
(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
(let* ((t_0
(+
(/ (- 1.0 u) (+ 1.0 (exp (/ PI s))))
(/ u (+ 1.0 (exp (- 0.0 (/ PI s))))))))
(*
s
(log (/ (+ (pow t_0 -2.0) (+ 1.0 (/ 1.0 t_0))) (+ -1.0 (pow t_0 -3.0)))))))
float code(float u, float s) {
float t_0 = ((1.0f - u) / (1.0f + expf((((float) M_PI) / s)))) + (u / (1.0f + expf((0.0f - (((float) M_PI) / s)))));
return s * logf(((powf(t_0, -2.0f) + (1.0f + (1.0f / t_0))) / (-1.0f + powf(t_0, -3.0f))));
}
function code(u, s) t_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)))))) return Float32(s * log(Float32(Float32((t_0 ^ Float32(-2.0)) + Float32(Float32(1.0) + Float32(Float32(1.0) / t_0))) / Float32(Float32(-1.0) + (t_0 ^ Float32(-3.0)))))) end
function tmp = code(u, s) t_0 = ((single(1.0) - u) / (single(1.0) + exp((single(pi) / s)))) + (u / (single(1.0) + exp((single(0.0) - (single(pi) / s))))); tmp = s * log((((t_0 ^ single(-2.0)) + (single(1.0) + (single(1.0) / t_0))) / (single(-1.0) + (t_0 ^ single(-3.0))))); end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \frac{1 - u}{1 + e^{\frac{\pi}{s}}} + \frac{u}{1 + e^{0 - \frac{\pi}{s}}}\\
s \cdot \log \left(\frac{{t\_0}^{-2} + \left(1 + \frac{1}{t\_0}\right)}{-1 + {t\_0}^{-3}}\right)
\end{array}
\end{array}
Initial program 99.0%
Simplified99.0%
Applied egg-rr99.0%
Final simplification99.0%
(FPCore (u s)
:precision binary32
(*
(- s)
(log
(+
(/
1.0
(+
(/ (- 1.0 u) (+ 1.0 (exp (/ PI s))))
(/ u (+ 1.0 (exp (- 0.0 (/ PI s)))))))
-1.0))))
float code(float u, float s) {
return -s * logf(((1.0f / (((1.0f - u) / (1.0f + expf((((float) M_PI) / s)))) + (u / (1.0f + expf((0.0f - (((float) M_PI) / s))))))) + -1.0f));
}
function code(u, s) return Float32(Float32(-s) * log(Float32(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))))))) + Float32(-1.0)))) end
function tmp = code(u, s) tmp = -s * log(((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))))))) + single(-1.0))); end
\begin{array}{l}
\\
\left(-s\right) \cdot \log \left(\frac{1}{\frac{1 - u}{1 + e^{\frac{\pi}{s}}} + \frac{u}{1 + e^{0 - \frac{\pi}{s}}}} + -1\right)
\end{array}
Initial program 99.0%
Simplified99.0%
+-commutativeN/A
flip-+N/A
/-lowering-/.f32N/A
Applied egg-rr98.9%
metadata-evalN/A
metadata-evalN/A
pow-prod-upN/A
inv-powN/A
inv-powN/A
Applied egg-rr99.0%
Final simplification99.0%
(FPCore (u s) :precision binary32 (* (- s) (log (/ (+ 1.0 (- (exp (- 0.0 (/ PI s))) u)) u))))
float code(float u, float s) {
return -s * logf(((1.0f + (expf((0.0f - (((float) M_PI) / s))) - u)) / u));
}
function code(u, s) return Float32(Float32(-s) * log(Float32(Float32(Float32(1.0) + Float32(exp(Float32(Float32(0.0) - Float32(Float32(pi) / s))) - u)) / u))) end
function tmp = code(u, s) tmp = -s * log(((single(1.0) + (exp((single(0.0) - (single(pi) / s))) - u)) / u)); end
\begin{array}{l}
\\
\left(-s\right) \cdot \log \left(\frac{1 + \left(e^{0 - \frac{\pi}{s}} - u\right)}{u}\right)
\end{array}
Initial program 99.0%
Simplified99.0%
Taylor expanded in s around -inf
+-lowering-+.f32N/A
associate-*r/N/A
/-lowering-/.f32N/A
Simplified94.0%
Applied egg-rr94.0%
Taylor expanded in s around 0
/-lowering-/.f32N/A
+-lowering-+.f32N/A
neg-mul-1N/A
exp-lowering-exp.f32N/A
neg-sub0N/A
--lowering--.f32N/A
/-lowering-/.f32N/A
PI-lowering-PI.f3297.6%
Simplified97.6%
Taylor expanded in u around 0
/-lowering-/.f32N/A
+-lowering-+.f32N/A
+-lowering-+.f32N/A
neg-mul-1N/A
exp-lowering-exp.f32N/A
neg-mul-1N/A
distribute-neg-frac2N/A
mul-1-negN/A
/-lowering-/.f32N/A
PI-lowering-PI.f32N/A
mul-1-negN/A
neg-lowering-neg.f32N/A
mul-1-negN/A
neg-lowering-neg.f3297.6%
Simplified97.6%
