
(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 (exp (- 0.0 (/ PI s)))))
(*
s
(log
(/
(+ 1.0 (/ -1.0 (+ (/ u (- -1.0 t_1)) (/ (- 1.0 u) (- -1.0 t_0)))))
(+ (pow (+ (/ u (+ 1.0 t_1)) (/ (- 1.0 u) (+ 1.0 t_0))) -2.0) -1.0))))))
float code(float u, float s) {
float t_0 = expf((((float) M_PI) / s));
float t_1 = expf((0.0f - (((float) M_PI) / s)));
return s * logf(((1.0f + (-1.0f / ((u / (-1.0f - t_1)) + ((1.0f - u) / (-1.0f - t_0))))) / (powf(((u / (1.0f + t_1)) + ((1.0f - u) / (1.0f + t_0))), -2.0f) + -1.0f)));
}
function code(u, s) t_0 = exp(Float32(Float32(pi) / s)) t_1 = exp(Float32(Float32(0.0) - Float32(Float32(pi) / s))) return Float32(s * log(Float32(Float32(Float32(1.0) + Float32(Float32(-1.0) / Float32(Float32(u / Float32(Float32(-1.0) - t_1)) + Float32(Float32(Float32(1.0) - u) / Float32(Float32(-1.0) - t_0))))) / Float32((Float32(Float32(u / Float32(Float32(1.0) + t_1)) + Float32(Float32(Float32(1.0) - u) / Float32(Float32(1.0) + t_0))) ^ Float32(-2.0)) + Float32(-1.0))))) end
function tmp = code(u, s) t_0 = exp((single(pi) / s)); t_1 = exp((single(0.0) - (single(pi) / s))); tmp = s * log(((single(1.0) + (single(-1.0) / ((u / (single(-1.0) - t_1)) + ((single(1.0) - u) / (single(-1.0) - t_0))))) / ((((u / (single(1.0) + t_1)) + ((single(1.0) - u) / (single(1.0) + t_0))) ^ single(-2.0)) + single(-1.0)))); end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := e^{\frac{\pi}{s}}\\
t_1 := e^{0 - \frac{\pi}{s}}\\
s \cdot \log \left(\frac{1 + \frac{-1}{\frac{u}{-1 - t\_1} + \frac{1 - u}{-1 - t\_0}}}{{\left(\frac{u}{1 + t\_1} + \frac{1 - u}{1 + t\_0}\right)}^{-2} + -1}\right)
\end{array}
\end{array}
Initial program 98.8%
Simplified98.8%
flip-+N/A
clear-numN/A
log-recN/A
Applied egg-rr99.0%
Final simplification99.0%
(FPCore (u s)
:precision binary32
(let* ((t_0 (exp (/ PI s))) (t_1 (exp (- 0.0 (/ PI s)))))
(*
(- s)
(log
(/
(- 1.0 (pow (+ (/ u (+ 1.0 t_1)) (/ (- 1.0 u) (+ 1.0 t_0))) -2.0))
(+ -1.0 (/ 1.0 (+ (/ u (- -1.0 t_1)) (/ (- 1.0 u) (- -1.0 t_0))))))))))
float code(float u, float s) {
float t_0 = expf((((float) M_PI) / s));
float t_1 = expf((0.0f - (((float) M_PI) / s)));
return -s * logf(((1.0f - powf(((u / (1.0f + t_1)) + ((1.0f - u) / (1.0f + t_0))), -2.0f)) / (-1.0f + (1.0f / ((u / (-1.0f - t_1)) + ((1.0f - u) / (-1.0f - t_0)))))));
}
function code(u, s) t_0 = exp(Float32(Float32(pi) / s)) t_1 = exp(Float32(Float32(0.0) - Float32(Float32(pi) / s))) return Float32(Float32(-s) * log(Float32(Float32(Float32(1.0) - (Float32(Float32(u / Float32(Float32(1.0) + t_1)) + 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) - t_1)) + Float32(Float32(Float32(1.0) - u) / Float32(Float32(-1.0) - t_0)))))))) end
function tmp = code(u, s) t_0 = exp((single(pi) / s)); t_1 = exp((single(0.0) - (single(pi) / s))); tmp = -s * log(((single(1.0) - (((u / (single(1.0) + t_1)) + ((single(1.0) - u) / (single(1.0) + t_0))) ^ single(-2.0))) / (single(-1.0) + (single(1.0) / ((u / (single(-1.0) - t_1)) + ((single(1.0) - u) / (single(-1.0) - t_0))))))); end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := e^{\frac{\pi}{s}}\\
