
(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 14 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(s * Float32(-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}
\\
s \cdot \left(-\log \left(\frac{1}{\frac{u}{1 + e^{\frac{-\pi}{s}}} + \frac{1 - u}{1 + e^{\frac{\pi}{s}}}} + -1\right)\right)
\end{array}
Initial program 99.1%
Simplified99.1%
Final simplification99.1%
(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 99.1%
Simplified99.1%
Taylor expanded in s around inf 24.5%
+-commutative24.5%
fma-define24.5%
associate--r+24.5%
cancel-sign-sub-inv24.5%
distribute-rgt-out--24.5%
*-commutative24.5%
metadata-eval24.5%
metadata-eval24.5%
*-commutative24.5%
Simplified24.5%
Taylor expanded in u around 0 24.7%
*-commutative24.7%
Simplified24.7%
Taylor expanded in s around 0 24.8%
+-commutative24.8%
mul-1-neg24.8%
unsub-neg24.8%
mul-1-neg24.8%
distribute-neg-frac224.8%
mul-1-neg24.8%
unsub-neg24.8%
Simplified24.8%
Taylor expanded in s around 0 24.8%
neg-mul-124.8%
unsub-neg24.8%
Simplified24.8%
Final simplification24.8%
(FPCore (u s) :precision binary32 (* s (- (- (log s) (log PI)) (/ s PI))))
float code(float u, float s) {
return s * ((logf(s) - logf(((float) M_PI))) - (s / ((float) M_PI)));
}
function code(u, s) return Float32(s * Float32(Float32(log(s) - log(Float32(pi))) - Float32(s / Float32(pi)))) end
function tmp = code(u, s) tmp = s * ((log(s) - log(single(pi))) - (s / single(pi))); end
\begin{array}{l}
\\
s \cdot \left(\left(\log s - \log \pi\right) - \frac{s}{\pi}\right)
\end{array}
Initial program 99.1%
Simplified99.1%
Taylor expanded in s around inf 24.5%
+-commutative24.5%
fma-define24.5%
associate--r+24.5%
cancel-sign-sub-inv24.5%
distribute-rgt-out--24.5%
*-commutative24.5%
metadata-eval24.5%
metadata-eval24.5%
*-commutative24.5%
Simplified24.5%
Taylor expanded in u around 0 24.7%
*-commutative24.7%
Simplified24.7%
Taylor expanded in s around 0 24.8%
+-commutative24.8%
mul-1-neg24.8%
unsub-neg24.8%
mul-1-neg24.8%
distribute-neg-frac224.8%
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 99.1%
Simplified99.1%
Taylor expanded in s around inf 24.5%
+-commutative24.5%
fma-define24.5%
associate--r+24.5%
cancel-sign-sub-inv24.5%
distribute-rgt-out--24.5%
*-commutative24.5%
metadata-eval24.5%
metadata-eval24.5%
*-commutative24.5%
Simplified24.5%
Taylor expanded in u around 0 24.7%
*-commutative24.7%
Simplified24.7%
Taylor expanded in s around 0 24.8%
+-commutative24.8%
mul-1-neg24.8%
unsub-neg24.8%
mul-1-neg24.8%
distribute-neg-frac224.8%
mul-1-neg24.8%
unsub-neg24.8%
Simplified24.8%
Taylor expanded in s around 0 24.8%
Final simplification24.8%
(FPCore (u s) :precision binary32 (* s (+ (/ s PI) (log (/ s PI)))))
float code(float u, float s) {
return s * ((s / ((float) M_PI)) + logf((s / ((float) M_PI))));
}
function code(u, s) return Float32(s * Float32(Float32(s / Float32(pi)) + log(Float32(s / Float32(pi))))) end
function tmp = code(u, s) tmp = s * ((s / single(pi)) + log((s / single(pi)))); end
\begin{array}{l}
\\
s \cdot \left(\frac{s}{\pi} + \log \left(\frac{s}{\pi}\right)\right)
\end{array}
Initial program 99.1%
Simplified99.1%
Taylor expanded in s around inf 24.5%
+-commutative24.5%
fma-define24.5%
associate--r+24.5%
cancel-sign-sub-inv24.5%
distribute-rgt-out--24.5%
*-commutative24.5%
metadata-eval24.5%
metadata-eval24.5%
*-commutative24.5%
Simplified24.5%
Taylor expanded in u around 0 24.7%
*-commutative24.7%
Simplified24.7%
Taylor expanded in s around 0 24.8%
+-commutative24.8%
mul-1-neg24.8%
unsub-neg24.8%
mul-1-neg24.8%
distribute-neg-frac224.8%
mul-1-neg24.8%
unsub-neg24.8%
Simplified24.8%
pow124.8%
Applied egg-rr24.8%
