
(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 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 (exp (/ PI s)))
(t_1 (/ u (+ 1.0 (exp (/ PI (- s))))))
(t_2 (+ t_1 (/ (- 1.0 u) (+ 1.0 t_0)))))
(*
(- s)
(log
(/
(+ -1.0 (pow t_2 -3.0))
(+
(pow t_2 -2.0)
(+ 1.0 (/ -1.0 (- (/ (- 1.0 u) (- -1.0 t_0)) t_1)))))))))
float code(float u, float s) {
float t_0 = expf((((float) M_PI) / s));
float t_1 = u / (1.0f + expf((((float) M_PI) / -s)));
float t_2 = t_1 + ((1.0f - u) / (1.0f + t_0));
return -s * logf(((-1.0f + powf(t_2, -3.0f)) / (powf(t_2, -2.0f) + (1.0f + (-1.0f / (((1.0f - u) / (-1.0f - t_0)) - t_1))))));
}
function code(u, s) t_0 = exp(Float32(Float32(pi) / s)) t_1 = Float32(u / Float32(Float32(1.0) + exp(Float32(Float32(pi) / Float32(-s))))) t_2 = Float32(t_1 + Float32(Float32(Float32(1.0) - u) / Float32(Float32(1.0) + t_0))) return Float32(Float32(-s) * log(Float32(Float32(Float32(-1.0) + (t_2 ^ Float32(-3.0))) / Float32((t_2 ^ Float32(-2.0)) + Float32(Float32(1.0) + Float32(Float32(-1.0) / Float32(Float32(Float32(Float32(1.0) - u) / Float32(Float32(-1.0) - t_0)) - t_1))))))) end
function tmp = code(u, s) t_0 = exp((single(pi) / s)); t_1 = u / (single(1.0) + exp((single(pi) / -s))); t_2 = t_1 + ((single(1.0) - u) / (single(1.0) + t_0)); tmp = -s * log(((single(-1.0) + (t_2 ^ single(-3.0))) / ((t_2 ^ single(-2.0)) + (single(1.0) + (single(-1.0) / (((single(1.0) - u) / (single(-1.0) - t_0)) - t_1)))))); end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := e^{\frac{\pi}{s}}\\
t_1 := \frac{u}{1 + e^{\frac{\pi}{-s}}}\\
t_2 := t\_1 + \frac{1 - u}{1 + t\_0}\\
\left(-s\right) \cdot \log \left(\frac{-1 + {t\_2}^{-3}}{{t\_2}^{-2} + \left(1 + \frac{-1}{\frac{1 - u}{-1 - t\_0} - t\_1}\right)}\right)
\end{array}
\end{array}
Initial program 98.6%
Simplified98.6%
clear-num98.6%
associate-/r/98.6%
Applied egg-rr98.6%
Applied egg-rr98.8%
+-commutative98.8%
associate-*l/98.8%
metadata-eval98.8%
Simplified98.8%
Final simplification98.8%
(FPCore (u s)
:precision binary32
(*
(- s)
(log
(+
-1.0
(pow
(sqrt
(+
(/ u (+ 1.0 (exp (/ PI (- s)))))
(/ (- 1.0 u) (+ 1.0 (exp (/ PI s))))))
-2.0)))))
float code(float u, float s) {
return -s * logf((-1.0f + powf(sqrtf(((u / (1.0f + expf((((float) M_PI) / -s)))) + ((1.0f - u) / (1.0f + expf((((float) M_PI) / s)))))), -2.0f)));
}
function code(u, s) return Float32(Float32(-s) * log(Float32(Float32(-1.0) + (sqrt(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)))))) ^ Float32(-2.0))))) end
function tmp = code(u, s) tmp = -s * log((single(-1.0) + (sqrt(((u / (single(1.0) + exp((single(pi) / -s)))) + ((single(1.0) - u) / (single(1.0) + exp((single(pi) / s)))))) ^ single(-2.0)))); end
\begin{array}{l}
\\
\left(-s\right) \cdot \log \left(-1 + {\left(\sqrt{\frac{u}{1 + e^{\frac{\pi}{-s}}} + \frac{1 - u}{1 + e^{\frac{\pi}{s}}}}\right)}^{-2}\right)
\end{array}