t_1 := e^{0 - \frac{\pi}{s}}\\
\left(-s\right) \cdot \log \left(\frac{1 - {\left(\frac{u}{1 + t\_1} + \frac{1 - u}{1 + t\_0}\right)}^{-2}}{-1 + \frac{1}{\frac{u}{-1 - t\_1} + \frac{1 - u}{-1 - t\_0}}}\right)
\end{array}
\end{array}
Initial program 98.8%
Simplified98.8%
+-commutativeN/A
flip-+N/A
/-lowering-/.f32N/A
Applied egg-rr98.9%
Final simplification98.9%
(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) (/ 1.0 s)) (/ (/ PI 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) / (1.0f / s)) * ((((float) M_PI) / 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(Float32(pi) / s) / Float32(Float32(1.0) / s)) * Float32(Float32(Float32(pi) / 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(1.0) / s)) * ((single(pi) / 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{\frac{\pi}{s}}{\frac{1}{s}} \cdot \frac{\frac{\pi}{s}}{\pi}}}}\right)
\end{array}
Initial program 98.8%
Simplified98.8%
+-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
Applied egg-rr98.8%
Final simplification98.8%
(FPCore (u s)
:precision binary32
(*
(- s)
(log
(+
(/
-1.0
(+
(/ u (- -1.0 (exp (- 0.0 (/ PI s)))))
(/ (- 1.0 u) (- -1.0 (exp (/ PI s))))))
-1.0))))
float code(float u, float s) {
return -s * logf(((-1.0f / ((u / (-1.0f - expf((0.0f - (((float) M_PI) / s))))) + ((1.0f - u) / (-1.0f - expf((((float) M_PI) / s)))))) + -1.0f));
}
function code(u, s) return Float32(Float32(-s) * log(Float32(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(pi) / s)))))) + Float32(-1.0)))) end
function tmp = code(u, s) tmp = -s * log(((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(-1.0))); end
\begin{array}{l}
\\
\left(-s\right) \cdot \log \left(\frac{-1}{\frac{u}{-1 - e^{0 - \frac{\pi}{s}}} + \frac{1 - u}{-1 - e^{\frac{\pi}{s}}}} + -1\right)
\end{array}
Initial program 98.8%
Simplified98.8%
sub0-negN/A
distribute-neg-fracN/A
/-lowering-/.f32N/A
neg-lowering-neg.f32N/A
PI-lowering-PI.f3298.8%
Applied egg-rr98.8%
Final simplification98.8%
(FPCore (u s) :precision binary32 (* (- s) (log (+ 1.0 (* (+ (* (* u PI) 0.5) (* PI -0.25)) (/ -4.0 s))))))
float code(float u, float s) {
return -s * logf((1.0f + ((((u * ((float) M_PI)) * 0.5f) + (((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(u * Float32(pi)) * Float32(0.5)) + Float32(Float32(pi) * Float32(-0.25))) * Float32(Float32(-4.0) / s))))) end
function tmp = code(u, s) tmp = -s * log((single(1.0) + ((((u * single(pi)) * single(0.5)) + (single(pi) * single(-0.25))) * (single(-4.0) / s)))); end
\begin{array}{l}
\\
\left(-s\right) \cdot \log \left(1 + \left(\left(u \cdot \pi\right) \cdot 0.5 + \pi \cdot -0.25\right) \cdot \frac{-4}{s}\right)
\end{array}
Initial program 98.8%
Simplified98.8%
Taylor expanded in s around inf
metadata-evalN/A
distribute-lft-neg-inN/A
+-lowering-+.f32N/A
distribute-lft-neg-inN/A
metadata-evalN/A
