \left(0.5 + -0.125 \cdot s\right) - \log 2\right)\right)}} \]
      2. log1p-define98.6%

        \[\leadsto {\left({e}^{c\_p}\right)}^{\left(\color{blue}{\mathsf{log1p}\left(e^{-t}\right)} + \left(s \cdot \left(0.5 + -0.125 \cdot s\right) - \log 2\right)\right)} \]
      3. *-commutative98.6%

        \[\leadsto {\left({e}^{c\_p}\right)}^{\left(\mathsf{log1p}\left(e^{-t}\right) + \left(s \cdot \left(0.5 + \color{blue}{s \cdot -0.125}\right) - \log 2\right)\right)} \]
    14. Simplified98.6%

      \[\leadsto {\left({e}^{c\_p}\right)}^{\color{blue}{\left(\mathsf{log1p}\left(e^{-t}\right) + \left(s \cdot \left(0.5 + s \cdot -0.125\right) - \log 2\right)\right)}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification99.5%

    \[\leadsto \begin{array}{l} \mathbf{if}\;c\_p \leq 5 \cdot 10^{-85}:\\ \;\;\;\;\frac{e^{\mathsf{fma}\left(\mathsf{log1p}\left(\frac{1}{1 + e^{s}}\right), c\_n, \mathsf{log1p}\left(e^{s}\right) \cdot \left(-c\_p\right) - c\_n \cdot \mathsf{log1p}\left(\frac{1}{1 + e^{t}}\right)\right)}}{{\left(1 + e^{t}\right)}^{\left(-c\_p\right)}}\\ \mathbf{else}:\\ \;\;\;\;{\left({e}^{c\_p}\right)}^{\left(\mathsf{log1p}\left(e^{-t}\right) + \left(s \cdot \left(0.5 + s \cdot -0.125\right) - \log 2\right)\right)}\\ \end{array} \]
  5. Add Preprocessing

Alternative 2: 99.0% accurate, 2.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_1 := e^{-t}\\ \mathbf{if}\;-t \leq 2 \cdot 10^{-18}:\\ \;\;\;\;e^{\left(s \cdot \left(-0.125 \cdot \left(c\_p \cdot s\right) + c\_p \cdot 0.5\right) - c\_p \cdot \log 2\right) + c\_p \cdot \mathsf{log1p}\left(t\_1\right)}\\ \mathbf{else}:\\ \;\;\;\;\frac{{\left(1 + \frac{1}{-1 - e^{-s}}\right)}^{c\_n}}{{\left(1 + \frac{1}{-1 - t\_1}\right)}^{c\_n}}\\ \end{array} \end{array} \]
(FPCore (c_p c_n t s)
 :precision binary64
 (let* ((t_1 (exp (- t))))
   (if (<= (- t) 2e-18)
     (exp
      (+
       (- (* s (+ (* -0.125 (* c_p s)) (* c_p 0.5))) (* c_p (log 2.0)))
       (* c_p (log1p t_1))))
     (/
      (pow (+ 1.0 (/ 1.0 (- -1.0 (exp (- s))))) 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 <= 2e-18) {
		tmp = exp((((s * ((-0.125 * (c_p * s)) + (c_p * 0.5))) - (c_p * log(2.0))) + (c_p * log1p(t_1))));
	} else {
		tmp = pow((1.0 + (1.0 / (-1.0 - exp(-s)))), c_n) / pow((1.0 + (1.0 / (-1.0 - t_1))), c_n);
	}
	return tmp;
}
public static double code(double c_p, double c_n, double t, double s) {
	double t_1 = Math.exp(-t);
	double tmp;
	if (-t <= 2e-18) {
		tmp = Math.exp((((s * ((-0.125 * (c_p * s)) + (c_p * 0.5))) - (c_p * Math.log(2.0))) + (c_p * Math.log1p(t_1))));
	} else {
		tmp = Math.pow((1.0 + (1.0 / (-1.0 - Math.exp(-s)))), 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 <= 2e-18:
		tmp = math.exp((((s * ((-0.125 * (c_p * s)) + (c_p * 0.5))) - (c_p * math.log(2.0))) + (c_p * math.log1p(t_1))))
	else:
		tmp = math.pow((1.0 + (1.0 / (-1.0 - math.exp(-s)))), 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) <= 2e-18)
		tmp = exp(Float64(Float64(Float64(s * Float64(Float64(-0.125 * Float64(c_p * s)) + Float64(c_p * 0.5))) - Float64(c_p * log(2.0))) + Float64(c_p * log1p(t_1))));
	else
		tmp = Float64((Float64(1.0 + Float64(1.0 / Float64(-1.0 - exp(Float64(-s))))) ^ c_n) / (Float64(1.0 + Float64(1.0 / Float64(-1.0 - t_1))) ^ c_n));
	end
	return tmp
end
code[c$95$p_, c$95$n_, t_, s_] := Block[{t$95$1 = N[Exp[(-t)], $MachinePrecision]}, If[LessEqual[(-t), 2e-18], N[Exp[N[(N[(N[(s * N[(N[(-0.125 * N[(c$95$p * s), $MachinePrecision]), $MachinePrecision] + N[(c$95$p * 0.5), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - N[(c$95$p * N[Log[2.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[(c$95$p * N[Log[1 + t$95$1], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision], N[(N[Power[N[(1.0 + N[(1.0 / N[(-1.0 - N[Exp[(-s)], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], 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 2 \cdot 10^{-18}:\\
\;\;\;\;e^{\left(s \cdot \left(-0.125 \cdot \left(c\_p \cdot s\right) + c\_p \cdot 0.5\right) - c\_p \cdot \log 2\right) + c\_p \cdot \mathsf{log1p}\left(t\_1\right)}\\

\mathbf{else}:\\
\;\;\;\;\frac{{\left(1 + \frac{1}{-1 - e^{-s}}\right)}^{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) < 2.0000000000000001e-18

    1. Initial program 93.1%

      \[\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}} \]
    2. Step-by-step derivation
      1. associate-/l/93.1%

