
(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 11 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
(*
(- s)
(log
(+
(/
1.0
(+
(/ u (+ 1.0 (exp (- (/ PI s)))))
(/ (- 1.0 u) (+ 1.0 (pow E (/ PI s))))))
-1.0))))
float code(float u, float s) {
return -s * logf(((1.0f / ((u / (1.0f + expf(-(((float) M_PI) / s)))) + ((1.0f - u) / (1.0f + powf(((float) M_E), (((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(Float32(pi) / s))))) + Float32(Float32(Float32(1.0) - u) / Float32(Float32(1.0) + (Float32(exp(1)) ^ 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(pi) / s)))) + ((single(1.0) - u) / (single(1.0) + (single(2.71828182845904523536) ^ (single(pi) / s)))))) + single(-1.0))); end
\begin{array}{l}
\\
\left(-s\right) \cdot \log \left(\frac{1}{\frac{u}{1 + e^{-\frac{\pi}{s}}} + \frac{1 - u}{1 + {e}^{\left(\frac{\pi}{s}\right)}}} + -1\right)
\end{array}
Initial program 98.8%
Simplified98.8%
*-lft-identityN/A
exp-prodN/A
pow-lowering-pow.f32N/A
exp-1-eN/A
E-lowering-E.f32N/A
/-lowering-/.f32N/A
PI-lowering-PI.f3298.8%
Applied egg-rr98.8%
*-commutativeN/A
distribute-rgt-neg-outN/A
distribute-lft-neg-inN/A
*-lowering-*.f32N/A
Applied egg-rr98.8%
*-lft-identityN/A
exp-prodN/A
pow-lowering-pow.f32N/A
exp-1-eN/A
E-lowering-E.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
(+
(/ u (+ 1.0 (exp (- (/ PI s)))))
(/ (- 1.0 u) (+ 1.0 (exp (/ PI s))))))))))
float code(float u, float s) {
return -s * logf((-1.0f + (1.0f / ((u / (1.0f + expf(-(((float) M_PI) / s)))) + ((1.0f - 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(u / Float32(Float32(1.0) + exp(Float32(-Float32(Float32(pi) / s))))) + Float32(Float32(Float32(1.0) - u) / 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) + exp(-(single(pi) / s)))) + ((single(1.0) - u) / (single(1.0) + exp((single(pi) / s)))))))); end
\begin{array}{l}
\\
\left(-s\right) \cdot \log \left(-1 + \frac{1}{\frac{u}{1 + e^{-\frac{\pi}{s}}} + \frac{1 - u}{1 + e^{\frac{\pi}{s}}}}\right)
\end{array}
Initial program 98.8%
Simplified98.8%
*-commutativeN/A
neg-mul-1N/A
associate-*r*N/A
*-lowering-*.f32N/A
Applied egg-rr98.8%
Final simplification98.8%
(FPCore (u s) :precision binary32 (* (- s) (log (+ (/ 1.0 u) (+ -1.0 (/ (exp (- (/ PI s))) u))))))
float code(float u, float s) {
return -s * logf(((1.0f / u) + (-1.0f + (expf(-(((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(Float32(pi) / s))) / u))))) end
function tmp = code(u, s) tmp = -s * log(((single(1.0) / u) + (single(-1.0) + (exp(-(single(pi) / s)) / u)))); end
\begin{array}{l}
\\
\left(-s\right) \cdot \log \left(\frac{1}{u} + \left(-1 + \frac{e^{-\frac{\pi}{s}}}{u}\right)\right)
\end{array}
Initial program 98.8%
Simplified98.8%
Taylor expanded in s around -inf
mul-1-negN/A
unsub-negN/A
--lowering--.f32N/A
/-lowering-/.f32N/A
Simplified94.2%
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
Simplified96.9%
Final simplification96.9%
(FPCore (u s) :precision binary32 (* (- s) (log (+ 1.0 (/ (* (+ (* PI (* u 0.5)) (* PI -0.25)) -4.0) s)))))
