
(FPCore (cosTheta alpha)
:precision binary32
(let* ((t_0 (- (* alpha alpha) 1.0)))
(/
t_0
(* (* PI (log (* alpha alpha))) (+ 1.0 (* (* t_0 cosTheta) cosTheta))))))
float code(float cosTheta, float alpha) {
float t_0 = (alpha * alpha) - 1.0f;
return t_0 / ((((float) M_PI) * logf((alpha * alpha))) * (1.0f + ((t_0 * cosTheta) * cosTheta)));
}
function code(cosTheta, alpha) t_0 = Float32(Float32(alpha * alpha) - Float32(1.0)) return Float32(t_0 / Float32(Float32(Float32(pi) * log(Float32(alpha * alpha))) * Float32(Float32(1.0) + Float32(Float32(t_0 * cosTheta) * cosTheta)))) end
function tmp = code(cosTheta, alpha) t_0 = (alpha * alpha) - single(1.0); tmp = t_0 / ((single(pi) * log((alpha * alpha))) * (single(1.0) + ((t_0 * cosTheta) * cosTheta))); end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \alpha \cdot \alpha - 1\\
\frac{t\_0}{\left(\pi \cdot \log \left(\alpha \cdot \alpha\right)\right) \cdot \left(1 + \left(t\_0 \cdot cosTheta\right) \cdot cosTheta\right)}
\end{array}
\end{array}
Herbie found 9 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (cosTheta alpha)
:precision binary32
(let* ((t_0 (- (* alpha alpha) 1.0)))
(/
t_0
(* (* PI (log (* alpha alpha))) (+ 1.0 (* (* t_0 cosTheta) cosTheta))))))
float code(float cosTheta, float alpha) {
float t_0 = (alpha * alpha) - 1.0f;
return t_0 / ((((float) M_PI) * logf((alpha * alpha))) * (1.0f + ((t_0 * cosTheta) * cosTheta)));
}
function code(cosTheta, alpha) t_0 = Float32(Float32(alpha * alpha) - Float32(1.0)) return Float32(t_0 / Float32(Float32(Float32(pi) * log(Float32(alpha * alpha))) * Float32(Float32(1.0) + Float32(Float32(t_0 * cosTheta) * cosTheta)))) end
function tmp = code(cosTheta, alpha) t_0 = (alpha * alpha) - single(1.0); tmp = t_0 / ((single(pi) * log((alpha * alpha))) * (single(1.0) + ((t_0 * cosTheta) * cosTheta))); end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \alpha \cdot \alpha - 1\\
\frac{t\_0}{\left(\pi \cdot \log \left(\alpha \cdot \alpha\right)\right) \cdot \left(1 + \left(t\_0 \cdot cosTheta\right) \cdot cosTheta\right)}
\end{array}
\end{array}
(FPCore (cosTheta alpha) :precision binary32 (let* ((t_0 (* (/ 1.0 (/ 1.0 alpha)) alpha)) (t_1 (- t_0 1.0))) (/ t_1 (* (log (pow t_0 PI)) (+ 1.0 (* (* t_1 cosTheta) cosTheta))))))
float code(float cosTheta, float alpha) {
float t_0 = (1.0f / (1.0f / alpha)) * alpha;
float t_1 = t_0 - 1.0f;
return t_1 / (logf(powf(t_0, ((float) M_PI))) * (1.0f + ((t_1 * cosTheta) * cosTheta)));
}
function code(cosTheta, alpha) t_0 = Float32(Float32(Float32(1.0) / Float32(Float32(1.0) / alpha)) * alpha) t_1 = Float32(t_0 - Float32(1.0)) return Float32(t_1 / Float32(log((t_0 ^ Float32(pi))) * Float32(Float32(1.0) + Float32(Float32(t_1 * cosTheta) * cosTheta)))) end
function tmp = code(cosTheta, alpha) t_0 = (single(1.0) / (single(1.0) / alpha)) * alpha; t_1 = t_0 - single(1.0); tmp = t_1 / (log((t_0 ^ single(pi))) * (single(1.0) + ((t_1 * cosTheta) * cosTheta))); end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \frac{1}{\frac{1}{\alpha}} \cdot \alpha\\
t_1 := t\_0 - 1\\