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

      \[\leadsto \color{blue}{\frac{\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 + \frac{1}{-1 - e^{-s}}\right)}^{c\_n}}{{\left(1 + \frac{1}{-1 - e^{-t}}\right)}^{c\_n}}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}}} \]
    4. Add Preprocessing
    5. Taylor expanded in c_n around 0 95.1%

      \[\leadsto \color{blue}{\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}}} \]
    6. Step-by-step derivation
      1. add-exp-log95.1%

        \[\leadsto \color{blue}{e^{\log \left(\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}}\right)}} \]
      2. log-div95.1%

        \[\leadsto e^{\color{blue}{\log \left({\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p}\right) - \log \left({\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}\right)}} \]
      3. log-pow95.1%

        \[\leadsto e^{\color{blue}{c\_p \cdot \log \left(\frac{1}{1 + e^{-s}}\right)} - \log \left({\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}\right)} \]
      4. log-rec95.1%

        \[\leadsto e^{c\_p \cdot \color{blue}{\left(-\log \left(1 + e^{-s}\right)\right)} - \log \left({\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}\right)} \]
      5. log1p-define95.1%

        \[\leadsto e^{c\_p \cdot \left(-\color{blue}{\mathsf{log1p}\left(e^{-s}\right)}\right) - \log \left({\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}\right)} \]
      6. log-pow97.1%

        \[\leadsto e^{c\_p \cdot \left(-\mathsf{log1p}\left(e^{-s}\right)\right) - \color{blue}{c\_p \cdot \log \left(\frac{1}{1 + e^{-t}}\right)}} \]
      7. neg-log97.1%

        \[\leadsto e^{c\_p \cdot \left(-\mathsf{log1p}\left(e^{-s}\right)\right) - c\_p \cdot \color{blue}{\left(-\log \left(1 + e^{-t}\right)\right)}} \]
      8. log1p-define97.1%

        \[\leadsto e^{c\_p \cdot \left(-\mathsf{log1p}\left(e^{-s}\right)\right) - c\_p \cdot \left(-\color{blue}{\mathsf{log1p}\left(e^{-t}\right)}\right)} \]
    7. Applied egg-rr97.1%

      \[\leadsto \color{blue}{e^{c\_p \cdot \left(-\mathsf{log1p}\left(e^{-s}\right)\right) - c\_p \cdot \left(-\mathsf{log1p}\left(e^{-t}\right)\right)}} \]
    8. Taylor expanded in s around 0 99.4%

      \[\leadsto e^{\color{blue}{\left(-1 \cdot \left(c\_p \cdot \log 2\right) + s \cdot \left(-0.125 \cdot \left(c\_p \cdot s\right) + 0.5 \cdot c\_p\right)\right)} - c\_p \cdot \left(-\mathsf{log1p}\left(e^{-t}\right)\right)} \]

    if 2.0000000000000001e-18 < (neg.f64 t)

    1. Initial program 34.0%

      \[\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}} \]
    2. Step-by-step derivation
      1. associate-/l/34.0%

        \[\leadsto \color{blue}{\frac{\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}}} \]
    3. Simplified34.0%

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

      \[\leadsto \color{blue}{\frac{{\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification99.5%

    \[\leadsto \begin{array}{l} \mathbf{if}\;-t \leq 2 \cdot 10^{-18}:\\ \;\;\;\;e^{\left(s \cdot \left(-0.125 \cdot \left(c\_p \cdot s\right) + c\_p \cdot 0.5\right) - c\_p \cdot \log 2\right) + c\_p \cdot \mathsf{log1p}\left(e^{-t}\right)}\\ \mathbf{else}:\\ \;\;\;\;\frac{{\left(1 + \frac{1}{-1 - e^{-s}}\right)}^{c\_n}}{{\left(1 + \frac{1}{-1 - e^{-t}}\right)}^{c\_n}}\\ \end{array} \]
  5. Add Preprocessing

Alternative 3: 99.0% accurate, 2.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_1 := e^{-t}\\ \mathbf{if}\;-t \leq 2 \cdot 10^{-18}:\\ \;\;\;\;e^{c\_p \cdot \left(s \cdot \left(0.5 + s \cdot -0.125\right) - \log 2\right) + c\_p \cdot \mathsf{log1p}\left(t\_1\right)}\\ \mathbf{else}:\\ \;\;\;\;\frac{{\left(1 + \frac{1}{-1 - e^{-s}}\right)}^{c\_n}}{{\left(1 + \frac{1}{-1 - t\_1}\right)}^{c\_n}}\\ \end{array} \end{array} \]
(FPCore (c_p c_n t s)
 :precision binary64
 (let* ((t_1 (exp (- t))))
   (if (<= (- t) 2e-18)
     (exp
      (+ (* c_p (- (* s (+ 0.5 (* s -0.125))) (log 2.0))) (* c_p (log1p t_1))))
     (/
      (pow (+ 1.0 (/ 1.0 (- -1.0 (exp (- s))))) 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 <= 2e-18) {
		tmp = exp(((c_p * ((s * (0.5 + (s * -0.125))) - log(2.0))) + (c_p * log1p(t_1))));
	} else {
		tmp = pow((1.0 + (1.0 / (-1.0 - exp(-s)))), c_n) / pow((1.0 + (1.0 / (-1.0 - t_1))), c_n);
	}
	return tmp;
}
public static double code(double c_p, double c_n, double t, double s) {
	double t_1 = Math.exp(-t);
	double tmp;
	if (-t <= 2e-18) {
		tmp = Math.exp(((c_p * ((s * (0.5 + (s * -0.125))) - Math.log(2.0))) + (c_p * Math.log1p(t_1))));
	} else {
		tmp = Math.pow((1.0 + (1.0 / (-1.0 - Math.exp(-s)))), 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 <= 2e-18:
		tmp = math.exp(((c_p * ((s * (0.5 + (s * -0.125))) - math.log(2.0))) + (c_p * math.log1p(t_1))))
	else:
		tmp = math.pow((1.0 + (1.0 / (-1.0 - math.exp(-s)))), 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) <= 2e-18)
		tmp = exp(Float64(Float64(c_p * Float64(Float64(s * Float64(0.5 + Float64(s * -0.125))) - log(2.0))) + Float64(c_p * log1p(t_1))));
	else
		tmp = Float64((Float64(1.0 + Float64(1.0 / Float64(-1.0 - exp(Float64(-s))))) ^ c_n) / (Float64(1.0 + Float64(1.0 / Float64(-1.0 - t_1))) ^ c_n));
	end
	return tmp
end
code[c$95$p_, c$95$n_, t_, s_] := Block[{t$95$1 = N[Exp[(-t)], $MachinePrecision]}, If[LessEqual[(-t), 2e-18], N[Exp[N[(N[(c$95$p * N[(N[(s * N[(0.5 + N[(s * -0.125), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - N[Log[2.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[(c$95$p * N[Log[1 + t$95$1], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision], N[(N[Power[N[(1.0 + N[(1.0 / N[(-1.0 - N[Exp[(-s)], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], 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 2 \cdot 10^{-18}:\\
\;\;\;\;e^{c\_p \cdot \left(s \cdot \left(0.5 + s \cdot -0.125\right) - \log 2\right) + c\_p \cdot \mathsf{log1p}\left(t\_1\right)}\\