float code(float u, float s) {
return -s * logf((1.0f + ((((((float) M_PI) * (u * 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(Float32(pi) * Float32(u * Float32(0.5))) + Float32(Float32(pi) * Float32(-0.25))) * Float32(-4.0)) / s)))) end
function tmp = code(u, s) tmp = -s * log((single(1.0) + ((((single(pi) * (u * single(0.5))) + (single(pi) * single(-0.25))) * single(-4.0)) / s))); end
\begin{array}{l}
\\
\left(-s\right) \cdot \log \left(1 + \frac{\left(\pi \cdot \left(u \cdot 0.5\right) + \pi \cdot -0.25\right) \cdot -4}{s}\right)
\end{array}
Initial program 98.8%
Simplified98.8%
*-lft-identityN/A
exp-prodN/A
pow-lowering-pow.f32N/A
exp-1-eN/A
E-lowering-E.f32N/A
/-lowering-/.f32N/A
PI-lowering-PI.f3298.8%
Applied egg-rr98.8%
*-commutativeN/A
distribute-rgt-neg-outN/A
distribute-lft-neg-inN/A
*-lowering-*.f32N/A
Applied egg-rr98.8%
Taylor expanded in s around inf
+-lowering-+.f32N/A
associate-*r/N/A
/-lowering-/.f32N/A
Simplified25.5%
Final simplification25.5%
(FPCore (u s) :precision binary32 (* (/ PI s) (/ (* (- s) (+ s (* u (* s -2.0)))) s)))
float code(float u, float s) {
return (((float) M_PI) / s) * ((-s * (s + (u * (s * -2.0f)))) / s);
}
function code(u, s) return Float32(Float32(Float32(pi) / s) * Float32(Float32(Float32(-s) * Float32(s + Float32(u * Float32(s * Float32(-2.0))))) / s)) end
function tmp = code(u, s) tmp = (single(pi) / s) * ((-s * (s + (u * (s * single(-2.0))))) / s); end
\begin{array}{l}
\\
\frac{\pi}{s} \cdot \frac{\left(-s\right) \cdot \left(s + u \cdot \left(s \cdot -2\right)\right)}{s}
\end{array}
Initial program 98.8%
Simplified98.8%
Taylor expanded in s around inf
associate-*r/N/A
*-commutativeN/A
associate-/l*N/A
*-lowering-*.f32N/A
Simplified12.2%
Taylor expanded in u around 0
+-commutativeN/A
+-lowering-+.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.f3212.2%
Simplified12.2%
+-commutativeN/A
clear-numN/A
frac-addN/A
/-lowering-/.f32N/A
Applied egg-rr10.7%
associate-*r/N/A
associate-/r/N/A
*-lowering-*.f32N/A
Applied egg-rr14.7%
Final simplification14.7%
(FPCore (u s) :precision binary32 (* s (* (/ PI s) (/ (+ -0.25 (/ u 2.0)) (- -0.25)))))
float code(float u, float s) {
return s * ((((float) M_PI) / s) * ((-0.25f + (u / 2.0f)) / -(-0.25f)));
}
function code(u, s) return Float32(s * Float32(Float32(Float32(pi) / s) * Float32(Float32(Float32(-0.25) + Float32(u / Float32(2.0))) / Float32(-Float32(-0.25))))) end
function tmp = code(u, s) tmp = s * ((single(pi) / s) * ((single(-0.25) + (u / single(2.0))) / -single(-0.25))); end
\begin{array}{l}
\\
s \cdot \left(\frac{\pi}{s} \cdot \frac{-0.25 + \frac{u}{2}}{--0.25}\right)
\end{array}
Initial program 98.8%
Simplified98.8%
Taylor expanded in s around inf
associate-*r/N/A
*-commutativeN/A
associate-/l*N/A
*-lowering-*.f32N/A
Simplified12.2%
clear-numN/A
un-div-invN/A
associate-*l*N/A
distribute-lft-outN/A
div-invN/A
metadata-evalN/A
times-fracN/A
*-lowering-*.f32N/A
/-lowering-/.f32N/A
PI-lowering-PI.f32N/A
/-lowering-/.f32N/A
+-lowering-+.f32N/A
metadata-evalN/A
