Harley's example

Percentage Accurate: 90.7% → 99.5%
Time: 55.0s
Alternatives: 7
Speedup: 896.0×

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: 90.7% 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: 99.5% accurate, 2.5× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_1 := \log 0.5 \cdot c\_n\\ e^{\mathsf{fma}\left(\left(c\_p - c\_n\right) \cdot t, -0.5, \mathsf{fma}\left(\mathsf{fma}\left(-0.5, c\_n - c\_p, \left(-0.125 \cdot \mathsf{fma}\left(c\_n, 1, c\_p\right)\right) \cdot s\right), s, t\_1\right)\right) - t\_1} \end{array} \end{array} \]
(FPCore (c_p c_n t s)
 :precision binary64
 (let* ((t_1 (* (log 0.5) c_n)))
   (exp
    (-
     (fma
      (* (- c_p c_n) t)
      -0.5
      (fma (fma -0.5 (- c_n c_p) (* (* -0.125 (fma c_n 1.0 c_p)) s)) s t_1))
     t_1))))
double code(double c_p, double c_n, double t, double s) {
	double t_1 = log(0.5) * c_n;
	return exp((fma(((c_p - c_n) * t), -0.5, fma(fma(-0.5, (c_n - c_p), ((-0.125 * fma(c_n, 1.0, c_p)) * s)), s, t_1)) - t_1));
}
function code(c_p, c_n, t, s)
	t_1 = Float64(log(0.5) * c_n)
	return exp(Float64(fma(Float64(Float64(c_p - c_n) * t), -0.5, fma(fma(-0.5, Float64(c_n - c_p), Float64(Float64(-0.125 * fma(c_n, 1.0, c_p)) * s)), s, t_1)) - t_1))
end
code[c$95$p_, c$95$n_, t_, s_] := Block[{t$95$1 = N[(N[Log[0.5], $MachinePrecision] * c$95$n), $MachinePrecision]}, N[Exp[N[(N[(N[(N[(c$95$p - c$95$n), $MachinePrecision] * t), $MachinePrecision] * -0.5 + N[(N[(-0.5 * N[(c$95$n - c$95$p), $MachinePrecision] + N[(N[(-0.125 * N[(c$95$n * 1.0 + c$95$p), $MachinePrecision]), $MachinePrecision] * s), $MachinePrecision]), $MachinePrecision] * s + t$95$1), $MachinePrecision]), $MachinePrecision] - t$95$1), $MachinePrecision]], $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
t_1 := \log 0.5 \cdot c\_n\\
e^{\mathsf{fma}\left(\left(c\_p - c\_n\right) \cdot t, -0.5, \mathsf{fma}\left(\mathsf{fma}\left(-0.5, c\_n - c\_p, \left(-0.125 \cdot \mathsf{fma}\left(c\_n, 1, c\_p\right)\right) \cdot s\right), s, t\_1\right)\right) - t\_1}
\end{array}
\end{array}
Derivation
  1. Initial program 88.4%

    \[\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}} \]
  2. Add Preprocessing
  3. Applied rewrites93.7%

    \[\leadsto \color{blue}{e^{\mathsf{fma}\left(-\mathsf{log1p}\left(e^{-s}\right), c\_p, \mathsf{log1p}\left(e^{-t}\right) \cdot c\_p\right) + \mathsf{fma}\left(\mathsf{log1p}\left(-e^{-\mathsf{log1p}\left(e^{-s}\right)}\right), c\_n, \left(-c\_n\right) \cdot \mathsf{log1p}\left(-e^{-\mathsf{log1p}\left(e^{-t}\right)}\right)\right)}} \]
  4. Taylor expanded in t around 0

    \[\leadsto e^{\color{blue}{-1 \cdot \left(c\_n \cdot \log \left(1 - e^{\mathsf{neg}\left(\log 2\right)}\right)\right) + \left(-1 \cdot \left(c\_p \cdot \log \left(1 + e^{\mathsf{neg}\left(s\right)}\right)\right) + \left(c\_n \cdot \log \left(1 - e^{\mathsf{neg}\left(\log \left(1 + e^{\mathsf{neg}\left(s\right)}\right)\right)}\right) + \left(c\_p \cdot \log 2 + t \cdot \left(\frac{-1}{2} \cdot c\_p + \frac{1}{2} \cdot \frac{c\_n \cdot e^{\mathsf{neg}\left(\log 2\right)}}{1 - e^{\mathsf{neg}\left(\log 2\right)}}\right)\right)\right)\right)}} \]
  5. Applied rewrites97.3%

    \[\leadsto e^{\color{blue}{\left(-\mathsf{fma}\left(\log 0.5, c\_n, \mathsf{log1p}\left(e^{-s}\right) \cdot c\_p\right)\right) + \mathsf{fma}\left(\log \left(1 - e^{-\mathsf{log1p}\left(e^{-s}\right)}\right), c\_n, \mathsf{fma}\left(-0.5 \cdot \left(c\_p - c\_n \cdot 1\right), t, \log 2 \cdot c\_p\right)\right)}} \]
  6. Taylor expanded in s around 0

    \[\leadsto e^{\left(\frac{-1}{2} \cdot \left(t \cdot \left(c\_p - c\_n\right)\right) + \left(c\_n \cdot \log \left(1 - e^{\mathsf{neg}\left(\log 2\right)}\right) + s \cdot \left(\left(\frac{-1}{2} \cdot \frac{c\_n \cdot e^{\mathsf{neg}\left(\log 2\right)}}{1 - e^{\mathsf{neg}\left(\log 2\right)}} + s \cdot \left(\frac{-1}{8} \cdot \frac{c\_n \cdot {\left(e^{\mathsf{neg}\left(\log 2\right)}\right)}^{2}}{{\left(1 - e^{\mathsf{neg}\left(\log 2\right)}\right)}^{2}} - \frac{1}{8} \cdot c\_p\right)\right) - \frac{-1}{2} \cdot c\_p\right)\right)\right) - \color{blue}{c\_n \cdot \log \frac{1}{2}}} \]
  7. Applied rewrites99.4%

    \[\leadsto e^{\mathsf{fma}\left(\left(c\_p - c\_n\right) \cdot t, -0.5, \mathsf{fma}\left(\mathsf{fma}\left(-0.5, c\_n \cdot 1 - c\_p, \left(-0.125 \cdot \mathsf{fma}\left(c\_n, 1, c\_p\right)\right) \cdot s\right), s, \log 0.5 \cdot c\_n\right)\right) - \color{blue}{\log 0.5 \cdot c\_n}} \]
  8. Final simplification99.4%

    \[\leadsto e^{\mathsf{fma}\left(\left(c\_p - c\_n\right) \cdot t, -0.5, \mathsf{fma}\left(\mathsf{fma}\left(-0.5, c\_n - c\_p, \left(-0.125 \cdot \mathsf{fma}\left(c\_n, 1, c\_p\right)\right) \cdot s\right), s, \log 0.5 \cdot c\_n\right)\right) - \log 0.5 \cdot c\_n} \]
  9. Add Preprocessing

