
(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
(let* ((t_0 (exp (/ PI s))))
(*
(- s)
(log
(/
(-
1.0
(pow (+ (/ u (+ 1.0 (/ 1.0 t_0))) (/ (- 1.0 u) (+ 1.0 t_0))) -2.0))
(+
-1.0
(/ 1.0 (+ (/ u (+ -1.0 (/ -1.0 t_0))) (/ (- 1.0 u) (- -1.0 t_0))))))))))
float code(float u, float s) {
float t_0 = expf((((float) M_PI) / s));
return -s * logf(((1.0f - powf(((u / (1.0f + (1.0f / t_0))) + ((1.0f - u) / (1.0f + t_0))), -2.0f)) / (-1.0f + (1.0f / ((u / (-1.0f + (-1.0f / t_0))) + ((1.0f - u) / (-1.0f - t_0)))))));
}
function code(u, s) t_0 = exp(Float32(Float32(pi) / s)) return Float32(Float32(-s) * log(Float32(Float32(Float32(1.0) - (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))) ^ Float32(-2.0))) / Float32(Float32(-1.0) + Float32(Float32(1.0) / 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)))))))) end
function tmp = code(u, s) t_0 = exp((single(pi) / s)); tmp = -s * log(((single(1.0) - (((u / (single(1.0) + (single(1.0) / t_0))) + ((single(1.0) - u) / (single(1.0) + t_0))) ^ single(-2.0))) / (single(-1.0) + (single(1.0) / ((u / (single(-1.0) + (single(-1.0) / t_0))) + ((single(1.0) - u) / (single(-1.0) - t_0))))))); end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := e^{\frac{\pi}{s}}\\
\left(-s\right) \cdot \log \left(\frac{1 - {\left(\frac{u}{1 + \frac{1}{t\_0}} + \frac{1 - u}{1 + t\_0}\right)}^{-2}}{-1 + \frac{1}{\frac{u}{-1 + \frac{-1}{t\_0}} + \frac{1 - u}{-1 - t\_0}}}\right)
\end{array}
\end{array}
Initial program 98.7%
Simplified98.7%
+-commutativeN/A
flip-+N/A
/-lowering-/.f32N/A
Applied egg-rr98.9%
Final simplification98.9%
(FPCore (u s)
:precision binary32
(let* ((t_0 (exp (/ PI s))))
(*
(- s)
(log
(+
-1.0
(pow
(pow (+ (/ u (+ 1.0 (/ 1.0 t_0))) (/ (- 1.0 u) (+ 1.0 t_0))) 2.0)
-0.5))))))
float code(float u, float s) {
float t_0 = expf((((float) M_PI) / s));
return -s * logf((-1.0f + powf(powf(((u / (1.0f + (1.0f / t_0))) + ((1.0f - u) / (1.0f + t_0))), 2.0f), -0.5f)));
}
function code(u, s) t_0 = exp(Float32(Float32(pi) / s)) return Float32(Float32(-s) * log(Float32(Float32(-1.0) + ((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))) ^ Float32(2.0)) ^ Float32(-0.5))))) end
function tmp = code(u, s) t_0 = exp((single(pi) / s)); tmp = -s * log((single(-1.0) + ((((u / (single(1.0) + (single(1.0) / t_0))) + ((single(1.0) - u) / (single(1.0) + t_0))) ^ single(2.0)) ^ single(-0.5)))); end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := e^{\frac{\pi}{s}}\\
\left(-s\right) \cdot \log \left(-1 + {\left({\left(\frac{u}{1 + \frac{1}{t\_0}} + \frac{1 - u}{1 + t\_0}\right)}^{2}\right)}^{-0.5}\right)
\end{array}
\end{array}
Initial program 98.7%
Simplified98.7%
inv-powN/A
sqr-powN/A
pow-prod-downN/A
pow-lowering-pow.f32N/A
Applied egg-rr98.8%
Final simplification98.8%
(FPCore (u s)
:precision binary32
(let* ((t_0 (exp (/ PI s))))
(*
(- s)
(log
(expm1