associate-*r/N/A
*-commutativeN/A
associate-/l*N/A
*-lowering-*.f32N/A
Simplified24.5%
Final simplification24.5%
(FPCore (u s) :precision binary32 (/ (/ (* (+ u (+ u -1.0)) (* PI (* s s))) s) s))
float code(float u, float s) {
return (((u + (u + -1.0f)) * (((float) M_PI) * (s * s))) / s) / s;
}
function code(u, s) return Float32(Float32(Float32(Float32(u + Float32(u + Float32(-1.0))) * Float32(Float32(pi) * Float32(s * s))) / s) / s) end
function tmp = code(u, s) tmp = (((u + (u + single(-1.0))) * (single(pi) * (s * s))) / s) / s; end
\begin{array}{l}
\\
\frac{\frac{\left(u + \left(u + -1\right)\right) \cdot \left(\pi \cdot \left(s \cdot s\right)\right)}{s}}{s}
\end{array}
Initial program 98.8%
Simplified98.8%
Taylor expanded in s around -inf
Simplified11.9%
Applied egg-rr12.0%
Applied egg-rr9.0%
sqr-negN/A
associate-/r*N/A
/-lowering-/.f32N/A
Applied egg-rr14.3%
(FPCore (u s) :precision binary32 (* (/ PI s) (/ (* (+ u (+ u -1.0)) (* s s)) s)))
float code(float u, float s) {
return (((float) M_PI) / s) * (((u + (u + -1.0f)) * (s * s)) / s);
}
function code(u, s) return Float32(Float32(Float32(pi) / s) * Float32(Float32(Float32(u + Float32(u + Float32(-1.0))) * Float32(s * s)) / s)) end
function tmp = code(u, s) tmp = (single(pi) / s) * (((u + (u + single(-1.0))) * (s * s)) / s); end
\begin{array}{l}
\\
\frac{\pi}{s} \cdot \frac{\left(u + \left(u + -1\right)\right) \cdot \left(s \cdot s\right)}{s}
\end{array}
Initial program 98.8%
Simplified98.8%
Taylor expanded in s around -inf
Simplified11.9%
Applied egg-rr12.0%
Applied egg-rr9.0%
associate-*l*N/A
sqr-negN/A
times-fracN/A
*-lowering-*.f32N/A
/-lowering-/.f32N/A
PI-lowering-PI.f32N/A
/-lowering-/.f32N/A
*-lowering-*.f32N/A
+-commutativeN/A
+-lowering-+.f32N/A
+-commutativeN/A
*-commutativeN/A
associate-*r*N/A
metadata-evalN/A
*-lft-identityN/A
+-lowering-+.f32N/A
*-lowering-*.f3214.2%
Applied egg-rr14.2%
(FPCore (u s) :precision binary32 (* (* s (* PI (- (- 1.0 u) u))) (/ -1.0 s)))
float code(float u, float s) {
return (s * (((float) M_PI) * ((1.0f - u) - u))) * (-1.0f / s);
}
function code(u, s) return Float32(Float32(s * Float32(Float32(pi) * Float32(Float32(Float32(1.0) - u) - u))) * Float32(Float32(-1.0) / s)) end
function tmp = code(u, s) tmp = (s * (single(pi) * ((single(1.0) - u) - u))) * (single(-1.0) / s); end
\begin{array}{l}
\\
\left(s \cdot \left(\pi \cdot \left(\left(1 - u\right) - u\right)\right)\right) \cdot \frac{-1}{s}
\end{array}
Initial program 98.8%
Simplified98.8%
Taylor expanded in s around -inf
Simplified11.9%
Applied egg-rr12.0%
Applied egg-rr9.0%
associate-/r*N/A
div-invN/A
*-lowering-*.f32N/A
Applied egg-rr12.0%
Final simplification12.0%
(FPCore (u s) :precision binary32 (/ 1.0 (/ 1.0 (* PI (+ u (+ u -1.0))))))
float code(float u, float s) {
return 1.0f / (1.0f / (((float) M_PI) * (u + (u + -1.0f))));
}
function code(u, s) return Float32(Float32(1.0) / Float32(Float32(1.0) / Float32(Float32(pi) * Float32(u + Float32(u + Float32(-1.0)))))) end
