
(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}
Sampling outcomes in binary32 precision:
Herbie found 13 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
(*
(- s)
(log
(+
(/
1.0
(+ (/ u (+ 1.0 (exp (/ (- PI) s)))) (/ (- 1.0 u) (+ 1.0 (exp (/ PI s))))))
-1.0))))
float code(float u, float s) {
return -s * logf(((1.0f / ((u / (1.0f + 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(u / Float32(Float32(1.0) + exp(Float32(Float32(-Float32(pi)) / s)))) + Float32(Float32(Float32(1.0) - u) / Float32(Float32(1.0) + exp(Float32(Float32(pi) / s)))))) + Float32(-1.0)))) end
function tmp = code(u, s) tmp = -s * log(((single(1.0) / ((u / (single(1.0) + 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{u}{1 + e^{\frac{-\pi}{s}}} + \frac{1 - u}{1 + e^{\frac{\pi}{s}}}} + -1\right)
\end{array}
Initial program 99.0%
Simplified99.0%
Final simplification99.0%
(FPCore (u s) :precision binary32 (let* ((t_0 (* PI (+ 0.25 (* u 0.5))))) (* s (- (- (log s) (* 0.25 (/ s t_0))) (log (* 4.0 t_0))))))
float code(float u, float s) {
float t_0 = ((float) M_PI) * (0.25f + (u * 0.5f));
return s * ((logf(s) - (0.25f * (s / t_0))) - logf((4.0f * t_0)));
}
function code(u, s) t_0 = Float32(Float32(pi) * Float32(Float32(0.25) + Float32(u * Float32(0.5)))) return Float32(s * Float32(Float32(log(s) - Float32(Float32(0.25) * Float32(s / t_0))) - log(Float32(Float32(4.0) * t_0)))) end
function tmp = code(u, s) t_0 = single(pi) * (single(0.25) + (u * single(0.5))); tmp = s * ((log(s) - (single(0.25) * (s / t_0))) - log((single(4.0) * t_0))); end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \pi \cdot \left(0.25 + u \cdot 0.5\right)\\
s \cdot \left(\left(\log s - 0.25 \cdot \frac{s}{t\_0}\right) - \log \left(4 \cdot t\_0\right)\right)
\end{array}
\end{array}
Initial program 99.0%
Simplified99.0%
Taylor expanded in s around inf 24.3%
+-commutative24.3%
fma-define24.3%
associate--r+24.3%
cancel-sign-sub-inv24.3%
distribute-rgt-out--24.3%
*-commutative24.3%
metadata-eval24.3%
metadata-eval24.3%
*-commutative24.3%
Simplified24.3%
Applied egg-rr24.6%
fma-undefine24.6%
fma-undefine24.6%
distribute-lft-out24.6%
associate-+r+24.6%
*-commutative24.6%
associate-*r*24.6%
*-commutative24.6%
distribute-lft-in24.6%
distribute-lft-out24.6%
metadata-eval24.6%
associate-*r*24.6%
*-commutative24.6%
metadata-eval24.6%
distribute-rgt-neg-in24.6%
associate-*r*24.6%
neg-sub024.6%
associate--r-24.6%
Simplified24.6%
Taylor expanded in s around 0 24.8%
Final simplification24.8%
(FPCore (u s) :precision binary32 (* s (- (- (log s) (/ s PI)) (log PI))))
float code(float u, float s) {
return s * ((logf(s) - (s / ((float) M_PI))) - logf(((float) M_PI)));
}
function code(u, s) return Float32(s * Float32(Float32(log(s) - Float32(s / Float32(pi))) - log(Float32(pi)))) end
function tmp = code(u, s) tmp = s * ((log(s) - (s / single(pi))) - log(single(pi))); end
\begin{array}{l}
\\
s \cdot \left(\left(\log s - \frac{s}{\pi}\right) - \log \pi\right)
\end{array}
Initial program 99.0%
Simplified99.0%
Taylor expanded in s around inf 24.3%
+-commutative24.3%
fma-define24.3%
associate--r+24.3%
cancel-sign-sub-inv24.3%
distribute-rgt-out--24.3%
*-commutative24.3%
metadata-eval24.3%
metadata-eval24.3%
*-commutative24.3%
