
(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 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) / 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) + 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(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^{-\frac{\pi}{s}}} + \frac{1 - u}{1 + e^{\frac{\pi}{s}}}} + -1\right)
\end{array}
Initial program 99.0%
Simplified99.0%
Final simplification99.0%
(FPCore (u s)
:precision binary32
(*
(- s)
(log
(+
-1.0
(/ 1.0 (+ (/ u 2.0) (/ (- 1.0 u) (+ 1.0 (exp (/ (* PI (log E)) s))))))))))
float code(float u, float s) {
return -s * logf((-1.0f + (1.0f / ((u / 2.0f) + ((1.0f - u) / (1.0f + expf(((((float) M_PI) * logf(((float) M_E))) / s))))))));
}
function code(u, s) return Float32(Float32(-s) * log(Float32(Float32(-1.0) + Float32(Float32(1.0) / Float32(Float32(u / Float32(2.0)) + Float32(Float32(Float32(1.0) - u) / Float32(Float32(1.0) + exp(Float32(Float32(Float32(pi) * log(Float32(exp(1)))) / s))))))))) end
function tmp = code(u, s) tmp = -s * log((single(-1.0) + (single(1.0) / ((u / single(2.0)) + ((single(1.0) - u) / (single(1.0) + exp(((single(pi) * log(single(2.71828182845904523536))) / s)))))))); end
\begin{array}{l}
\\
\left(-s\right) \cdot \log \left(-1 + \frac{1}{\frac{u}{2} + \frac{1 - u}{1 + e^{\frac{\pi \cdot \log e}{s}}}}\right)
\end{array}
Initial program 99.0%
Simplified99.0%
Taylor expanded in s around inf 37.3%
*-un-lft-identity37.3%
exp-prod37.3%
Applied egg-rr37.3%
exp-1-e37.3%
Simplified37.3%
Taylor expanded in s around 0 37.3%
Final simplification37.3%
(FPCore (u s) :precision binary32 (* (- s) (log (+ -1.0 (/ 1.0 (+ (/ u 2.0) (/ (- 1.0 u) (+ 1.0 (pow E (/ PI s))))))))))
float code(float u, float s) {
return -s * logf((-1.0f + (1.0f / ((u / 2.0f) + ((1.0f - u) / (1.0f + powf(((float) M_E), (((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(2.0)) + Float32(Float32(Float32(1.0) - u) / Float32(Float32(1.0) + (Float32(exp(1)) ^ Float32(Float32(pi) / s))))))))) end
function tmp = code(u, s) tmp = -s * log((single(-1.0) + (single(1.0) / ((u / single(2.0)) + ((single(1.0) - u) / (single(1.0) + (single(2.71828182845904523536) ^ (single(pi) / s)))))))); end
\begin{array}{l}
\\
\left(-s\right) \cdot \log \left(-1 + \frac{1}{\frac{u}{2} + \frac{1 - u}{1 + {e}^{\left(\frac{\pi}{s}\right)}}}\right)
\end{array}
Initial program 99.0%
Simplified99.0%
Taylor expanded in s around inf 37.3%
*-un-lft-identity37.3%
exp-prod37.3%
Applied egg-rr37.3%
exp-1-e37.3%
Simplified37.3%
Final simplification37.3%
(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(s * Float32(-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}
\\
s \cdot \left(-\log \left(-1 + \frac{1}{\frac{1 - u}{1 + e^{\frac{\pi}{s}}} + \frac{u}{2}}\right)\right)
\end{array}
Initial program 99.0%
Simplified99.0%
Taylor expanded in s around inf 37.3%
Final simplification37.3%
(FPCore (u s)
:precision binary32
(*
(- s)
(log
(+
-1.0
(/ 1.0 (+ (/ u 2.0) (/ (- 1.0 u) (+ 1.0 (+ 1.0 (* PI (/ 1.0 s)))))))))))
float code(float u, float s) {
return -s * logf((-1.0f + (1.0f / ((u / 2.0f) + ((1.0f - u) / (1.0f + (1.0f + (((float) M_PI) * (1.0f / s)))))))));
}
function code(u, s) return Float32(Float32(-s) * log(Float32(Float32(-1.0) + Float32(Float32(1.0) / Float32(Float32(u / Float32(2.0)) + Float32(Float32(Float32(1.0) - u) / Float32(Float32(1.0) + Float32(Float32(1.0) + Float32(Float32(pi) * Float32(Float32(1.0) / s)))))))))) end
function tmp = code(u, s) tmp = -s * log((single(-1.0) + (single(1.0) / ((u / single(2.0)) + ((single(1.0) - u) / (single(1.0) + (single(1.0) + (single(pi) * (single(1.0) / s))))))))); end
\begin{array}{l}
\\
\left(-s\right) \cdot \log \left(-1 + \frac{1}{\frac{u}{2} + \frac{1 - u}{1 + \left(1 + \pi \cdot \frac{1}{s}\right)}}\right)
\end{array}
Initial program 99.0%
Simplified99.0%
Taylor expanded in s around inf 37.3%
*-un-lft-identity37.3%
exp-prod37.3%
Applied egg-rr37.3%
exp-1-e37.3%
Simplified37.3%
Taylor expanded in s around inf 35.5%
log-E35.5%
associate-/l*35.5%
Simplified35.5%
Final simplification35.5%
(FPCore (u s)
:precision binary32
(*
s
(-
(log
(+ -1.0 (/ 1.0 (+ (/ u 2.0) (/ (- 1.0 u) (+ 1.0 (+ 1.0 (/ PI s)))))))))))
float code(float u, float s) {
return s * -logf((-1.0f + (1.0f / ((u / 2.0f) + ((1.0f - u) / (1.0f + (1.0f + (((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(2.0)) + Float32(Float32(Float32(1.0) - u) / Float32(Float32(1.0) + Float32(Float32(1.0) + Float32(Float32(pi) / s)))))))))) end