\frac{t\_1}{\log \left({t\_0}^{\pi}\right) \cdot \left(1 + \left(t\_1 \cdot cosTheta\right) \cdot cosTheta\right)}
\end{array}
\end{array}
Initial program 98.6%
lift-PI.f32N/A
lift-*.f32N/A
lift-*.f32N/A
lift-log.f32N/A
log-pow-revN/A
pow2N/A
lower-log.f32N/A
lower-pow.f32N/A
pow2N/A
lift-*.f32N/A
lift-PI.f3298.7
Applied rewrites98.7%
lift-*.f32N/A
pow2N/A
metadata-evalN/A
pow-plus-revN/A
metadata-evalN/A
lower-*.f32N/A
metadata-evalN/A
metadata-evalN/A
pow-negN/A
inv-powN/A
lower-/.f32N/A
lower-/.f3298.6
Applied rewrites98.6%
lift-*.f32N/A
pow2N/A
metadata-evalN/A
pow-plus-revN/A
metadata-evalN/A
lower-*.f32N/A
metadata-evalN/A
metadata-evalN/A
pow-negN/A
inv-powN/A
lower-/.f32N/A
lower-/.f3298.7
Applied rewrites98.7%
lift-*.f32N/A
pow2N/A
metadata-evalN/A
pow-plus-revN/A
metadata-evalN/A
lower-*.f32N/A
metadata-evalN/A
metadata-evalN/A
pow-negN/A
inv-powN/A
lower-/.f32N/A
lower-/.f3298.7
Applied rewrites98.7%
(FPCore (cosTheta alpha)
:precision binary32
(let* ((t_0 (- (* alpha alpha) 1.0)))
(/
t_0
(* (log (pow (* alpha alpha) PI)) (+ 1.0 (* (* t_0 cosTheta) cosTheta))))))
float code(float cosTheta, float alpha) {
float t_0 = (alpha * alpha) - 1.0f;
return t_0 / (logf(powf((alpha * alpha), ((float) M_PI))) * (1.0f + ((t_0 * cosTheta) * cosTheta)));
}
function code(cosTheta, alpha) t_0 = Float32(Float32(alpha * alpha) - Float32(1.0)) return Float32(t_0 / Float32(log((Float32(alpha * alpha) ^ Float32(pi))) * Float32(Float32(1.0) + Float32(Float32(t_0 * cosTheta) * cosTheta)))) end
function tmp = code(cosTheta, alpha) t_0 = (alpha * alpha) - single(1.0); tmp = t_0 / (log(((alpha * alpha) ^ single(pi))) * (single(1.0) + ((t_0 * cosTheta) * cosTheta))); end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \alpha \cdot \alpha - 1\\
\frac{t\_0}{\log \left({\left(\alpha \cdot \alpha\right)}^{\pi}\right) \cdot \left(1 + \left(t\_0 \cdot cosTheta\right) \cdot cosTheta\right)}
\end{array}
\end{array}
Initial program 98.6%
lift-PI.f32N/A
lift-*.f32N/A
lift-*.f32N/A
lift-log.f32N/A
log-pow-revN/A
pow2N/A
lower-log.f32N/A
lower-pow.f32N/A
pow2N/A
lift-*.f32N/A
lift-PI.f3298.7
Applied rewrites98.7%
(FPCore (cosTheta alpha)
:precision binary32
(let* ((t_0 (- (* alpha alpha) 1.0)))
(/
t_0
(* (* PI (log (* alpha alpha))) (fma (* t_0 cosTheta) cosTheta 1.0)))))
float code(float cosTheta, float alpha) {
float t_0 = (alpha * alpha) - 1.0f;
return t_0 / ((((float) M_PI) * logf((alpha * alpha))) * fmaf((t_0 * cosTheta), cosTheta, 1.0f));
}
function code(cosTheta, alpha) t_0 = Float32(Float32(alpha * alpha) - Float32(1.0)) return Float32(t_0 / Float32(Float32(Float32(pi) * log(Float32(alpha * alpha))) * fma(Float32(t_0 * cosTheta), cosTheta, Float32(1.0)))) end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \alpha \cdot \alpha - 1\\
\frac{t\_0}{\left(\pi \cdot \log \left(\alpha \cdot \alpha\right)\right) \cdot \mathsf{fma}\left(t\_0 \cdot cosTheta, cosTheta, 1\right)}
\end{array}
\end{array}
Initial program 98.6%
lift-+.f32N/A
lift-*.f32N/A
lift-*.f32N/A
lift-*.f32N/A
lift--.f32N/A
+-commutativeN/A
lower-fma.f32N/A
lift--.f32N/A
lift-*.f32N/A
lift-*.f3298.6
Applied rewrites98.6%