Simplified24.3%
Taylor expanded in u around 0 24.6%
Taylor expanded in s around 0 24.8%
+-commutative24.8%
mul-1-neg24.8%
unsub-neg24.8%
Simplified24.8%
Final simplification24.8%
(FPCore (u s) :precision binary32 (* s (- (log s) (log PI))))
float code(float u, float s) {
return s * (logf(s) - logf(((float) M_PI)));
}
function code(u, s) return Float32(s * Float32(log(s) - log(Float32(pi)))) end
function tmp = code(u, s) tmp = s * (log(s) - log(single(pi))); end
\begin{array}{l}
\\
s \cdot \left(\log s - \log \pi\right)
\end{array}
Initial program 99.0%
Simplified99.0%
Taylor expanded in s around inf 24.3%
+-commutative24.3%
fma-define24.3%
associate--r+24.3%
cancel-sign-sub-inv24.3%
distribute-rgt-out--24.3%
*-commutative24.3%
metadata-eval24.3%
metadata-eval24.3%
*-commutative24.3%
Simplified24.3%
Taylor expanded in u around 0 24.6%
Taylor expanded in s around 0 24.7%
mul-1-neg24.7%
*-commutative24.7%
distribute-rgt-neg-in24.7%
mul-1-neg24.7%
unsub-neg24.7%
Simplified24.7%
Final simplification24.7%
(FPCore (u s) :precision binary32 (- (* u (* PI (/ -2.0 (- 1.0 (/ PI s))))) (* s (log1p (/ PI s)))))
float code(float u, float s) {
return (u * (((float) M_PI) * (-2.0f / (1.0f - (((float) M_PI) / s))))) - (s * log1pf((((float) M_PI) / s)));
}
function code(u, s) return Float32(Float32(u * Float32(Float32(pi) * Float32(Float32(-2.0) / Float32(Float32(1.0) - Float32(Float32(pi) / s))))) - Float32(s * log1p(Float32(Float32(pi) / s)))) end
\begin{array}{l}
\\
u \cdot \left(\pi \cdot \frac{-2}{1 - \frac{\pi}{s}}\right) - s \cdot \mathsf{log1p}\left(\frac{\pi}{s}\right)
\end{array}
Initial program 99.0%
Simplified99.0%
Taylor expanded in s around inf 24.3%
+-commutative24.3%
fma-define24.3%
associate--r+24.3%
cancel-sign-sub-inv24.3%
distribute-rgt-out--24.3%
*-commutative24.3%
metadata-eval24.3%
metadata-eval24.3%
*-commutative24.3%
Simplified24.3%
Applied egg-rr24.6%
fma-undefine24.6%
fma-undefine24.6%
distribute-lft-out24.6%
associate-+r+24.6%
*-commutative24.6%
associate-*r*24.6%
*-commutative24.6%
distribute-lft-in24.6%
distribute-lft-out24.6%
metadata-eval24.6%
associate-*r*24.6%
*-commutative24.6%
metadata-eval24.6%
distribute-rgt-neg-in24.6%
associate-*r*24.6%
neg-sub024.6%
associate--r-24.6%
Simplified24.6%
Taylor expanded in u around 0 24.6%
neg-mul-124.6%
unsub-neg24.6%
*-commutative24.6%
associate-/l*24.6%
associate-*r*24.6%
*-commutative24.6%
associate-*r/24.6%
*-rgt-identity24.6%
times-frac24.6%
+-commutative24.6%
/-rgt-identity24.6%
log1p-define24.6%
Simplified24.6%
add-sqr-sqrt24.6%
sqrt-unprod24.6%
sqr-neg24.6%
sqrt-unprod-0.0%
add-sqr-sqrt24.6%
distribute-frac-neg224.6%
Applied egg-rr24.6%
Final simplification24.6%
(FPCore (u s) :precision binary32 (- (* u (* s -2.0)) (* s (log1p (/ PI s)))))
float code(float u, float s) {
return (u * (s * -2.0f)) - (s * log1pf((((float) M_PI) / s)));
}
function code(u, s) return Float32(Float32(u * Float32(s * Float32(-2.0))) - Float32(s * log1p(Float32(Float32(pi) / s)))) end
\begin{array}{l}
\\
u \cdot \left(s \cdot -2\right) - s \cdot \mathsf{log1p}\left(\frac{\pi}{s}\right)
\end{array}
Initial program 99.0%
Simplified99.0%
Taylor expanded in s around inf 24.3%
+-commutative24.3%
fma-define24.3%
associate--r+24.3%