metadata-evalN/A
div-invN/A
/-lowering-/.f32N/A
metadata-eval12.2%
Applied egg-rr12.2%
Final simplification12.2%
(FPCore (u s) :precision binary32 (/ s (/ 1.0 (/ (* PI (- -1.0 (* u -2.0))) s))))
float code(float u, float s) {
return s / (1.0f / ((((float) M_PI) * (-1.0f - (u * -2.0f))) / s));
}
function code(u, s) return Float32(s / Float32(Float32(1.0) / Float32(Float32(Float32(pi) * Float32(Float32(-1.0) - Float32(u * Float32(-2.0)))) / s))) end
function tmp = code(u, s) tmp = s / (single(1.0) / ((single(pi) * (single(-1.0) - (u * single(-2.0)))) / s)); end
\begin{array}{l}
\\
\frac{s}{\frac{1}{\frac{\pi \cdot \left(-1 - u \cdot -2\right)}{s}}}
\end{array}
Initial program 98.8%
Simplified98.8%
Taylor expanded in s around inf
associate-*r/N/A
*-commutativeN/A
associate-/l*N/A
*-lowering-*.f32N/A
Simplified12.2%
Taylor expanded in u around 0
+-commutativeN/A
+-lowering-+.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.f3212.2%
Simplified12.2%
Applied egg-rr12.2%
Final simplification12.2%
(FPCore (u s) :precision binary32 (* s (/ (* PI (- -1.0 (* u -2.0))) s)))
float code(float u, float s) {
return s * ((((float) M_PI) * (-1.0f - (u * -2.0f))) / s);
}
function code(u, s) return Float32(s * Float32(Float32(Float32(pi) * Float32(Float32(-1.0) - Float32(u * Float32(-2.0)))) / s)) end
function tmp = code(u, s) tmp = s * ((single(pi) * (single(-1.0) - (u * single(-2.0)))) / s); end
\begin{array}{l}
\\
s \cdot \frac{\pi \cdot \left(-1 - u \cdot -2\right)}{s}
\end{array}
Initial program 98.8%
Simplified98.8%
Taylor expanded in s around inf
associate-*r/N/A
*-commutativeN/A
associate-/l*N/A
*-lowering-*.f32N/A
Simplified12.2%
Taylor expanded in u around 0
+-commutativeN/A
+-lowering-+.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.f3212.2%
Simplified12.2%
Applied egg-rr12.2%
Final simplification12.2%
(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
associate-*r/N/A
*-commutativeN/A
associate-/l*N/A
*-lowering-*.f32N/A
Simplified12.2%
Taylor expanded in u around 0
+-commutativeN/A
+-lowering-+.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.f3212.2%
Simplified12.2%
Taylor expanded in s around 0
+-commutativeN/A
distribute-lft-inN/A
associate-*r*N/A
metadata-evalN/A
associate-*r*N/A
distribute-rgt-outN/A
*-lowering-*.f32N/A
PI-lowering-PI.f32N/A
+-lowering-+.f32N/A
*-lowering-*.f3212.2%
Simplified12.2%
Final simplification12.2%
(FPCore (u s) :precision binary32 (- 0.0 (* s (/ PI s))))
float code(float u, float s) {
return 0.0f - (s * (((float) M_PI) / s));
}
function code(u, s) return Float32(Float32(0.0) - Float32(s * Float32(Float32(pi) / s))) end
function tmp = code(u, s) tmp = single(0.0) - (s * (single(pi) / s)); end
\begin{array}{l}
\\
0 - s \cdot \frac{\pi}{s}
\end{array}
Initial program 98.8%
Simplified98.8%
Taylor expanded in u around 0
/-lowering-/.f32N/A
PI-lowering-PI.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.f3212.0%
Simplified12.0%
herbie shell --seed 2024164
(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))))