\mathbf{else}:\\
\;\;\;\;\frac{{\left(1 + \frac{1}{-1 - e^{-s}}\right)}^{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) < 2.0000000000000001e-18

    1. Initial program 93.1%

      \[\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}} \]
    2. Step-by-step derivation
      1. associate-/l/93.1%

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

      \[\leadsto \color{blue}{\frac{\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 + \frac{1}{-1 - e^{-s}}\right)}^{c\_n}}{{\left(1 + \frac{1}{-1 - e^{-t}}\right)}^{c\_n}}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}}} \]
    4. Add Preprocessing
    5. Taylor expanded in c_n around 0 95.1%

      \[\leadsto \color{blue}{\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}}} \]
    6. Step-by-step derivation
      1. add-exp-log95.1%

        \[\leadsto \color{blue}{e^{\log \left(\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}}\right)}} \]
      2. log-div95.1%

        \[\leadsto e^{\color{blue}{\log \left({\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p}\right) - \log \left({\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}\right)}} \]
      3. log-pow95.1%

        \[\leadsto e^{\color{blue}{c\_p \cdot \log \left(\frac{1}{1 + e^{-s}}\right)} - \log \left({\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}\right)} \]
      4. log-rec95.1%

        \[\leadsto e^{c\_p \cdot \color{blue}{\left(-\log \left(1 + e^{-s}\right)\right)} - \log \left({\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}\right)} \]
      5. log1p-define95.1%

        \[\leadsto e^{c\_p \cdot \left(-\color{blue}{\mathsf{log1p}\left(e^{-s}\right)}\right) - \log \left({\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}\right)} \]
      6. log-pow97.1%

        \[\leadsto e^{c\_p \cdot \left(-\mathsf{log1p}\left(e^{-s}\right)\right) - \color{blue}{c\_p \cdot \log \left(\frac{1}{1 + e^{-t}}\right)}} \]
      7. neg-log97.1%

        \[\leadsto e^{c\_p \cdot \left(-\mathsf{log1p}\left(e^{-s}\right)\right) - c\_p \cdot \color{blue}{\left(-\log \left(1 + e^{-t}\right)\right)}} \]
      8. log1p-define97.1%

        \[\leadsto e^{c\_p \cdot \left(-\mathsf{log1p}\left(e^{-s}\right)\right) - c\_p \cdot \left(-\color{blue}{\mathsf{log1p}\left(e^{-t}\right)}\right)} \]
    7. Applied egg-rr97.1%

      \[\leadsto \color{blue}{e^{c\_p \cdot \left(-\mathsf{log1p}\left(e^{-s}\right)\right) - c\_p \cdot \left(-\mathsf{log1p}\left(e^{-t}\right)\right)}} \]
    8. Taylor expanded in s around 0 99.4%

      \[\leadsto e^{c\_p \cdot \color{blue}{\left(s \cdot \left(0.5 + -0.125 \cdot s\right) - \log 2\right)} - c\_p \cdot \left(-\mathsf{log1p}\left(e^{-t}\right)\right)} \]
    9. Step-by-step derivation
      1. *-commutative99.4%

        \[\leadsto e^{c\_p \cdot \left(s \cdot \left(0.5 + \color{blue}{s \cdot -0.125}\right) - \log 2\right) - c\_p \cdot \left(-\mathsf{log1p}\left(e^{-t}\right)\right)} \]
    10. Simplified99.4%

      \[\leadsto e^{c\_p \cdot \color{blue}{\left(s \cdot \left(0.5 + s \cdot -0.125\right) - \log 2\right)} - c\_p \cdot \left(-\mathsf{log1p}\left(e^{-t}\right)\right)} \]

    if 2.0000000000000001e-18 < (neg.f64 t)

    1. Initial program 34.0%

      \[\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}} \]
    2. Step-by-step derivation
      1. associate-/l/34.0%

        \[\leadsto \color{blue}{\frac{\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}}} \]
    3. Simplified34.0%

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

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

    \[\leadsto \begin{array}{l} \mathbf{if}\;-t \leq 2 \cdot 10^{-18}:\\ \;\;\;\;e^{c\_p \cdot \left(s \cdot \left(0.5 + s \cdot -0.125\right) - \log 2\right) + c\_p \cdot \mathsf{log1p}\left(e^{-t}\right)}\\ \mathbf{else}:\\ \;\;\;\;\frac{{\left(1 + \frac{1}{-1 - e^{-s}}\right)}^{c\_n}}{{\left(1 + \frac{1}{-1 - e^{-t}}\right)}^{c\_n}}\\ \end{array} \]
  5. Add Preprocessing