Alternative 2: 99.5% accurate, 2.6× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_1 := \log 0.5 \cdot c\_n\\ e^{\mathsf{fma}\left(\left(c\_p - c\_n\right) \cdot t, -0.5, \mathsf{fma}\left(-0.5 \cdot \left(c\_n - c\_p\right), s, t\_1\right)\right) - t\_1} \end{array} \end{array} \]
(FPCore (c_p c_n t s)
 :precision binary64
 (let* ((t_1 (* (log 0.5) c_n)))
   (exp
    (- (fma (* (- c_p c_n) t) -0.5 (fma (* -0.5 (- c_n c_p)) s t_1)) t_1))))
double code(double c_p, double c_n, double t, double s) {
	double t_1 = log(0.5) * c_n;
	return exp((fma(((c_p - c_n) * t), -0.5, fma((-0.5 * (c_n - c_p)), s, t_1)) - t_1));
}
function code(c_p, c_n, t, s)
	t_1 = Float64(log(0.5) * c_n)
	return exp(Float64(fma(Float64(Float64(c_p - c_n) * t), -0.5, fma(Float64(-0.5 * Float64(c_n - c_p)), s, t_1)) - t_1))
end
code[c$95$p_, c$95$n_, t_, s_] := Block[{t$95$1 = N[(N[Log[0.5], $MachinePrecision] * c$95$n), $MachinePrecision]}, N[Exp[N[(N[(N[(N[(c$95$p - c$95$n), $MachinePrecision] * t), $MachinePrecision] * -0.5 + N[(N[(-0.5 * N[(c$95$n - c$95$p), $MachinePrecision]), $MachinePrecision] * s + t$95$1), $MachinePrecision]), $MachinePrecision] - t$95$1), $MachinePrecision]], $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
t_1 := \log 0.5 \cdot c\_n\\
e^{\mathsf{fma}\left(\left(c\_p - c\_n\right) \cdot t, -0.5, \mathsf{fma}\left(-0.5 \cdot \left(c\_n - c\_p\right), s, t\_1\right)\right) - t\_1}
\end{array}
\end{array}
Derivation
  1. Initial program 88.4%

    \[\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}} \]
  2. Add Preprocessing
  3. Applied rewrites93.7%

    \[\leadsto \color{blue}{e^{\mathsf{fma}\left(-\mathsf{log1p}\left(e^{-s}\right), c\_p, \mathsf{log1p}\left(e^{-t}\right) \cdot c\_p\right) + \mathsf{fma}\left(\mathsf{log1p}\left(-e^{-\mathsf{log1p}\left(e^{-s}\right)}\right), c\_n, \left(-c\_n\right) \cdot \mathsf{log1p}\left(-e^{-\mathsf{log1p}\left(e^{-t}\right)}\right)\right)}} \]
  4. Taylor expanded in t around 0

    \[\leadsto e^{\color{blue}{-1 \cdot \left(c\_n \cdot \log \left(1 - e^{\mathsf{neg}\left(\log 2\right)}\right)\right) + \left(-1 \cdot \left(c\_p \cdot \log \left(1 + e^{\mathsf{neg}\left(s\right)}\right)\right) + \left(c\_n \cdot \log \left(1 - e^{\mathsf{neg}\left(\log \left(1 + e^{\mathsf{neg}\left(s\right)}\right)\right)}\right) + \left(c\_p \cdot \log 2 + t \cdot \left(\frac{-1}{2} \cdot c\_p + \frac{1}{2} \cdot \frac{c\_n \cdot e^{\mathsf{neg}\left(\log 2\right)}}{1 - e^{\mathsf{neg}\left(\log 2\right)}}\right)\right)\right)\right)}} \]
  5. Applied rewrites97.3%

    \[\leadsto e^{\color{blue}{\left(-\mathsf{fma}\left(\log 0.5, c\_n, \mathsf{log1p}\left(e^{-s}\right) \cdot c\_p\right)\right) + \mathsf{fma}\left(\log \left(1 - e^{-\mathsf{log1p}\left(e^{-s}\right)}\right), c\_n, \mathsf{fma}\left(-0.5 \cdot \left(c\_p - c\_n \cdot 1\right), t, \log 2 \cdot c\_p\right)\right)}} \]
  6. Taylor expanded in s around 0

    \[\leadsto e^{\left(\frac{-1}{2} \cdot \left(t \cdot \left(c\_p - c\_n\right)\right) + \left(c\_n \cdot \log \left(1 - e^{\mathsf{neg}\left(\log 2\right)}\right) + s \cdot \left(\frac{-1}{2} \cdot \frac{c\_n \cdot e^{\mathsf{neg}\left(\log 2\right)}}{1 - e^{\mathsf{neg}\left(\log 2\right)}} - \frac{-1}{2} \cdot c\_p\right)\right)\right) - \color{blue}{c\_n \cdot \log \frac{1}{2}}} \]
  7. Applied rewrites99.3%

    \[\leadsto e^{\mathsf{fma}\left(\left(c\_p - c\_n\right) \cdot t, -0.5, \mathsf{fma}\left(-0.5 \cdot \left(c\_n \cdot 1 - c\_p\right), s, \log 0.5 \cdot c\_n\right)\right) - \color{blue}{\log 0.5 \cdot c\_n}} \]
  8. Final simplification99.3%

    \[\leadsto e^{\mathsf{fma}\left(\left(c\_p - c\_n\right) \cdot t, -0.5, \mathsf{fma}\left(-0.5 \cdot \left(c\_n - c\_p\right), s, \log 0.5 \cdot c\_n\right)\right) - \log 0.5 \cdot c\_n} \]
  9. Add Preprocessing

Alternative 3: 98.6% accurate, 7.9× speedup?

