
(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 14 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 (exp (/ PI s))))
(t_1 (/ u (+ 1.0 (exp (/ PI (- s))))))
(t_2 (+ t_1 (/ (- 1.0 u) t_0))))
(*
(- s)
(log
(/
(+ -1.0 (pow t_2 -3.0))
(+ (+ 1.0 (pow t_2 -2.0)) (/ -1.0 (- (/ (+ -1.0 u) t_0) t_1))))))))
float code(float u, float s) {
float t_0 = 1.0f + expf((((float) M_PI) / s));
float t_1 = u / (1.0f + expf((((float) M_PI) / -s)));
float t_2 = t_1 + ((1.0f - u) / t_0);
return -s * logf(((-1.0f + powf(t_2, -3.0f)) / ((1.0f + powf(t_2, -2.0f)) + (-1.0f / (((-1.0f + u) / t_0) - t_1)))));
}
function code(u, s) t_0 = Float32(Float32(1.0) + exp(Float32(Float32(pi) / s))) t_1 = Float32(u / Float32(Float32(1.0) + exp(Float32(Float32(pi) / Float32(-s))))) t_2 = Float32(t_1 + Float32(Float32(Float32(1.0) - u) / t_0)) return Float32(Float32(-s) * log(Float32(Float32(Float32(-1.0) + (t_2 ^ Float32(-3.0))) / Float32(Float32(Float32(1.0) + (t_2 ^ Float32(-2.0))) + Float32(Float32(-1.0) / Float32(Float32(Float32(Float32(-1.0) + u) / t_0) - t_1)))))) end
function tmp = code(u, s) t_0 = single(1.0) + exp((single(pi) / s)); t_1 = u / (single(1.0) + exp((single(pi) / -s))); t_2 = t_1 + ((single(1.0) - u) / t_0); tmp = -s * log(((single(-1.0) + (t_2 ^ single(-3.0))) / ((single(1.0) + (t_2 ^ single(-2.0))) + (single(-1.0) / (((single(-1.0) + u) / t_0) - t_1))))); end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := 1 + e^{\frac{\pi}{s}}\\
t_1 := \frac{u}{1 + e^{\frac{\pi}{-s}}}\\
t_2 := t\_1 + \frac{1 - u}{t\_0}\\
\left(-s\right) \cdot \log \left(\frac{-1 + {t\_2}^{-3}}{\left(1 + {t\_2}^{-2}\right) + \frac{-1}{\frac{-1 + u}{t\_0} - t\_1}}\right)
\end{array}
\end{array}
Initial program 99.0%
Simplified98.9%
div-inv99.0%
Applied egg-rr99.0%
flip3-+98.9%
Applied egg-rr99.0%
+-commutative99.0%
associate-+r-99.0%
associate-*l/99.0%
Simplified99.0%
Final simplification99.0%
(FPCore (u s)
:precision binary32
(let* ((t_0 (exp (/ PI s))))
(*
s
(-
(log
(+
-1.0
(cbrt
(pow
(+
(/ 1.0 (+ 1.0 t_0))
(+ (/ u (+ 1.0 (exp (/ PI (- s))))) (/ u (- -1.0 t_0))))
-3.0))))))))
float code(float u, float s) {
float t_0 = expf((((float) M_PI) / s));
return s * -logf((-1.0f + cbrtf(powf(((1.0f / (1.0f + t_0)) + ((u / (1.0f + expf((((float) M_PI) / -s)))) + (u / (-1.0f - t_0)))), -3.0f))));
}
function code(u, s) t_0 = exp(Float32(Float32(pi) / s)) return Float32(s * Float32(-log(Float32(Float32(-1.0) + cbrt((Float32(Float32(Float32(1.0) / Float32(Float32(1.0) + t_0)) + Float32(Float32(u / Float32(Float32(1.0) + exp(Float32(Float32(pi) / Float32(-s))))) + Float32(u / Float32(Float32(-1.0) - t_0)))) ^ Float32(-3.0))))))) end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := e^{\frac{\pi}{s}}\\
s \cdot \left(-\log \left(-1 + \sqrt[3]{{\left(\frac{1}{1 + t\_0} + \left(\frac{u}{1 + e^{\frac{\pi}{-s}}} + \frac{u}{-1 - t\_0}\right)\right)}^{-3}}\right)\right)
\end{array}
\end{array}
Initial program 99.0%
Simplified98.9%
Taylor expanded in s around 0 99.0%
associate-*r*99.0%
mul-1-neg99.0%
sub-neg99.0%
Simplified99.0%
add-cbrt-cube98.9%
pow1/398.5%
Applied egg-rr98.4%
unpow1/399.0%
Simplified99.0%
Final simplification99.0%
(FPCore (u s)
:precision binary32
(*
s
(-
(log
(+
-1.0
(/
1.0
(+
(/ u (+ 1.0 (exp (/ PI (- s)))))
(/ (- 1.0 u) (+ 1.0 (exp (* PI (/ 1.0 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) * (1.0f / 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) * Float32(Float32(1.0) / 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) * (single(1.0) / 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^{\pi \cdot \frac{1}{s}}}}\right)\right)