(FPCore (cosTheta alpha) :precision binary32 (let* ((t_0 (- (* alpha alpha) 1.0))) (/ t_0 (* PI (* (* (log alpha) 2.0) (fma (* cosTheta cosTheta) t_0 1.0))))))
float code(float cosTheta, float alpha) {
float t_0 = (alpha * alpha) - 1.0f;
return t_0 / (((float) M_PI) * ((logf(alpha) * 2.0f) * fmaf((cosTheta * cosTheta), t_0, 1.0f)));
}
function code(cosTheta, alpha) t_0 = Float32(Float32(alpha * alpha) - Float32(1.0)) return Float32(t_0 / Float32(Float32(pi) * Float32(Float32(log(alpha) * Float32(2.0)) * fma(Float32(cosTheta * cosTheta), t_0, Float32(1.0))))) end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \alpha \cdot \alpha - 1\\
\frac{t\_0}{\pi \cdot \left(\left(\log \alpha \cdot 2\right) \cdot \mathsf{fma}\left(cosTheta \cdot cosTheta, t\_0, 1\right)\right)}
\end{array}
\end{array}
Initial program 98.6%
lift-*.f32N/A
lift-PI.f32N/A
lift-*.f32N/A
lift-*.f32N/A
pow2N/A
lower-log.f32N/A
lift-+.f32N/A
lift-*.f32N/A
lift-*.f32N/A
lift-*.f32N/A
lift--.f32N/A
associate-*l*N/A
lower-*.f32N/A
lift-PI.f32N/A
lower-*.f32N/A
Applied rewrites98.5%
(FPCore (cosTheta alpha) :precision binary32 (/ (- (* alpha alpha) 1.0) (* (* 2.0 PI) (* (log alpha) (fma (- cosTheta) cosTheta 1.0)))))
float code(float cosTheta, float alpha) {
return ((alpha * alpha) - 1.0f) / ((2.0f * ((float) M_PI)) * (logf(alpha) * fmaf(-cosTheta, cosTheta, 1.0f)));
}
function code(cosTheta, alpha) return Float32(Float32(Float32(alpha * alpha) - Float32(1.0)) / Float32(Float32(Float32(2.0) * Float32(pi)) * Float32(log(alpha) * fma(Float32(-cosTheta), cosTheta, Float32(1.0))))) end
\begin{array}{l}
\\
\frac{\alpha \cdot \alpha - 1}{\left(2 \cdot \pi\right) \cdot \left(\log \alpha \cdot \mathsf{fma}\left(-cosTheta, cosTheta, 1\right)\right)}
\end{array}
Initial program 98.6%
lift-PI.f32N/A
lift-*.f32N/A
lift-*.f32N/A
lift-log.f32N/A
log-pow-revN/A
pow2N/A
lower-log.f32N/A
lower-pow.f32N/A
pow2N/A
lift-*.f32N/A
lift-PI.f3298.7
Applied rewrites98.7%
Taylor expanded in alpha around 0
associate-*r*N/A
lower-*.f32N/A
lower-*.f32N/A
lift-PI.f32N/A
lower-*.f32N/A
lift-log.f32N/A
mul-1-negN/A
+-commutativeN/A
pow2N/A
distribute-lft-neg-inN/A
mul-1-negN/A
lower-fma.f32N/A
mul-1-negN/A
lower-neg.f3297.4
Applied rewrites97.4%
(FPCore (cosTheta alpha) :precision binary32 (/ (- (* alpha alpha) 1.0) (* (* (* (log alpha) PI) (- 1.0 (* cosTheta cosTheta))) 2.0)))
float code(float cosTheta, float alpha) {
return ((alpha * alpha) - 1.0f) / (((logf(alpha) * ((float) M_PI)) * (1.0f - (cosTheta * cosTheta))) * 2.0f);
}
function code(cosTheta, alpha) return Float32(Float32(Float32(alpha * alpha) - Float32(1.0)) / Float32(Float32(Float32(log(alpha) * Float32(pi)) * Float32(Float32(1.0) - Float32(cosTheta * cosTheta))) * Float32(2.0))) end
function tmp = code(cosTheta, alpha) tmp = ((alpha * alpha) - single(1.0)) / (((log(alpha) * single(pi)) * (single(1.0) - (cosTheta * cosTheta))) * single(2.0)); end
\begin{array}{l}
\\
\frac{\alpha \cdot \alpha - 1}{\left(\left(\log \alpha \cdot \pi\right) \cdot \left(1 - cosTheta \cdot cosTheta\right)\right) \cdot 2}
\end{array}
Initial program 98.6%
Taylor expanded in alpha around inf
