
(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
(let* ((t_0 (exp (/ PI s)))
(t_1 (+ (/ u (+ 1.0 (/ 1.0 t_0))) (/ (- 1.0 u) (+ 1.0 t_0)))))
(* s (log (/ (+ 1.0 (/ 1.0 t_1)) (+ (pow t_1 -2.0) -1.0))))))
float code(float u, float s) {
float t_0 = expf((((float) M_PI) / s));
float t_1 = (u / (1.0f + (1.0f / t_0))) + ((1.0f - u) / (1.0f + t_0));
return s * logf(((1.0f + (1.0f / t_1)) / (powf(t_1, -2.0f) + -1.0f)));
}
function code(u, s) t_0 = exp(Float32(Float32(pi) / s)) t_1 = Float32(Float32(u / Float32(Float32(1.0) + Float32(Float32(1.0) / t_0))) + Float32(Float32(Float32(1.0) - u) / Float32(Float32(1.0) + t_0))) return Float32(s * log(Float32(Float32(Float32(1.0) + Float32(Float32(1.0) / t_1)) / Float32((t_1 ^ Float32(-2.0)) + Float32(-1.0))))) end
function tmp = code(u, s) t_0 = exp((single(pi) / s)); t_1 = (u / (single(1.0) + (single(1.0) / t_0))) + ((single(1.0) - u) / (single(1.0) + t_0)); tmp = s * log(((single(1.0) + (single(1.0) / t_1)) / ((t_1 ^ single(-2.0)) + single(-1.0)))); end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := e^{\frac{\pi}{s}}\\
t_1 := \frac{u}{1 + \frac{1}{t\_0}} + \frac{1 - u}{1 + t\_0}\\
s \cdot \log \left(\frac{1 + \frac{1}{t\_1}}{{t\_1}^{-2} + -1}\right)
\end{array}
\end{array}
Initial program 99.0%
Simplified99.0%
flip-+N/A
clear-numN/A
log-recN/A
Applied egg-rr99.0%
Final simplification99.0%
(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(pi) / Float32(-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 99.0%
Simplified99.0%
Final simplification99.0%
(FPCore (u s)
:precision binary32
(*
(- s)
(log
(+
-1.0
(/
(/ 1.0 u)
(+
(/ 1.0 (+ 1.0 (exp (/ PI (- s)))))
(/ 1.0 (- -1.0 (exp (/ PI s))))))))))
float code(float u, float s) {
return -s * logf((-1.0f + ((1.0f / u) / ((1.0f / (1.0f + expf((((float) M_PI) / -s)))) + (1.0f / (-1.0f - expf((((float) M_PI) / s))))))));
}
function code(u, s) return Float32(Float32(-s) * log(Float32(Float32(-1.0) + Float32(Float32(Float32(1.0) / u) / Float32(Float32(Float32(1.0) / Float32(Float32(1.0) + exp(Float32(Float32(pi) / Float32(-s))))) + Float32(Float32(1.0) / 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) / (single(1.0) + exp((single(pi) / -s)))) + (single(1.0) / (single(-1.0) - exp((single(pi) / s)))))))); end
\begin{array}{l}
\\
\left(-s\right) \cdot \log \left(-1 + \frac{\frac{1}{u}}{\frac{1}{1 + e^{\frac{\pi}{-s}}} + \frac{1}{-1 - e^{\frac{\pi}{s}}}}\right)
\end{array}
Initial program 99.0%
Simplified99.0%
+-commutativeN/A
flip-+N/A
/-lowering-/.f32N/A
Applied egg-rr99.0%
Taylor expanded in u around inf
sub-negN/A
metadata-evalN/A
+-lowering-+.f32N/A
Simplified98.0%
Final simplification98.0%
(FPCore (u s)
:precision binary32
(*
(- s)
(log
(+
1.0
(/ (* (- (* (* u PI) -0.25) (+ (* (* u PI) 0.25) (* PI -0.25))) 4.0) s)))))
float code(float u, float s) {
return -s * logf((1.0f + (((((u * ((float) M_PI)) * -0.25f) - (((u * ((float) M_PI)) * 0.25f) + (((float) M_PI) * -0.25f))) * 4.0f) / s)));
}
function code(u, s) return Float32(Float32(-s) * log(Float32(Float32(1.0) + Float32(Float32(Float32(Float32(Float32(u * Float32(pi)) * Float32(-0.25)) - Float32(Float32(Float32(u * Float32(pi)) * Float32(0.25)) + Float32(Float32(pi) * Float32(-0.25)))) * Float32(4.0)) / s)))) end