unpow124.8%
Simplified24.8%
Final simplification24.8%
(FPCore (u s) :precision binary32 (* s (- (log (+ 1.0 (/ PI s))))))
float code(float u, float s) {
return s * -logf((1.0f + (((float) M_PI) / s)));
}
function code(u, s) return Float32(s * Float32(-log(Float32(Float32(1.0) + Float32(Float32(pi) / s))))) end
function tmp = code(u, s) tmp = s * -log((single(1.0) + (single(pi) / s))); end
\begin{array}{l}
\\
s \cdot \left(-\log \left(1 + \frac{\pi}{s}\right)\right)
\end{array}
Initial program 99.1%
Simplified99.1%
Taylor expanded in s around inf 24.5%
+-commutative24.5%
fma-define24.5%
associate--r+24.5%
cancel-sign-sub-inv24.5%
distribute-rgt-out--24.5%
*-commutative24.5%
metadata-eval24.5%
metadata-eval24.5%
*-commutative24.5%
Simplified24.5%
Taylor expanded in u around 0 24.7%
*-commutative24.7%
Simplified24.7%
*-un-lft-identity24.7%
log-prod24.7%
metadata-eval24.7%
associate-/l*24.7%
Applied egg-rr24.7%
+-lft-identity24.7%
fma-undefine24.7%
*-commutative24.7%
associate-*l/24.7%
associate-*r/24.7%
*-rgt-identity24.7%
associate-*r/24.7%
associate-*r*24.7%
metadata-eval24.7%
associate-*l*24.7%
*-lft-identity24.7%
+-commutative24.7%
associate-*r/24.7%
*-rgt-identity24.7%
Simplified24.7%
Final simplification24.7%
(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(Float32(-s) * log1p(Float32(Float32(pi) / s))) end
\begin{array}{l}
\\
\left(-s\right) \cdot \mathsf{log1p}\left(\frac{\pi}{s}\right)
\end{array}
Initial program 99.1%
Simplified99.1%
Taylor expanded in s around inf 24.5%
+-commutative24.5%
fma-define24.5%
associate--r+24.5%
cancel-sign-sub-inv24.5%
distribute-rgt-out--24.5%
*-commutative24.5%
metadata-eval24.5%
metadata-eval24.5%
*-commutative24.5%
Simplified24.5%
Taylor expanded in u around 0 24.7%
*-commutative24.7%
Simplified24.7%
*-un-lft-identity24.7%
log-prod24.7%
metadata-eval24.7%
associate-/l*24.7%
Applied egg-rr24.7%
+-lft-identity24.7%
fma-undefine24.7%
*-commutative24.7%
associate-*l/24.7%
associate-*r/24.7%
*-rgt-identity24.7%
associate-*r/24.7%
associate-*r*24.7%
metadata-eval24.7%
associate-*l*24.7%
*-lft-identity24.7%
+-commutative24.7%
log1p-define24.7%
associate-*r/24.7%
*-rgt-identity24.7%
Simplified24.7%
Final simplification24.7%
(FPCore (u s) :precision binary32 (/ (pow s 2.0) (- PI)))
float code(float u, float s) {
return powf(s, 2.0f) / -((float) M_PI);
}
function code(u, s) return Float32((s ^ Float32(2.0)) / Float32(-Float32(pi))) end
function tmp = code(u, s) tmp = (s ^ single(2.0)) / -single(pi); end
\begin{array}{l}
\\
\frac{{s}^{2}}{-\pi}
\end{array}
Initial program 99.1%
Simplified99.1%
Taylor expanded in s around inf 24.5%
+-commutative24.5%
fma-define24.5%
associate--r+24.5%
cancel-sign-sub-inv24.5%
distribute-rgt-out--24.5%
*-commutative24.5%
metadata-eval24.5%
metadata-eval24.5%
*-commutative24.5%
Simplified24.5%
Taylor expanded in u around 0 24.7%
*-commutative24.7%
Simplified24.7%
Taylor expanded in s around 0 24.8%
+-commutative24.8%
mul-1-neg24.8%
unsub-neg24.8%
mul-1-neg24.8%
distribute-neg-frac224.8%
mul-1-neg24.8%
unsub-neg24.8%
Simplified24.8%
Taylor expanded in s around inf 12.9%
mul-1-neg12.9%
distribute-neg-frac212.9%
Simplified12.9%
Final simplification12.9%
(FPCore (u s) :precision binary32 (* 4.0 (+ (* 0.25 (* u PI)) (* u (* 0.25 (+ PI (* PI (/ -1.0 u))))))))
float code(float u, float s) {
return 4.0f * ((0.25f * (u * ((float) M_PI))) + (u * (0.25f * (((float) M_PI) + (((float) M_PI) * (-1.0f / u))))));
}
function code(u, s) return Float32(Float32(4.0) * Float32(Float32(Float32(0.25) * Float32(u * Float32(pi))) + Float32(u * Float32(Float32(0.25) * Float32(Float32(pi) + Float32(Float32(pi) * Float32(Float32(-1.0) / u))))))) end