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

\\
e^{\left(\left(c\_n - c\_p\right) \cdot s\right) \cdot -0.5}
\end{array}
Derivation
  1. Initial program 88.4%

    \[\frac{{\left(\frac{1}{1 + e^{-s}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-s}}\right)}^{c\_n}}{{\left(\frac{1}{1 + e^{-t}}\right)}^{c\_p} \cdot {\left(1 - \frac{1}{1 + e^{-t}}\right)}^{c\_n}} \]
  2. Add Preprocessing
  3. Applied rewrites93.7%

    \[\leadsto \color{blue}{e^{\mathsf{fma}\left(-\mathsf{log1p}\left(e^{-s}\right), c\_p, \mathsf{log1p}\left(e^{-t}\right) \cdot c\_p\right) + \mathsf{fma}\left(\mathsf{log1p}\left(-e^{-\mathsf{log1p}\left(e^{-s}\right)}\right), c\_n, \left(-c\_n\right) \cdot \mathsf{log1p}\left(-e^{-\mathsf{log1p}\left(e^{-t}\right)}\right)\right)}} \]
  4. Taylor expanded in t around 0

    \[\leadsto e^{\color{blue}{-1 \cdot \left(c\_n \cdot \log \left(1 - e^{\mathsf{neg}\left(\log 2\right)}\right)\right) + \left(-1 \cdot \left(c\_p \cdot \log \left(1 + e^{\mathsf{neg}\left(s\right)}\right)\right) + \left(c\_n \cdot \log \left(1 - e^{\mathsf{neg}\left(\log \left(1 + e^{\mathsf{neg}\left(s\right)}\right)\right)}\right) + \left(c\_p \cdot \log 2 + t \cdot \left(\frac{-1}{2} \cdot c\_p + \frac{1}{2} \cdot \frac{c\_n \cdot e^{\mathsf{neg}\left(\log 2\right)}}{1 - e^{\mathsf{neg}\left(\log 2\right)}}\right)\right)\right)\right)}} \]
  5. Applied rewrites97.3%

    \[\leadsto e^{\color{blue}{\left(-\mathsf{fma}\left(\log 0.5, c\_n, \mathsf{log1p}\left(e^{-s}\right) \cdot c\_p\right)\right) + \mathsf{fma}\left(\log \left(1 - e^{-\mathsf{log1p}\left(e^{-s}\right)}\right), c\_n, \mathsf{fma}\left(-0.5 \cdot \left(c\_p - c\_n \cdot 1\right), t, \log 2 \cdot c\_p\right)\right)}} \]
  6. Taylor expanded in s around 0

    \[\leadsto e^{\left(\frac{-1}{2} \cdot \left(t \cdot \left(c\_p - c\_n\right)\right) + \left(c\_n \cdot \log \left(1 - e^{\mathsf{neg}\left(\log 2\right)}\right) + s \cdot \left(\frac{-1}{2} \cdot \frac{c\_n \cdot e^{\mathsf{neg}\left(\log 2\right)}}{1 - e^{\mathsf{neg}\left(\log 2\right)}} - \frac{-1}{2} \cdot c\_p\right)\right)\right) - \color{blue}{c\_n \cdot \log \frac{1}{2}}} \]
  7. Applied rewrites99.3%

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

    \[\leadsto e^{\frac{-1}{2} \cdot \left(s \cdot \color{blue}{\left(c\_n - c\_p\right)}\right)} \]
  9. Step-by-step derivation
    1. Applied rewrites98.5%

      \[\leadsto e^{\left(\left(c\_n - c\_p\right) \cdot s\right) \cdot -0.5} \]
    2. Add Preprocessing

    Alternative 4: 95.3% accurate, 44.8× speedup?

    \[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;-s \leq 1000000000:\\ \;\;\;\;\mathsf{fma}\left(s \cdot c\_p, 0.5, 1\right)\\ \mathbf{else}:\\ \;\;\;\;\left(t \cdot c\_n\right) \cdot 0.5\\ \end{array} \end{array} \]
    (FPCore (c_p c_n t s)
     :precision binary64
     (if (<= (- s) 1000000000.0) (fma (* s c_p) 0.5 1.0) (* (* t c_n) 0.5)))
    double code(double c_p, double c_n, double t, double s) {
    	double tmp;
    	if (-s <= 1000000000.0) {
    		tmp = fma((s * c_p), 0.5, 1.0);
    	} else {
    		tmp = (t * c_n) * 0.5;
    	}
    	return tmp;
    }
    
    function code(c_p, c_n, t, s)
    	tmp = 0.0
    	if (Float64(-s) <= 1000000000.0)
    		tmp = fma(Float64(s * c_p), 0.5, 1.0);
    	else
    		tmp = Float64(Float64(t * c_n) * 0.5);
    	end
    	return tmp
    end
    
    code[c$95$p_, c$95$n_, t_, s_] := If[LessEqual[(-s), 1000000000.0], N[(N[(s * c$95$p), $MachinePrecision] * 0.5 + 1.0), $MachinePrecision], N[(N[(t * c$95$n), $MachinePrecision] * 0.5), $MachinePrecision]]
    
    \begin{array}{l}
    
    \\
    \begin{array}{l}
    \mathbf{if}\;-s \leq 1000000000:\\
    \;\;\;\;\mathsf{fma}\left(s \cdot c\_p, 0.5, 1\right)\\
    
    \mathbf{else}:\\
    \;\;\;\;\left(t \cdot c\_n\right) \cdot 0.5\\
    
    
    \end{array}
    \end{array}
    
    Derivation
    1. Split input into 2 regimes
    2. if (neg.f64 s) < 1e9

      1. Initial program 89.6%

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

        \[\leadsto \color{blue}{\frac{{\left(\frac{1}{1 + e^{\mathsf{neg}\left(s\right)}}\right)}^{c\_p}}{{\left(\frac{1}{1 + e^{\mathsf{neg}\left(t\right)}}\right)}^{c\_p}}} \]
      4. Step-by-step derivation
        1. lower-/.f64N/A

          \[\leadsto \color{blue}{\frac{{\left(\frac{1}{1 + e^{\mathsf{neg}\left(s\right)}}\right)}^{c\_p}}{{\left(\frac{1}{1 + e^{\mathsf{neg}\left(t\right)}}\right)}^{c\_p}}} \]
        2. lower-pow.f64N/A

