
(FPCore (u s)
:precision binary32
(let* ((t_0 (/ 1.0 (+ 1.0 (exp (/ PI s))))))
(*
(- s)
(log
(-
(/ 1.0 (+ (* u (- (/ 1.0 (+ 1.0 (exp (/ (- PI) s)))) t_0)) t_0))
1.0)))))
float code(float u, float s) {
float t_0 = 1.0f / (1.0f + expf((((float) M_PI) / s)));
return -s * logf(((1.0f / ((u * ((1.0f / (1.0f + expf((-((float) M_PI) / s)))) - t_0)) + t_0)) - 1.0f));
}
function code(u, s) t_0 = Float32(Float32(1.0) / Float32(Float32(1.0) + exp(Float32(Float32(pi) / s)))) return Float32(Float32(-s) * log(Float32(Float32(Float32(1.0) / Float32(Float32(u * Float32(Float32(Float32(1.0) / Float32(Float32(1.0) + exp(Float32(Float32(-Float32(pi)) / s)))) - t_0)) + t_0)) - Float32(1.0)))) end
function tmp = code(u, s) t_0 = single(1.0) / (single(1.0) + exp((single(pi) / s))); tmp = -s * log(((single(1.0) / ((u * ((single(1.0) / (single(1.0) + exp((-single(pi) / s)))) - t_0)) + t_0)) - single(1.0))); end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \frac{1}{1 + e^{\frac{\pi}{s}}}\\
\left(-s\right) \cdot \log \left(\frac{1}{u \cdot \left(\frac{1}{1 + e^{\frac{-\pi}{s}}} - t\_0\right) + t\_0} - 1\right)
\end{array}
\end{array}
Herbie found 11 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (u s)
:precision binary32
(let* ((t_0 (/ 1.0 (+ 1.0 (exp (/ PI s))))))
(*
(- s)
(log
(-
(/ 1.0 (+ (* u (- (/ 1.0 (+ 1.0 (exp (/ (- PI) s)))) t_0)) t_0))
1.0)))))
float code(float u, float s) {
float t_0 = 1.0f / (1.0f + expf((((float) M_PI) / s)));
return -s * logf(((1.0f / ((u * ((1.0f / (1.0f + expf((-((float) M_PI) / s)))) - t_0)) + t_0)) - 1.0f));
}
function code(u, s) t_0 = Float32(Float32(1.0) / Float32(Float32(1.0) + exp(Float32(Float32(pi) / s)))) return Float32(Float32(-s) * log(Float32(Float32(Float32(1.0) / Float32(Float32(u * Float32(Float32(Float32(1.0) / Float32(Float32(1.0) + exp(Float32(Float32(-Float32(pi)) / s)))) - t_0)) + t_0)) - Float32(1.0)))) end
function tmp = code(u, s) t_0 = single(1.0) / (single(1.0) + exp((single(pi) / s))); tmp = -s * log(((single(1.0) / ((u * ((single(1.0) / (single(1.0) + exp((-single(pi) / s)))) - t_0)) + t_0)) - single(1.0))); end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \frac{1}{1 + e^{\frac{\pi}{s}}}\\
\left(-s\right) \cdot \log \left(\frac{1}{u \cdot \left(\frac{1}{1 + e^{\frac{-\pi}{s}}} - t\_0\right) + t\_0} - 1\right)
\end{array}
\end{array}
(FPCore (u s)
:precision binary32
(let* ((t_0
(-
(/ u (- (exp (/ (- PI) s)) -1.0))
(/ (- u 1.0) (- (exp (/ PI s)) -1.0)))))
(* (- s) (log (/ (- (pow t_0 -2.0) (* -1.0 -1.0)) (- (/ 1.0 t_0) -1.0))))))
float code(float u, float s) {
float t_0 = (u / (expf((-((float) M_PI) / s)) - -1.0f)) - ((u - 1.0f) / (expf((((float) M_PI) / s)) - -1.0f));
return -s * logf(((powf(t_0, -2.0f) - (-1.0f * -1.0f)) / ((1.0f / t_0) - -1.0f)));
}
