
(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
(+
(/ (- 1.0 u) (+ (exp (/ PI s)) 1.0))
(/ u (+ (exp (- 0.0 (/ PI s))) 1.0)))))
(*
(- s)
(log (/ (+ -1.0 (pow t_0 -3.0)) (+ (pow t_0 -2.0) (+ (/ 1.0 t_0) 1.0)))))))
float code(float u, float s) {
float t_0 = ((1.0f - u) / (expf((((float) M_PI) / s)) + 1.0f)) + (u / (expf((0.0f - (((float) M_PI) / s))) + 1.0f));
return -s * logf(((-1.0f + powf(t_0, -3.0f)) / (powf(t_0, -2.0f) + ((1.0f / t_0) + 1.0f))));
}
function code(u, s) t_0 = Float32(Float32(Float32(Float32(1.0) - u) / Float32(exp(Float32(Float32(pi) / s)) + Float32(1.0))) + Float32(u / Float32(exp(Float32(Float32(0.0) - Float32(Float32(pi) / s))) + Float32(1.0)))) return Float32(Float32(-s) * log(Float32(Float32(Float32(-1.0) + (t_0 ^ Float32(-3.0))) / Float32((t_0 ^ Float32(-2.0)) + Float32(Float32(Float32(1.0) / t_0) + Float32(1.0)))))) end
function tmp = code(u, s) t_0 = ((single(1.0) - u) / (exp((single(pi) / s)) + single(1.0))) + (u / (exp((single(0.0) - (single(pi) / s))) + single(1.0))); tmp = -s * log(((single(-1.0) + (t_0 ^ single(-3.0))) / ((t_0 ^ single(-2.0)) + ((single(1.0) / t_0) + single(1.0))))); end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \frac{1 - u}{e^{\frac{\pi}{s}} + 1} + \frac{u}{e^{0 - \frac{\pi}{s}} + 1}\\
\left(-s\right) \cdot \log \left(\frac{-1 + {t\_0}^{-3}}{{t\_0}^{-2} + \left(\frac{1}{t\_0} + 1\right)}\right)
\end{array}
\end{array}
Initial program 99.0%
Simplified99.0%
sub0-negN/A
distribute-neg-fracN/A
/-lowering-/.f32N/A
neg-lowering-neg.f32N/A
PI-lowering-PI.f3299.0%
Applied egg-rr99.0%
Applied egg-rr99.1%
Final simplification99.1%
(FPCore (u s)
:precision binary32
(*
(- s)
(log
(+
-1.0
(/
1.0
(+
(/ (- 1.0 u) (+ (exp (/ PI s)) 1.0))
(/ u (+ (exp (- 0.0 (/ PI s))) 1.0))))))))
float code(float u, float s) {
return -s * logf((-1.0f + (1.0f / (((1.0f - u) / (expf((((float) M_PI) / s)) + 1.0f)) + (u / (expf((0.0f - (((float) M_PI) / s))) + 1.0f))))));
}
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(exp(Float32(Float32(pi) / s)) + Float32(1.0))) + Float32(u / Float32(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) / (((single(1.0) - u) / (exp((single(pi) / s)) + single(1.0))) + (u / (exp((single(0.0) - (single(pi) / s))) + single(1.0))))))); end
\begin{array}{l}
\\
\left(-s\right) \cdot \log \left(-1 + \frac{1}{\frac{1 - u}{e^{\frac{\pi}{s}} + 1} + \frac{u}{e^{0 - \frac{\pi}{s}} + 1}}\right)
\end{array}
Initial program 99.0%
Simplified99.0%
sub0-negN/A
distribute-neg-fracN/A
/-lowering-/.f32N/A
neg-lowering-neg.f32N/A
PI-lowering-PI.f3299.0%
Applied egg-rr99.0%
Final simplification99.0%
(FPCore (u s) :precision binary32 (* (- s) (log (+ (/ 1.0 u) (+ -1.0 (/ (exp (- 0.0 (/ PI s))) u))))))
float code(float u, float s) {
return -s * logf(((1.0f / u) + (-1.0f + (expf((0.0f - (((float) M_PI) / s))) / u))));
}
function code(u, s) return Float32(Float32(-s) * log(Float32(Float32(Float32(1.0) / u) + Float32(Float32(-1.0) + Float32(exp(Float32(Float32(0.0) - Float32(Float32(pi) / s))) / u))))) end
function tmp = code(u, s) tmp = -s * log(((single(1.0) / u) + (single(-1.0) + (exp((single(0.0) - (single(pi) / s))) / u)))); end
\begin{array}{l}
\\