          \[\leadsto \frac{\color{blue}{{\left(\frac{1}{1 + e^{\mathsf{neg}\left(s\right)}}\right)}^{c\_p}}}{{\left(\frac{1}{1 + e^{\mathsf{neg}\left(t\right)}}\right)}^{c\_p}} \]
        3. lower-/.f64N/A

          \[\leadsto \frac{{\color{blue}{\left(\frac{1}{1 + e^{\mathsf{neg}\left(s\right)}}\right)}}^{c\_p}}{{\left(\frac{1}{1 + e^{\mathsf{neg}\left(t\right)}}\right)}^{c\_p}} \]
        4. +-commutativeN/A

          \[\leadsto \frac{{\left(\frac{1}{\color{blue}{e^{\mathsf{neg}\left(s\right)} + 1}}\right)}^{c\_p}}{{\left(\frac{1}{1 + e^{\mathsf{neg}\left(t\right)}}\right)}^{c\_p}} \]
        5. lower-+.f64N/A

          \[\leadsto \frac{{\left(\frac{1}{\color{blue}{e^{\mathsf{neg}\left(s\right)} + 1}}\right)}^{c\_p}}{{\left(\frac{1}{1 + e^{\mathsf{neg}\left(t\right)}}\right)}^{c\_p}} \]
        6. lower-exp.f64N/A

          \[\leadsto \frac{{\left(\frac{1}{\color{blue}{e^{\mathsf{neg}\left(s\right)}} + 1}\right)}^{c\_p}}{{\left(\frac{1}{1 + e^{\mathsf{neg}\left(t\right)}}\right)}^{c\_p}} \]
        7. lower-neg.f64N/A

          \[\leadsto \frac{{\left(\frac{1}{e^{\color{blue}{-s}} + 1}\right)}^{c\_p}}{{\left(\frac{1}{1 + e^{\mathsf{neg}\left(t\right)}}\right)}^{c\_p}} \]
        8. lower-pow.f64N/A

          \[\leadsto \frac{{\left(\frac{1}{e^{-s} + 1}\right)}^{c\_p}}{\color{blue}{{\left(\frac{1}{1 + e^{\mathsf{neg}\left(t\right)}}\right)}^{c\_p}}} \]
        9. lower-/.f64N/A

          \[\leadsto \frac{{\left(\frac{1}{e^{-s} + 1}\right)}^{c\_p}}{{\color{blue}{\left(\frac{1}{1 + e^{\mathsf{neg}\left(t\right)}}\right)}}^{c\_p}} \]
        10. +-commutativeN/A

          \[\leadsto \frac{{\left(\frac{1}{e^{-s} + 1}\right)}^{c\_p}}{{\left(\frac{1}{\color{blue}{e^{\mathsf{neg}\left(t\right)} + 1}}\right)}^{c\_p}} \]
        11. lower-+.f64N/A

          \[\leadsto \frac{{\left(\frac{1}{e^{-s} + 1}\right)}^{c\_p}}{{\left(\frac{1}{\color{blue}{e^{\mathsf{neg}\left(t\right)} + 1}}\right)}^{c\_p}} \]
        12. lower-exp.f64N/A

          \[\leadsto \frac{{\left(\frac{1}{e^{-s} + 1}\right)}^{c\_p}}{{\left(\frac{1}{\color{blue}{e^{\mathsf{neg}\left(t\right)}} + 1}\right)}^{c\_p}} \]
        13. lower-neg.f6490.1

          \[\leadsto \frac{{\left(\frac{1}{e^{-s} + 1}\right)}^{c\_p}}{{\left(\frac{1}{e^{\color{blue}{-t}} + 1}\right)}^{c\_p}} \]
      5. Applied rewrites90.1%

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

        \[\leadsto 1 + \color{blue}{c\_p \cdot \left(\log \left(\frac{1}{1 + e^{\mathsf{neg}\left(s\right)}}\right) - \log \left(\frac{1}{1 + e^{\mathsf{neg}\left(t\right)}}\right)\right)} \]
      7. Step-by-step derivation
        1. Applied rewrites91.7%

          \[\leadsto \mathsf{fma}\left(\mathsf{log1p}\left(e^{-t}\right) - \mathsf{log1p}\left(e^{-s}\right), \color{blue}{c\_p}, 1\right) \]
        2. Taylor expanded in s around 0

          \[\leadsto 1 + \left(\frac{1}{2} \cdot \left(c\_p \cdot s\right) + \color{blue}{c\_p \cdot \left(\log \left(1 + e^{\mathsf{neg}\left(t\right)}\right) - \log 2\right)}\right) \]
        3. Step-by-step derivation
          1. Applied rewrites93.8%

            \[\leadsto \mathsf{fma}\left(c\_p \cdot s, 0.5, \left(\mathsf{log1p}\left(e^{-t}\right) - \log 2\right) \cdot c\_p\right) + 1 \]
          2. Taylor expanded in t around 0

            \[\leadsto 1 + \frac{1}{2} \cdot \left(c\_p \cdot \color{blue}{s}\right) \]
          3. Step-by-step derivation
            1. Applied rewrites95.5%

              \[\leadsto \mathsf{fma}\left(s \cdot c\_p, 0.5, 1\right) \]

            if 1e9 < (neg.f64 s)

            1. Initial program 55.6%

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

              \[\leadsto \color{blue}{-1 \cdot \frac{t \cdot \left(\left(\frac{-1}{2} \cdot \left(c\_n \cdot \left({\frac{1}{2}}^{c\_n} \cdot {\frac{1}{2}}^{c\_p}\right)\right) + \frac{1}{2} \cdot \left(c\_p \cdot \left({\frac{1}{2}}^{c\_n} \cdot {\frac{1}{2}}^{c\_p}\right)\right)\right) \cdot \left({\left(1 - \frac{1}{1 + e^{\mathsf{neg}\left(s\right)}}\right)}^{c\_n} \cdot {\left(\frac{1}{1 + e^{\mathsf{neg}\left(s\right)}}\right)}^{c\_p}\right)\right)}{{\left({\frac{1}{2}}^{c\_n}\right)}^{2} \cdot {\left({\frac{1}{2}}^{c\_p}\right)}^{2}} + \frac{{\left(1 - \frac{1}{1 + e^{\mathsf{neg}\left(s\right)}}\right)}^{c\_n} \cdot {\left(\frac{1}{1 + e^{\mathsf{neg}\left(s\right)}}\right)}^{c\_p}}{{\frac{1}{2}}^{c\_n} \cdot {\frac{1}{2}}^{c\_p}}} \]
            4. Applied rewrites55.6%