function code(u, s) t_0 = Float32(Float32(u / Float32(exp(Float32(Float32(-Float32(pi)) / s)) - Float32(-1.0))) - Float32(Float32(u - Float32(1.0)) / Float32(exp(Float32(Float32(pi) / s)) - Float32(-1.0)))) return Float32(Float32(-s) * log(Float32(Float32((t_0 ^ Float32(-2.0)) - Float32(Float32(-1.0) * Float32(-1.0))) / Float32(Float32(Float32(1.0) / t_0) - Float32(-1.0))))) end
function tmp = code(u, s) t_0 = (u / (exp((-single(pi) / s)) - single(-1.0))) - ((u - single(1.0)) / (exp((single(pi) / s)) - single(-1.0))); tmp = -s * log((((t_0 ^ single(-2.0)) - (single(-1.0) * single(-1.0))) / ((single(1.0) / t_0) - single(-1.0)))); end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \frac{u}{e^{\frac{-\pi}{s}} - -1} - \frac{u - 1}{e^{\frac{\pi}{s}} - -1}\\
\left(-s\right) \cdot \log \left(\frac{{t\_0}^{-2} - -1 \cdot -1}{\frac{1}{t\_0} - -1}\right)
\end{array}
\end{array}
Initial program 98.9%
lift-+.f32N/A
add-flipN/A
lower--.f32N/A
Applied rewrites98.9%
lift-/.f32N/A
div-flipN/A
lower-unsound-/.f32N/A
lower-unsound-/.f3298.9
Applied rewrites98.9%
lift--.f32N/A
lift-+.f32N/A
associate--l+N/A
lift-/.f32N/A
frac-2negN/A
metadata-evalN/A
mult-flipN/A
lower-fma.f32N/A
Applied rewrites98.9%
Applied rewrites98.9%
(FPCore (u s)
:precision binary32
(*
(- s)
(log
(-
(/
1.0
(fma
-1.0
(/ -1.0 (/ (- (exp (/ (- PI) s)) -1.0) u))
(/ (- u 1.0) (- -1.0 (exp (/ PI s))))))
1.0))))
float code(float u, float s) {
return -s * logf(((1.0f / fmaf(-1.0f, (-1.0f / ((expf((-((float) M_PI) / s)) - -1.0f) / u)), ((u - 1.0f) / (-1.0f - expf((((float) M_PI) / s)))))) - 1.0f));
}
function code(u, s) return Float32(Float32(-s) * log(Float32(Float32(Float32(1.0) / fma(Float32(-1.0), Float32(Float32(-1.0) / Float32(Float32(exp(Float32(Float32(-Float32(pi)) / s)) - Float32(-1.0)) / u)), Float32(Float32(u - Float32(1.0)) / Float32(Float32(-1.0) - exp(Float32(Float32(pi) / s)))))) - Float32(1.0)))) end
\begin{array}{l}
\\
\left(-s\right) \cdot \log \left(\frac{1}{\mathsf{fma}\left(-1, \frac{-1}{\frac{e^{\frac{-\pi}{s}} - -1}{u}}, \frac{u - 1}{-1 - e^{\frac{\pi}{s}}}\right)} - 1\right)
\end{array}
Initial program 98.9%
lift-+.f32N/A
add-flipN/A
lower--.f32N/A
Applied rewrites98.9%
lift-/.f32N/A
div-flipN/A
lower-unsound-/.f32N/A
lower-unsound-/.f3298.9
Applied rewrites98.9%
lift--.f32N/A
lift-+.f32N/A
associate--l+N/A
lift-/.f32N/A
frac-2negN/A
metadata-evalN/A
mult-flipN/A
lower-fma.f32N/A
Applied rewrites98.9%
(FPCore (u s)
:precision binary32
(*
(- s)
(log
(-
(/
1.0
(-
(/ (- 1.0 u) (- (exp (/ PI s)) -1.0))
(/ u (- -1.0 (exp (/ (- PI) s))))))
1.0))))
float code(float u, float s) {
return -s * logf(((1.0f / (((1.0f - u) / (expf((((float) M_PI) / s)) - -1.0f)) - (u / (-1.0f - expf((-((float) M_PI) / s)))))) - 1.0f));
}
function code(u, s) return Float32(Float32(-s) * log(Float32(Float32(Float32(1.0) / Float32(Float32(Float32(Float32(1.0) - u) / Float32(exp(Float32(Float32(pi) / s)) - Float32(-1.0))) - Float32(u / Float32(Float32(-1.0) - exp(Float32(Float32(-Float32(pi)) / s)))))) - Float32(1.0)))) end