function tmp = code(u, s) tmp = single(1.0) / (single(1.0) / (single(pi) * (u + (u + single(-1.0))))); end
\begin{array}{l}
\\
\frac{1}{\frac{1}{\pi \cdot \left(u + \left(u + -1\right)\right)}}
\end{array}
Initial program 98.8%
Simplified98.8%
Taylor expanded in s around -inf
Simplified11.9%
Applied egg-rr12.0%
Applied egg-rr9.0%
sqr-negN/A
clear-numN/A
/-lowering-/.f32N/A
*-commutativeN/A
associate-/r*N/A
*-inversesN/A
/-lowering-/.f32N/A
*-lowering-*.f32N/A
PI-lowering-PI.f32N/A
+-commutativeN/A
+-lowering-+.f32N/A
+-commutativeN/A
*-commutativeN/A
associate-*r*N/A
metadata-evalN/A
*-lft-identityN/A
+-lowering-+.f3212.0%
Applied egg-rr12.0%
(FPCore (u s) :precision binary32 (* PI (+ u (+ u -1.0))))
float code(float u, float s) {
return ((float) M_PI) * (u + (u + -1.0f));
}
function code(u, s) return Float32(Float32(pi) * Float32(u + Float32(u + Float32(-1.0)))) end
function tmp = code(u, s) tmp = single(pi) * (u + (u + single(-1.0))); end
\begin{array}{l}
\\
\pi \cdot \left(u + \left(u + -1\right)\right)
\end{array}
Initial program 98.8%
Simplified98.8%
Taylor expanded in s around -inf
Simplified11.9%
Applied egg-rr12.0%
Applied egg-rr9.0%
sqr-negN/A
associate-/l*N/A
*-inversesN/A
*-commutativeN/A
associate-*l*N/A
*-un-lft-identityN/A
*-commutativeN/A
*-lowering-*.f32N/A
+-commutativeN/A
+-lowering-+.f32N/A
+-commutativeN/A
*-commutativeN/A
associate-*r*N/A
metadata-evalN/A
*-lft-identityN/A
+-lowering-+.f32N/A
PI-lowering-PI.f3212.0%
Applied egg-rr12.0%
Final simplification12.0%
(FPCore (u s) :precision binary32 (* PI (+ -1.0 (* u 2.0))))
float code(float u, float s) {
return ((float) M_PI) * (-1.0f + (u * 2.0f));
}
function code(u, s) return Float32(Float32(pi) * Float32(Float32(-1.0) + Float32(u * Float32(2.0)))) end
function tmp = code(u, s) tmp = single(pi) * (single(-1.0) + (u * single(2.0))); end
\begin{array}{l}
\\
\pi \cdot \left(-1 + u \cdot 2\right)
\end{array}
Initial program 98.8%
Simplified98.8%
Taylor expanded in s around -inf
Simplified11.9%
Applied egg-rr12.0%
Applied egg-rr9.0%
Taylor expanded in s around 0
*-lowering-*.f32N/A
PI-lowering-PI.f32N/A
sub-negN/A
metadata-evalN/A
+-lowering-+.f32N/A
*-commutativeN/A
*-lowering-*.f3212.0%
Simplified12.0%
Final simplification12.0%
(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 98.8%
Simplified98.8%
Taylor expanded in u around 0
mul-1-negN/A
neg-lowering-neg.f32N/A
PI-lowering-PI.f3211.6%
Simplified11.6%
(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 98.8%
Simplified98.8%
Taylor expanded in s around -inf
Simplified11.9%
Taylor expanded in s around 0
distribute-rgt-outN/A
metadata-evalN/A
mul0-rgtN/A
mul0-lftN/A
metadata-evalN/A
distribute-lft1-inN/A
associate-*r/N/A
distribute-lft1-inN/A
metadata-evalN/A
mul0-lftN/A
metadata-evalN/A
/-lowering-/.f3210.2%
Simplified10.2%
div010.2%
Applied egg-rr10.2%
herbie shell --seed 2024170
(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))))