\left(-s\right) \cdot \log \left(\frac{1}{u} + \left(-1 + \frac{e^{0 - \frac{\pi}{s}}}{u}\right)\right)
\end{array}
Initial program 99.0%
Simplified99.0%
Taylor expanded in s around -inf
mul-1-negN/A
unsub-negN/A
--lowering--.f32N/A
/-lowering-/.f32N/A
Simplified92.7%
Taylor expanded in s around 0
associate-*r*N/A
*-lowering-*.f32N/A
mul-1-negN/A
neg-lowering-neg.f32N/A
log-lowering-log.f32N/A
associate--l+N/A
+-lowering-+.f32N/A
/-lowering-/.f32N/A
sub-negN/A
metadata-evalN/A
+-lowering-+.f32N/A
Simplified97.0%
Final simplification97.0%
(FPCore (u s)
:precision binary32
(*
(- s)
(log
(+
-1.0
(/
1.0
(+
(/ u (+ 1.0 1.0))
(/
(- 1.0 u)
(+
(+
(/
(+
PI
(/
(+
(* 0.16666666666666666 (/ (* PI (* PI PI)) s))
(* (* PI PI) 0.5))
s))
s)
1.0)
1.0))))))))
float code(float u, float s) {
return -s * logf((-1.0f + (1.0f / ((u / (1.0f + 1.0f)) + ((1.0f - u) / ((((((float) M_PI) + (((0.16666666666666666f * ((((float) M_PI) * (((float) M_PI) * ((float) M_PI))) / s)) + ((((float) M_PI) * ((float) M_PI)) * 0.5f)) / s)) / s) + 1.0f) + 1.0f))))));
}
function code(u, s) return Float32(Float32(-s) * log(Float32(Float32(-1.0) + Float32(Float32(1.0) / Float32(Float32(u / Float32(Float32(1.0) + Float32(1.0))) + Float32(Float32(Float32(1.0) - u) / Float32(Float32(Float32(Float32(Float32(pi) + Float32(Float32(Float32(Float32(0.16666666666666666) * Float32(Float32(Float32(pi) * Float32(Float32(pi) * Float32(pi))) / s)) + Float32(Float32(Float32(pi) * Float32(pi)) * Float32(0.5))) / s)) / s) + Float32(1.0)) + Float32(1.0)))))))) end
function tmp = code(u, s) tmp = -s * log((single(-1.0) + (single(1.0) / ((u / (single(1.0) + single(1.0))) + ((single(1.0) - u) / ((((single(pi) + (((single(0.16666666666666666) * ((single(pi) * (single(pi) * single(pi))) / s)) + ((single(pi) * single(pi)) * single(0.5))) / s)) / s) + single(1.0)) + single(1.0))))))); end
\begin{array}{l}
\\
\left(-s\right) \cdot \log \left(-1 + \frac{1}{\frac{u}{1 + 1} + \frac{1 - u}{\left(\frac{\pi + \frac{0.16666666666666666 \cdot \frac{\pi \cdot \left(\pi \cdot \pi\right)}{s} + \left(\pi \cdot \pi\right) \cdot 0.5}{s}}{s} + 1\right) + 1}}\right)
\end{array}
Initial program 99.0%
Simplified99.0%
Taylor expanded in s around inf
Simplified38.2%
Taylor expanded in s around -inf
mul-1-negN/A
unsub-negN/A
--lowering--.f32N/A
/-lowering-/.f32N/A
Simplified37.4%
Final simplification37.4%
(FPCore (u s)
:precision binary32
(*
(- s)
(log
(+
-1.0
(/
1.0
(+
(/ u (+ 1.0 1.0))
(/ (- 1.0 u) (+ (+ (/ (- PI (/ (* (* PI PI) -0.5) s)) s) 1.0) 1.0))))))))
float code(float u, float s) {
return -s * logf((-1.0f + (1.0f / ((u / (1.0f + 1.0f)) + ((1.0f - u) / ((((((float) M_PI) - (((((float) M_PI) * ((float) M_PI)) * -0.5f) / s)) / s) + 1.0f) + 1.0f))))));
}
function code(u, s) return Float32(Float32(-s) * log(Float32(Float32(-1.0) + Float32(Float32(1.0) / Float32(Float32(u / Float32(Float32(1.0) + Float32(1.0))) + Float32(Float32(Float32(1.0) - u) / Float32(Float32(Float32(Float32(Float32(pi) - Float32(Float32(Float32(Float32(pi) * Float32(pi)) * Float32(-0.5)) / s)) / s) + Float32(1.0)) + Float32(1.0)))))))) end
function tmp = code(u, s) tmp = -s * log((single(-1.0) + (single(1.0) / ((u / (single(1.0) + single(1.0))) + ((single(1.0) - u) / ((((single(pi) - (((single(pi) * single(pi)) * single(-0.5)) / s)) / s) + single(1.0)) + single(1.0))))))); end
