
(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 15 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
(sqrt
(+
-1.0
(/
1.0
(+
(/ (- 1.0 u) (+ 1.0 (exp (/ PI s))))
(/ u (+ 1.0 (exp (- (/ PI s))))))))))
(- 2.0))))
float code(float u, float s) {
return s * (logf(sqrtf((-1.0f + (1.0f / (((1.0f - u) / (1.0f + expf((((float) M_PI) / s)))) + (u / (1.0f + expf(-(((float) M_PI) / s))))))))) * -2.0f);
}
function code(u, s) return Float32(s * Float32(log(sqrt(Float32(Float32(-1.0) + Float32(Float32(1.0) / Float32(Float32(Float32(Float32(1.0) - u) / Float32(Float32(1.0) + exp(Float32(Float32(pi) / s)))) + Float32(u / Float32(Float32(1.0) + exp(Float32(-Float32(Float32(pi) / s)))))))))) * Float32(-Float32(2.0)))) end
function tmp = code(u, s) tmp = s * (log(sqrt((single(-1.0) + (single(1.0) / (((single(1.0) - u) / (single(1.0) + exp((single(pi) / s)))) + (u / (single(1.0) + exp(-(single(pi) / s))))))))) * -single(2.0)); end
\begin{array}{l}
\\
s \cdot \left(\log \left(\sqrt{-1 + \frac{1}{\frac{1 - u}{1 + e^{\frac{\pi}{s}}} + \frac{u}{1 + e^{-\frac{\pi}{s}}}}}\right) \cdot \left(-2\right)\right)
\end{array}
Initial program 98.9%
Simplified98.9%
clear-num98.9%
inv-pow98.9%
Applied egg-rr98.9%
unpow-198.9%
Simplified98.9%
clear-num98.9%
add-sqr-sqrt99.0%
log-prod99.0%
Applied egg-rr99.0%
count-299.0%
Simplified99.0%
Final simplification99.0%
(FPCore (u s)
:precision binary32
(*
(- s)
(log
(+
-1.0
(/
1.0
(+
(/ u (+ 1.0 (exp (- (/ PI s)))))
(/ (- 1.0 u) (+ 1.0 (exp (/ 1.0 (/ s PI)))))))))))
float code(float u, float s) {
return -s * logf((-1.0f + (1.0f / ((u / (1.0f + expf(-(((float) M_PI) / s)))) + ((1.0f - u) / (1.0f + expf((1.0f / (s / ((float) M_PI))))))))));
}
function code(u, s) return Float32(Float32(-s) * log(Float32(Float32(-1.0) + 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(1.0) / Float32(s / Float32(pi))))))))))) end
function tmp = code(u, s) tmp = -s * log((single(-1.0) + (single(1.0) / ((u / (single(1.0) + exp(-(single(pi) / s)))) + ((single(1.0) - u) / (single(1.0) + exp((single(1.0) / (s / single(pi)))))))))); end
\begin{array}{l}
\\
\left(-s\right) \cdot \log \left(-1 + \frac{1}{\frac{u}{1 + e^{-\frac{\pi}{s}}} + \frac{1 - u}{1 + e^{\frac{1}{\frac{s}{\pi}}}}}\right)
\end{array}
Initial program 98.9%
Simplified98.9%
clear-num98.9%
inv-pow98.9%
Applied egg-rr98.9%
unpow-198.9%
Simplified98.9%
Final simplification98.9%
(FPCore (u s)
:precision binary32
(*
(- s)
(log
(+
-1.0
(/
1.0
(+
(/ (- 1.0 u) (+ 1.0 (exp (/ PI s))))
(/ u (+ 1.0 (exp (- (/ PI s)))))))))))
float code(float u, float s) {
return -s * logf((-1.0f + (1.0f / (((1.0f - u) / (1.0f + expf((((float) M_PI) / s)))) + (u / (1.0f + expf(-(((float) M_PI) / s))))))));
}
function code(u, s) return Float32(Float32(-s) * log(Float32(Float32(-1.0) + Float32(Float32(1.0) / Float32(Float32(Float32(Float32(1.0) - u) / Float32(Float32(1.0) + exp(Float32(Float32(pi) / s)))) + Float32(u / Float32(Float32(1.0) + exp(Float32(-Float32(Float32(pi) / s)))))))))) end