function tmp = code(u, s) tmp = -s * log(((single(1.0) / (((single(1.0) - u) / (exp((single(pi) / s)) - single(-1.0))) - (u / (single(-1.0) - exp((-single(pi) / s)))))) - single(1.0))); end
\begin{array}{l}
\\
\left(-s\right) \cdot \log \left(\frac{1}{\frac{1 - u}{e^{\frac{\pi}{s}} - -1} - \frac{u}{-1 - e^{\frac{-\pi}{s}}}} - 1\right)
\end{array}
Initial program 98.9%
lift-+.f32N/A
add-flipN/A
lower--.f32N/A
Applied rewrites98.9%
lift-/.f32N/A
div-flipN/A
lower-unsound-/.f32N/A
lower-unsound-/.f3298.9
Applied rewrites98.9%
lift--.f32N/A
lift-+.f32N/A
associate--l+N/A
lift-/.f32N/A
frac-2negN/A
metadata-evalN/A
mult-flipN/A
lower-fma.f32N/A
Applied rewrites98.9%
Applied rewrites98.9%
(FPCore (u s)
:precision binary32
(*
(- s)
(log
(-
(/
1.0
(fma
-1.0
(/ -1.0 (/ (- (exp (/ (- PI) s)) -1.0) u))
(/ (- u 1.0) (- -1.0 (+ 1.0 (/ PI s))))))
1.0))))
float code(float u, float s) {
return -s * logf(((1.0f / fmaf(-1.0f, (-1.0f / ((expf((-((float) M_PI) / s)) - -1.0f) / u)), ((u - 1.0f) / (-1.0f - (1.0f + (((float) M_PI) / s)))))) - 1.0f));
}
function code(u, s) return Float32(Float32(-s) * log(Float32(Float32(Float32(1.0) / fma(Float32(-1.0), Float32(Float32(-1.0) / Float32(Float32(exp(Float32(Float32(-Float32(pi)) / s)) - Float32(-1.0)) / u)), Float32(Float32(u - Float32(1.0)) / Float32(Float32(-1.0) - Float32(Float32(1.0) + Float32(Float32(pi) / s)))))) - Float32(1.0)))) end
\begin{array}{l}
\\
\left(-s\right) \cdot \log \left(\frac{1}{\mathsf{fma}\left(-1, \frac{-1}{\frac{e^{\frac{-\pi}{s}} - -1}{u}}, \frac{u - 1}{-1 - \left(1 + \frac{\pi}{s}\right)}\right)} - 1\right)
\end{array}
Initial program 98.9%
lift-+.f32N/A
add-flipN/A
lower--.f32N/A
Applied rewrites98.9%
lift-/.f32N/A
div-flipN/A
lower-unsound-/.f32N/A
lower-unsound-/.f3298.9
Applied rewrites98.9%
lift--.f32N/A
lift-+.f32N/A
associate--l+N/A
lift-/.f32N/A
frac-2negN/A
metadata-evalN/A
mult-flipN/A
lower-fma.f32N/A
Applied rewrites98.9%
Taylor expanded in s around inf
lower-+.f32N/A
lower-/.f32N/A
lower-PI.f3286.2
Applied rewrites86.2%
(FPCore (u s)
:precision binary32
(*
(- s)
(log
(-
(/ 1.0 (fma -1.0 (* -0.5 u) (/ (- u 1.0) (- -1.0 (exp (/ PI s))))))
1.0))))
float code(float u, float s) {
return -s * logf(((1.0f / fmaf(-1.0f, (-0.5f * u), ((u - 1.0f) / (-1.0f - expf((((float) M_PI) / s)))))) - 1.0f));
}
function code(u, s) return Float32(Float32(-s) * log(Float32(Float32(Float32(1.0) / fma(Float32(-1.0), Float32(Float32(-0.5) * u), Float32(Float32(u - Float32(1.0)) / Float32(Float32(-1.0) - exp(Float32(Float32(pi) / s)))))) - Float32(1.0)))) end
\begin{array}{l}
\\
\left(-s\right) \cdot \log \left(\frac{1}{\mathsf{fma}\left(-1, -0.5 \cdot u, \frac{u - 1}{-1 - e^{\frac{\pi}{s}}}\right)} - 1\right)
\end{array}
Initial program 98.9%
lift-+.f32N/A
add-flipN/A
lower--.f32N/A
Applied rewrites98.9%
lift-/.f32N/A
div-flipN/A
lower-unsound-/.f32N/A
lower-unsound-/.f3298.9