\end{array}
Initial program 99.0%
Simplified98.9%
div-inv99.0%
Applied egg-rr99.0%
Final simplification99.0%
(FPCore (u s)
:precision binary32
(*
(- s)
(log
(+
-1.0
(/
-1.0
(-
(/ (+ -1.0 u) (+ 1.0 (exp (/ PI s))))
(/ u (+ 1.0 (exp (/ PI (- s)))))))))))
float code(float u, float s) {
return -s * logf((-1.0f + (-1.0f / (((-1.0f + u) / (1.0f + expf((((float) M_PI) / s)))) - (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(Float32(Float32(-1.0) + u) / Float32(Float32(1.0) + exp(Float32(Float32(pi) / s)))) - Float32(u / Float32(Float32(1.0) + exp(Float32(Float32(pi) / Float32(-s)))))))))) 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(1.0) + exp((single(pi) / -s)))))))); end
\begin{array}{l}
\\
\left(-s\right) \cdot \log \left(-1 + \frac{-1}{\frac{-1 + u}{1 + e^{\frac{\pi}{s}}} - \frac{u}{1 + e^{\frac{\pi}{-s}}}}\right)
\end{array}
Initial program 99.0%
Simplified98.9%
Final simplification98.9%
(FPCore (u s) :precision binary32 (* (- s) (log (+ -1.0 (/ 1.0 (+ (/ 1.0 (+ 1.0 (exp (/ PI s)))) (/ u 2.0)))))))
float code(float u, float s) {
return -s * logf((-1.0f + (1.0f / ((1.0f / (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(1.0) / 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) / (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}{1 + e^{\frac{\pi}{s}}} + \frac{u}{2}}\right)
\end{array}
Initial program 99.0%
Simplified98.9%
div-inv99.0%
Applied egg-rr99.0%
Taylor expanded in s around inf 37.7%
Taylor expanded in u around 0 37.7%
Final simplification37.7%
(FPCore (u s) :precision binary32 (* (- s) (log (+ -1.0 (/ 1.0 (+ (/ u 2.0) (/ (- 1.0 u) (+ (/ PI s) 2.0))))))))
float code(float u, float s) {
return -s * logf((-1.0f + (1.0f / ((u / 2.0f) + ((1.0f - u) / ((((float) M_PI) / s) + 2.0f))))));
}
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(Float32(pi) / s) + Float32(2.0)))))))) end
function tmp = code(u, s) tmp = -s * log((single(-1.0) + (single(1.0) / ((u / single(2.0)) + ((single(1.0) - u) / ((single(pi) / s) + single(2.0))))))); end
\begin{array}{l}
\\
\left(-s\right) \cdot \log \left(-1 + \frac{1}{\frac{u}{2} + \frac{1 - u}{\frac{\pi}{s} + 2}}\right)
\end{array}
Initial program 99.0%
Simplified98.9%
div-inv99.0%
Applied egg-rr99.0%
Taylor expanded in s around inf 37.7%
Taylor expanded in s around inf 36.1%
+-commutative36.1%
Simplified36.1%
Final simplification36.1%
(FPCore (u s) :precision binary32 (* s (- (log (+ 1.0 (/ (* 4.0 (+ (* u (* PI -0.5)) (* PI 0.25))) s))))))
float code(float u, float s) {
return s * -logf((1.0f + ((4.0f * ((u * (((float) M_PI) * -0.5f)) + (((float) M_PI) * 0.25f))) / s)));
}
function code(u, s) return Float32(s * Float32(-log(Float32(Float32(1.0) + Float32(Float32(Float32(4.0) * Float32(Float32(u * Float32(Float32(pi) * Float32(-0.5))) + Float32(Float32(pi) * Float32(0.25)))) / s))))) end
function tmp = code(u, s) tmp = s * -log((single(1.0) + ((single(4.0) * ((u * (single(pi) * single(-0.5))) + (single(pi) * single(0.25)))) / s))); end
\begin{array}{l}
\\
s \cdot \left(-\log \left(1 + \frac{4 \cdot \left(u \cdot \left(\pi \cdot -0.5\right) + \pi \cdot 0.25\right)}{s}\right)\right)
\end{array}
Initial program 99.0%
Taylor expanded in s around -inf 24.9%
associate-*r/24.9%
cancel-sign-sub-inv24.9%
distribute-rgt-out--24.9%
metadata-eval24.9%
metadata-eval24.9%
*-commutative24.9%
Simplified24.9%
Final simplification24.9%