function tmp = code(u, s) tmp = -s * log((single(-1.0) + (single(1.0) / (((single(1.0) - u) / (single(1.0) + exp((single(pi) / s)))) + (u / (single(1.0) + exp(-(single(pi) / s)))))))); end
\begin{array}{l}
\\
\left(-s\right) \cdot \log \left(-1 + \frac{1}{\frac{1 - u}{1 + e^{\frac{\pi}{s}}} + \frac{u}{1 + e^{-\frac{\pi}{s}}}}\right)
\end{array}
Initial program 98.9%
Simplified98.9%
Final simplification98.9%
(FPCore (u s)
:precision binary32
(*
s
(-
(log
(+
-1.0
(/
1.0
(+
(/ u (+ 1.0 (exp (- (/ PI s)))))
(/ (- 1.0 u) (+ 1.0 (+ 1.0 (/ PI s)))))))))))
float code(float u, float s) {
return s * -logf((-1.0f + (1.0f / ((u / (1.0f + expf(-(((float) M_PI) / s)))) + ((1.0f - u) / (1.0f + (1.0f + (((float) M_PI) / s))))))));
}
function code(u, s) return Float32(s * Float32(-log(Float32(Float32(-1.0) + 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) + Float32(Float32(1.0) + Float32(Float32(pi) / s)))))))))) end
function tmp = code(u, s) tmp = s * -log((single(-1.0) + (single(1.0) / ((u / (single(1.0) + exp(-(single(pi) / s)))) + ((single(1.0) - u) / (single(1.0) + (single(1.0) + (single(pi) / s)))))))); end
\begin{array}{l}
\\
s \cdot \left(-\log \left(-1 + \frac{1}{\frac{u}{1 + e^{-\frac{\pi}{s}}} + \frac{1 - u}{1 + \left(1 + \frac{\pi}{s}\right)}}\right)\right)
\end{array}
Initial program 98.9%
Simplified98.9%
Taylor expanded in s around inf 84.8%
Final simplification84.8%
(FPCore (u s) :precision binary32 (* s (- (- (log s) (* u -2.0)) (log PI))))
float code(float u, float s) {
return s * ((logf(s) - (u * -2.0f)) - logf(((float) M_PI)));
}
function code(u, s) return Float32(s * Float32(Float32(log(s) - Float32(u * Float32(-2.0))) - log(Float32(pi)))) end
function tmp = code(u, s) tmp = s * ((log(s) - (u * single(-2.0))) - log(single(pi))); end
\begin{array}{l}
\\
s \cdot \left(\left(\log s - u \cdot -2\right) - \log \pi\right)
\end{array}
Initial program 98.9%
Simplified98.9%
Taylor expanded in s around inf 25.0%
+-commutative25.0%
fma-define25.0%
Simplified25.0%
Taylor expanded in u around 0 25.1%
log1p-define25.1%
associate-/l*25.1%
associate-/r*25.1%
Simplified25.1%
neg-sub025.1%
flip--21.5%
metadata-eval21.5%
pow221.5%
add-sqr-sqrt21.5%
sqrt-unprod16.4%
sqr-neg16.4%
sqrt-unprod-0.0%
add-sqr-sqrt8.2%
sub-neg8.2%
neg-sub08.2%
add-sqr-sqrt-0.0%
sqrt-unprod16.4%
sqr-neg16.4%
sqrt-unprod21.5%
add-sqr-sqrt21.5%
Applied egg-rr21.5%
sub0-neg21.5%
Simplified21.5%
Taylor expanded in s around 0 25.4%
mul-1-neg25.4%
*-commutative25.4%
distribute-rgt-neg-in25.4%
mul-1-neg25.4%
unsub-neg25.4%
*-commutative25.4%
Simplified25.4%
Final simplification25.4%
(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 98.9%
Simplified98.9%
Taylor expanded in s around inf 25.0%
+-commutative25.0%
fma-define25.0%
Simplified25.0%
Taylor expanded in u around 0 25.1%
associate-*r*25.1%
neg-mul-125.1%
log1p-define25.1%