              \[\leadsto \color{blue}{\mathsf{fma}\left(\frac{{\left(\frac{1}{e^{-s} + 1}\right)}^{c\_p}}{{0.5}^{c\_p} \cdot {0.5}^{c\_n}}, {\left(1 - \frac{1}{e^{-s} + 1}\right)}^{c\_n}, \frac{\left(\left(\left(\left({0.5}^{c\_p} \cdot {0.5}^{c\_n}\right) \cdot \mathsf{fma}\left(0.5, c\_p, -0.5 \cdot c\_n\right)\right) \cdot t\right) \cdot {\left(\frac{1}{e^{-s} + 1}\right)}^{c\_p}\right) \cdot {\left(1 - \frac{1}{e^{-s} + 1}\right)}^{c\_n}}{-{\left({0.5}^{c\_p}\right)}^{2} \cdot {\left({0.5}^{c\_n}\right)}^{2}}\right)} \]
            5. Taylor expanded in s around 0

              \[\leadsto 1 + \color{blue}{-1 \cdot \left(t \cdot \left(\frac{-1}{2} \cdot c\_n + \frac{1}{2} \cdot c\_p\right)\right)} \]
            6. Step-by-step derivation
              1. Applied rewrites3.1%

                \[\leadsto \mathsf{fma}\left(-0.5 \cdot \left(c\_n - c\_p\right), \color{blue}{-t}, 1\right) \]
              2. Taylor expanded in c_n around inf

                \[\leadsto \frac{1}{2} \cdot \left(c\_n \cdot \color{blue}{t}\right) \]
              3. Step-by-step derivation
                1. Applied rewrites48.3%

                  \[\leadsto \left(t \cdot c\_n\right) \cdot 0.5 \]
              4. Recombined 2 regimes into one program.
              5. Add Preprocessing

              Alternative 5: 95.3% accurate, 44.8× speedup?

              \[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;-s \leq 750000000:\\ \;\;\;\;\mathsf{fma}\left(t \cdot c\_p, -0.5, 1\right)\\ \mathbf{else}:\\ \;\;\;\;\left(t \cdot c\_n\right) \cdot 0.5\\ \end{array} \end{array} \]
              (FPCore (c_p c_n t s)
               :precision binary64
               (if (<= (- s) 750000000.0) (fma (* t c_p) -0.5 1.0) (* (* t c_n) 0.5)))
              double code(double c_p, double c_n, double t, double s) {
              	double tmp;
              	if (-s <= 750000000.0) {
              		tmp = fma((t * c_p), -0.5, 1.0);
              	} else {
              		tmp = (t * c_n) * 0.5;
              	}
              	return tmp;
              }
              
              function code(c_p, c_n, t, s)
              	tmp = 0.0
              	if (Float64(-s) <= 750000000.0)
              		tmp = fma(Float64(t * c_p), -0.5, 1.0);
              	else
              		tmp = Float64(Float64(t * c_n) * 0.5);
              	end
              	return tmp
              end
              
              code[c$95$p_, c$95$n_, t_, s_] := If[LessEqual[(-s), 750000000.0], N[(N[(t * c$95$p), $MachinePrecision] * -0.5 + 1.0), $MachinePrecision], N[(N[(t * c$95$n), $MachinePrecision] * 0.5), $MachinePrecision]]
              
              \begin{array}{l}
              
              \\
              \begin{array}{l}
              \mathbf{if}\;-s \leq 750000000:\\
              \;\;\;\;\mathsf{fma}\left(t \cdot c\_p, -0.5, 1\right)\\
              
              \mathbf{else}:\\
              \;\;\;\;\left(t \cdot c\_n\right) \cdot 0.5\\
              
              
              \end{array}
              \end{array}
              
              Derivation
              1. Split input into 2 regimes
              2. if (neg.f64 s) < 7.5e8

                1. Initial program 89.6%

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

                  \[\leadsto \color{blue}{-1 \cdot \frac{t \cdot \left(\left(\frac{-1}{2} \cdot \left(c\_n \cdot \left({\frac{1}{2}}^{c\_n} \cdot {\frac{1}{2}}^{c\_p}\right)\right) + \frac{1}{2} \cdot \left(c\_p \cdot \left({\frac{1}{2}}^{c\_n} \cdot {\frac{1}{2}}^{c\_p}\right)\right)\right) \cdot \left({\left(1 - \frac{1}{1 + e^{\mathsf{neg}\left(s\right)}}\right)}^{c\_n} \cdot {\left(\frac{1}{1 + e^{\mathsf{neg}\left(s\right)}}\right)}^{c\_p}\right)\right)}{{\left({\frac{1}{2}}^{c\_n}\right)}^{2} \cdot {\left({\frac{1}{2}}^{c\_p}\right)}^{2}} + \frac{{\left(1 - \frac{1}{1 + e^{\mathsf{neg}\left(s\right)}}\right)}^{c\_n} \cdot {\left(\frac{1}{1 + e^{\mathsf{neg}\left(s\right)}}\right)}^{c\_p}}{{\frac{1}{2}}^{c\_n} \cdot {\frac{1}{2}}^{c\_p}}} \]
                4. Applied rewrites90.6%

                  \[\leadsto \color{blue}{\mathsf{fma}\left(\frac{{\left(\frac{1}{e^{-s} + 1}\right)}^{c\_p}}{{0.5}^{c\_p} \cdot {0.5}^{c\_n}}, {\left(1 - \frac{1}{e^{-s} + 1}\right)}^{c\_n}, \frac{\left(\left(\left(\left({0.5}^{c\_p} \cdot {0.5}^{c\_n}\right) \cdot \mathsf{fma}\left(0.5, c\_p, -0.5 \cdot c\_n\right)\right) \cdot t\right) \cdot {\left(\frac{1}{e^{-s} + 1}\right)}^{c\_p}\right) \cdot {\left(1 - \frac{1}{e^{-s} + 1}\right)}^{c\_n}}{-{\left({0.5}^{c\_p}\right)}^{2} \cdot {\left({0.5}^{c\_n}\right)}^{2}}\right)} \]
                5. Taylor expanded in s around 0

                  \[\leadsto 1 + \color{blue}{-1 \cdot \left(t \cdot \left(\frac{-1}{2} \cdot c\_n + \frac{1}{2} \cdot c\_p\right)\right)} \]
                6. Step-by-step derivation
                  1. Applied rewrites95.4%

                    \[\leadsto \mathsf{fma}\left(-0.5 \cdot \left(c\_n - c\_p\right), \color{blue}{-t}, 1\right) \]
                  2. Taylor expanded in c_n around 0

                    \[\leadsto 1 + \frac{-1}{2} \cdot \color{blue}{\left(c\_p \cdot t\right)} \]
                  3. Step-by-step derivation
                    1. Applied rewrites95.4%

                      \[\leadsto \mathsf{fma}\left(t \cdot c\_p, -0.5, 1\right) \]

                    if 7.5e8 < (neg.f64 s)