(- (log (+ (/ u (+ 1.0 (/ 1.0 t_0))) (/ (- 1.0 u) (+ 1.0 t_0))))))))))
float code(float u, float s) {
float t_0 = expf((((float) M_PI) / s));
return -s * logf(expm1f(-logf(((u / (1.0f + (1.0f / t_0))) + ((1.0f - u) / (1.0f + t_0))))));
}
function code(u, s) t_0 = exp(Float32(Float32(pi) / s)) return Float32(Float32(-s) * log(expm1(Float32(-log(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)))))))) end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := e^{\frac{\pi}{s}}\\
\left(-s\right) \cdot \log \left(\mathsf{expm1}\left(-\log \left(\frac{u}{1 + \frac{1}{t\_0}} + \frac{1 - u}{1 + t\_0}\right)\right)\right)
\end{array}
\end{array}
Initial program 98.7%
Simplified98.7%
div-invN/A
fma-defineN/A
metadata-evalN/A
fmm-defN/A
div-invN/A
inv-powN/A
pow-to-expN/A
Applied egg-rr98.8%
(FPCore (u s)
:precision binary32
(*
(- s)
(log
(+
-1.0
(/
1.0
(+
(/ u (+ 1.0 (exp (- 0.0 (/ PI s)))))
(/ (- 1.0 u) (+ 1.0 (exp (* (/ PI s) (* (/ PI s) (/ s PI))))))))))))
float code(float u, float s) {
return -s * logf((-1.0f + (1.0f / ((u / (1.0f + expf((0.0f - (((float) M_PI) / s))))) + ((1.0f - u) / (1.0f + expf(((((float) M_PI) / s) * ((((float) M_PI) / s) * (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(0.0) - Float32(Float32(pi) / s))))) + Float32(Float32(Float32(1.0) - u) / Float32(Float32(1.0) + exp(Float32(Float32(Float32(pi) / s) * Float32(Float32(Float32(pi) / s) * 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(0.0) - (single(pi) / s))))) + ((single(1.0) - u) / (single(1.0) + exp(((single(pi) / s) * ((single(pi) / s) * (s / single(pi))))))))))); end
\begin{array}{l}
\\
\left(-s\right) \cdot \log \left(-1 + \frac{1}{\frac{u}{1 + e^{0 - \frac{\pi}{s}}} + \frac{1 - u}{1 + e^{\frac{\pi}{s} \cdot \left(\frac{\pi}{s} \cdot \frac{s}{\pi}\right)}}}\right)
\end{array}
Initial program 98.7%
Simplified98.7%
+-lft-identityN/A
flip-+N/A
metadata-evalN/A
sub0-negN/A
+-lft-identityN/A
+-commutativeN/A
distribute-rgt-outN/A
+-lft-identityN/A
metadata-evalN/A
sub0-negN/A
frac-2negN/A
/-lowering-/.f32N/A
Applied egg-rr98.4%
div-invN/A
associate-/l*N/A
clear-numN/A
associate-*l*N/A
*-lowering-*.f32N/A
/-lowering-/.f32N/A
PI-lowering-PI.f32N/A
*-lowering-*.f32N/A
/-lowering-/.f32N/A
PI-lowering-PI.f32N/A
/-lowering-/.f32N/A
PI-lowering-PI.f3298.8%
Applied egg-rr98.8%
Final simplification98.8%
(FPCore (u s)
:precision binary32
(*
(- s)
(log
(+
-1.0
(/
1.0
(+
(/ (- 1.0 u) (+ 1.0 (exp (/ PI s))))
(/ u (+ 1.0 (exp (- 0.0 (/ 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((0.0f - (((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(0.0) - 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(0.0) - (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^{0 - \frac{\pi}{s}}}}\right)
\end{array}
Initial program 98.7%
Simplified98.7%
+-commutativeN/A
flip-+N/A
/-lowering-/.f32N/A
Applied egg-rr98.9%
Applied egg-rr98.8%
*-lowering-*.f32N/A
neg-lowering-neg.f32N/A