function tmp = code(u, s) tmp = single(4.0) * ((single(0.25) * (u * single(pi))) + (u * (single(0.25) * (single(pi) + (single(pi) * (single(-1.0) / u)))))); end
\begin{array}{l}
\\
4 \cdot \left(0.25 \cdot \left(u \cdot \pi\right) + u \cdot \left(0.25 \cdot \left(\pi + \pi \cdot \frac{-1}{u}\right)\right)\right)
\end{array}
Initial program 99.1%
Simplified99.1%
Taylor expanded in s around inf 11.4%
Taylor expanded in u around inf 11.4%
+-commutative11.4%
metadata-eval11.4%
cancel-sign-sub-inv11.4%
distribute-lft-out--11.4%
Simplified11.4%
div-inv11.5%
Applied egg-rr11.5%
Final simplification11.5%
(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 99.1%
Simplified99.1%
Taylor expanded in s around inf 11.4%
Taylor expanded in u around inf 11.4%
Final simplification11.4%
(FPCore (u s) :precision binary32 (* -4.0 (* u (+ (* PI -0.5) (* 0.25 (/ PI u))))))
float code(float u, float s) {
return -4.0f * (u * ((((float) M_PI) * -0.5f) + (0.25f * (((float) M_PI) / u))));
}
function code(u, s) return Float32(Float32(-4.0) * Float32(u * Float32(Float32(Float32(pi) * Float32(-0.5)) + Float32(Float32(0.25) * Float32(Float32(pi) / u))))) end
function tmp = code(u, s) tmp = single(-4.0) * (u * ((single(pi) * single(-0.5)) + (single(0.25) * (single(pi) / u)))); end
\begin{array}{l}
\\
-4 \cdot \left(u \cdot \left(\pi \cdot -0.5 + 0.25 \cdot \frac{\pi}{u}\right)\right)
\end{array}
Initial program 99.1%
Simplified99.1%
Taylor expanded in s around -inf 11.4%
associate--r+11.4%
cancel-sign-sub-inv11.4%
metadata-eval11.4%
cancel-sign-sub-inv11.4%
associate-*r*11.4%
distribute-rgt-out11.4%
*-commutative11.4%
metadata-eval11.4%
*-commutative11.4%
associate-*l*11.4%
Simplified11.4%
Taylor expanded in u around inf 11.4%
Final simplification11.4%
(FPCore (u s) :precision binary32 (* 4.0 (* PI (+ -0.25 (* u 0.5)))))
float code(float u, float s) {
return 4.0f * (((float) M_PI) * (-0.25f + (u * 0.5f)));
}
function code(u, s) return Float32(Float32(4.0) * Float32(Float32(pi) * Float32(Float32(-0.25) + Float32(u * Float32(0.5))))) end
function tmp = code(u, s) tmp = single(4.0) * (single(pi) * (single(-0.25) + (u * single(0.5)))); end
\begin{array}{l}
\\
4 \cdot \left(\pi \cdot \left(-0.25 + u \cdot 0.5\right)\right)
\end{array}
Initial program 99.1%
Simplified99.1%
clear-num99.1%
associate-/r/99.1%
Applied egg-rr99.1%
Taylor expanded in s around inf 11.4%
associate--r+11.4%
cancel-sign-sub-inv11.4%
*-commutative11.4%
*-commutative11.4%
distribute-rgt-out--11.4%
metadata-eval11.4%
*-commutative11.4%
*-commutative11.4%
metadata-eval11.4%
+-commutative11.4%
associate-*r*11.4%
*-commutative11.4%
distribute-rgt-out11.4%
Simplified11.4%
Final simplification11.4%
(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 99.1%
Simplified99.1%
Taylor expanded in u around 0 11.1%
neg-mul-111.1%
Simplified11.1%
Final simplification11.1%
(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 99.1%
Simplified99.1%
Taylor expanded in s around inf 24.5%
+-commutative24.5%
fma-define24.5%
associate--r+24.5%
cancel-sign-sub-inv24.5%
distribute-rgt-out--24.5%
*-commutative24.5%
metadata-eval24.5%
metadata-eval24.5%
*-commutative24.5%
Simplified24.5%
Taylor expanded in u around 0 24.7%
*-commutative24.7%
Simplified24.7%
Taylor expanded in s around inf 11.1%
associate-*r/11.1%
add-sqr-sqrt-0.0%
sqrt-unprod8.6%
sqr-neg8.6%
sqrt-unprod4.8%
add-sqr-sqrt4.8%
Applied egg-rr4.8%
*-commutative4.8%
associate-/l*4.8%
*-inverses4.8%
*-rgt-identity4.8%
Simplified4.8%
Final simplification4.8%
herbie shell --seed 2024075
(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))))