\begin{array}{l}
\\
\left(-s\right) \cdot \log \left(-1 + \frac{1}{\frac{u}{1 + 1} + \frac{1 - u}{\left(\frac{\pi - \frac{\left(\pi \cdot \pi\right) \cdot -0.5}{s}}{s} + 1\right) + 1}}\right)
\end{array}
Initial program 99.0%
Simplified99.0%
Taylor expanded in s around -inf
mul-1-negN/A
unsub-negN/A
--lowering--.f32N/A
/-lowering-/.f32N/A
Simplified92.7%
Taylor expanded in s around inf
Simplified37.1%
Final simplification37.1%
(FPCore (u s)
:precision binary32
(*
(- s)
(log
(+
-1.0
(/ 1.0 (+ (/ u (+ 1.0 1.0)) (/ (- 1.0 u) (+ (+ (/ PI s) 1.0) 1.0))))))))
float code(float u, float s) {
return -s * logf((-1.0f + (1.0f / ((u / (1.0f + 1.0f)) + ((1.0f - u) / (((((float) M_PI) / s) + 1.0f) + 1.0f))))));
}
function code(u, s) return Float32(Float32(-s) * log(Float32(Float32(-1.0) + Float32(Float32(1.0) / Float32(Float32(u / Float32(Float32(1.0) + Float32(1.0))) + Float32(Float32(Float32(1.0) - u) / Float32(Float32(Float32(Float32(pi) / s) + Float32(1.0)) + Float32(1.0)))))))) end
function tmp = code(u, s) tmp = -s * log((single(-1.0) + (single(1.0) / ((u / (single(1.0) + single(1.0))) + ((single(1.0) - u) / (((single(pi) / s) + single(1.0)) + single(1.0))))))); end
\begin{array}{l}
\\
\left(-s\right) \cdot \log \left(-1 + \frac{1}{\frac{u}{1 + 1} + \frac{1 - u}{\left(\frac{\pi}{s} + 1\right) + 1}}\right)
\end{array}
Initial program 99.0%
Simplified99.0%
Taylor expanded in s around inf
Simplified38.2%
Taylor expanded in s around inf
+-lowering-+.f32N/A
/-lowering-/.f32N/A
PI-lowering-PI.f3236.6%
Simplified36.6%
Final simplification36.6%
(FPCore (u s) :precision binary32 (* (- s) (log (+ (/ (* 4.0 (* -0.25 (- (* u PI) PI))) s) 1.0))))
float code(float u, float s) {
return -s * logf((((4.0f * (-0.25f * ((u * ((float) M_PI)) - ((float) M_PI)))) / s) + 1.0f));
}
function code(u, s) return Float32(Float32(-s) * log(Float32(Float32(Float32(Float32(4.0) * Float32(Float32(-0.25) * Float32(Float32(u * Float32(pi)) - Float32(pi)))) / s) + Float32(1.0)))) end
function tmp = code(u, s) tmp = -s * log((((single(4.0) * (single(-0.25) * ((u * single(pi)) - single(pi)))) / s) + single(1.0))); end
\begin{array}{l}
\\
\left(-s\right) \cdot \log \left(\frac{4 \cdot \left(-0.25 \cdot \left(u \cdot \pi - \pi\right)\right)}{s} + 1\right)
\end{array}
Initial program 99.0%
Simplified99.0%
Taylor expanded in s around inf
Simplified38.2%
Taylor expanded in s around -inf
associate-*r/N/A
+-lowering-+.f32N/A
/-lowering-/.f32N/A
*-lowering-*.f32N/A
distribute-lft-out--N/A
*-lowering-*.f32N/A
--lowering--.f32N/A
*-commutativeN/A
*-lowering-*.f32N/A
PI-lowering-PI.f32N/A
PI-lowering-PI.f3225.5%
Simplified25.5%
Final simplification25.5%
(FPCore (u s) :precision binary32 (* (/ (* s (- s)) s) (/ (* -4.0 (+ (* PI -0.25) (* 0.5 (* u PI)))) s)))
float code(float u, float s) {
return ((s * -s) / s) * ((-4.0f * ((((float) M_PI) * -0.25f) + (0.5f * (u * ((float) M_PI))))) / s);
}
function code(u, s) return Float32(Float32(Float32(s * Float32(-s)) / s) * Float32(Float32(Float32(-4.0) * Float32(Float32(Float32(pi) * Float32(-0.25)) + Float32(Float32(0.5) * Float32(u * Float32(pi))))) / s)) end