Applied rewrites98.9%
lift--.f32N/A
lift-+.f32N/A
associate--l+N/A
lift-/.f32N/A
frac-2negN/A
metadata-evalN/A
mult-flipN/A
lower-fma.f32N/A
Applied rewrites98.9%
Taylor expanded in s around inf
lower-*.f3237.5
Applied rewrites37.5%
(FPCore (u s) :precision binary32 (* (- s) (log (+ 1.0 (* 4.0 (/ (- (* u (- (* -0.25 PI) (* 0.25 PI))) (* -0.25 PI)) s))))))
float code(float u, float s) {
return -s * logf((1.0f + (4.0f * (((u * ((-0.25f * ((float) M_PI)) - (0.25f * ((float) M_PI)))) - (-0.25f * ((float) M_PI))) / s))));
}
function code(u, s) return Float32(Float32(-s) * log(Float32(Float32(1.0) + Float32(Float32(4.0) * Float32(Float32(Float32(u * Float32(Float32(Float32(-0.25) * Float32(pi)) - Float32(Float32(0.25) * Float32(pi)))) - Float32(Float32(-0.25) * Float32(pi))) / s))))) end
function tmp = code(u, s) tmp = -s * log((single(1.0) + (single(4.0) * (((u * ((single(-0.25) * single(pi)) - (single(0.25) * single(pi)))) - (single(-0.25) * single(pi))) / s)))); end
\begin{array}{l}
\\
\left(-s\right) \cdot \log \left(1 + 4 \cdot \frac{u \cdot \left(-0.25 \cdot \pi - 0.25 \cdot \pi\right) - -0.25 \cdot \pi}{s}\right)
\end{array}
Initial program 98.9%
Taylor expanded in s around -inf
lower-+.f32N/A
lower-*.f32N/A
lower-/.f32N/A
Applied rewrites24.8%
(FPCore (u s) :precision binary32 (* (- s) (/ 1.0 (* u (- 0.5 (/ 1.0 (+ 2.0 (/ PI s))))))))
float code(float u, float s) {
return -s * (1.0f / (u * (0.5f - (1.0f / (2.0f + (((float) M_PI) / s))))));
}
function code(u, s) return Float32(Float32(-s) * Float32(Float32(1.0) / Float32(u * Float32(Float32(0.5) - Float32(Float32(1.0) / Float32(Float32(2.0) + Float32(Float32(pi) / s))))))) end
function tmp = code(u, s) tmp = -s * (single(1.0) / (u * (single(0.5) - (single(1.0) / (single(2.0) + (single(pi) / s)))))); end
\begin{array}{l}
\\
\left(-s\right) \cdot \frac{1}{u \cdot \left(0.5 - \frac{1}{2 + \frac{\pi}{s}}\right)}
\end{array}
Initial program 98.9%
Taylor expanded in u around inf
lower-/.f32N/A
lower-*.f32N/A
lower--.f32N/A
Applied rewrites17.2%
Taylor expanded in s around inf
lower-+.f32N/A
lower-/.f32N/A
lower-PI.f3217.2
Applied rewrites17.2%
Taylor expanded in s around inf
Applied rewrites16.7%
(FPCore (u s) :precision binary32 (* (- s) (/ 1.0 (* (/ 1.0 s) (* (* 0.5 PI) u)))))
float code(float u, float s) {
return -s * (1.0f / ((1.0f / s) * ((0.5f * ((float) M_PI)) * u)));
}
function code(u, s) return Float32(Float32(-s) * Float32(Float32(1.0) / Float32(Float32(Float32(1.0) / s) * Float32(Float32(Float32(0.5) * Float32(pi)) * u)))) end
function tmp = code(u, s) tmp = -s * (single(1.0) / ((single(1.0) / s) * ((single(0.5) * single(pi)) * u))); end
\begin{array}{l}
\\
\left(-s\right) \cdot \frac{1}{\frac{1}{s} \cdot \left(\left(0.5 \cdot \pi\right) \cdot u\right)}
\end{array}
Initial program 98.9%
Taylor expanded in u around inf
lower-/.f32N/A
lower-*.f32N/A
lower--.f32N/A
Applied rewrites17.2%