Final simplification97.6%
(FPCore (u s) :precision binary32 (* (- s) (log (+ -1.0 (/ (+ 1.0 (exp (- 0.0 (/ PI s)))) u)))))
float code(float u, float s) {
return -s * logf((-1.0f + ((1.0f + expf((0.0f - (((float) M_PI) / s)))) / u)));
}
function code(u, s) return Float32(Float32(-s) * log(Float32(Float32(-1.0) + Float32(Float32(Float32(1.0) + exp(Float32(Float32(0.0) - Float32(Float32(pi) / s)))) / u)))) end
function tmp = code(u, s) tmp = -s * log((single(-1.0) + ((single(1.0) + exp((single(0.0) - (single(pi) / s)))) / u))); end
\begin{array}{l}
\\
\left(-s\right) \cdot \log \left(-1 + \frac{1 + e^{0 - \frac{\pi}{s}}}{u}\right)
\end{array}
Initial program 99.0%
Simplified99.0%
Taylor expanded in s around -inf
+-lowering-+.f32N/A
associate-*r/N/A
/-lowering-/.f32N/A
Simplified94.0%
Applied egg-rr94.0%
Taylor expanded in s around 0
/-lowering-/.f32N/A
+-lowering-+.f32N/A
neg-mul-1N/A
exp-lowering-exp.f32N/A
neg-sub0N/A
--lowering--.f32N/A
/-lowering-/.f32N/A
PI-lowering-PI.f3297.6%
Simplified97.6%
--lowering--.f32N/A
/-lowering-/.f32N/A
+-lowering-+.f32N/A
exp-lowering-exp.f32N/A
sub0-negN/A
distribute-frac-neg2N/A
/-lowering-/.f32N/A
PI-lowering-PI.f32N/A
neg-lowering-neg.f3297.6%
Applied egg-rr97.6%
Final simplification97.6%
(FPCore (u s) :precision binary32 (* (- s) (log (/ (+ 1.0 (exp (- 0.0 (/ PI s)))) u))))
float code(float u, float s) {
return -s * logf(((1.0f + expf((0.0f - (((float) M_PI) / s)))) / u));
}
function code(u, s) return Float32(Float32(-s) * log(Float32(Float32(Float32(1.0) + exp(Float32(Float32(0.0) - Float32(Float32(pi) / s)))) / u))) end
function tmp = code(u, s) tmp = -s * log(((single(1.0) + exp((single(0.0) - (single(pi) / s)))) / u)); end
\begin{array}{l}
\\
\left(-s\right) \cdot \log \left(\frac{1 + e^{0 - \frac{\pi}{s}}}{u}\right)
\end{array}
Initial program 99.0%
Simplified99.0%
Taylor expanded in s around -inf
+-lowering-+.f32N/A
associate-*r/N/A
/-lowering-/.f32N/A
Simplified94.0%
Applied egg-rr94.0%
Taylor expanded in s around 0
/-lowering-/.f32N/A
+-lowering-+.f32N/A
neg-mul-1N/A
exp-lowering-exp.f32N/A
neg-sub0N/A
--lowering--.f32N/A
/-lowering-/.f32N/A
PI-lowering-PI.f3297.6%
Simplified97.6%
Taylor expanded in u around 0
/-lowering-/.f32N/A
+-lowering-+.f32N/A
neg-mul-1N/A
exp-lowering-exp.f32N/A
neg-mul-1N/A
distribute-neg-frac2N/A
mul-1-negN/A
/-lowering-/.f32N/A
PI-lowering-PI.f32N/A
mul-1-negN/A
neg-lowering-neg.f3277.2%
Simplified77.2%
Final simplification77.2%
(FPCore (u s) :precision binary32 (* (- s) (log (+ -1.0 (/ 2.0 u)))))
float code(float u, float s) {
return -s * logf((-1.0f + (2.0f / u)));
}
real(4) function code(u, s)
real(4), intent (in) :: u
real(4), intent (in) :: s
code = -s * log(((-1.0e0) + (2.0e0 / u)))
end function
function code(u, s) return Float32(Float32(-s) * log(Float32(Float32(-1.0) + Float32(Float32(2.0) / u)))) end
function tmp = code(u, s) tmp = -s * log((single(-1.0) + (single(2.0) / u))); end
\begin{array}{l}
\\
\left(-s\right) \cdot \log \left(-1 + \frac{2}{u}\right)
\end{array}
Initial program 99.0%
Simplified99.0%
Taylor expanded in s around -inf
+-lowering-+.f32N/A
associate-*r/N/A
/-lowering-/.f32N/A
Simplified94.0%
Applied egg-rr94.0%
Taylor expanded in s around 0
/-lowering-/.f32N/A
+-lowering-+.f32N/A
neg-mul-1N/A
exp-lowering-exp.f32N/A
neg-sub0N/A
--lowering--.f32N/A
/-lowering-/.f32N/A
PI-lowering-PI.f3297.6%
Simplified97.6%
Taylor expanded in s around inf
/-lowering-/.f3237.3%
Simplified37.3%
Final simplification37.3%
(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 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
Simplified25.2%
Taylor expanded in u around 0