Simplified25.1%
Taylor expanded in s around 0 25.4%
mul-1-neg25.4%
*-commutative25.4%
distribute-rgt-neg-in25.4%
mul-1-neg25.4%
unsub-neg25.4%
Simplified25.4%
Final simplification25.4%
(FPCore (u s) :precision binary32 (* s (- (* -2.0 (* u (+ -1.0 (/ s PI)))) (log1p (/ PI s)))))
float code(float u, float s) {
return s * ((-2.0f * (u * (-1.0f + (s / ((float) M_PI))))) - log1pf((((float) M_PI) / s)));
}
function code(u, s) return Float32(s * Float32(Float32(Float32(-2.0) * Float32(u * Float32(Float32(-1.0) + Float32(s / Float32(pi))))) - log1p(Float32(Float32(pi) / s)))) end
\begin{array}{l}
\\
s \cdot \left(-2 \cdot \left(u \cdot \left(-1 + \frac{s}{\pi}\right)\right) - \mathsf{log1p}\left(\frac{\pi}{s}\right)\right)
\end{array}
Initial program 98.9%
Simplified98.9%
Taylor expanded in s around inf 25.0%
+-commutative25.0%
fma-define25.0%
Simplified25.0%
Taylor expanded in u around 0 25.1%
log1p-define25.1%
associate-/l*25.1%
associate-/r*25.1%
Simplified25.1%
Taylor expanded in s around 0 25.1%
mul-1-neg25.1%
distribute-frac-neg225.1%
Simplified25.1%
Final simplification25.1%
(FPCore (u s) :precision binary32 (* (- s) (log1p (* PI (/ 1.0 s)))))
float code(float u, float s) {
return -s * log1pf((((float) M_PI) * (1.0f / s)));
}
function code(u, s) return Float32(Float32(-s) * log1p(Float32(Float32(pi) * Float32(Float32(1.0) / s)))) end
\begin{array}{l}
\\
\left(-s\right) \cdot \mathsf{log1p}\left(\pi \cdot \frac{1}{s}\right)
\end{array}
Initial program 98.9%
Simplified98.9%
Taylor expanded in s around inf 25.0%
+-commutative25.0%
fma-define25.0%
Simplified25.0%
Taylor expanded in u around 0 25.1%
associate-*r*25.1%
neg-mul-125.1%
log1p-define25.1%
Simplified25.1%
clear-num25.1%
associate-/r/25.1%
Applied egg-rr25.1%
Final simplification25.1%
(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 98.9%
Simplified98.9%
Taylor expanded in s around inf 25.0%
+-commutative25.0%
fma-define25.0%
Simplified25.0%
Taylor expanded in u around 0 25.1%
associate-*r*25.1%
neg-mul-125.1%
log1p-define25.1%
Simplified25.1%
(FPCore (u s) :precision binary32 (* 4.0 (- (* 0.25 (* u PI)) (* u (+ (* PI -0.25) (* 0.25 (/ PI u)))))))
float code(float u, float s) {
return 4.0f * ((0.25f * (u * ((float) M_PI))) - (u * ((((float) M_PI) * -0.25f) + (0.25f * (((float) M_PI) / u)))));
}
function code(u, s) return Float32(Float32(4.0) * Float32(Float32(Float32(0.25) * Float32(u * Float32(pi))) - Float32(u * Float32(Float32(Float32(pi) * Float32(-0.25)) + Float32(Float32(0.25) * Float32(Float32(pi) / u)))))) end
function tmp = code(u, s) tmp = single(4.0) * ((single(0.25) * (u * single(pi))) - (u * ((single(pi) * single(-0.25)) + (single(0.25) * (single(pi) / u))))); end
\begin{array}{l}
\\
4 \cdot \left(0.25 \cdot \left(u \cdot \pi\right) - u \cdot \left(\pi \cdot -0.25 + 0.25 \cdot \frac{\pi}{u}\right)\right)
\end{array}
Initial program 98.9%
Simplified98.9%
Taylor expanded in s around inf 11.8%