Alternative 4: 99.0% accurate, 2.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;-t \leq 2 \cdot 10^{-18}:\\ \;\;\;\;e^{c\_p \cdot \left(s \cdot \left(0.5 + s \cdot -0.125\right) - \log 2\right) + c\_p \cdot \mathsf{log1p}\left(e^{-t}\right)}\\ \mathbf{else}:\\ \;\;\;\;\frac{{0.5}^{c\_n}}{{\left(0.5 + t \cdot -0.25\right)}^{c\_n}}\\ \end{array} \end{array} \]
(FPCore (c_p c_n t s)
 :precision binary64
 (if (<= (- t) 2e-18)
   (exp
    (+
     (* c_p (- (* s (+ 0.5 (* s -0.125))) (log 2.0)))
     (* c_p (log1p (exp (- t))))))
   (/ (pow 0.5 c_n) (pow (+ 0.5 (* t -0.25)) c_n))))
double code(double c_p, double c_n, double t, double s) {
	double tmp;
	if (-t <= 2e-18) {
		tmp = exp(((c_p * ((s * (0.5 + (s * -0.125))) - log(2.0))) + (c_p * log1p(exp(-t)))));
	} else {
		tmp = pow(0.5, c_n) / pow((0.5 + (t * -0.25)), c_n);
	}
	return tmp;
}
public static double code(double c_p, double c_n, double t, double s) {
	double tmp;
	if (-t <= 2e-18) {
		tmp = Math.exp(((c_p * ((s * (0.5 + (s * -0.125))) - Math.log(2.0))) + (c_p * Math.log1p(Math.exp(-t)))));
	} else {
		tmp = Math.pow(0.5, c_n) / Math.pow((0.5 + (t * -0.25)), c_n);
	}
	return tmp;
}
def code(c_p, c_n, t, s):
	tmp = 0
	if -t <= 2e-18:
		tmp = math.exp(((c_p * ((s * (0.5 + (s * -0.125))) - math.log(2.0))) + (c_p * math.log1p(math.exp(-t)))))
	else:
		tmp = math.pow(0.5, c_n) / math.pow((0.5 + (t * -0.25)), c_n)
	return tmp
function code(c_p, c_n, t, s)
	tmp = 0.0
	if (Float64(-t) <= 2e-18)
		tmp = exp(Float64(Float64(c_p * Float64(Float64(s * Float64(0.5 + Float64(s * -0.125))) - log(2.0))) + Float64(c_p * log1p(exp(Float64(-t))))));
	else
		tmp = Float64((0.5 ^ c_n) / (Float64(0.5 + Float64(t * -0.25)) ^ c_n));
	end
	return tmp
end
code[c$95$p_, c$95$n_, t_, s_] := If[LessEqual[(-t), 2e-18], N[Exp[N[(N[(c$95$p * N[(N[(s * N[(0.5 + N[(s * -0.125), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - N[Log[2.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[(c$95$p * N[Log[1 + N[Exp[(-t)], $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision], N[(N[Power[0.5, c$95$n], $MachinePrecision] / N[Power[N[(0.5 + N[(t * -0.25), $MachinePrecision]), $MachinePrecision], c$95$n], $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;-t \leq 2 \cdot 10^{-18}:\\
\;\;\;\;e^{c\_p \cdot \left(s \cdot \left(0.5 + s \cdot -0.125\right) - \log 2\right) + c\_p \cdot \mathsf{log1p}\left(e^{-t}\right)}\\

\mathbf{else}:\\
\;\;\;\;\frac{{0.5}^{c\_n}}{{\left(0.5 + t \cdot -0.25\right)}^{c\_n}}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if (neg.f64 t) < 2.0000000000000001e-18

    1. Initial program 93.1%

      \[\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}} \]
    2. Step-by-step derivation
      1. associate-/l/93.1%

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

      \[\leadsto \color{blue}{\frac{\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 + \frac{1}{-1 - e^{-s}}\right)}^{c\_n}}{{\left(1 + \frac{1}{-1 - e^{-t}}\right)}^{c\_n}}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}}} \]
    4. Add Preprocessing
    5. Taylor expanded in c_n around 0 95.1%

      \[\leadsto \color{blue}{\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}}} \]
    6. Step-by-step derivation
      1. add-exp-log95.1%

        \[\leadsto \color{blue}{e^{\log \left(\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}}\right)}} \]
      2. log-div95.1%

        \[\leadsto e^{\color{blue}{\log \left({\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p}\right) - \log \left({\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}\right)}} \]
      3. log-pow95.1%

        \[\leadsto e^{\color{blue}{c\_p \cdot \log \left(\frac{1}{1 + e^{-s}}\right)} - \log \left({\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}\right)} \]
      4. log-rec95.1%

        \[\leadsto e^{c\_p \cdot \color{blue}{\left(-\log \left(1 + e^{-s}\right)\right)} - \log \left({\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}\right)} \]
      5. log1p-define95.1%

        \[\leadsto e^{c\_p \cdot \left(-\color{blue}{\mathsf{log1p}\left(e^{-s}\right)}\right) - \log \left({\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}\right)} \]
      6. log-pow97.1%

        \[\leadsto e^{c\_p \cdot \left(-\mathsf{log1p}\left(e^{-s}\right)\right) - \color{blue}{c\_p \cdot \log \left(\frac{1}{1 + e^{-t}}\right)}} \]
      7. neg-log97.1%

        \[\leadsto e^{c\_p \cdot \left(-\mathsf{log1p}\left(e^{-s}\right)\right) - c\_p \cdot \color{blue}{\left(-\log \left(1 + e^{-t}\right)\right)}} \]
      8. log1p-define97.1%

        \[\leadsto e^{c\_p \cdot \left(-\mathsf{log1p}\left(e^{-s}\right)\right) - c\_p \cdot \left(-\color{blue}{\mathsf{log1p}\left(e^{-t}\right)}\right)} \]
    7. Applied egg-rr97.1%

      \[\leadsto \color{blue}{e^{c\_p \cdot \left(-\mathsf{log1p}\left(e^{-s}\right)\right) - c\_p \cdot \left(-\mathsf{log1p}\left(e^{-t}\right)\right)}} \]
    8. Taylor expanded in s around 0 99.4%

      \[\leadsto e^{c\_p \cdot \color{blue}{\left(s \cdot \left(0.5 + -0.125 \cdot s\right) - \log 2\right)} - c\_p \cdot \left(-\mathsf{log1p}\left(e^{-t}\right)\right)} \]
    9. Step-by-step derivation
      1. *-commutative99.4%

        \[\leadsto e^{c\_p \cdot \left(s \cdot \left(0.5 + \color{blue}{s \cdot -0.125}\right) - \log 2\right) - c\_p \cdot \left(-\mathsf{log1p}\left(e^{-t}\right)\right)} \]
    10. Simplified99.4%

      \[\leadsto e^{c\_p \cdot \color{blue}{\left(s \cdot \left(0.5 + s \cdot -0.125\right) - \log 2\right)} - c\_p \cdot \left(-\mathsf{log1p}\left(e^{-t}\right)\right)} \]

    if 2.0000000000000001e-18 < (neg.f64 t)