log1p-defineN/A
log1p-lowering-log1p.f32N/A
/-lowering-/.f32N/A
PI-lowering-PI.f3225.5%
Simplified25.5%
(FPCore (u s) :precision binary32 (* (- s) (log (/ PI s))))
float code(float u, float s) {
return -s * logf((((float) M_PI) / s));
}
function code(u, s) return Float32(Float32(-s) * log(Float32(Float32(pi) / s))) end
function tmp = code(u, s) tmp = -s * log((single(pi) / s)); end
\begin{array}{l}
\\
\left(-s\right) \cdot \log \left(\frac{\pi}{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
Simplified25.2%
Taylor expanded in s around 0
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
sub-negN/A
metadata-evalN/A
+-lowering-+.f32N/A
*-lowering-*.f3225.2%
Simplified25.2%
Taylor expanded in u around 0
associate-*r*N/A
*-lowering-*.f32N/A
mul-1-negN/A
neg-lowering-neg.f32N/A
log-lowering-log.f32N/A
/-lowering-/.f32N/A
PI-lowering-PI.f3225.4%
Simplified25.4%
(FPCore (u s) :precision binary32 (* 4.0 (+ (* (* u PI) 0.5) (* PI -0.25))))
float code(float u, float s) {
return 4.0f * (((u * ((float) M_PI)) * 0.5f) + (((float) M_PI) * -0.25f));
}
function code(u, s) return Float32(Float32(4.0) * Float32(Float32(Float32(u * Float32(pi)) * Float32(0.5)) + Float32(Float32(pi) * Float32(-0.25)))) end
function tmp = code(u, s) tmp = single(4.0) * (((u * single(pi)) * single(0.5)) + (single(pi) * single(-0.25))); end
\begin{array}{l}
\\
4 \cdot \left(\left(u \cdot \pi\right) \cdot 0.5 + \pi \cdot -0.25\right)
\end{array}
Initial program 99.0%
Simplified99.0%
Taylor expanded in s around inf
*-lowering-*.f32N/A
associate--r+N/A
cancel-sign-sub-invN/A
metadata-evalN/A
+-lowering-+.f32N/A
distribute-rgt-out--N/A
metadata-evalN/A
*-lowering-*.f32N/A
*-commutativeN/A
*-lowering-*.f32N/A
PI-lowering-PI.f32N/A
*-commutativeN/A
*-lowering-*.f32N/A
PI-lowering-PI.f3211.5%
Simplified11.5%
Final simplification11.5%
(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 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
/-lowering-/.f32N/A
metadata-evalN/A
--lowering--.f32N/A
*-lowering-*.f32N/A
+-lowering-+.f3213.9%
Applied egg-rr13.9%
Final simplification13.9%
(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 99.0%
Simplified99.0%
Taylor expanded in u around 0
/-lowering-/.f32N/A
PI-lowering-PI.f3211.3%
Simplified11.3%
associate-*r/N/A
clear-numN/A
/-lowering-/.f32N/A
/-lowering-/.f32N/A
*-lowering-*.f32N/A
neg-lowering-neg.f32N/A
PI-lowering-PI.f3211.3%
Applied egg-rr11.3%
Final simplification11.3%
(FPCore (u s) :precision binary32 (/ s (- 0.0 (/ s PI))))
float code(float u, float s) {
return s / (0.0f - (s / ((float) M_PI)));
}
function code(u, s) return Float32(s / Float32(Float32(0.0) - Float32(s / Float32(pi)))) end
function tmp = code(u, s) tmp = s / (single(0.0) - (s / single(pi))); end
\begin{array}{l}
\\
\frac{s}{0 - \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 (/ (* (- s) PI) s))
float code(float u, float s) {
return (-s * ((float) M_PI)) / s;
}
function code(u, s) return Float32(Float32(Float32(-s) * Float32(pi)) / s) end
function tmp = code(u, s) tmp = (-s * single(pi)) / s; end
\begin{array}{l}
\\
\frac{\left(-s\right) \cdot \pi}{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%
associate-*r/N/A
/-lowering-/.f32N/A
*-lowering-*.f32N/A
neg-lowering-neg.f32N/A
PI-lowering-PI.f3211.3%
Applied egg-rr11.3%
(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%
(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 99.0%
Simplified99.0%
Taylor expanded in s around inf
Simplified10.3%
metadata-evalN/A
mul0-rgt10.3%
Applied egg-rr10.3%
herbie shell --seed 2024141
(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))))