                    1. Initial program 55.6%

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

                      \[\leadsto \color{blue}{-1 \cdot \frac{t \cdot \left(\left(\frac{-1}{2} \cdot \left(c\_n \cdot \left({\frac{1}{2}}^{c\_n} \cdot {\frac{1}{2}}^{c\_p}\right)\right) + \frac{1}{2} \cdot \left(c\_p \cdot \left({\frac{1}{2}}^{c\_n} \cdot {\frac{1}{2}}^{c\_p}\right)\right)\right) \cdot \left({\left(1 - \frac{1}{1 + e^{\mathsf{neg}\left(s\right)}}\right)}^{c\_n} \cdot {\left(\frac{1}{1 + e^{\mathsf{neg}\left(s\right)}}\right)}^{c\_p}\right)\right)}{{\left({\frac{1}{2}}^{c\_n}\right)}^{2} \cdot {\left({\frac{1}{2}}^{c\_p}\right)}^{2}} + \frac{{\left(1 - \frac{1}{1 + e^{\mathsf{neg}\left(s\right)}}\right)}^{c\_n} \cdot {\left(\frac{1}{1 + e^{\mathsf{neg}\left(s\right)}}\right)}^{c\_p}}{{\frac{1}{2}}^{c\_n} \cdot {\frac{1}{2}}^{c\_p}}} \]
                    4. Applied rewrites55.6%

                      \[\leadsto \color{blue}{\mathsf{fma}\left(\frac{{\left(\frac{1}{e^{-s} + 1}\right)}^{c\_p}}{{0.5}^{c\_p} \cdot {0.5}^{c\_n}}, {\left(1 - \frac{1}{e^{-s} + 1}\right)}^{c\_n}, \frac{\left(\left(\left(\left({0.5}^{c\_p} \cdot {0.5}^{c\_n}\right) \cdot \mathsf{fma}\left(0.5, c\_p, -0.5 \cdot c\_n\right)\right) \cdot t\right) \cdot {\left(\frac{1}{e^{-s} + 1}\right)}^{c\_p}\right) \cdot {\left(1 - \frac{1}{e^{-s} + 1}\right)}^{c\_n}}{-{\left({0.5}^{c\_p}\right)}^{2} \cdot {\left({0.5}^{c\_n}\right)}^{2}}\right)} \]
                    5. Taylor expanded in s around 0

                      \[\leadsto 1 + \color{blue}{-1 \cdot \left(t \cdot \left(\frac{-1}{2} \cdot c\_n + \frac{1}{2} \cdot c\_p\right)\right)} \]
                    6. Step-by-step derivation
                      1. Applied rewrites3.1%

                        \[\leadsto \mathsf{fma}\left(-0.5 \cdot \left(c\_n - c\_p\right), \color{blue}{-t}, 1\right) \]
                      2. Taylor expanded in c_n around inf

                        \[\leadsto \frac{1}{2} \cdot \left(c\_n \cdot \color{blue}{t}\right) \]
                      3. Step-by-step derivation
                        1. Applied rewrites48.3%

                          \[\leadsto \left(t \cdot c\_n\right) \cdot 0.5 \]
                      4. Recombined 2 regimes into one program.
                      5. Add Preprocessing

                      Alternative 6: 95.3% accurate, 47.1× speedup?

                      \[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;-s \leq 750000000:\\ \;\;\;\;1\\ \mathbf{else}:\\ \;\;\;\;\left(t \cdot c\_n\right) \cdot 0.5\\ \end{array} \end{array} \]
                      (FPCore (c_p c_n t s)
                       :precision binary64
                       (if (<= (- s) 750000000.0) 1.0 (* (* t c_n) 0.5)))
                      double code(double c_p, double c_n, double t, double s) {
                      	double tmp;
                      	if (-s <= 750000000.0) {
                      		tmp = 1.0;
                      	} else {
                      		tmp = (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 <= 750000000.0d0) then
                              tmp = 1.0d0
                          else
                              tmp = (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 <= 750000000.0) {
                      		tmp = 1.0;
                      	} else {
                      		tmp = (t * c_n) * 0.5;
                      	}
                      	return tmp;
                      }
                      
                      def code(c_p, c_n, t, s):
                      	tmp = 0
                      	if -s <= 750000000.0:
                      		tmp = 1.0
                      	else:
                      		tmp = (t * c_n) * 0.5
                      	return tmp
                      
                      function code(c_p, c_n, t, s)
                      	tmp = 0.0
                      	if (Float64(-s) <= 750000000.0)
                      		tmp = 1.0;
                      	else
                      		tmp = Float64(Float64(t * c_n) * 0.5);
                      	end
                      	return tmp
                      end
                      
                      function tmp_2 = code(c_p, c_n, t, s)
                      	tmp = 0.0;
                      	if (-s <= 750000000.0)
                      		tmp = 1.0;
                      	else
                      		tmp = (t * c_n) * 0.5;
                      	end
                      	tmp_2 = tmp;
                      end
                      
                      code[c$95$p_, c$95$n_, t_, s_] := If[LessEqual[(-s), 750000000.0], 1.0, N[(N[(t * c$95$n), $MachinePrecision] * 0.5), $MachinePrecision]]
                      
                      \begin{array}{l}
                      
                      \\
                      \begin{array}{l}
                      \mathbf{if}\;-s \leq 750000000:\\
                      \;\;\;\;1\\
                      
                      \mathbf{else}:\\
                      \;\;\;\;\left(t \cdot c\_n\right) \cdot 0.5\\
                      
                      
                      \end{array}
                      \end{array}
                      
                      Derivation
                      1. Split input into 2 regimes
                      2. if (neg.f64 s) < 7.5e8