Taylor expanded in u around inf 11.8%
Final simplification11.8%
(FPCore (u s) :precision binary32 (* u (- (* 4.0 (* PI 0.5)) (/ PI u))))
float code(float u, float s) {
return u * ((4.0f * (((float) M_PI) * 0.5f)) - (((float) M_PI) / u));
}
function code(u, s) return Float32(u * Float32(Float32(Float32(4.0) * Float32(Float32(pi) * Float32(0.5))) - Float32(Float32(pi) / u))) end
function tmp = code(u, s) tmp = u * ((single(4.0) * (single(pi) * single(0.5))) - (single(pi) / u)); end
\begin{array}{l}
\\
u \cdot \left(4 \cdot \left(\pi \cdot 0.5\right) - \frac{\pi}{u}\right)
\end{array}
Initial program 98.9%
Simplified98.9%
Taylor expanded in s around inf 11.8%
Taylor expanded in u around inf 11.8%
+-commutative11.8%
mul-1-neg11.8%
unsub-neg11.8%
distribute-rgt-out--11.8%
metadata-eval11.8%
Simplified11.8%
(FPCore (u s) :precision binary32 (- (* PI (* 2.0 u)) PI))
float code(float u, float s) {
return (((float) M_PI) * (2.0f * u)) - ((float) M_PI);
}
function code(u, s) return Float32(Float32(Float32(pi) * Float32(Float32(2.0) * u)) - Float32(pi)) end
function tmp = code(u, s) tmp = (single(pi) * (single(2.0) * u)) - single(pi); end
\begin{array}{l}
\\
\pi \cdot \left(2 \cdot u\right) - \pi
\end{array}
Initial program 98.9%
Simplified98.9%
Taylor expanded in s around inf 25.0%
+-commutative25.0%
fma-define25.0%
Simplified25.0%
Taylor expanded in u around 0 25.1%
log1p-define25.1%
associate-/l*25.1%
associate-/r*25.1%
Simplified25.1%
neg-sub025.1%
flip--21.5%
metadata-eval21.5%
pow221.5%
add-sqr-sqrt21.5%
sqrt-unprod16.4%
sqr-neg16.4%
sqrt-unprod-0.0%
add-sqr-sqrt8.2%
sub-neg8.2%
neg-sub08.2%
add-sqr-sqrt-0.0%
sqrt-unprod16.4%
sqr-neg16.4%
sqrt-unprod21.5%
add-sqr-sqrt21.5%
Applied egg-rr21.5%
sub0-neg21.5%
Simplified21.5%
Taylor expanded in s around -inf 11.8%
+-commutative11.8%
mul-1-neg11.8%
unsub-neg11.8%
associate-*r*11.8%
Simplified11.8%
Final simplification11.8%
(FPCore (u s) :precision binary32 (/ (* s (- PI)) s))
float code(float u, float s) {
return (s * -((float) M_PI)) / s;
}
function code(u, s) return Float32(Float32(s * Float32(-Float32(pi))) / s) end
function tmp = code(u, s) tmp = (s * -single(pi)) / s; end
\begin{array}{l}
\\
\frac{s \cdot \left(-\pi\right)}{s}
\end{array}
Initial program 98.9%
Simplified98.9%
Taylor expanded in u around 0 11.6%
associate-*r/11.6%
Applied egg-rr11.6%
Final simplification11.6%
(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%
Simplified98.9%
Taylor expanded in u around 0 11.6%
neg-mul-111.6%
Simplified11.6%
(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 98.9%
Simplified98.9%
Taylor expanded in u around 0 11.6%
neg-sub011.6%
sub-neg11.6%
add-sqr-sqrt-0.0%
sqrt-unprod7.5%
sqr-neg7.5%
sqrt-unprod4.5%
add-sqr-sqrt4.5%
Applied egg-rr4.5%
+-lft-identity4.5%
Simplified4.5%
Taylor expanded in s around 0 4.5%
herbie shell --seed 2024145
(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))))