(FPCore (u s) :precision binary32 (* s (* 4.0 (/ (- (* PI (- (- 0.25) (* u -0.25))) (* -0.25 (* u PI))) s))))
float code(float u, float s) {
return s * (4.0f * (((((float) M_PI) * (-0.25f - (u * -0.25f))) - (-0.25f * (u * ((float) M_PI)))) / s));
}
function code(u, s) return Float32(s * Float32(Float32(4.0) * Float32(Float32(Float32(Float32(pi) * Float32(Float32(-Float32(0.25)) - Float32(u * Float32(-0.25)))) - Float32(Float32(-0.25) * Float32(u * Float32(pi)))) / s))) end
function tmp = code(u, s) tmp = s * (single(4.0) * (((single(pi) * (-single(0.25) - (u * single(-0.25)))) - (single(-0.25) * (u * single(pi)))) / s)); end
\begin{array}{l}
\\
s \cdot \left(4 \cdot \frac{\pi \cdot \left(\left(-0.25\right) - u \cdot -0.25\right) - -0.25 \cdot \left(u \cdot \pi\right)}{s}\right)
\end{array}
Initial program 99.0%
Simplified98.9%
Taylor expanded in s around 0 99.0%
associate-*r*99.0%
mul-1-neg99.0%
sub-neg99.0%
Simplified99.0%
Taylor expanded in s around -inf 11.7%
Simplified11.7%
Final simplification11.7%
(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 99.0%
Simplified98.9%
Taylor expanded in s around 0 99.0%
associate-*r*99.0%
mul-1-neg99.0%
sub-neg99.0%
Simplified99.0%
Taylor expanded in s around inf 11.7%
metadata-eval11.7%
distribute-lft-neg-in11.7%
associate-*r/11.7%
distribute-neg-frac211.7%
Simplified11.7%
Final simplification11.7%
(FPCore (u s) :precision binary32 (* u (- (* PI 2.0) (/ PI u))))
float code(float u, float s) {
return u * ((((float) M_PI) * 2.0f) - (((float) M_PI) / u));
}
function code(u, s) return Float32(u * Float32(Float32(Float32(pi) * Float32(2.0)) - Float32(Float32(pi) / u))) end
function tmp = code(u, s) tmp = u * ((single(pi) * single(2.0)) - (single(pi) / u)); end
\begin{array}{l}
\\
u \cdot \left(\pi \cdot 2 - \frac{\pi}{u}\right)
\end{array}
Initial program 99.0%
Taylor expanded in s around inf 11.7%
cancel-sign-sub-inv11.7%
distribute-rgt-out--11.7%
metadata-eval11.7%
metadata-eval11.7%
*-commutative11.7%
Simplified11.7%
Taylor expanded in u around inf 11.7%
+-commutative11.7%
mul-1-neg11.7%
unsub-neg11.7%
*-commutative11.7%
Simplified11.7%
(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 99.0%
Simplified98.9%
Taylor expanded in s around 0 99.0%
associate-*r*99.0%
mul-1-neg99.0%
sub-neg99.0%
Simplified99.0%
Taylor expanded in s around inf 11.7%
associate--r+11.7%
cancel-sign-sub-inv11.7%
*-commutative11.7%
*-commutative11.7%
*-commutative11.7%
*-commutative11.7%
distribute-lft-out--11.7%
metadata-eval11.7%
metadata-eval11.7%
*-commutative11.7%
distribute-rgt-out11.7%
+-commutative11.7%
associate-*l*11.7%
metadata-eval11.7%
*-commutative11.7%
associate-*l*11.7%
Simplified11.7%
Final simplification11.7%
(FPCore (u s) :precision binary32 (* s (/ PI (- s))))
float code(float u, float s) {
return s * (((float) M_PI) / -s);
}
function code(u, s) return Float32(s * Float32(Float32(pi) / Float32(-s))) end
function tmp = code(u, s) tmp = s * (single(pi) / -s); end
\begin{array}{l}
\\
s \cdot \frac{\pi}{-s}
\end{array}
Initial program 99.0%
Simplified98.9%
Taylor expanded in u around 0 11.4%
Final simplification11.4%
(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%
Simplified98.9%
Taylor expanded in u around 0 11.4%
mul-1-neg11.4%
Simplified11.4%
(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%
Taylor expanded in s around inf 10.3%
Taylor expanded in s around 0 10.3%
herbie shell --seed 2024114
(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))))