
(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 12 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 (exp (/ PI s))))
(*
(- s)
(log
(+
(/
1.0
(+
(/ 1.0 (+ 1.0 t_0))
(+ (/ u (+ 1.0 (exp (/ PI (- s))))) (/ u (- -1.0 t_0)))))
-1.0)))))
float code(float u, float s) {
float t_0 = expf((((float) M_PI) / s));
return -s * logf(((1.0f / ((1.0f / (1.0f + t_0)) + ((u / (1.0f + expf((((float) M_PI) / -s)))) + (u / (-1.0f - t_0))))) + -1.0f));
}
function code(u, s) t_0 = exp(Float32(Float32(pi) / s)) return Float32(Float32(-s) * log(Float32(Float32(Float32(1.0) / Float32(Float32(Float32(1.0) / Float32(Float32(1.0) + t_0)) + Float32(Float32(u / Float32(Float32(1.0) + exp(Float32(Float32(pi) / Float32(-s))))) + Float32(u / Float32(Float32(-1.0) - t_0))))) + Float32(-1.0)))) end
function tmp = code(u, s) t_0 = exp((single(pi) / s)); tmp = -s * log(((single(1.0) / ((single(1.0) / (single(1.0) + t_0)) + ((u / (single(1.0) + exp((single(pi) / -s)))) + (u / (single(-1.0) - t_0))))) + single(-1.0))); end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := e^{\frac{\pi}{s}}\\
\left(-s\right) \cdot \log \left(\frac{1}{\frac{1}{1 + t\_0} + \left(\frac{u}{1 + e^{\frac{\pi}{-s}}} + \frac{u}{-1 - t\_0}\right)} + -1\right)
\end{array}
\end{array}
Initial program 98.9%
Simplified98.9%
Taylor expanded in s around 0 98.9%
sub-neg98.9%
associate--l+98.9%
neg-mul-198.9%
distribute-neg-frac98.9%
metadata-eval98.9%
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 (exp (/ 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 + expf((((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(pi) / Float32(-s))))) + Float32(Float32(Float32(1.0) - u) / Float32(Float32(1.0) + exp(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) + exp((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 + e^{\frac{\pi}{s}}}}\right)\right)
\end{array}
Initial program 98.9%
Simplified98.9%
Final simplification98.9%
(FPCore (u s) :precision binary32 (* s (+ (* -0.25 (/ s (* PI (+ (* u 0.5) 0.25)))) (- (log s) (log (+ PI (* (* PI u) 2.0)))))))
float code(float u, float s) {
return s * ((-0.25f * (s / (((float) M_PI) * ((u * 0.5f) + 0.25f)))) + (logf(s) - logf((((float) M_PI) + ((((float) M_PI) * u) * 2.0f)))));
}
function code(u, s) return Float32(s * Float32(Float32(Float32(-0.25) * Float32(s / Float32(Float32(pi) * Float32(Float32(u * Float32(0.5)) + Float32(0.25))))) + Float32(log(s) - log(Float32(Float32(pi) + Float32(Float32(Float32(pi) * u) * Float32(2.0))))))) end
function tmp = code(u, s) tmp = s * ((single(-0.25) * (s / (single(pi) * ((u * single(0.5)) + single(0.25))))) + (log(s) - log((single(pi) + ((single(pi) * u) * single(2.0)))))); end
\begin{array}{l}
\\
s \cdot \left(-0.25 \cdot \frac{s}{\pi \cdot \left(u \cdot 0.5 + 0.25\right)} + \left(\log s - \log \left(\pi + \left(\pi \cdot u\right) \cdot 2\right)\right)\right)