function tmp = code(u, s) tmp = -s * log((single(1.0) + (((((u * single(pi)) * single(-0.25)) - (((u * single(pi)) * single(0.25)) + (single(pi) * single(-0.25)))) * single(4.0)) / s))); end
\begin{array}{l}
\\
\left(-s\right) \cdot \log \left(1 + \frac{\left(\left(u \cdot \pi\right) \cdot -0.25 - \left(\left(u \cdot \pi\right) \cdot 0.25 + \pi \cdot -0.25\right)\right) \cdot 4}{s}\right)
\end{array}
Initial program 99.0%
Simplified99.0%
+-commutativeN/A
flip-+N/A
/-lowering-/.f32N/A
Applied egg-rr99.0%
Taylor expanded in s around -inf
associate--l+N/A
associate-*r/N/A
associate-*r/N/A
div-subN/A
+-lowering-+.f32N/A
Simplified24.7%
Final simplification24.7%
(FPCore (u s) :precision binary32 (if (<= s 1.5000000170217692e-19) (/ (* -0.5 (* 0.0 (* u u))) s) (* (- s) (log1p (- (/ PI s) (/ (* -0.5 (* PI PI)) (* s s)))))))
float code(float u, float s) {
float tmp;
if (s <= 1.5000000170217692e-19f) {
tmp = (-0.5f * (0.0f * (u * u))) / s;
} else {
tmp = -s * log1pf(((((float) M_PI) / s) - ((-0.5f * (((float) M_PI) * ((float) M_PI))) / (s * s))));
}
return tmp;
}
function code(u, s) tmp = Float32(0.0) if (s <= Float32(1.5000000170217692e-19)) tmp = Float32(Float32(Float32(-0.5) * Float32(Float32(0.0) * Float32(u * u))) / s); else tmp = Float32(Float32(-s) * log1p(Float32(Float32(Float32(pi) / s) - Float32(Float32(Float32(-0.5) * Float32(Float32(pi) * Float32(pi))) / Float32(s * s))))); end return tmp end
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;s \leq 1.5000000170217692 \cdot 10^{-19}:\\
\;\;\;\;\frac{-0.5 \cdot \left(0 \cdot \left(u \cdot u\right)\right)}{s}\\
\mathbf{else}:\\
\;\;\;\;\left(-s\right) \cdot \mathsf{log1p}\left(\frac{\pi}{s} - \frac{-0.5 \cdot \left(\pi \cdot \pi\right)}{s \cdot s}\right)\\
\end{array}
\end{array}
if s < 1.50000002e-19Initial program 98.9%
Simplified98.9%
Taylor expanded in s around inf
Simplified7.7%
Taylor expanded in u around -inf
*-lowering-*.f32N/A
unpow2N/A
*-lowering-*.f32N/A
+-commutativeN/A
+-lowering-+.f32N/A
*-lowering-*.f32N/A
unpow2N/A
*-lowering-*.f32N/A
PI-lowering-PI.f32N/A
PI-lowering-PI.f32N/A
mul-1-negN/A
neg-lowering-neg.f32N/A
/-lowering-/.f32N/A
Simplified5.1%
Taylor expanded in u around inf
associate-*r/N/A
/-lowering-/.f32N/A
*-lowering-*.f32N/A
distribute-rgt-outN/A
metadata-evalN/A
mul0-rgtN/A
*-lowering-*.f32N/A
unpow2N/A
*-lowering-*.f3213.5%
Simplified13.5%
if 1.50000002e-19 < s Initial program 99.1%
Simplified99.1%
Taylor expanded in s around inf
Simplified25.6%
Taylor expanded in u around 0
associate--l+N/A
log1p-defineN/A
log1p-lowering-log1p.f32N/A
--lowering--.f32N/A
/-lowering-/.f32N/A
PI-lowering-PI.f32N/A
associate-*r/N/A
/-lowering-/.f32N/A
*-commutativeN/A
*-lowering-*.f32N/A
unpow2N/A
*-lowering-*.f32N/A
PI-lowering-PI.f32N/A
PI-lowering-PI.f32N/A
unpow2N/A
*-lowering-*.f3225.6%
Simplified25.6%
Final simplification19.2%
(FPCore (u s) :precision binary32 (- (* s (log (+ 1.0 (/ (* -4.0 (+ (* PI -0.25) (* (* u PI) 0.5))) s))))))
float code(float u, float s) {
return -(s * logf((1.0f + ((-4.0f * ((((float) M_PI) * -0.25f) + ((u * ((float) M_PI)) * 0.5f))) / s))));
}