function tmp = code(u, s) tmp = ((s * -s) / s) * ((single(-4.0) * ((single(pi) * single(-0.25)) + (single(0.5) * (u * single(pi))))) / s); end
\begin{array}{l}
\\
\frac{s \cdot \left(-s\right)}{s} \cdot \frac{-4 \cdot \left(\pi \cdot -0.25 + 0.5 \cdot \left(u \cdot \pi\right)\right)}{s}
\end{array}
Initial program 99.0%
Simplified99.0%
Taylor expanded in s around inf
Simplified12.1%
neg-sub0N/A
flip--N/A
metadata-evalN/A
+-rgt-identityN/A
distribute-rgt-outN/A
+-lft-identityN/A
+-commutativeN/A
+-rgt-identityN/A
/-lowering-/.f32N/A
--lowering--.f32N/A
+-lft-identityN/A
distribute-rgt-outN/A
+-rgt-identityN/A
*-lowering-*.f3214.5%
Applied egg-rr14.5%
Taylor expanded in s around inf
*-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.f3214.5%
Simplified14.5%
Final simplification14.5%
(FPCore (u s) :precision binary32 (* (/ (* s s) s) (/ (- (/ 0.0 s) PI) s)))
float code(float u, float s) {
return ((s * s) / s) * (((0.0f / s) - ((float) M_PI)) / s);
}
function code(u, s) return Float32(Float32(Float32(s * s) / s) * Float32(Float32(Float32(Float32(0.0) / s) - Float32(pi)) / s)) end
function tmp = code(u, s) tmp = ((s * s) / s) * (((single(0.0) / s) - single(pi)) / s); end
\begin{array}{l}
\\
\frac{s \cdot s}{s} \cdot \frac{\frac{0}{s} - \pi}{s}
\end{array}
Initial program 99.0%
Simplified99.0%
Taylor expanded in s around inf
Simplified12.1%
neg-sub0N/A
flip--N/A
metadata-evalN/A
+-rgt-identityN/A
distribute-rgt-outN/A
+-lft-identityN/A
+-commutativeN/A
+-rgt-identityN/A
/-lowering-/.f32N/A
--lowering--.f32N/A
+-lft-identityN/A
distribute-rgt-outN/A
+-rgt-identityN/A
*-lowering-*.f3214.5%
Applied egg-rr14.5%
Taylor expanded in u around 0
associate-*r/N/A
distribute-lft1-inN/A
metadata-evalN/A
mul0-lftN/A
metadata-evalN/A
metadata-evalN/A
mul0-rgtN/A
mul0-rgtN/A
metadata-evalN/A
distribute-rgt-outN/A
metadata-evalN/A
distribute-rgt-outN/A
+-lowering-+.f32N/A
Simplified14.3%
Final simplification14.3%
(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(u * Float32(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}
\\
u \cdot \left(\pi \cdot 2\right) - \pi
\end{array}
Initial program 99.0%
Simplified99.0%
sub0-negN/A
distribute-neg-fracN/A
/-lowering-/.f32N/A
neg-lowering-neg.f32N/A
PI-lowering-PI.f3299.0%
Applied egg-rr99.0%
Applied egg-rr99.1%
Taylor expanded in s around -inf
sub-negN/A
+-lowering-+.f32N/A
Simplified12.1%
Taylor expanded in u around 0
associate-+r+N/A
distribute-rgt-outN/A
metadata-evalN/A
*-commutativeN/A
+-lowering-+.f32N/A
mul-1-negN/A
neg-lowering-neg.f32N/A
PI-lowering-PI.f32N/A
distribute-rgt-outN/A
metadata-evalN/A
*-commutativeN/A
*-lowering-*.f32N/A
*-commutativeN/A
*-lowering-*.f32N/A
PI-lowering-PI.f3212.1%
Simplified12.1%
Final simplification12.1%
(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.f3211.9%
Simplified11.9%
(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 99.0%
Simplified99.0%
Taylor expanded in s around inf
Simplified12.1%
Taylor expanded in s around 0
associate-*r/N/A
distribute-rgt-outN/A
metadata-evalN/A
mul0-rgtN/A
metadata-evalN/A
/-lowering-/.f3210.1%
Simplified10.1%
div010.1%
Applied egg-rr10.1%
herbie shell --seed 2024191
(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))))