
(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}
Herbie found 9 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))))) (* (- s) (log (- (/ (+ 1.0 t_0) (fma (- 1.0 u) t_0 u)) 1.0)))))
float code(float u, float s) {
float t_0 = expf(-(((float) M_PI) / s));
return -s * logf((((1.0f + t_0) / fmaf((1.0f - u), t_0, u)) - 1.0f));
}
function code(u, s) t_0 = exp(Float32(-Float32(Float32(pi) / s))) return Float32(Float32(-s) * log(Float32(Float32(Float32(Float32(1.0) + t_0) / fma(Float32(Float32(1.0) - u), t_0, u)) - Float32(1.0)))) end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := e^{-\frac{\pi}{s}}\\
\left(-s\right) \cdot \log \left(\frac{1 + t\_0}{\mathsf{fma}\left(1 - u, t\_0, u\right)} - 1\right)
\end{array}
\end{array}
Initial program 99.0%
Applied rewrites99.0%
Applied rewrites99.0%
(FPCore (u s) :precision binary32 (let* ((t_0 (exp (- (/ PI s))))) (* (- s) (log (- (/ (+ 1.0 t_0) (fma 1.0 t_0 u)) 1.0)))))
float code(float u, float s) {
float t_0 = expf(-(((float) M_PI) / s));
return -s * logf((((1.0f + t_0) / fmaf(1.0f, t_0, u)) - 1.0f));
}
function code(u, s) t_0 = exp(Float32(-Float32(Float32(pi) / s))) return Float32(Float32(-s) * log(Float32(Float32(Float32(Float32(1.0) + t_0) / fma(Float32(1.0), t_0, u)) - Float32(1.0)))) end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := e^{-\frac{\pi}{s}}\\
\left(-s\right) \cdot \log \left(\frac{1 + t\_0}{\mathsf{fma}\left(1, t\_0, u\right)} - 1\right)
\end{array}
\end{array}
Initial program 99.0%
Applied rewrites99.0%
Applied rewrites99.0%
Taylor expanded in u around 0
Applied rewrites98.7%
(FPCore (u s) :precision binary32 (let* ((t_0 (- (/ PI s)))) (* (- s) (log (- (/ (+ 1.0 (exp t_0)) (* -1.0 (* u (expm1 t_0)))) 1.0)))))
float code(float u, float s) {
float t_0 = -(((float) M_PI) / s);
return -s * logf((((1.0f + expf(t_0)) / (-1.0f * (u * expm1f(t_0)))) - 1.0f));
}
function code(u, s) t_0 = Float32(-Float32(Float32(pi) / s)) return Float32(Float32(-s) * log(Float32(Float32(Float32(Float32(1.0) + exp(t_0)) / Float32(Float32(-1.0) * Float32(u * expm1(t_0)))) - Float32(1.0)))) end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := -\frac{\pi}{s}\\
\left(-s\right) \cdot \log \left(\frac{1 + e^{t\_0}}{-1 \cdot \left(u \cdot \mathsf{expm1}\left(t\_0\right)\right)} - 1\right)
\end{array}
\end{array}
Initial program 99.0%
Applied rewrites99.0%
Applied rewrites99.0%
Taylor expanded in u around -inf
Applied rewrites97.8%
(FPCore (u s) :precision binary32 (* (- s) (log (+ 1.0 (* -1.0 (/ (- PI (* 2.0 PI)) s))))))
float code(float u, float s) {
return -s * logf((1.0f + (-1.0f * ((((float) M_PI) - (2.0f * ((float) M_PI))) / s))));
}
function code(u, s) return Float32(Float32(-s) * log(Float32(Float32(1.0) + Float32(Float32(-1.0) * Float32(Float32(Float32(pi) - Float32(Float32(2.0) * Float32(pi))) / s))))) end
function tmp = code(u, s) tmp = -s * log((single(1.0) + (single(-1.0) * ((single(pi) - (single(2.0) * single(pi))) / s)))); end
\begin{array}{l}
\\
\left(-s\right) \cdot \log \left(1 + -1 \cdot \frac{\pi - 2 \cdot \pi}{s}\right)
\end{array}
Initial program 99.0%
Applied rewrites99.0%
Applied rewrites99.0%
Taylor expanded in s around -inf
Applied rewrites24.9%
Taylor expanded in u around 0
Applied rewrites25.1%
(FPCore (u s) :precision binary32 (/ s (* u (- 0.5 (+ 0.5 (* 0.25 (/ PI s)))))))
float code(float u, float s) {
return s / (u * (0.5f - (0.5f + (0.25f * (((float) M_PI) / s)))));
}
function code(u, s) return Float32(s / Float32(u * Float32(Float32(0.5) - Float32(Float32(0.5) + Float32(Float32(0.25) * Float32(Float32(pi) / s)))))) end
function tmp = code(u, s) tmp = s / (u * (single(0.5) - (single(0.5) + (single(0.25) * (single(pi) / s))))); end
\begin{array}{l}
\\
\frac{s}{u \cdot \left(0.5 - \left(0.5 + 0.25 \cdot \frac{\pi}{s}\right)\right)}
\end{array}
Initial program 99.0%
Applied rewrites99.0%
Taylor expanded in u around -inf
Applied rewrites17.3%
Taylor expanded in s around inf
Applied rewrites14.4%
Taylor expanded in s around inf
Applied rewrites14.4%
(FPCore (u s) :precision binary32 (* u (- (+ PI PI) (/ PI u))))
float code(float u, float s) {
return u * ((((float) M_PI) + ((float) M_PI)) - (((float) M_PI) / u));
}
function code(u, s) return Float32(u * Float32(Float32(Float32(pi) + Float32(pi)) - Float32(Float32(pi) / u))) end
function tmp = code(u, s) tmp = u * ((single(pi) + single(pi)) - (single(pi) / u)); end
\begin{array}{l}
\\
u \cdot \left(\left(\pi + \pi\right) - \frac{\pi}{u}\right)
\end{array}
Initial program 99.0%
Taylor expanded in s around inf
Applied rewrites11.4%
Applied rewrites11.4%
Taylor expanded in u around inf
Applied rewrites11.4%
Applied rewrites11.4%
(FPCore (u s) :precision binary32 (- PI (* 2.0 (* PI (- 1.0 u)))))
float code(float u, float s) {
return ((float) M_PI) - (2.0f * (((float) M_PI) * (1.0f - u)));
}
function code(u, s) return Float32(Float32(pi) - Float32(Float32(2.0) * Float32(Float32(pi) * Float32(Float32(1.0) - u)))) end
function tmp = code(u, s) tmp = single(pi) - (single(2.0) * (single(pi) * (single(1.0) - u))); end
\begin{array}{l}
\\
\pi - 2 \cdot \left(\pi \cdot \left(1 - u\right)\right)
\end{array}
Initial program 99.0%
Applied rewrites99.0%
Applied rewrites99.0%
Taylor expanded in s around -inf
Applied rewrites11.4%
(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(Float32(-s) * Float32(Float32(pi) / s)) end
function tmp = code(u, s) tmp = -s * (single(pi) / s); end
\begin{array}{l}
\\
\left(-s\right) \cdot \frac{\pi}{s}
\end{array}
Initial program 99.0%
Taylor expanded in u around 0
Applied rewrites11.2%
(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%
Taylor expanded in u around 0
Applied rewrites11.2%
Applied rewrites11.2%
herbie shell --seed 2025153
(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))))