Taylor expanded in s around inf
lower-/.f32N/A
lower-*.f32N/A
lower--.f32N/A
lower-*.f32N/A
lower-PI.f32N/A
lower-*.f32N/A
lower-PI.f3214.4
Applied rewrites14.4%
lift-/.f32N/A
mult-flipN/A
*-commutativeN/A
lower-*.f32N/A
lower-/.f3214.4
lift-*.f32N/A
*-commutativeN/A
lower-*.f3214.4
lift--.f32N/A
lift-*.f32N/A
lift-*.f32N/A
distribute-rgt-out--N/A
*-commutativeN/A
lower-*.f32N/A
metadata-eval14.4
Applied rewrites14.4%
(FPCore (u s) :precision binary32 (- (* (/ 1.0 (/ (* (* 0.5 PI) u) s)) s)))
float code(float u, float s) {
return -((1.0f / (((0.5f * ((float) M_PI)) * u) / s)) * s);
}
function code(u, s) return Float32(-Float32(Float32(Float32(1.0) / Float32(Float32(Float32(Float32(0.5) * Float32(pi)) * u) / s)) * s)) end
function tmp = code(u, s) tmp = -((single(1.0) / (((single(0.5) * single(pi)) * u) / s)) * s); end
\begin{array}{l}
\\
-\frac{1}{\frac{\left(0.5 \cdot \pi\right) \cdot u}{s}} \cdot s
\end{array}
Initial program 98.9%
Taylor expanded in u around inf
lower-/.f32N/A
lower-*.f32N/A
lower--.f32N/A
Applied rewrites17.2%
Taylor expanded in s around inf
lower-/.f32N/A
lower-*.f32N/A
lower--.f32N/A
lower-*.f32N/A
lower-PI.f32N/A
lower-*.f32N/A
lower-PI.f3214.4
Applied rewrites14.4%
lift-*.f32N/A
lift-neg.f32N/A
distribute-lft-neg-outN/A
Applied rewrites14.4%
(FPCore (u s) :precision binary32 (* (- s) (/ (+ PI (* -2.0 (* u PI))) s)))
float code(float u, float s) {
return -s * ((((float) M_PI) + (-2.0f * (u * ((float) M_PI)))) / s);
}
function code(u, s) return Float32(Float32(-s) * Float32(Float32(Float32(pi) + Float32(Float32(-2.0) * Float32(u * Float32(pi)))) / s)) end
function tmp = code(u, s) tmp = -s * ((single(pi) + (single(-2.0) * (u * single(pi)))) / s); end
\begin{array}{l}
\\
\left(-s\right) \cdot \frac{\pi + -2 \cdot \left(u \cdot \pi\right)}{s}
\end{array}
Initial program 98.9%
Taylor expanded in s around -inf
lower-*.f32N/A
lower-/.f32N/A
Applied rewrites11.5%
lift-*.f32N/A
lift-/.f32N/A
associate-*r/N/A
lower-/.f32N/A
Applied rewrites11.5%
Taylor expanded in u around 0
lower-+.f32N/A
lower-PI.f32N/A
lower-*.f32N/A
lower-*.f32N/A
lower-PI.f3211.5
Applied rewrites11.5%
(FPCore (u s) :precision binary32 (- PI))
float code(float u, float s) {
return -((float) M_PI);
}
function code(u, s) return Float32(-Float32(pi)) end
function tmp = code(u, s) tmp = -single(pi); end
\begin{array}{l}
\\
-\pi
\end{array}
Initial program 98.9%
Taylor expanded in u around 0
lower-*.f32N/A
lower-PI.f3211.3
Applied rewrites11.3%
lift-*.f32N/A
mul-1-negN/A
lift-neg.f3211.3
Applied rewrites11.3%
herbie shell --seed 2025155
(FPCore (u s)
:name "Sample trimmed logistic on [-pi, pi]"
:precision binary32
:pre (and (and (<= 2.328306437e-10 u) (<= u 1.0)) (and (<= 0.0 s) (<= s 1.0651631)))
(* (- s) (log (- (/ 1.0 (+ (* u (- (/ 1.0 (+ 1.0 (exp (/ (- PI) s)))) (/ 1.0 (+ 1.0 (exp (/ PI s)))))) (/ 1.0 (+ 1.0 (exp (/ PI s)))))) 1.0))))