\end{array}
Initial program 98.9%
Taylor expanded in s around -inf 24.1%
cancel-sign-sub-inv24.1%
distribute-rgt-out--24.1%
metadata-eval24.1%
metadata-eval24.1%
*-commutative24.1%
Simplified24.1%
add-sqr-sqrt24.1%
sqrt-unprod24.1%
sqr-neg24.1%
sqrt-unprod-0.0%
add-sqr-sqrt24.5%
neg-sub024.5%
Applied egg-rr24.5%
Taylor expanded in s around 0 24.7%
Simplified24.7%
Final simplification24.7%
(FPCore (u s) :precision binary32 (- (* -2.0 (* u (/ PI (+ 1.0 (/ PI s))))) (* s (log1p (/ PI s)))))
float code(float u, float s) {
return (-2.0f * (u * (((float) M_PI) / (1.0f + (((float) M_PI) / s))))) - (s * log1pf((((float) M_PI) / s)));
}
function code(u, s) return Float32(Float32(Float32(-2.0) * Float32(u * Float32(Float32(pi) / Float32(Float32(1.0) + Float32(Float32(pi) / s))))) - Float32(s * log1p(Float32(Float32(pi) / s)))) end
\begin{array}{l}
\\
-2 \cdot \left(u \cdot \frac{\pi}{1 + \frac{\pi}{s}}\right) - s \cdot \mathsf{log1p}\left(\frac{\pi}{s}\right)
\end{array}
Initial program 98.9%
Taylor expanded in s around -inf 24.1%
cancel-sign-sub-inv24.1%
distribute-rgt-out--24.1%
metadata-eval24.1%
metadata-eval24.1%
*-commutative24.1%
Simplified24.1%
add-sqr-sqrt24.1%
sqrt-unprod24.1%
sqr-neg24.1%
sqrt-unprod-0.0%
add-sqr-sqrt24.5%
neg-sub024.5%
Applied egg-rr24.5%
Taylor expanded in u around 0 24.5%
mul-1-neg24.5%
unsub-neg24.5%
associate-/l*24.5%
log1p-define24.5%
Simplified24.5%
Final simplification24.5%
(FPCore (u s) :precision binary32 (* (- s) (log1p (/ (+ PI (* (* PI u) 2.0)) s))))
float code(float u, float s) {
return -s * log1pf(((((float) M_PI) + ((((float) M_PI) * u) * 2.0f)) / s));
}
function code(u, s) return Float32(Float32(-s) * log1p(Float32(Float32(Float32(pi) + Float32(Float32(Float32(pi) * u) * Float32(2.0))) / s))) end
\begin{array}{l}
\\
\left(-s\right) \cdot \mathsf{log1p}\left(\frac{\pi + \left(\pi \cdot u\right) \cdot 2}{s}\right)
\end{array}
Initial program 98.9%
Taylor expanded in s around -inf 24.1%
cancel-sign-sub-inv24.1%
distribute-rgt-out--24.1%
metadata-eval24.1%
metadata-eval24.1%
*-commutative24.1%
Simplified24.1%
add-sqr-sqrt24.1%
sqrt-unprod24.1%
sqr-neg24.1%
sqrt-unprod-0.0%
add-sqr-sqrt24.5%
neg-sub024.5%
Applied egg-rr24.5%
pow124.5%
log1p-define24.5%
fma-define24.5%
sub0-neg24.5%
Applied egg-rr24.5%
unpow124.5%
distribute-lft-neg-in24.5%
distribute-rgt-neg-in24.5%
*-commutative24.5%
associate-*l/24.5%
Simplified24.5%
Final simplification24.5%
(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%
Taylor expanded in s around -inf 24.1%
cancel-sign-sub-inv24.1%
distribute-rgt-out--24.1%
metadata-eval24.1%
metadata-eval24.1%
*-commutative24.1%
Simplified24.1%
add-sqr-sqrt24.1%
sqrt-unprod24.1%
sqr-neg24.1%
sqrt-unprod-0.0%
add-sqr-sqrt24.5%
neg-sub024.5%
Applied egg-rr24.5%
Taylor expanded in u around 0 24.5%
associate-*r*24.5%
