
(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
(*
s
(-
(log
(+
(/
1.0
(+
(/ u (+ 1.0 (exp (/ PI (- s)))))
(/ (- 1.0 u) (+ 1.0 (exp (* PI (/ 1.0 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 + expf((((float) M_PI) * (1.0f / s))))))) + -1.0f));
}
function code(u, s) return Float32(s * Float32(-log(Float32(Float32(Float32(1.0) / Float32(Float32(u / Float32(Float32(1.0) + exp(Float32(Float32(pi) / Float32(-s))))) + Float32(Float32(Float32(1.0) - u) / Float32(Float32(1.0) + exp(Float32(Float32(pi) * Float32(Float32(1.0) / 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) + exp((single(pi) * (single(1.0) / s))))))) + single(-1.0))); end
\begin{array}{l}
\\
s \cdot \left(-\log \left(\frac{1}{\frac{u}{1 + e^{\frac{\pi}{-s}}} + \frac{1 - u}{1 + e^{\pi \cdot \frac{1}{s}}}} + -1\right)\right)
\end{array}
Initial program 98.8%
Simplified98.8%
clear-num98.8%
associate-/r/98.8%
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(s * Float32(-log(Float32(Float32(-1.0) + Float32(Float32(1.0) / Float32(Float32(u / Float32(Float32(1.0) + exp(Float32(Float32(pi) / Float32(-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}
\\
s \cdot \left(-\log \left(-1 + \frac{1}{\frac{u}{1 + e^{\frac{\pi}{-s}}} + \frac{1 - u}{1 + e^{\frac{\pi}{s}}}}\right)\right)
\end{array}
Initial program 98.8%
Simplified98.8%
Final simplification98.8%
(FPCore (u s)
:precision binary32
(*
(- s)
(log
(+
-1.0
(/ 1.0 (+ (/ (- 1.0 u) (+ 1.0 (exp (* PI (/ 1.0 s))))) (/ u 2.0)))))))
float code(float u, float s) {
return -s * logf((-1.0f + (1.0f / (((1.0f - u) / (1.0f + expf((((float) M_PI) * (1.0f / s))))) + (u / 2.0f)))));
}
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(Float32(1.0) + exp(Float32(Float32(pi) * Float32(Float32(1.0) / s))))) + Float32(u / Float32(2.0))))))) 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) * (single(1.0) / s))))) + (u / single(2.0)))))); end
\begin{array}{l}
\\
\left(-s\right) \cdot \log \left(-1 + \frac{1}{\frac{1 - u}{1 + e^{\pi \cdot \frac{1}{s}}} + \frac{u}{2}}\right)
\end{array}
Initial program 98.8%
Simplified98.8%
clear-num98.8%
associate-/r/98.8%
Applied egg-rr98.8%
Taylor expanded in s around inf 37.6%
Final simplification37.6%
(FPCore (u s) :precision binary32 (* (- s) (log (+ -1.0 (/ 1.0 (+ (/ (- 1.0 u) (+ 1.0 (exp (/ PI s)))) (/ u 2.0)))))))
float code(float u, float s) {
return -s * logf((-1.0f + (1.0f / (((1.0f - u) / (1.0f + expf((((float) M_PI) / s)))) + (u / 2.0f)))));
}
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(Float32(1.0) + exp(Float32(Float32(pi) / s)))) + Float32(u / Float32(2.0))))))) 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(2.0)))))); end
\begin{array}{l}
\\
\left(-s\right) \cdot \log \left(-1 + \frac{1}{\frac{1 - u}{1 + e^{\frac{\pi}{s}}} + \frac{u}{2}}\right)
\end{array}
Initial program 98.8%
Simplified98.8%
Taylor expanded in s around inf 37.6%
Final simplification37.6%
(FPCore (u s) :precision binary32 (pow (cbrt (* 4.0 (- (* 0.25 (* u PI)) (+ (* (* u PI) -0.25) (* PI 0.25))))) 3.0))
float code(float u, float s) {
return powf(cbrtf((4.0f * ((0.25f * (u * ((float) M_PI))) - (((u * ((float) M_PI)) * -0.25f) + (((float) M_PI) * 0.25f))))), 3.0f);
}
function code(u, s) return cbrt(Float32(Float32(4.0) * Float32(Float32(Float32(0.25) * Float32(u * Float32(pi))) - Float32(Float32(Float32(u * Float32(pi)) * Float32(-0.25)) + Float32(Float32(pi) * Float32(0.25)))))) ^ Float32(3.0) end
\begin{array}{l}
\\
{\left(\sqrt[3]{4 \cdot \left(0.25 \cdot \left(u \cdot \pi\right) - \left(\left(u \cdot \pi\right) \cdot -0.25 + \pi \cdot 0.25\right)\right)}\right)}^{3}
\end{array}
Initial program 98.8%