function tmp = code(u, s) tmp = s * -log((single(-1.0) + (single(1.0) / ((u / single(2.0)) + ((single(1.0) - u) / (single(1.0) + (single(1.0) + (single(pi) / s)))))))); end
\begin{array}{l}
\\
s \cdot \left(-\log \left(-1 + \frac{1}{\frac{u}{2} + \frac{1 - u}{1 + \left(1 + \frac{\pi}{s}\right)}}\right)\right)
\end{array}
Initial program 99.0%
Simplified99.0%
Taylor expanded in s around inf 37.3%
Taylor expanded in s around inf 35.5%
Final simplification35.5%
(FPCore (u s) :precision binary32 (* 4.0 (* u (* PI (+ 0.5 (/ -0.25 u))))))
float code(float u, float s) {
return 4.0f * (u * (((float) M_PI) * (0.5f + (-0.25f / u))));
}
function code(u, s) return Float32(Float32(4.0) * Float32(u * Float32(Float32(pi) * Float32(Float32(0.5) + Float32(Float32(-0.25) / u))))) end
function tmp = code(u, s) tmp = single(4.0) * (u * (single(pi) * (single(0.5) + (single(-0.25) / u)))); end
\begin{array}{l}
\\
4 \cdot \left(u \cdot \left(\pi \cdot \left(0.5 + \frac{-0.25}{u}\right)\right)\right)
\end{array}
Initial program 99.0%
Simplified99.0%
Taylor expanded in s around inf 12.5%
associate--r+12.5%
cancel-sign-sub-inv12.5%
distribute-rgt-out--12.5%
metadata-eval12.5%
*-commutative12.5%
metadata-eval12.5%
*-commutative12.5%
Simplified12.5%
Taylor expanded in u around inf 12.5%
+-commutative12.5%
*-commutative12.5%
fma-define12.5%
associate-*r/12.5%
*-commutative12.5%
associate-/l*12.5%
Simplified12.5%
Taylor expanded in u around inf 12.5%
associate-*r/12.5%
*-commutative12.5%
*-commutative12.5%
associate-/l*12.5%
distribute-lft-out12.5%
Simplified12.5%
Final simplification12.5%
(FPCore (u s) :precision binary32 (* 4.0 (* PI (* u (- 0.5 (/ 0.25 u))))))
float code(float u, float s) {
return 4.0f * (((float) M_PI) * (u * (0.5f - (0.25f / u))));
}
function code(u, s) return Float32(Float32(4.0) * Float32(Float32(pi) * Float32(u * Float32(Float32(0.5) - Float32(Float32(0.25) / u))))) end
function tmp = code(u, s) tmp = single(4.0) * (single(pi) * (u * (single(0.5) - (single(0.25) / u)))); end
\begin{array}{l}
\\
4 \cdot \left(\pi \cdot \left(u \cdot \left(0.5 - \frac{0.25}{u}\right)\right)\right)
\end{array}
Initial program 99.0%
Simplified99.0%
Taylor expanded in s around inf 12.5%
associate--r+12.5%
cancel-sign-sub-inv12.5%
distribute-rgt-out--12.5%
metadata-eval12.5%
*-commutative12.5%
metadata-eval12.5%
*-commutative12.5%
Simplified12.5%
*-commutative12.5%
metadata-eval12.5%
distribute-rgt-out--12.5%
fma-neg12.5%
*-commutative12.5%
associate-*r*12.5%
*-commutative12.5%
*-commutative12.5%
metadata-eval12.5%
cancel-sign-sub-inv12.5%
*-commutative12.5%
associate-*r*12.5%
*-commutative12.5%
fma-neg12.5%
associate--r+12.5%
associate-*r*12.5%
Applied egg-rr12.5%
Taylor expanded in u around inf 12.5%
associate-*r/12.5%
metadata-eval12.5%
Simplified12.5%
Final simplification12.5%
(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 99.0%
Simplified99.0%
Taylor expanded in s around inf 12.5%
associate--r+12.5%
cancel-sign-sub-inv12.5%
distribute-rgt-out--12.5%
metadata-eval12.5%
*-commutative12.5%
metadata-eval12.5%
*-commutative12.5%
Simplified12.5%
associate-*l*12.5%
distribute-lft-out12.5%
Applied egg-rr12.5%
Final simplification12.5%
(FPCore (u s) :precision binary32 (* PI (+ u -1.0)))
float code(float u, float s) {
return ((float) M_PI) * (u + -1.0f);
}
function code(u, s) return Float32(Float32(pi) * Float32(u + Float32(-1.0))) end
function tmp = code(u, s) tmp = single(pi) * (u + single(-1.0)); end
\begin{array}{l}
\\
\pi \cdot \left(u + -1\right)
\end{array}
Initial program 99.0%
Simplified99.0%
Taylor expanded in s around inf 37.3%
*-un-lft-identity37.3%
exp-prod37.3%
Applied egg-rr37.3%
exp-1-e37.3%
Simplified37.3%
Taylor expanded in s around inf 12.1%
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 12.0%
neg-mul-112.0%
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(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 s around inf 37.3%
Taylor expanded in u around 0 12.0%
add-sqr-sqrt-0.0%
sqrt-unprod7.3%
sqr-neg7.3%
sqrt-unprod4.6%
add-sqr-sqrt4.6%
clear-num4.6%
un-div-inv4.7%
Applied egg-rr4.7%
associate-/r/4.7%
*-inverses4.7%
*-lft-identity4.7%
Simplified4.7%
Final simplification4.7%
herbie shell --seed 2024080
(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))))