Initial program 98.6%
Simplified98.6%
clear-num98.6%
associate-/r/98.6%
Applied egg-rr98.6%
inv-pow98.6%
add-sqr-sqrt98.6%
unpow-prod-down98.6%
Applied egg-rr98.6%
pow-sqr98.7%
metadata-eval98.7%
Simplified98.7%
Final simplification98.7%
(FPCore (u s)
:precision binary32
(*
(- s)
(log
(+
-1.0
(/
1.0
(+
(/ u (+ 1.0 (exp (/ PI (- s)))))
(/ (- 1.0 u) (+ 1.0 (exp (* PI (/ 1.0 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) * (1.0f / s)))))))));
}
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(pi) / Float32(-s))))) + Float32(Float32(Float32(1.0) - u) / Float32(Float32(1.0) + exp(Float32(Float32(pi) * Float32(Float32(1.0) / 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) * (single(1.0) / s))))))))); 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^{\pi \cdot \frac{1}{s}}}}\right)
\end{array}
Initial program 98.6%
Simplified98.6%
clear-num98.6%
associate-/r/98.6%
Applied egg-rr98.6%
Final simplification98.6%
(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(Float32(-s) * 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}
\\
\left(-s\right) \cdot \log \left(-1 + \frac{1}{\frac{u}{1 + e^{\frac{\pi}{-s}}} + \frac{1 - u}{1 + e^{\frac{\pi}{s}}}}\right)
\end{array}
Initial program 98.6%
Simplified98.6%
Final simplification98.6%
(FPCore (u s) :precision binary32 (* s (- (log (+ -1.0 (/ (+ 1.0 (exp (/ PI (- s)))) u))))))
float code(float u, float s) {
return s * -logf((-1.0f + ((1.0f + expf((((float) M_PI) / -s))) / u)));
}
function code(u, s) return Float32(s * Float32(-log(Float32(Float32(-1.0) + Float32(Float32(Float32(1.0) + exp(Float32(Float32(pi) / Float32(-s)))) / u))))) end
function tmp = code(u, s) tmp = s * -log((single(-1.0) + ((single(1.0) + exp((single(pi) / -s))) / u))); end
\begin{array}{l}
\\
s \cdot \left(-\log \left(-1 + \frac{1 + e^{\frac{\pi}{-s}}}{u}\right)\right)
\end{array}
Initial program 98.6%
Simplified98.6%
Taylor expanded in s around inf 86.0%
Taylor expanded in s around 0 97.1%
mul-1-neg97.1%
distribute-frac-neg297.1%
Simplified97.1%
Final simplification97.1%
(FPCore (u s) :precision binary32 (- (* -4.0 (/ (* s (* u (- (* (/ PI s) 0.25) (* (/ PI s) -0.25)))) (+ -1.0 (/ PI s)))) (* s (log (+ 1.0 (/ PI s))))))
float code(float u, float s) {
return (-4.0f * ((s * (u * (((((float) M_PI) / s) * 0.25f) - ((((float) M_PI) / s) * -0.25f)))) / (-1.0f + (((float) M_PI) / s)))) - (s * logf((1.0f + (((float) M_PI) / s))));
}
function code(u, s) return Float32(Float32(Float32(-4.0) * Float32(Float32(s * Float32(u * Float32(Float32(Float32(Float32(pi) / s) * Float32(0.25)) - Float32(Float32(Float32(pi) / s) * Float32(-0.25))))) / Float32(Float32(-1.0) + Float32(Float32(pi) / s)))) - Float32(s * log(Float32(Float32(1.0) + Float32(Float32(pi) / s))))) end