*-commutativeN/A
lower-*.f32N/A
Applied rewrites98.2%
Taylor expanded in alpha around 0
*-commutativeN/A
lower-*.f32N/A
Applied rewrites97.4%
(FPCore (cosTheta alpha) :precision binary32 (/ (- (* alpha alpha) 1.0) (* (* PI (log (* alpha alpha))) 1.0)))
float code(float cosTheta, float alpha) {
return ((alpha * alpha) - 1.0f) / ((((float) M_PI) * logf((alpha * alpha))) * 1.0f);
}
function code(cosTheta, alpha) return Float32(Float32(Float32(alpha * alpha) - Float32(1.0)) / Float32(Float32(Float32(pi) * log(Float32(alpha * alpha))) * Float32(1.0))) end
function tmp = code(cosTheta, alpha) tmp = ((alpha * alpha) - single(1.0)) / ((single(pi) * log((alpha * alpha))) * single(1.0)); end
\begin{array}{l}
\\
\frac{\alpha \cdot \alpha - 1}{\left(\pi \cdot \log \left(\alpha \cdot \alpha\right)\right) \cdot 1}
\end{array}
Initial program 98.6%
Taylor expanded in cosTheta around 0
Applied rewrites95.1%
(FPCore (cosTheta alpha) :precision binary32 (/ (- (* alpha alpha) 1.0) (* (* (log alpha) PI) 2.0)))
float code(float cosTheta, float alpha) {
return ((alpha * alpha) - 1.0f) / ((logf(alpha) * ((float) M_PI)) * 2.0f);
}
function code(cosTheta, alpha) return Float32(Float32(Float32(alpha * alpha) - Float32(1.0)) / Float32(Float32(log(alpha) * Float32(pi)) * Float32(2.0))) end
function tmp = code(cosTheta, alpha) tmp = ((alpha * alpha) - single(1.0)) / ((log(alpha) * single(pi)) * single(2.0)); end
\begin{array}{l}
\\
\frac{\alpha \cdot \alpha - 1}{\left(\log \alpha \cdot \pi\right) \cdot 2}
\end{array}
Initial program 98.6%
Taylor expanded in cosTheta around 0
log-pow-revN/A
pow-powN/A
log-pow-revN/A
associate-*r*N/A
*-commutativeN/A
lower-*.f32N/A
*-commutativeN/A
lower-*.f32N/A
lower-log.f32N/A
lift-PI.f3295.0
Applied rewrites95.0%
(FPCore (cosTheta alpha) :precision binary32 (* (/ 0.5 (* (log alpha) PI)) (- alpha 1.0)))
float code(float cosTheta, float alpha) {
return (0.5f / (logf(alpha) * ((float) M_PI))) * (alpha - 1.0f);
}
function code(cosTheta, alpha) return Float32(Float32(Float32(0.5) / Float32(log(alpha) * Float32(pi))) * Float32(alpha - Float32(1.0))) end
function tmp = code(cosTheta, alpha) tmp = (single(0.5) / (log(alpha) * single(pi))) * (alpha - single(1.0)); end
\begin{array}{l}
\\
\frac{0.5}{\log \alpha \cdot \pi} \cdot \left(\alpha - 1\right)
\end{array}
Initial program 98.6%
lift-/.f32N/A
lift-*.f32N/A
lift--.f32N/A
difference-of-sqr-1N/A
lift-*.f32N/A
lift-PI.f32N/A
lift-*.f32N/A
lift-*.f32N/A
pow2N/A
lower-log.f32N/A
lift-+.f32N/A
lift-*.f32N/A
lift-*.f32N/A
lift-*.f32N/A
lift--.f32N/A
Applied rewrites98.1%
Taylor expanded in cosTheta around 0
lift--.f3294.7
Applied rewrites94.7%
Taylor expanded in alpha around 0
lower-/.f32N/A
*-commutativeN/A
lift-log.f32N/A
lift-*.f32N/A
lift-PI.f3247.1
Applied rewrites47.1%
herbie shell --seed 2025116
(FPCore (cosTheta alpha)
:name "GTR1 distribution"
:precision binary32
:pre (and (and (<= 0.0 cosTheta) (<= cosTheta 1.0)) (and (<= 0.0001 alpha) (<= alpha 1.0)))
(/ (- (* alpha alpha) 1.0) (* (* PI (log (* alpha alpha))) (+ 1.0 (* (* (- (* alpha alpha) 1.0) cosTheta) cosTheta)))))