neg-mul-124.5%
log1p-define24.5%
Simplified24.5%
Final simplification24.5%
(FPCore (u s) :precision binary32 (* -4.0 (+ (* u (+ (* 0.25 (+ -1.0 (/ (+ PI u) u))) (* PI -0.25))) (* PI (* u -0.25)))))
float code(float u, float s) {
return -4.0f * ((u * ((0.25f * (-1.0f + ((((float) M_PI) + u) / u))) + (((float) M_PI) * -0.25f))) + (((float) M_PI) * (u * -0.25f)));
}
function code(u, s) return Float32(Float32(-4.0) * Float32(Float32(u * Float32(Float32(Float32(0.25) * Float32(Float32(-1.0) + Float32(Float32(Float32(pi) + u) / u))) + Float32(Float32(pi) * Float32(-0.25)))) + Float32(Float32(pi) * Float32(u * Float32(-0.25))))) end
function tmp = code(u, s) tmp = single(-4.0) * ((u * ((single(0.25) * (single(-1.0) + ((single(pi) + u) / u))) + (single(pi) * single(-0.25)))) + (single(pi) * (u * single(-0.25)))); end
\begin{array}{l}
\\
-4 \cdot \left(u \cdot \left(0.25 \cdot \left(-1 + \frac{\pi + u}{u}\right) + \pi \cdot -0.25\right) + \pi \cdot \left(u \cdot -0.25\right)\right)
\end{array}
Initial program 98.9%
Simplified98.9%
Taylor expanded in s around -inf 11.8%
associate--r+11.8%
cancel-sign-sub-inv11.8%
metadata-eval11.8%
cancel-sign-sub-inv11.8%
associate-*r*11.8%
distribute-rgt-out11.8%
metadata-eval11.8%
associate-*r*11.8%
Simplified11.8%
Taylor expanded in u around inf 11.8%
expm1-log1p-u11.8%
expm1-undefine11.8%
Applied egg-rr11.8%
Taylor expanded in u around 0 11.8%
Final simplification11.8%
(FPCore (u s) :precision binary32 (* -4.0 (+ (* PI (* u -0.25)) (* u (/ (* PI (+ 0.25 (* u -0.25))) u)))))
float code(float u, float s) {
return -4.0f * ((((float) M_PI) * (u * -0.25f)) + (u * ((((float) M_PI) * (0.25f + (u * -0.25f))) / u)));
}
function code(u, s) return Float32(Float32(-4.0) * Float32(Float32(Float32(pi) * Float32(u * Float32(-0.25))) + Float32(u * Float32(Float32(Float32(pi) * Float32(Float32(0.25) + Float32(u * Float32(-0.25)))) / u)))) end
function tmp = code(u, s) tmp = single(-4.0) * ((single(pi) * (u * single(-0.25))) + (u * ((single(pi) * (single(0.25) + (u * single(-0.25)))) / u))); end
\begin{array}{l}
\\
-4 \cdot \left(\pi \cdot \left(u \cdot -0.25\right) + u \cdot \frac{\pi \cdot \left(0.25 + u \cdot -0.25\right)}{u}\right)
\end{array}
Initial program 98.9%
Simplified98.9%
Taylor expanded in s around -inf 11.8%
associate--r+11.8%
cancel-sign-sub-inv11.8%
metadata-eval11.8%
cancel-sign-sub-inv11.8%
associate-*r*11.8%
distribute-rgt-out11.8%
metadata-eval11.8%
associate-*r*11.8%
Simplified11.8%
Taylor expanded in u around inf 11.8%
expm1-log1p-u11.8%
expm1-undefine11.8%
Applied egg-rr11.8%
Taylor expanded in u around 0 11.8%
associate-*r*11.8%
*-commutative11.8%
distribute-rgt-out11.8%
Simplified11.8%
Final simplification11.8%
(FPCore (u s) :precision binary32 (* -4.0 (+ (* PI (* u -0.25)) (* u (* PI (+ -0.25 (/ 0.25 u)))))))
float code(float u, float s) {