function tmp = code(u, s) tmp = (single(-4.0) * ((s * (u * (((single(pi) / s) * single(0.25)) - ((single(pi) / s) * single(-0.25))))) / (single(-1.0) + (single(pi) / s)))) - (s * log((single(1.0) + (single(pi) / s)))); end
\begin{array}{l}
\\
-4 \cdot \frac{s \cdot \left(u \cdot \left(\frac{\pi}{s} \cdot 0.25 - \frac{\pi}{s} \cdot -0.25\right)\right)}{-1 + \frac{\pi}{s}} - s \cdot \log \left(1 + \frac{\pi}{s}\right)
\end{array}
Initial program 98.6%
Simplified98.6%
Taylor expanded in s around -inf 25.4%
Taylor expanded in u around 0 25.5%
add-sqr-sqrt25.5%
sqrt-unprod25.5%
sqr-neg25.5%
sqrt-unprod-0.0%
add-sqr-sqrt25.5%
distribute-frac-neg225.5%
Applied egg-rr25.5%
Final simplification25.5%
(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(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 98.6%
Simplified98.6%
Taylor expanded in s around -inf 25.4%
Taylor expanded in u around 0 25.5%
log1p-define25.5%
associate-*r*25.5%
neg-mul-125.5%
Simplified25.5%
Final simplification25.5%
(FPCore (u s) :precision binary32 (* u (- (* PI 2.0) (/ PI u))))
float code(float u, float s) {
return u * ((((float) M_PI) * 2.0f) - (((float) M_PI) / u));
}
function code(u, s) return Float32(u * Float32(Float32(Float32(pi) * Float32(2.0)) - Float32(Float32(pi) / u))) end
function tmp = code(u, s) tmp = u * ((single(pi) * single(2.0)) - (single(pi) / u)); end
\begin{array}{l}
\\
u \cdot \left(\pi \cdot 2 - \frac{\pi}{u}\right)
\end{array}
Initial program 98.6%
Simplified98.6%
Taylor expanded in s around inf 11.7%
associate--r+11.7%
cancel-sign-sub-inv11.7%
distribute-rgt-out--11.7%
*-commutative11.7%
metadata-eval11.7%
metadata-eval11.7%
*-commutative11.7%
Simplified11.7%
Taylor expanded in u around inf 11.7%
+-commutative11.7%
mul-1-neg11.7%
unsub-neg11.7%
*-commutative11.7%
Simplified11.7%
(FPCore (u s) :precision binary32 (- (* 2.0 (* u PI)) PI))
float code(float u, float s) {
return (2.0f * (u * ((float) M_PI))) - ((float) M_PI);
}
function code(u, s) return Float32(Float32(Float32(2.0) * Float32(u * Float32(pi))) - Float32(pi)) end
function tmp = code(u, s) tmp = (single(2.0) * (u * single(pi))) - single(pi); end
\begin{array}{l}
\\
2 \cdot \left(u \cdot \pi\right) - \pi
\end{array}
Initial program 98.6%
Simplified98.6%
Taylor expanded in s around inf 11.7%
associate--r+11.7%
cancel-sign-sub-inv11.7%
distribute-rgt-out--11.7%
*-commutative11.7%
metadata-eval11.7%
metadata-eval11.7%
*-commutative11.7%
Simplified11.7%
Taylor expanded in u around 0 11.7%
neg-mul-111.7%
+-commutative11.7%
unsub-neg11.7%
*-commutative11.7%
*-commutative11.7%
Simplified11.7%
Final simplification11.7%
(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 98.6%
Simplified98.6%
Taylor expanded in u around 0 11.5%
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 98.6%
Simplified98.6%
Taylor expanded in u around 0 11.6%
neg-mul-111.6%
Simplified11.6%
herbie shell --seed 2024132
(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))))