log-lowering-log.f32N/A
Applied egg-rr98.7%
Final simplification98.7%
(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(Float32(2.0) * Float32(u * Float32(pi))) / Float32(Float32(1.0) + Float32(Float32(pi) / s))) - Float32(s * log1p(Float32(Float32(pi) / s)))) end
\begin{array}{l}
\\
\frac{2 \cdot \left(u \cdot \pi\right)}{1 + \frac{\pi}{s}} - s \cdot \mathsf{log1p}\left(\frac{\pi}{s}\right)
\end{array}
Initial program 98.7%
Simplified98.7%
Taylor expanded in s around -inf
+-lowering-+.f32N/A
associate-*r/N/A
*-commutativeN/A
associate-/l*N/A
*-lowering-*.f32N/A
Simplified24.3%
Taylor expanded in u around 0
+-lowering-+.f32N/A
associate-*r*N/A
*-lowering-*.f32N/A
mul-1-negN/A
neg-lowering-neg.f32N/A
log1p-defineN/A
log1p-lowering-log1p.f32N/A
/-lowering-/.f32N/A
PI-lowering-PI.f32N/A
associate-*r/N/A
/-lowering-/.f32N/A
*-lowering-*.f32N/A
*-commutativeN/A
*-lowering-*.f32N/A
PI-lowering-PI.f32N/A
+-lowering-+.f32N/A
/-lowering-/.f32N/A
PI-lowering-PI.f3224.6%
Simplified24.6%
Final simplification24.6%
(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(Float32(-s) * 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}
\\
\left(-s\right) \cdot \log \left(1 + \frac{\pi}{s}\right)
\end{array}
Initial program 98.7%
Simplified98.7%
Taylor expanded in s around -inf
+-lowering-+.f32N/A
associate-*r/N/A
*-commutativeN/A
associate-/l*N/A
*-lowering-*.f32N/A
Simplified24.3%
Taylor expanded in u around 0
+-lowering-+.f32N/A
/-lowering-/.f32N/A
PI-lowering-PI.f3224.6%
Simplified24.6%
(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 98.7%
Simplified98.7%
Taylor expanded in s around -inf
+-lowering-+.f32N/A
associate-*r/N/A
*-commutativeN/A
associate-/l*N/A
*-lowering-*.f32N/A
Simplified24.3%
Taylor expanded in u around 0
associate-*r*N/A
*-lowering-*.f32N/A
mul-1-negN/A
neg-lowering-neg.f32N/A
log1p-defineN/A
log1p-lowering-log1p.f32N/A
/-lowering-/.f32N/A
PI-lowering-PI.f3224.6%
Simplified24.6%
(FPCore (u s) :precision binary32 (* (/ (* s s) (- s)) (/ (* 4.0 (+ (* (* u PI) -0.25) (* PI (+ 0.25 (* u -0.25))))) s)))
float code(float u, float s) {
return ((s * s) / -s) * ((4.0f * (((u * ((float) M_PI)) * -0.25f) + (((float) M_PI) * (0.25f + (u * -0.25f))))) / s);
}
function code(u, s) return Float32(Float32(Float32(s * s) / Float32(-s)) * Float32(Float32(Float32(4.0) * Float32(Float32(Float32(u * Float32(pi)) * Float32(-0.25)) + Float32(Float32(pi) * Float32(Float32(0.25) + Float32(u * Float32(-0.25)))))) / s)) end
function tmp = code(u, s) tmp = ((s * s) / -s) * ((single(4.0) * (((u * single(pi)) * single(-0.25)) + (single(pi) * (single(0.25) + (u * single(-0.25)))))) / s); end
\begin{array}{l}
\\
\frac{s \cdot s}{-s} \cdot \frac{4 \cdot \left(\left(u \cdot \pi\right) \cdot -0.25 + \pi \cdot \left(0.25 + u \cdot -0.25\right)\right)}{s}
\end{array}
Initial program 98.7%
Simplified98.7%
Taylor expanded in s around -inf