function code(u, s) return Float32(-Float32(s * log(Float32(Float32(1.0) + Float32(Float32(Float32(-4.0) * Float32(Float32(Float32(pi) * Float32(-0.25)) + Float32(Float32(u * Float32(pi)) * Float32(0.5)))) / s))))) end
function tmp = code(u, s) tmp = -(s * log((single(1.0) + ((single(-4.0) * ((single(pi) * single(-0.25)) + ((u * single(pi)) * single(0.5)))) / s)))); end
\begin{array}{l}
\\
-s \cdot \log \left(1 + \frac{-4 \cdot \left(\pi \cdot -0.25 + \left(u \cdot \pi\right) \cdot 0.5\right)}{s}\right)
\end{array}
Initial program 99.0%
Simplified99.0%
Taylor expanded in s around inf
Simplified14.0%
Taylor expanded in s around inf
+-lowering-+.f32N/A
associate-*r/N/A
/-lowering-/.f32N/A
*-lowering-*.f32N/A
+-lowering-+.f32N/A
*-commutativeN/A
*-lowering-*.f32N/A
PI-lowering-PI.f32N/A
*-commutativeN/A
*-lowering-*.f32N/A
*-commutativeN/A
*-lowering-*.f32N/A
PI-lowering-PI.f3224.7%
Simplified24.7%
Final simplification24.7%
(FPCore (u s) :precision binary32 (* (- s) (log (+ 1.0 (* (+ (* PI -0.25) (* (* u PI) 0.5)) (/ -4.0 s))))))
float code(float u, float s) {
return -s * logf((1.0f + (((((float) M_PI) * -0.25f) + ((u * ((float) M_PI)) * 0.5f)) * (-4.0f / s))));
}
function code(u, s) return Float32(Float32(-s) * log(Float32(Float32(1.0) + Float32(Float32(Float32(Float32(pi) * Float32(-0.25)) + Float32(Float32(u * Float32(pi)) * Float32(0.5))) * Float32(Float32(-4.0) / s))))) end
function tmp = code(u, s) tmp = -s * log((single(1.0) + (((single(pi) * single(-0.25)) + ((u * single(pi)) * single(0.5))) * (single(-4.0) / s)))); end
\begin{array}{l}
\\
\left(-s\right) \cdot \log \left(1 + \left(\pi \cdot -0.25 + \left(u \cdot \pi\right) \cdot 0.5\right) \cdot \frac{-4}{s}\right)
\end{array}
Initial program 99.0%
Simplified99.0%
Taylor expanded in s around inf
+-lowering-+.f32N/A
associate-*r/N/A
*-commutativeN/A
associate-/l*N/A
*-lowering-*.f32N/A
Simplified24.7%
Final simplification24.7%
(FPCore (u s)
:precision binary32
(let* ((t_0 (+ (* PI -0.25) (* (* u PI) 0.5))))
(*
(/
(+
(* -4.0 t_0)
(/ (* 0.5 (+ (* t_0 (* t_0 -16.0)) (* (* t_0 t_0) 16.0))) s))
s)
(/ (* s (- s)) s))))
float code(float u, float s) {
float t_0 = (((float) M_PI) * -0.25f) + ((u * ((float) M_PI)) * 0.5f);
return (((-4.0f * t_0) + ((0.5f * ((t_0 * (t_0 * -16.0f)) + ((t_0 * t_0) * 16.0f))) / s)) / s) * ((s * -s) / s);
}
function code(u, s) t_0 = Float32(Float32(Float32(pi) * Float32(-0.25)) + Float32(Float32(u * Float32(pi)) * Float32(0.5))) return Float32(Float32(Float32(Float32(Float32(-4.0) * t_0) + Float32(Float32(Float32(0.5) * Float32(Float32(t_0 * Float32(t_0 * Float32(-16.0))) + Float32(Float32(t_0 * t_0) * Float32(16.0)))) / s)) / s) * Float32(Float32(s * Float32(-s)) / s)) end
function tmp = code(u, s) t_0 = (single(pi) * single(-0.25)) + ((u * single(pi)) * single(0.5)); tmp = (((single(-4.0) * t_0) + ((single(0.5) * ((t_0 * (t_0 * single(-16.0))) + ((t_0 * t_0) * single(16.0)))) / s)) / s) * ((s * -s) / s); end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \pi \cdot -0.25 + \left(u \cdot \pi\right) \cdot 0.5\\
\frac{-4 \cdot t\_0 + \frac{0.5 \cdot \left(t\_0 \cdot \left(t\_0 \cdot -16\right) + \left(t\_0 \cdot t\_0\right) \cdot 16\right)}{s}}{s} \cdot \frac{s \cdot \left(-s\right)}{s}