Simplified98.8%
clear-num98.8%
associate-/r/98.8%
Applied egg-rr98.8%
add-cube-cbrt97.2%
pow397.4%
Applied egg-rr97.4%
Taylor expanded in s around inf 11.5%
Final simplification11.5%
(FPCore (u s)
:precision binary32
(*
4.0
(+
(* 0.25 (* u PI))
(*
u
(* 0.25 (/ (+ (/ -1.0 (pow (/ u PI) 2.0)) (* PI PI)) (+ PI (/ PI u))))))))
float code(float u, float s) {
return 4.0f * ((0.25f * (u * ((float) M_PI))) + (u * (0.25f * (((-1.0f / powf((u / ((float) M_PI)), 2.0f)) + (((float) M_PI) * ((float) M_PI))) / (((float) M_PI) + (((float) M_PI) / u))))));
}
function code(u, s) return Float32(Float32(4.0) * Float32(Float32(Float32(0.25) * Float32(u * Float32(pi))) + Float32(u * Float32(Float32(0.25) * Float32(Float32(Float32(Float32(-1.0) / (Float32(u / Float32(pi)) ^ Float32(2.0))) + Float32(Float32(pi) * Float32(pi))) / Float32(Float32(pi) + Float32(Float32(pi) / u))))))) end
function tmp = code(u, s) tmp = single(4.0) * ((single(0.25) * (u * single(pi))) + (u * (single(0.25) * (((single(-1.0) / ((u / single(pi)) ^ single(2.0))) + (single(pi) * single(pi))) / (single(pi) + (single(pi) / u)))))); end
\begin{array}{l}
\\
4 \cdot \left(0.25 \cdot \left(u \cdot \pi\right) + u \cdot \left(0.25 \cdot \frac{\frac{-1}{{\left(\frac{u}{\pi}\right)}^{2}} + \pi \cdot \pi}{\pi + \frac{\pi}{u}}\right)\right)
\end{array}
Initial program 98.8%
Simplified98.8%
Taylor expanded in s around inf 11.5%
Taylor expanded in u around inf 11.5%
+-commutative11.5%
metadata-eval11.5%
cancel-sign-sub-inv11.5%
distribute-lft-out--11.5%
Simplified11.5%
flip--11.5%
div-sub11.5%
pow211.5%
Applied egg-rr11.5%
unpow211.5%
div-sub11.5%
Simplified11.5%
metadata-eval11.5%
pow-prod-up11.5%
pow-prod-down11.5%
pow211.5%
Applied egg-rr11.5%
unpow-111.5%
Simplified11.5%
Final simplification11.5%
(FPCore (u s) :precision binary32 (* 4.0 (- (* 0.25 (* u PI)) (* u (* 0.25 (/ (- (pow (/ u PI) -2.0) (* PI PI)) (+ PI (/ PI u))))))))
float code(float u, float s) {
return 4.0f * ((0.25f * (u * ((float) M_PI))) - (u * (0.25f * ((powf((u / ((float) M_PI)), -2.0f) - (((float) M_PI) * ((float) M_PI))) / (((float) M_PI) + (((float) M_PI) / u))))));
}
function code(u, s) return Float32(Float32(4.0) * Float32(Float32(Float32(0.25) * Float32(u * Float32(pi))) - Float32(u * Float32(Float32(0.25) * Float32(Float32((Float32(u / Float32(pi)) ^ Float32(-2.0)) - Float32(Float32(pi) * Float32(pi))) / Float32(Float32(pi) + Float32(Float32(pi) / u))))))) end
function tmp = code(u, s) tmp = single(4.0) * ((single(0.25) * (u * single(pi))) - (u * (single(0.25) * ((((u / single(pi)) ^ single(-2.0)) - (single(pi) * single(pi))) / (single(pi) + (single(pi) / u)))))); end
\begin{array}{l}
\\
4 \cdot \left(0.25 \cdot \left(u \cdot \pi\right) - u \cdot \left(0.25 \cdot \frac{{\left(\frac{u}{\pi}\right)}^{-2} - \pi \cdot \pi}{\pi + \frac{\pi}{u}}\right)\right)
\end{array}
Initial program 98.8%
Simplified98.8%
Taylor expanded in s around inf 11.5%
Taylor expanded in u around inf 11.5%
+-commutative11.5%
metadata-eval11.5%
cancel-sign-sub-inv11.5%
distribute-lft-out--11.5%
Simplified11.5%
flip--11.5%
div-sub11.5%
pow211.5%
Applied egg-rr11.5%
unpow211.5%
div-sub11.5%
Simplified11.5%
(FPCore (u s) :precision binary32 (* 4.0 (- (* 0.25 (* u PI)) (* u (* 0.25 (fma PI (/ 1.0 u) (- PI)))))))
float code(float u, float s) {
return 4.0f * ((0.25f * (u * ((float) M_PI))) - (u * (0.25f * fmaf(((float) M_PI), (1.0f / u), -((float) M_PI)))));
}
function code(u, s) return Float32(Float32(4.0) * Float32(Float32(Float32(0.25) * Float32(u * Float32(pi))) - Float32(u * Float32(Float32(0.25) * fma(Float32(pi), Float32(Float32(1.0) / u), Float32(-Float32(pi))))))) end