return -4.0f * ((((float) M_PI) * (u * -0.25f)) + (u * (((float) M_PI) * (-0.25f + (0.25f / u)))));
}
function code(u, s) return Float32(Float32(-4.0) * Float32(Float32(Float32(pi) * Float32(u * Float32(-0.25))) + Float32(u * Float32(Float32(pi) * Float32(Float32(-0.25) + Float32(Float32(0.25) / u)))))) end
function tmp = code(u, s) tmp = single(-4.0) * ((single(pi) * (u * single(-0.25))) + (u * (single(pi) * (single(-0.25) + (single(0.25) / u))))); end
\begin{array}{l}
\\
-4 \cdot \left(\pi \cdot \left(u \cdot -0.25\right) + u \cdot \left(\pi \cdot \left(-0.25 + \frac{0.25}{u}\right)\right)\right)
\end{array}
Initial program 98.9%
Simplified98.9%
Taylor expanded in s around -inf 11.8%
associate--r+11.8%
cancel-sign-sub-inv11.8%
metadata-eval11.8%
cancel-sign-sub-inv11.8%
associate-*r*11.8%
distribute-rgt-out11.8%
metadata-eval11.8%
associate-*r*11.8%
Simplified11.8%
Taylor expanded in u around inf 11.8%
Taylor expanded in u around -inf 11.8%
mul-1-neg11.8%
distribute-rgt-neg-in11.8%
neg-sub011.8%
+-commutative11.8%
*-commutative11.8%
associate-*r/11.8%
*-commutative11.8%
metadata-eval11.8%
distribute-rgt-neg-in11.8%
distribute-frac-neg11.8%
*-commutative11.8%
associate-*l/11.8%
associate-/r/11.8%
sub-neg11.8%
associate-+l-11.8%
neg-sub011.8%
distribute-rgt-neg-in11.8%
metadata-eval11.8%
Simplified11.8%
Final simplification11.8%
(FPCore (u s) :precision binary32 (* 4.0 (+ (* 0.5 (* PI u)) (* PI -0.25))))
float code(float u, float s) {
return 4.0f * ((0.5f * (((float) M_PI) * u)) + (((float) M_PI) * -0.25f));
}
function code(u, s) return Float32(Float32(4.0) * Float32(Float32(Float32(0.5) * Float32(Float32(pi) * u)) + Float32(Float32(pi) * Float32(-0.25)))) end
function tmp = code(u, s) tmp = single(4.0) * ((single(0.5) * (single(pi) * u)) + (single(pi) * single(-0.25))); end
\begin{array}{l}
\\
4 \cdot \left(0.5 \cdot \left(\pi \cdot u\right) + \pi \cdot -0.25\right)
\end{array}
Initial program 98.9%
Simplified98.9%
Taylor expanded in s around inf 11.8%
associate--r+11.8%
cancel-sign-sub-inv11.8%
distribute-rgt-out--11.8%
*-commutative11.8%
metadata-eval11.8%
metadata-eval11.8%
*-commutative11.8%
Simplified11.8%
Final simplification11.8%
(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 98.9%
Simplified98.9%
Taylor expanded in s around -inf 11.8%
associate--r+11.8%
cancel-sign-sub-inv11.8%
metadata-eval11.8%
cancel-sign-sub-inv11.8%
associate-*r*11.8%
distribute-rgt-out11.8%
metadata-eval11.8%
associate-*r*11.8%
Simplified11.8%
Taylor expanded in u around 0 11.8%
+-commutative11.8%
associate-*r*11.8%
distribute-rgt-out11.8%
Simplified11.8%
Final simplification11.8%
(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%
mul-1-neg11.6%
Simplified11.6%
Final simplification11.6%
herbie shell --seed 2024076
(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))))