\end{array}
\end{array}
Initial program 99.0%
Simplified99.0%
Taylor expanded in s around inf
Simplified11.6%
neg-sub0N/A
flip--N/A
metadata-evalN/A
neg-sub0N/A
/-lowering-/.f32N/A
neg-lowering-neg.f32N/A
*-lowering-*.f32N/A
+-lowering-+.f3214.6%
Applied egg-rr14.6%
Final simplification14.6%
(FPCore (u s) :precision binary32 (* (/ PI s) (/ (* s (- s)) s)))
float code(float u, float s) {
return (((float) M_PI) / s) * ((s * -s) / s);
}
function code(u, s) return Float32(Float32(Float32(pi) / s) * Float32(Float32(s * Float32(-s)) / s)) end
function tmp = code(u, s) tmp = (single(pi) / s) * ((s * -s) / s); end
\begin{array}{l}
\\
\frac{\pi}{s} \cdot \frac{s \cdot \left(-s\right)}{s}
\end{array}
Initial program 99.0%
Simplified99.0%
Taylor expanded in u around 0
/-lowering-/.f32N/A
PI-lowering-PI.f3211.3%
Simplified11.3%
neg-sub0N/A
flip--N/A
metadata-evalN/A
neg-sub0N/A
/-lowering-/.f32N/A
distribute-rgt-neg-inN/A
*-lowering-*.f32N/A
neg-lowering-neg.f32N/A
+-lowering-+.f3214.3%
Applied egg-rr14.3%
Final simplification14.3%
(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 99.0%
Simplified99.0%
Taylor expanded in s around inf
Simplified11.6%
Taylor expanded in u around inf
Simplified11.4%
Taylor expanded in u around inf
metadata-evalN/A
cancel-sign-sub-invN/A
*-lowering-*.f32N/A
cancel-sign-sub-invN/A
metadata-evalN/A
+-commutativeN/A
mul-1-negN/A
unsub-negN/A
--lowering--.f32N/A
*-commutativeN/A
*-lowering-*.f32N/A
PI-lowering-PI.f32N/A
/-lowering-/.f32N/A
PI-lowering-PI.f3211.6%
Simplified11.6%
(FPCore (u s) :precision binary32 (- (* (* u PI) 2.0) PI))
float code(float u, float s) {
return ((u * ((float) M_PI)) * 2.0f) - ((float) M_PI);
}
function code(u, s) return Float32(Float32(Float32(u * Float32(pi)) * Float32(2.0)) - Float32(pi)) end
function tmp = code(u, s) tmp = ((u * single(pi)) * single(2.0)) - single(pi); end
\begin{array}{l}
\\
\left(u \cdot \pi\right) \cdot 2 - \pi
\end{array}
Initial program 99.0%
Simplified99.0%
Taylor expanded in s around inf
Simplified11.6%
Taylor expanded in u around inf
Simplified11.4%
Taylor expanded in u around 0
+-commutativeN/A
mul-1-negN/A
sub-negN/A
--lowering--.f32N/A
*-commutativeN/A
*-lowering-*.f32N/A
*-commutativeN/A
*-lowering-*.f32N/A
PI-lowering-PI.f32N/A
PI-lowering-PI.f3211.6%
Simplified11.6%
Final simplification11.6%
(FPCore (u s) :precision binary32 (/ s (/ s (- PI))))
float code(float u, float s) {
return s / (s / -((float) M_PI));
}
function code(u, s) return Float32(s / Float32(s / Float32(-Float32(pi)))) end
function tmp = code(u, s) tmp = s / (s / -single(pi)); end
\begin{array}{l}
\\
\frac{s}{\frac{s}{-\pi}}
\end{array}
Initial program 99.0%
Simplified99.0%
Taylor expanded in u around 0
/-lowering-/.f32N/A
PI-lowering-PI.f3211.3%
Simplified11.3%
clear-numN/A
un-div-invN/A
/-lowering-/.f32N/A
neg-lowering-neg.f32N/A
/-lowering-/.f32N/A
PI-lowering-PI.f3211.3%
Applied egg-rr11.3%
Final simplification11.3%
(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
mul-1-negN/A
neg-lowering-neg.f32N/A
PI-lowering-PI.f3211.3%
Simplified11.3%
herbie shell --seed 2024155
(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))))