\begin{array}{l}
\\
4 \cdot \left(0.25 \cdot \left(u \cdot \pi\right) - u \cdot \left(0.25 \cdot \mathsf{fma}\left(\pi, \frac{1}{u}, -\pi\right)\right)\right)
\end{array}
Initial program 98.8%
Simplified98.8%
Taylor expanded in s around inf 11.5%
Taylor expanded in u around inf 11.5%
+-commutative11.5%
metadata-eval11.5%
cancel-sign-sub-inv11.5%
distribute-lft-out--11.5%
Simplified11.5%
div-inv11.5%
fma-neg11.5%
Applied egg-rr11.5%
(FPCore (u s) :precision binary32 (* 4.0 (- (* 0.25 (* u PI)) (* PI (+ 0.25 (* u -0.25))))))
float code(float u, float s) {
return 4.0f * ((0.25f * (u * ((float) M_PI))) - (((float) M_PI) * (0.25f + (u * -0.25f))));
}
function code(u, s) return Float32(Float32(4.0) * Float32(Float32(Float32(0.25) * Float32(u * Float32(pi))) - Float32(Float32(pi) * Float32(Float32(0.25) + Float32(u * Float32(-0.25)))))) end
function tmp = code(u, s) tmp = single(4.0) * ((single(0.25) * (u * single(pi))) - (single(pi) * (single(0.25) + (u * single(-0.25))))); end
\begin{array}{l}
\\
4 \cdot \left(0.25 \cdot \left(u \cdot \pi\right) - \pi \cdot \left(0.25 + u \cdot -0.25\right)\right)
\end{array}
Initial program 98.8%
Simplified98.8%
Taylor expanded in s around inf 11.5%
Taylor expanded in u around inf 11.5%
+-commutative11.5%
metadata-eval11.5%
cancel-sign-sub-inv11.5%
distribute-lft-out--11.5%
Simplified11.5%
Taylor expanded in u around 0 11.5%
+-commutative11.5%
associate-*r*11.5%
distribute-rgt-out11.5%
Simplified11.5%
Final simplification11.5%
(FPCore (u s) :precision binary32 (* 4.0 (* u (+ (* -0.25 (/ PI u)) (* PI 0.5)))))
float code(float u, float s) {
return 4.0f * (u * ((-0.25f * (((float) M_PI) / u)) + (((float) M_PI) * 0.5f)));
}
function code(u, s) return Float32(Float32(4.0) * Float32(u * Float32(Float32(Float32(-0.25) * Float32(Float32(pi) / u)) + Float32(Float32(pi) * Float32(0.5))))) end
function tmp = code(u, s) tmp = single(4.0) * (u * ((single(-0.25) * (single(pi) / u)) + (single(pi) * single(0.5)))); end
\begin{array}{l}
\\
4 \cdot \left(u \cdot \left(-0.25 \cdot \frac{\pi}{u} + \pi \cdot 0.5\right)\right)
\end{array}
Initial program 98.8%
Simplified98.8%
Taylor expanded in s around inf 11.5%
associate--r+11.5%
distribute-rgt-out--11.5%
metadata-eval11.5%
fma-neg11.5%
*-commutative11.5%
remove-double-neg11.5%
neg-mul-111.5%
associate-*r*11.5%
metadata-eval11.5%
distribute-rgt-neg-out11.5%
remove-double-neg11.5%
*-commutative11.5%
Simplified11.5%
Taylor expanded in u around inf 11.5%
Final simplification11.5%
(FPCore (u s) :precision binary32 (* 4.0 (* PI (+ -0.25 (* u 0.5)))))
float code(float u, float s) {
return 4.0f * (((float) M_PI) * (-0.25f + (u * 0.5f)));
}
function code(u, s) return Float32(Float32(4.0) * Float32(Float32(pi) * Float32(Float32(-0.25) + Float32(u * Float32(0.5))))) end
function tmp = code(u, s) tmp = single(4.0) * (single(pi) * (single(-0.25) + (u * single(0.5)))); end
\begin{array}{l}
\\
4 \cdot \left(\pi \cdot \left(-0.25 + u \cdot 0.5\right)\right)
\end{array}
Initial program 98.8%
Simplified98.8%
clear-num98.8%
associate-/r/98.8%
Applied egg-rr98.8%
Taylor expanded in s around inf 11.5%
associate--r+11.5%
*-commutative11.5%
*-commutative11.5%
associate-*r*11.5%
*-commutative11.5%
*-commutative11.5%
cancel-sign-sub-inv11.5%
associate-*r*11.5%
distribute-lft-out--11.5%
metadata-eval11.5%
metadata-eval11.5%
*-commutative11.5%
*-commutative11.5%
+-commutative11.5%
Simplified11.5%
Final simplification11.5%
(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 11.3%
neg-mul-111.3%
Simplified11.3%
herbie shell --seed 2024096
(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))))