cancel-sign-sub-inv24.3%
distribute-rgt-out--24.3%
*-commutative24.3%
metadata-eval24.3%
metadata-eval24.3%
*-commutative24.3%
Simplified24.3%
Applied egg-rr24.6%
fma-undefine24.6%
fma-undefine24.6%
distribute-lft-out24.6%
associate-+r+24.6%
*-commutative24.6%
associate-*r*24.6%
*-commutative24.6%
distribute-lft-in24.6%
distribute-lft-out24.6%
metadata-eval24.6%
associate-*r*24.6%
*-commutative24.6%
metadata-eval24.6%
distribute-rgt-neg-in24.6%
associate-*r*24.6%
neg-sub024.6%
associate--r-24.6%
Simplified24.6%
Taylor expanded in u around 0 24.6%
neg-mul-124.6%
unsub-neg24.6%
*-commutative24.6%
associate-/l*24.6%
associate-*r*24.6%
*-commutative24.6%
associate-*r/24.6%
*-rgt-identity24.6%
times-frac24.6%
+-commutative24.6%
/-rgt-identity24.6%
log1p-define24.6%
Simplified24.6%
Taylor expanded in s around 0 24.6%
Final simplification24.6%
(FPCore (u s) :precision binary32 (* s (- (log1p (/ PI s)))))
float code(float u, float s) {
return s * -log1pf((((float) M_PI) / s));
}
function code(u, s) return Float32(s * Float32(-log1p(Float32(Float32(pi) / s)))) end
\begin{array}{l}
\\
s \cdot \left(-\mathsf{log1p}\left(\frac{\pi}{s}\right)\right)
\end{array}
Initial program 99.0%
Simplified99.0%
Taylor expanded in s around inf 24.3%
+-commutative24.3%
fma-define24.3%
associate--r+24.3%
cancel-sign-sub-inv24.3%
distribute-rgt-out--24.3%
*-commutative24.3%
metadata-eval24.3%
metadata-eval24.3%
*-commutative24.3%
Simplified24.3%
Applied egg-rr24.6%
fma-undefine24.6%
fma-undefine24.6%
distribute-lft-out24.6%
associate-+r+24.6%
*-commutative24.6%
associate-*r*24.6%
*-commutative24.6%
distribute-lft-in24.6%
distribute-lft-out24.6%
metadata-eval24.6%
associate-*r*24.6%
*-commutative24.6%
metadata-eval24.6%
distribute-rgt-neg-in24.6%
associate-*r*24.6%
neg-sub024.6%
associate--r-24.6%
Simplified24.6%
Taylor expanded in u around 0 24.6%
log1p-define24.6%
Simplified24.6%
Final simplification24.6%
(FPCore (u s) :precision binary32 (* 4.0 (* u (- (+ (* -0.25 (/ PI u)) (* PI 0.25)) (* PI -0.25)))))
float code(float u, float s) {
return 4.0f * (u * (((-0.25f * (((float) M_PI) / u)) + (((float) M_PI) * 0.25f)) - (((float) M_PI) * -0.25f)));
}
function code(u, s) return Float32(Float32(4.0) * Float32(u * Float32(Float32(Float32(Float32(-0.25) * Float32(Float32(pi) / u)) + Float32(Float32(pi) * Float32(0.25))) - Float32(Float32(pi) * Float32(-0.25))))) end
function tmp = code(u, s) tmp = single(4.0) * (u * (((single(-0.25) * (single(pi) / u)) + (single(pi) * single(0.25))) - (single(pi) * single(-0.25)))); end
\begin{array}{l}
\\
4 \cdot \left(u \cdot \left(\left(-0.25 \cdot \frac{\pi}{u} + \pi \cdot 0.25\right) - \pi \cdot -0.25\right)\right)
\end{array}
Initial program 99.0%
Simplified99.0%
Taylor expanded in s around inf 11.2%
Taylor expanded in u around inf 11.2%
Final simplification11.2%
(FPCore (u s) :precision binary32 (* 4.0 (* u (+ (* -0.25 (/ PI u)) (* PI 0.5)))))
float code(float u, float s) {
return 4.0f * (u * ((-0.25f * (((float) M_PI) / u)) + (((float) M_PI) * 0.5f)));
}
function code(u, s) return Float32(Float32(4.0) * Float32(u * Float32(Float32(Float32(-0.25) * Float32(Float32(pi) / u)) + Float32(Float32(pi) * Float32(0.5))))) end