+-lowering-+.f32N/A
associate-*r/N/A
*-commutativeN/A
associate-/l*N/A
*-lowering-*.f32N/A
Simplified24.3%
neg-sub0N/A
flip--N/A
/-lowering-/.f32N/A
metadata-evalN/A
--lowering--.f32N/A
*-lowering-*.f32N/A
+-lowering-+.f3220.0%
Applied egg-rr20.0%
Taylor expanded in s around inf
associate-*r/N/A
/-lowering-/.f32N/A
*-lowering-*.f32N/A
+-lowering-+.f32N/A
*-lowering-*.f32N/A
*-lowering-*.f32N/A
PI-lowering-PI.f32N/A
*-lowering-*.f32N/A
PI-lowering-PI.f32N/A
+-lowering-+.f32N/A
*-commutativeN/A
*-lowering-*.f3213.9%
Simplified13.9%
Final simplification13.9%
(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 * s) / Float32(-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 s}{-s}
\end{array}
Initial program 98.7%
Simplified98.7%
Taylor expanded in u around 0
/-lowering-/.f32N/A
PI-lowering-PI.f3210.8%
Simplified10.8%
+-lft-identityN/A
flip-+N/A
metadata-evalN/A
sub0-negN/A
neg-sub0N/A
frac-2negN/A
distribute-frac-neg2N/A
/-lowering-/.f32N/A
*-lowering-*.f32N/A
neg-lowering-neg.f3213.5%
Applied egg-rr13.5%
Final simplification13.5%
(FPCore (u s) :precision binary32 (/ -1.0 (/ s (* s PI))))
float code(float u, float s) {
return -1.0f / (s / (s * ((float) M_PI)));
}
function code(u, s) return Float32(Float32(-1.0) / Float32(s / Float32(s * Float32(pi)))) end
function tmp = code(u, s) tmp = single(-1.0) / (s / (s * single(pi))); end
\begin{array}{l}
\\
\frac{-1}{\frac{s}{s \cdot \pi}}
\end{array}
Initial program 98.7%
Simplified98.7%
Taylor expanded in u around 0
/-lowering-/.f32N/A
PI-lowering-PI.f3210.8%
Simplified10.8%
associate-*r/N/A
clear-numN/A
/-lowering-/.f32N/A
/-lowering-/.f32N/A
*-lowering-*.f32N/A
neg-lowering-neg.f32N/A
PI-lowering-PI.f3210.9%
Applied egg-rr10.9%
Final simplification10.9%
(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(Float32(-s) / 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 98.7%
Simplified98.7%
Taylor expanded in u around 0
/-lowering-/.f32N/A
PI-lowering-PI.f3210.8%
Simplified10.8%
clear-numN/A
un-div-invN/A
/-lowering-/.f32N/A
neg-lowering-neg.f32N/A
/-lowering-/.f32N/A
PI-lowering-PI.f3210.9%
Applied egg-rr10.9%
Final simplification10.9%
(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 98.7%
Simplified98.7%
Taylor expanded in u around 0
mul-1-negN/A
neg-lowering-neg.f32N/A
PI-lowering-PI.f3210.9%
Simplified10.9%
(FPCore (u s) :precision binary32 0.0)
float code(float u, float s) {
return 0.0f;
}
real(4) function code(u, s)
real(4), intent (in) :: u
real(4), intent (in) :: s
code = 0.0e0
end function
function code(u, s) return Float32(0.0) end
function tmp = code(u, s) tmp = single(0.0); end
\begin{array}{l}
\\
0
\end{array}
Initial program 98.7%
Simplified98.7%
Taylor expanded in s around inf
Simplified10.5%
metadata-evalN/A
mul0-rgt10.5%
Applied egg-rr10.5%
herbie shell --seed 2024160
(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))))