    1. Initial program 34.0%

      \[\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}} \]
    2. Step-by-step derivation
      1. associate-/l/34.0%

        \[\leadsto \color{blue}{\frac{\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}}} \]
    3. Simplified34.0%

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

      \[\leadsto \color{blue}{\frac{{\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}}} \]
    6. Taylor expanded in s around 0 89.2%

      \[\leadsto \color{blue}{\frac{{0.5}^{c\_n}}{{\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}}} \]
    7. Taylor expanded in t around 0 89.2%

      \[\leadsto \frac{{0.5}^{c\_n}}{{\color{blue}{\left(0.5 + -0.25 \cdot t\right)}}^{c\_n}} \]
    8. Step-by-step derivation
      1. *-commutative89.2%

        \[\leadsto \frac{{0.5}^{c\_n}}{{\left(0.5 + \color{blue}{t \cdot -0.25}\right)}^{c\_n}} \]
    9. Simplified89.2%

      \[\leadsto \frac{{0.5}^{c\_n}}{{\color{blue}{\left(0.5 + t \cdot -0.25\right)}}^{c\_n}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification99.1%

    \[\leadsto \begin{array}{l} \mathbf{if}\;-t \leq 2 \cdot 10^{-18}:\\ \;\;\;\;e^{c\_p \cdot \left(s \cdot \left(0.5 + s \cdot -0.125\right) - \log 2\right) + c\_p \cdot \mathsf{log1p}\left(e^{-t}\right)}\\ \mathbf{else}:\\ \;\;\;\;\frac{{0.5}^{c\_n}}{{\left(0.5 + t \cdot -0.25\right)}^{c\_n}}\\ \end{array} \]
  5. Add Preprocessing

Alternative 5: 97.7% accurate, 2.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;c\_p \leq 0.00033:\\ \;\;\;\;\frac{{\left(\frac{1}{2 + s \cdot \left(-1 + s \cdot 0.5\right)}\right)}^{c\_p}}{{0.5}^{c\_p}}\\ \mathbf{else}:\\ \;\;\;\;e^{s \cdot \left(c\_p \cdot 0.5\right) + c\_p \cdot \left(\mathsf{log1p}\left(e^{-t}\right) - \log 2\right)}\\ \end{array} \end{array} \]
(FPCore (c_p c_n t s)
 :precision binary64
 (if (<= c_p 0.00033)
   (/ (pow (/ 1.0 (+ 2.0 (* s (+ -1.0 (* s 0.5))))) c_p) (pow 0.5 c_p))
   (exp (+ (* s (* c_p 0.5)) (* c_p (- (log1p (exp (- t))) (log 2.0)))))))
double code(double c_p, double c_n, double t, double s) {
	double tmp;
	if (c_p <= 0.00033) {
		tmp = pow((1.0 / (2.0 + (s * (-1.0 + (s * 0.5))))), c_p) / pow(0.5, c_p);
	} else {
		tmp = exp(((s * (c_p * 0.5)) + (c_p * (log1p(exp(-t)) - log(2.0)))));
	}
	return tmp;
}
public static double code(double c_p, double c_n, double t, double s) {
	double tmp;
	if (c_p <= 0.00033) {
		tmp = Math.pow((1.0 / (2.0 + (s * (-1.0 + (s * 0.5))))), c_p) / Math.pow(0.5, c_p);
	} else {
		tmp = Math.exp(((s * (c_p * 0.5)) + (c_p * (Math.log1p(Math.exp(-t)) - Math.log(2.0)))));
	}
	return tmp;
}
def code(c_p, c_n, t, s):
	tmp = 0
	if c_p <= 0.00033:
		tmp = math.pow((1.0 / (2.0 + (s * (-1.0 + (s * 0.5))))), c_p) / math.pow(0.5, c_p)
	else:
		tmp = math.exp(((s * (c_p * 0.5)) + (c_p * (math.log1p(math.exp(-t)) - math.log(2.0)))))
	return tmp
function code(c_p, c_n, t, s)
	tmp = 0.0
	if (c_p <= 0.00033)
		tmp = Float64((Float64(1.0 / Float64(2.0 + Float64(s * Float64(-1.0 + Float64(s * 0.5))))) ^ c_p) / (0.5 ^ c_p));
	else
		tmp = exp(Float64(Float64(s * Float64(c_p * 0.5)) + Float64(c_p * Float64(log1p(exp(Float64(-t))) - log(2.0)))));
	end
	return tmp
end
code[c$95$p_, c$95$n_, t_, s_] := If[LessEqual[c$95$p, 0.00033], N[(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] / N[Power[0.5, c$95$p], $MachinePrecision]), $MachinePrecision], N[Exp[N[(N[(s * N[(c$95$p * 0.5), $MachinePrecision]), $MachinePrecision] + N[(c$95$p * N[(N[Log[1 + N[Exp[(-t)], $MachinePrecision]], $MachinePrecision] - N[Log[2.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;c\_p \leq 0.00033:\\
\;\;\;\;\frac{{\left(\frac{1}{2 + s \cdot \left(-1 + s \cdot 0.5\right)}\right)}^{c\_p}}{{0.5}^{c\_p}}\\

\mathbf{else}:\\
\;\;\;\;e^{s \cdot \left(c\_p \cdot 0.5\right) + c\_p \cdot \left(\mathsf{log1p}\left(e^{-t}\right) - \log 2\right)}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if c_p < 3.3e-4

    1. Initial program 93.0%

      \[\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}} \]
    2. Step-by-step derivation
      1. associate-/l/93.0%

        \[\leadsto \color{blue}{\frac{\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}}} \]
    3. Simplified93.0%

      \[\leadsto \color{blue}{\frac{\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 + \frac{1}{-1 - e^{-s}}\right)}^{c\_n}}{{\left(1 + \frac{1}{-1 - e^{-t}}\right)}^{c\_n}}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}}} \]
    4. Add Preprocessing
    5. Taylor expanded in c_n around 0 94.6%