function tmp = code(u, s) tmp = single(4.0) * (u * ((single(-0.25) * (single(pi) / u)) + (single(pi) * single(0.5)))); end
\begin{array}{l}
\\
4 \cdot \left(u \cdot \left(-0.25 \cdot \frac{\pi}{u} + \pi \cdot 0.5\right)\right)
\end{array}
Initial program 99.0%
Simplified99.0%
Taylor expanded in s around inf 11.2%
associate--r+11.2%
cancel-sign-sub-inv11.2%
distribute-rgt-out--11.2%
*-commutative11.2%
metadata-eval11.2%
metadata-eval11.2%
*-commutative11.2%
Simplified11.2%
Taylor expanded in u around inf 11.2%
Final simplification11.2%
(FPCore (u s) :precision binary32 (* 4.0 (+ (* PI -0.25) (* 0.5 (* u PI)))))
float code(float u, float s) {
return 4.0f * ((((float) M_PI) * -0.25f) + (0.5f * (u * ((float) M_PI))));
}
function code(u, s) return Float32(Float32(4.0) * Float32(Float32(Float32(pi) * Float32(-0.25)) + Float32(Float32(0.5) * Float32(u * Float32(pi))))) end
function tmp = code(u, s) tmp = single(4.0) * ((single(pi) * single(-0.25)) + (single(0.5) * (u * single(pi)))); end
\begin{array}{l}
\\
4 \cdot \left(\pi \cdot -0.25 + 0.5 \cdot \left(u \cdot \pi\right)\right)
\end{array}
Initial program 99.0%
Simplified99.0%
Taylor expanded in s around inf 11.2%
associate--r+11.2%
cancel-sign-sub-inv11.2%
distribute-rgt-out--11.2%
*-commutative11.2%
metadata-eval11.2%
metadata-eval11.2%
*-commutative11.2%
Simplified11.2%
Final simplification11.2%
(FPCore (u s) :precision binary32 (* 4.0 (* PI (+ (* u 0.5) -0.25))))
float code(float u, float s) {
return 4.0f * (((float) M_PI) * ((u * 0.5f) + -0.25f));
}
function code(u, s) return Float32(Float32(4.0) * Float32(Float32(pi) * Float32(Float32(u * Float32(0.5)) + Float32(-0.25)))) end
function tmp = code(u, s) tmp = single(4.0) * (single(pi) * ((u * single(0.5)) + single(-0.25))); end
\begin{array}{l}
\\
4 \cdot \left(\pi \cdot \left(u \cdot 0.5 + -0.25\right)\right)
\end{array}
Initial program 99.0%
Simplified99.0%
Taylor expanded in s around inf 11.2%
associate--r+11.2%
cancel-sign-sub-inv11.2%
distribute-rgt-out--11.2%
*-commutative11.2%
metadata-eval11.2%
metadata-eval11.2%
*-commutative11.2%
Simplified11.2%
associate-*l*11.2%
distribute-lft-out11.2%
Applied egg-rr11.2%
Final simplification11.2%
(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 99.0%
Simplified99.0%
Taylor expanded in u around 0 10.9%
neg-mul-110.9%
Simplified10.9%
Final simplification10.9%
(FPCore (u s) :precision binary32 PI)
float code(float u, float s) {
return (float) M_PI;
}
function code(u, s) return Float32(pi) end
function tmp = code(u, s) tmp = single(pi); end
\begin{array}{l}
\\
\pi
\end{array}
Initial program 99.0%
Simplified99.0%
Taylor expanded in s around inf 24.3%
+-commutative24.3%
fma-define24.3%
associate--r+24.3%
cancel-sign-sub-inv24.3%
distribute-rgt-out--24.3%
*-commutative24.3%
metadata-eval24.3%
metadata-eval24.3%
*-commutative24.3%
Simplified24.3%
Taylor expanded in u around 0 24.6%
add-sqr-sqrt-0.0%
sqrt-unprod8.9%
sqr-neg8.9%
sqrt-unprod7.6%
add-sqr-sqrt7.6%
add-exp-log7.6%
fma-undefine7.6%
+-commutative7.6%
associate-/l*7.6%
associate-*r*7.6%
metadata-eval7.6%
*-un-lft-identity7.6%
Applied egg-rr7.6%
Taylor expanded in s around inf 4.8%
Final simplification4.8%
herbie shell --seed 2024077
(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))))