                        1. Initial program 89.6%

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

                          \[\leadsto \color{blue}{\frac{{\left(\frac{1}{1 + e^{\mathsf{neg}\left(s\right)}}\right)}^{c\_p}}{{\left(\frac{1}{1 + e^{\mathsf{neg}\left(t\right)}}\right)}^{c\_p}}} \]
                        4. Step-by-step derivation
                          1. lower-/.f64N/A

                            \[\leadsto \color{blue}{\frac{{\left(\frac{1}{1 + e^{\mathsf{neg}\left(s\right)}}\right)}^{c\_p}}{{\left(\frac{1}{1 + e^{\mathsf{neg}\left(t\right)}}\right)}^{c\_p}}} \]
                          2. lower-pow.f64N/A

                            \[\leadsto \frac{\color{blue}{{\left(\frac{1}{1 + e^{\mathsf{neg}\left(s\right)}}\right)}^{c\_p}}}{{\left(\frac{1}{1 + e^{\mathsf{neg}\left(t\right)}}\right)}^{c\_p}} \]
                          3. lower-/.f64N/A

                            \[\leadsto \frac{{\color{blue}{\left(\frac{1}{1 + e^{\mathsf{neg}\left(s\right)}}\right)}}^{c\_p}}{{\left(\frac{1}{1 + e^{\mathsf{neg}\left(t\right)}}\right)}^{c\_p}} \]
                          4. +-commutativeN/A

                            \[\leadsto \frac{{\left(\frac{1}{\color{blue}{e^{\mathsf{neg}\left(s\right)} + 1}}\right)}^{c\_p}}{{\left(\frac{1}{1 + e^{\mathsf{neg}\left(t\right)}}\right)}^{c\_p}} \]
                          5. lower-+.f64N/A

                            \[\leadsto \frac{{\left(\frac{1}{\color{blue}{e^{\mathsf{neg}\left(s\right)} + 1}}\right)}^{c\_p}}{{\left(\frac{1}{1 + e^{\mathsf{neg}\left(t\right)}}\right)}^{c\_p}} \]
                          6. lower-exp.f64N/A

                            \[\leadsto \frac{{\left(\frac{1}{\color{blue}{e^{\mathsf{neg}\left(s\right)}} + 1}\right)}^{c\_p}}{{\left(\frac{1}{1 + e^{\mathsf{neg}\left(t\right)}}\right)}^{c\_p}} \]
                          7. lower-neg.f64N/A

                            \[\leadsto \frac{{\left(\frac{1}{e^{\color{blue}{-s}} + 1}\right)}^{c\_p}}{{\left(\frac{1}{1 + e^{\mathsf{neg}\left(t\right)}}\right)}^{c\_p}} \]
                          8. lower-pow.f64N/A

                            \[\leadsto \frac{{\left(\frac{1}{e^{-s} + 1}\right)}^{c\_p}}{\color{blue}{{\left(\frac{1}{1 + e^{\mathsf{neg}\left(t\right)}}\right)}^{c\_p}}} \]
                          9. lower-/.f64N/A

                            \[\leadsto \frac{{\left(\frac{1}{e^{-s} + 1}\right)}^{c\_p}}{{\color{blue}{\left(\frac{1}{1 + e^{\mathsf{neg}\left(t\right)}}\right)}}^{c\_p}} \]
                          10. +-commutativeN/A

                            \[\leadsto \frac{{\left(\frac{1}{e^{-s} + 1}\right)}^{c\_p}}{{\left(\frac{1}{\color{blue}{e^{\mathsf{neg}\left(t\right)} + 1}}\right)}^{c\_p}} \]
                          11. lower-+.f64N/A

                            \[\leadsto \frac{{\left(\frac{1}{e^{-s} + 1}\right)}^{c\_p}}{{\left(\frac{1}{\color{blue}{e^{\mathsf{neg}\left(t\right)} + 1}}\right)}^{c\_p}} \]
                          12. lower-exp.f64N/A

                            \[\leadsto \frac{{\left(\frac{1}{e^{-s} + 1}\right)}^{c\_p}}{{\left(\frac{1}{\color{blue}{e^{\mathsf{neg}\left(t\right)}} + 1}\right)}^{c\_p}} \]
                          13. lower-neg.f6490.1

                            \[\leadsto \frac{{\left(\frac{1}{e^{-s} + 1}\right)}^{c\_p}}{{\left(\frac{1}{e^{\color{blue}{-t}} + 1}\right)}^{c\_p}} \]
                        5. Applied rewrites90.1%

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

                          \[\leadsto 1 \]
                        7. Step-by-step derivation
                          1. Applied rewrites95.4%

                            \[\leadsto 1 \]

                          if 7.5e8 < (neg.f64 s)

                          1. Initial program 55.6%

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

                            \[\leadsto \color{blue}{-1 \cdot \frac{t \cdot \left(\left(\frac{-1}{2} \cdot \left(c\_n \cdot \left({\frac{1}{2}}^{c\_n} \cdot {\frac{1}{2}}^{c\_p}\right)\right) + \frac{1}{2} \cdot \left(c\_p \cdot \left({\frac{1}{2}}^{c\_n} \cdot {\frac{1}{2}}^{c\_p}\right)\right)\right) \cdot \left({\left(1 - \frac{1}{1 + e^{\mathsf{neg}\left(s\right)}}\right)}^{c\_n} \cdot {\left(\frac{1}{1 + e^{\mathsf{neg}\left(s\right)}}\right)}^{c\_p}\right)\right)}{{\left({\frac{1}{2}}^{c\_n}\right)}^{2} \cdot {\left({\frac{1}{2}}^{c\_p}\right)}^{2}} + \frac{{\left(1 - \frac{1}{1 + e^{\mathsf{neg}\left(s\right)}}\right)}^{c\_n} \cdot {\left(\frac{1}{1 + e^{\mathsf{neg}\left(s\right)}}\right)}^{c\_p}}{{\frac{1}{2}}^{c\_n} \cdot {\frac{1}{2}}^{c\_p}}} \]
                          4. Applied rewrites55.6%