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

      \[\leadsto \frac{{\left(\frac{1}{\color{blue}{2 + s \cdot \left(0.5 \cdot s - 1\right)}}\right)}^{c\_p}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}} \]
    7. Taylor expanded in t around 0 98.7%

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

    if 3.3e-4 < c_p

    1. Initial program 64.2%

      \[\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}} \]
    2. Step-by-step derivation
      1. associate-/l/64.2%

        \[\leadsto \color{blue}{\frac{\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}}} \]
    3. Simplified64.2%

      \[\leadsto \color{blue}{\frac{\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 + \frac{1}{-1 - e^{-s}}\right)}^{c\_n}}{{\left(1 + \frac{1}{-1 - e^{-t}}\right)}^{c\_n}}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}}} \]
    4. Add Preprocessing
    5. Taylor expanded in c_n around 0 70.1%

      \[\leadsto \color{blue}{\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}}} \]
    6. Step-by-step derivation
      1. add-exp-log70.1%

        \[\leadsto \color{blue}{e^{\log \left(\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}}\right)}} \]
      2. log-div70.1%

        \[\leadsto e^{\color{blue}{\log \left({\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p}\right) - \log \left({\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}\right)}} \]
      3. log-pow70.6%

        \[\leadsto e^{\color{blue}{c\_p \cdot \log \left(\frac{1}{1 + e^{-s}}\right)} - \log \left({\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}\right)} \]
      4. log-rec70.6%

        \[\leadsto e^{c\_p \cdot \color{blue}{\left(-\log \left(1 + e^{-s}\right)\right)} - \log \left({\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}\right)} \]
      5. log1p-define70.6%

        \[\leadsto e^{c\_p \cdot \left(-\color{blue}{\mathsf{log1p}\left(e^{-s}\right)}\right) - \log \left({\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}\right)} \]
      6. log-pow98.8%

        \[\leadsto e^{c\_p \cdot \left(-\mathsf{log1p}\left(e^{-s}\right)\right) - \color{blue}{c\_p \cdot \log \left(\frac{1}{1 + e^{-t}}\right)}} \]
      7. neg-log98.8%

        \[\leadsto e^{c\_p \cdot \left(-\mathsf{log1p}\left(e^{-s}\right)\right) - c\_p \cdot \color{blue}{\left(-\log \left(1 + e^{-t}\right)\right)}} \]
      8. log1p-define98.9%

        \[\leadsto e^{c\_p \cdot \left(-\mathsf{log1p}\left(e^{-s}\right)\right) - c\_p \cdot \left(-\color{blue}{\mathsf{log1p}\left(e^{-t}\right)}\right)} \]
    7. Applied egg-rr98.9%

      \[\leadsto \color{blue}{e^{c\_p \cdot \left(-\mathsf{log1p}\left(e^{-s}\right)\right) - c\_p \cdot \left(-\mathsf{log1p}\left(e^{-t}\right)\right)}} \]
    8. Taylor expanded in s around 0 97.9%

      \[\leadsto e^{\color{blue}{\left(-1 \cdot \left(c\_p \cdot \log 2\right) + 0.5 \cdot \left(c\_p \cdot s\right)\right) - -1 \cdot \left(c\_p \cdot \log \left(1 + e^{-t}\right)\right)}} \]
    9. Step-by-step derivation
      1. +-commutative97.9%

        \[\leadsto e^{\color{blue}{\left(0.5 \cdot \left(c\_p \cdot s\right) + -1 \cdot \left(c\_p \cdot \log 2\right)\right)} - -1 \cdot \left(c\_p \cdot \log \left(1 + e^{-t}\right)\right)} \]
      2. associate--l+98.6%

        \[\leadsto e^{\color{blue}{0.5 \cdot \left(c\_p \cdot s\right) + \left(-1 \cdot \left(c\_p \cdot \log 2\right) - -1 \cdot \left(c\_p \cdot \log \left(1 + e^{-t}\right)\right)\right)}} \]
      3. *-commutative98.6%

        \[\leadsto e^{\color{blue}{\left(c\_p \cdot s\right) \cdot 0.5} + \left(-1 \cdot \left(c\_p \cdot \log 2\right) - -1 \cdot \left(c\_p \cdot \log \left(1 + e^{-t}\right)\right)\right)} \]
      4. *-commutative98.6%

        \[\leadsto e^{\color{blue}{\left(s \cdot c\_p\right)} \cdot 0.5 + \left(-1 \cdot \left(c\_p \cdot \log 2\right) - -1 \cdot \left(c\_p \cdot \log \left(1 + e^{-t}\right)\right)\right)} \]
      5. associate-*r*98.6%

        \[\leadsto e^{\color{blue}{s \cdot \left(c\_p \cdot 0.5\right)} + \left(-1 \cdot \left(c\_p \cdot \log 2\right) - -1 \cdot \left(c\_p \cdot \log \left(1 + e^{-t}\right)\right)\right)} \]
      6. sub-neg98.6%

        \[\leadsto e^{s \cdot \left(c\_p \cdot 0.5\right) + \color{blue}{\left(-1 \cdot \left(c\_p \cdot \log 2\right) + \left(--1 \cdot \left(c\_p \cdot \log \left(1 + e^{-t}\right)\right)\right)\right)}} \]
      7. mul-1-neg98.6%

        \[\leadsto e^{s \cdot \left(c\_p \cdot 0.5\right) + \left(-1 \cdot \left(c\_p \cdot \log 2\right) + \left(-\color{blue}{\left(-c\_p \cdot \log \left(1 + e^{-t}\right)\right)}\right)\right)} \]
      8. remove-double-neg98.6%

        \[\leadsto e^{s \cdot \left(c\_p \cdot 0.5\right) + \left(-1 \cdot \left(c\_p \cdot \log 2\right) + \color{blue}{c\_p \cdot \log \left(1 + e^{-t}\right)}\right)} \]
      9. cancel-sign-sub98.6%

        \[\leadsto e^{s \cdot \left(c\_p \cdot 0.5\right) + \color{blue}{\left(-1 \cdot \left(c\_p \cdot \log 2\right) - \left(-c\_p\right) \cdot \log \left(1 + e^{-t}\right)\right)}} \]
      10. associate-*r*98.6%

        \[\leadsto e^{s \cdot \left(c\_p \cdot 0.5\right) + \left(\color{blue}{\left(-1 \cdot c\_p\right) \cdot \log 2} - \left(-c\_p\right) \cdot \log \left(1 + e^{-t}\right)\right)} \]
      11. neg-mul-198.6%

        \[\leadsto e^{s \cdot \left(c\_p \cdot 0.5\right) + \left(\color{blue}{\left(-c\_p\right)} \cdot \log 2 - \left(-c\_p\right) \cdot \log \left(1 + e^{-t}\right)\right)} \]
      12. distribute-lft-out--98.6%

        \[\leadsto e^{s \cdot \left(c\_p \cdot 0.5\right) + \color{blue}{\left(-c\_p\right) \cdot \left(\log 2 - \log \left(1 + e^{-t}\right)\right)}} \]
      13. log1p-define98.6%

        \[\leadsto e^{s \cdot \left(c\_p \cdot 0.5\right) + \left(-c\_p\right) \cdot \left(\log 2 - \color{blue}{\mathsf{log1p}\left(e^{-t}\right)}\right)} \]
    10. Simplified98.6%

      \[\leadsto e^{\color{blue}{s \cdot \left(c\_p \cdot 0.5\right) + \left(-c\_p\right) \cdot \left(\log 2 - \mathsf{log1p}\left(e^{-t}\right)\right)}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification98.7%

    \[\leadsto \begin{array}{l} \mathbf{if}\;c\_p \leq 0.00033:\\ \;\;\;\;\frac{{\left(\frac{1}{2 + s \cdot \left(-1 + s \cdot 0.5\right)}\right)}^{c\_p}}{{0.5}^{c\_p}}\\ \mathbf{else}:\\ \;\;\;\;e^{s \cdot \left(c\_p \cdot 0.5\right) + c\_p \cdot \left(\mathsf{log1p}\left(e^{-t}\right) - \log 2\right)}\\ \end{array} \]
  5. Add Preprocessing

Alternative 6: 96.9% accurate, 7.5× speedup?

\[\begin{array}{l} \\ e^{s \cdot \left(c\_p \cdot 0.5\right) + -0.5 \cdot \left(c\_p \cdot t\right)} \end{array} \]
(FPCore (c_p c_n t s)
 :precision binary64
 (exp (+ (* s (* c_p 0.5)) (* -0.5 (* c_p t)))))
double code(double c_p, double c_n, double t, double s) {
	return exp(((s * (c_p * 0.5)) + (-0.5 * (c_p * t))));
}
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 = exp(((s * (c_p * 0.5d0)) + ((-0.5d0) * (c_p * t))))
end function
public static double code(double c_p, double c_n, double t, double s) {
	return Math.exp(((s * (c_p * 0.5)) + (-0.5 * (c_p * t))));
}
def code(c_p, c_n, t, s):
	return math.exp(((s * (c_p * 0.5)) + (-0.5 * (c_p * t))))
function code(c_p, c_n, t, s)
	return exp(Float64(Float64(s * Float64(c_p * 0.5)) + Float64(-0.5 * Float64(c_p * t))))
end
function tmp = code(c_p, c_n, t, s)
	tmp = exp(((s * (c_p * 0.5)) + (-0.5 * (c_p * t))));
end
code[c$95$p_, c$95$n_, t_, s_] := N[Exp[N[(N[(s * N[(c$95$p * 0.5), $MachinePrecision]), $MachinePrecision] + N[(-0.5 * N[(c$95$p * t), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]
\begin{array}{l}

\\
e^{s \cdot \left(c\_p \cdot 0.5\right) + -0.5 \cdot \left(c\_p \cdot t\right)}
\end{array}
Derivation
  1. Initial program 91.1%

    \[\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}} \]
  2. Step-by-step derivation
    1. associate-/l/91.1%

      \[\leadsto \color{blue}{\frac{\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}}} \]
  3. Simplified91.1%

    \[\leadsto \color{blue}{\frac{\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 + \frac{1}{-1 - e^{-s}}\right)}^{c\_n}}{{\left(1 + \frac{1}{-1 - e^{-t}}\right)}^{c\_n}}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}}} \]
  4. Add Preprocessing
  5. Taylor expanded in c_n around 0 93.0%

    \[\leadsto \color{blue}{\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}}} \]
  6. Step-by-step derivation
    1. add-exp-log93.0%

      \[\leadsto \color{blue}{e^{\log \left(\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}}\right)}} \]
    2. log-div93.0%

      \[\leadsto e^{\color{blue}{\log \left({\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p}\right) - \log \left({\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}\right)}} \]
    3. log-pow93.0%

      \[\leadsto e^{\color{blue}{c\_p \cdot \log \left(\frac{1}{1 + e^{-s}}\right)} - \log \left({\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}\right)} \]
    4. log-rec93.0%

      \[\leadsto e^{c\_p \cdot \color{blue}{\left(-\log \left(1 + e^{-s}\right)\right)} - \log \left({\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}\right)} \]
    5. log1p-define93.0%

      \[\leadsto e^{c\_p \cdot \left(-\color{blue}{\mathsf{log1p}\left(e^{-s}\right)}\right) - \log \left({\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}\right)} \]
    6. log-pow94.9%

      \[\leadsto e^{c\_p \cdot \left(-\mathsf{log1p}\left(e^{-s}\right)\right) - \color{blue}{c\_p \cdot \log \left(\frac{1}{1 + e^{-t}}\right)}} \]
    7. neg-log94.9%

      \[\leadsto e^{c\_p \cdot \left(-\mathsf{log1p}\left(e^{-s}\right)\right) - c\_p \cdot \color{blue}{\left(-\log \left(1 + e^{-t}\right)\right)}} \]
    8. log1p-define94.9%