                            \[\leadsto \color{blue}{\mathsf{fma}\left(\frac{{\left(\frac{1}{e^{-s} + 1}\right)}^{c\_p}}{{0.5}^{c\_p} \cdot {0.5}^{c\_n}}, {\left(1 - \frac{1}{e^{-s} + 1}\right)}^{c\_n}, \frac{\left(\left(\left(\left({0.5}^{c\_p} \cdot {0.5}^{c\_n}\right) \cdot \mathsf{fma}\left(0.5, c\_p, -0.5 \cdot c\_n\right)\right) \cdot t\right) \cdot {\left(\frac{1}{e^{-s} + 1}\right)}^{c\_p}\right) \cdot {\left(1 - \frac{1}{e^{-s} + 1}\right)}^{c\_n}}{-{\left({0.5}^{c\_p}\right)}^{2} \cdot {\left({0.5}^{c\_n}\right)}^{2}}\right)} \]
                          5. Taylor expanded in s around 0

                            \[\leadsto 1 + \color{blue}{-1 \cdot \left(t \cdot \left(\frac{-1}{2} \cdot c\_n + \frac{1}{2} \cdot c\_p\right)\right)} \]
                          6. Step-by-step derivation
                            1. Applied rewrites3.1%

                              \[\leadsto \mathsf{fma}\left(-0.5 \cdot \left(c\_n - c\_p\right), \color{blue}{-t}, 1\right) \]
                            2. Taylor expanded in c_n around inf

                              \[\leadsto \frac{1}{2} \cdot \left(c\_n \cdot \color{blue}{t}\right) \]
                            3. Step-by-step derivation
                              1. Applied rewrites48.3%

                                \[\leadsto \left(t \cdot c\_n\right) \cdot 0.5 \]
                            4. Recombined 2 regimes into one program.
                            5. Add Preprocessing

                            Alternative 7: 94.2% accurate, 896.0× 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 88.4%

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

                              \[\leadsto \color{blue}{\frac{{\left(\frac{1}{1 + e^{\mathsf{neg}\left(s\right)}}\right)}^{c\_p}}{{\left(\frac{1}{1 + e^{\mathsf{neg}\left(t\right)}}\right)}^{c\_p}}} \]
                            4. Step-by-step derivation
                              1. lower-/.f64N/A

                                \[\leadsto \color{blue}{\frac{{\left(\frac{1}{1 + e^{\mathsf{neg}\left(s\right)}}\right)}^{c\_p}}{{\left(\frac{1}{1 + e^{\mathsf{neg}\left(t\right)}}\right)}^{c\_p}}} \]
                              2. lower-pow.f64N/A

                                \[\leadsto \frac{\color{blue}{{\left(\frac{1}{1 + e^{\mathsf{neg}\left(s\right)}}\right)}^{c\_p}}}{{\left(\frac{1}{1 + e^{\mathsf{neg}\left(t\right)}}\right)}^{c\_p}} \]
                              3. lower-/.f64N/A

                                \[\leadsto \frac{{\color{blue}{\left(\frac{1}{1 + e^{\mathsf{neg}\left(s\right)}}\right)}}^{c\_p}}{{\left(\frac{1}{1 + e^{\mathsf{neg}\left(t\right)}}\right)}^{c\_p}} \]
                              4. +-commutativeN/A

                                \[\leadsto \frac{{\left(\frac{1}{\color{blue}{e^{\mathsf{neg}\left(s\right)} + 1}}\right)}^{c\_p}}{{\left(\frac{1}{1 + e^{\mathsf{neg}\left(t\right)}}\right)}^{c\_p}} \]
                              5. lower-+.f64N/A

                                \[\leadsto \frac{{\left(\frac{1}{\color{blue}{e^{\mathsf{neg}\left(s\right)} + 1}}\right)}^{c\_p}}{{\left(\frac{1}{1 + e^{\mathsf{neg}\left(t\right)}}\right)}^{c\_p}} \]
                              6. lower-exp.f64N/A

                                \[\leadsto \frac{{\left(\frac{1}{\color{blue}{e^{\mathsf{neg}\left(s\right)}} + 1}\right)}^{c\_p}}{{\left(\frac{1}{1 + e^{\mathsf{neg}\left(t\right)}}\right)}^{c\_p}} \]
                              7. lower-neg.f64N/A

                                \[\leadsto \frac{{\left(\frac{1}{e^{\color{blue}{-s}} + 1}\right)}^{c\_p}}{{\left(\frac{1}{1 + e^{\mathsf{neg}\left(t\right)}}\right)}^{c\_p}} \]
                              8. lower-pow.f64N/A

                                \[\leadsto \frac{{\left(\frac{1}{e^{-s} + 1}\right)}^{c\_p}}{\color{blue}{{\left(\frac{1}{1 + e^{\mathsf{neg}\left(t\right)}}\right)}^{c\_p}}} \]
                              9. lower-/.f64N/A

                                \[\leadsto \frac{{\left(\frac{1}{e^{-s} + 1}\right)}^{c\_p}}{{\color{blue}{\left(\frac{1}{1 + e^{\mathsf{neg}\left(t\right)}}\right)}}^{c\_p}} \]
                              10. +-commutativeN/A

                                \[\leadsto \frac{{\left(\frac{1}{e^{-s} + 1}\right)}^{c\_p}}{{\left(\frac{1}{\color{blue}{e^{\mathsf{neg}\left(t\right)} + 1}}\right)}^{c\_p}} \]
                              11. lower-+.f64N/A

                                \[\leadsto \frac{{\left(\frac{1}{e^{-s} + 1}\right)}^{c\_p}}{{\left(\frac{1}{\color{blue}{e^{\mathsf{neg}\left(t\right)} + 1}}\right)}^{c\_p}} \]
                              12. lower-exp.f64N/A

                                \[\leadsto \frac{{\left(\frac{1}{e^{-s} + 1}\right)}^{c\_p}}{{\left(\frac{1}{\color{blue}{e^{\mathsf{neg}\left(t\right)}} + 1}\right)}^{c\_p}} \]
                              13. lower-neg.f6488.9

                                \[\leadsto \frac{{\left(\frac{1}{e^{-s} + 1}\right)}^{c\_p}}{{\left(\frac{1}{e^{\color{blue}{-t}} + 1}\right)}^{c\_p}} \]
                            5. Applied rewrites88.9%

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

                              \[\leadsto 1 \]
                            7. Step-by-step derivation
                              1. Applied rewrites92.2%

                                \[\leadsto 1 \]
                              2. Add Preprocessing

                              Developer Target 1: 96.5% accurate, 1.4× 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 2024332 
                              (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))))