      \[\leadsto e^{c\_p \cdot \left(-\mathsf{log1p}\left(e^{-s}\right)\right) - c\_p \cdot \left(-\color{blue}{\mathsf{log1p}\left(e^{-t}\right)}\right)} \]
  7. Applied egg-rr94.9%

    \[\leadsto \color{blue}{e^{c\_p \cdot \left(-\mathsf{log1p}\left(e^{-s}\right)\right) - c\_p \cdot \left(-\mathsf{log1p}\left(e^{-t}\right)\right)}} \]
  8. Taylor expanded in s around 0 95.9%

    \[\leadsto e^{\color{blue}{\left(-1 \cdot \left(c\_p \cdot \log 2\right) + 0.5 \cdot \left(c\_p \cdot s\right)\right) - -1 \cdot \left(c\_p \cdot \log \left(1 + e^{-t}\right)\right)}} \]
  9. Step-by-step derivation
    1. +-commutative95.9%

      \[\leadsto e^{\color{blue}{\left(0.5 \cdot \left(c\_p \cdot s\right) + -1 \cdot \left(c\_p \cdot \log 2\right)\right)} - -1 \cdot \left(c\_p \cdot \log \left(1 + e^{-t}\right)\right)} \]
    2. associate--l+96.0%

      \[\leadsto e^{\color{blue}{0.5 \cdot \left(c\_p \cdot s\right) + \left(-1 \cdot \left(c\_p \cdot \log 2\right) - -1 \cdot \left(c\_p \cdot \log \left(1 + e^{-t}\right)\right)\right)}} \]
    3. *-commutative96.0%

      \[\leadsto e^{\color{blue}{\left(c\_p \cdot s\right) \cdot 0.5} + \left(-1 \cdot \left(c\_p \cdot \log 2\right) - -1 \cdot \left(c\_p \cdot \log \left(1 + e^{-t}\right)\right)\right)} \]
    4. *-commutative96.0%

      \[\leadsto e^{\color{blue}{\left(s \cdot c\_p\right)} \cdot 0.5 + \left(-1 \cdot \left(c\_p \cdot \log 2\right) - -1 \cdot \left(c\_p \cdot \log \left(1 + e^{-t}\right)\right)\right)} \]
    5. associate-*r*96.0%

      \[\leadsto e^{\color{blue}{s \cdot \left(c\_p \cdot 0.5\right)} + \left(-1 \cdot \left(c\_p \cdot \log 2\right) - -1 \cdot \left(c\_p \cdot \log \left(1 + e^{-t}\right)\right)\right)} \]
    6. sub-neg96.0%

      \[\leadsto e^{s \cdot \left(c\_p \cdot 0.5\right) + \color{blue}{\left(-1 \cdot \left(c\_p \cdot \log 2\right) + \left(--1 \cdot \left(c\_p \cdot \log \left(1 + e^{-t}\right)\right)\right)\right)}} \]
    7. mul-1-neg96.0%

      \[\leadsto e^{s \cdot \left(c\_p \cdot 0.5\right) + \left(-1 \cdot \left(c\_p \cdot \log 2\right) + \left(-\color{blue}{\left(-c\_p \cdot \log \left(1 + e^{-t}\right)\right)}\right)\right)} \]
    8. remove-double-neg96.0%

      \[\leadsto e^{s \cdot \left(c\_p \cdot 0.5\right) + \left(-1 \cdot \left(c\_p \cdot \log 2\right) + \color{blue}{c\_p \cdot \log \left(1 + e^{-t}\right)}\right)} \]
    9. cancel-sign-sub96.0%

      \[\leadsto e^{s \cdot \left(c\_p \cdot 0.5\right) + \color{blue}{\left(-1 \cdot \left(c\_p \cdot \log 2\right) - \left(-c\_p\right) \cdot \log \left(1 + e^{-t}\right)\right)}} \]
    10. associate-*r*96.0%

      \[\leadsto e^{s \cdot \left(c\_p \cdot 0.5\right) + \left(\color{blue}{\left(-1 \cdot c\_p\right) \cdot \log 2} - \left(-c\_p\right) \cdot \log \left(1 + e^{-t}\right)\right)} \]
    11. neg-mul-196.0%

      \[\leadsto e^{s \cdot \left(c\_p \cdot 0.5\right) + \left(\color{blue}{\left(-c\_p\right)} \cdot \log 2 - \left(-c\_p\right) \cdot \log \left(1 + e^{-t}\right)\right)} \]
    12. distribute-lft-out--96.0%

      \[\leadsto e^{s \cdot \left(c\_p \cdot 0.5\right) + \color{blue}{\left(-c\_p\right) \cdot \left(\log 2 - \log \left(1 + e^{-t}\right)\right)}} \]
    13. log1p-define96.0%

      \[\leadsto e^{s \cdot \left(c\_p \cdot 0.5\right) + \left(-c\_p\right) \cdot \left(\log 2 - \color{blue}{\mathsf{log1p}\left(e^{-t}\right)}\right)} \]
  10. Simplified96.0%

    \[\leadsto e^{\color{blue}{s \cdot \left(c\_p \cdot 0.5\right) + \left(-c\_p\right) \cdot \left(\log 2 - \mathsf{log1p}\left(e^{-t}\right)\right)}} \]
  11. Taylor expanded in t around 0 96.9%

    \[\leadsto e^{s \cdot \left(c\_p \cdot 0.5\right) + \color{blue}{-0.5 \cdot \left(c\_p \cdot t\right)}} \]
  12. Add Preprocessing

Alternative 7: 94.3% 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 91.1%

    \[\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}} \]
  2. Step-by-step derivation
    1. associate-/l/91.1%

      \[\leadsto \color{blue}{\frac{\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}}} \]
  3. Simplified91.1%

    \[\leadsto \color{blue}{\frac{\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 + \frac{1}{-1 - e^{-s}}\right)}^{c\_n}}{{\left(1 + \frac{1}{-1 - e^{-t}}\right)}^{c\_n}}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}}} \]
  4. Add Preprocessing
  5. Taylor expanded in c_n around 0 93.0%

    \[\leadsto \color{blue}{\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p}}} \]
  6. Taylor expanded in c_p around 0 93.1%

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

Developer Target 1: 96.3% 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 2024145 
(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 default (* (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))))