
(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 11 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
(/
(- (* alpha alpha) 1.0)
(log
(pow
(* alpha alpha)
(* (fma (* (fma alpha alpha -1.0) cosTheta) cosTheta 1.0) PI)))))
float code(float cosTheta, float alpha) {
return ((alpha * alpha) - 1.0f) / logf(powf((alpha * alpha), (fmaf((fmaf(alpha, alpha, -1.0f) * cosTheta), cosTheta, 1.0f) * ((float) M_PI))));
}
function code(cosTheta, alpha) return Float32(Float32(Float32(alpha * alpha) - Float32(1.0)) / log((Float32(alpha * alpha) ^ Float32(fma(Float32(fma(alpha, alpha, Float32(-1.0)) * cosTheta), cosTheta, Float32(1.0)) * Float32(pi))))) end
\begin{array}{l}
\\
\frac{\alpha \cdot \alpha - 1}{\log \left({\left(\alpha \cdot \alpha\right)}^{\left(\mathsf{fma}\left(\mathsf{fma}\left(\alpha, \alpha, -1\right) \cdot cosTheta, cosTheta, 1\right) \cdot \pi\right)}\right)}
\end{array}
Initial program 98.5%
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
associate-*r*N/A
lift-log.f32N/A
log-pow-revN/A
lower-log.f32N/A
*-commutativeN/A
lower-pow.f32N/A
*-commutativeN/A
lower-*.f3298.7
Applied rewrites98.7%
(FPCore (cosTheta alpha)
:precision binary32
(/
(- (* alpha alpha) 1.0)
(*
(*
(fma (* (fma alpha alpha -1.0) cosTheta) cosTheta 1.0)
(log (* alpha alpha)))
PI)))
float code(float cosTheta, float alpha) {
return ((alpha * alpha) - 1.0f) / ((fmaf((fmaf(alpha, alpha, -1.0f) * cosTheta), cosTheta, 1.0f) * logf((alpha * alpha))) * ((float) M_PI));
}
function code(cosTheta, alpha) return Float32(Float32(Float32(alpha * alpha) - Float32(1.0)) / Float32(Float32(fma(Float32(fma(alpha, alpha, Float32(-1.0)) * cosTheta), cosTheta, Float32(1.0)) * log(Float32(alpha * alpha))) * Float32(pi))) end
\begin{array}{l}
\\
\frac{\alpha \cdot \alpha - 1}{\left(\mathsf{fma}\left(\mathsf{fma}\left(\alpha, \alpha, -1\right) \cdot cosTheta, cosTheta, 1\right) \cdot \log \left(\alpha \cdot \alpha\right)\right) \cdot \pi}
\end{array}
Initial program 98.5%
lift-*.f32N/A
lift-*.f32N/A
associate-*l*N/A
*-commutativeN/A
lower-*.f32N/A
Applied rewrites98.5%
(FPCore (cosTheta alpha) :precision binary32 (/ (fma alpha alpha -1.0) (* (* (log alpha) (+ PI PI)) (fma (* cosTheta cosTheta) (fma alpha alpha -1.0) 1.0))))
float code(float cosTheta, float alpha) {
return fmaf(alpha, alpha, -1.0f) / ((logf(alpha) * (((float) M_PI) + ((float) M_PI))) * fmaf((cosTheta * cosTheta), fmaf(alpha, alpha, -1.0f), 1.0f));
}
function code(cosTheta, alpha) return Float32(fma(alpha, alpha, Float32(-1.0)) / Float32(Float32(log(alpha) * Float32(Float32(pi) + Float32(pi))) * fma(Float32(cosTheta * cosTheta), fma(alpha, alpha, Float32(-1.0)), Float32(1.0)))) end
\begin{array}{l}
\\
\frac{\mathsf{fma}\left(\alpha, \alpha, -1\right)}{\left(\log \alpha \cdot \left(\pi + \pi\right)\right) \cdot \mathsf{fma}\left(cosTheta \cdot cosTheta, \mathsf{fma}\left(\alpha, \alpha, -1\right), 1\right)}
\end{array}
Initial program 98.5%
lift-*.f32N/A
lift-*.f32N/A
associate-*l*N/A
*-commutativeN/A
lower-*.f32N/A
Applied rewrites98.5%
lift--.f32N/A
lift-*.f32N/A
difference-of-sqr-1N/A
difference-of-sqr--1N/A
lift-fma.f3298.5
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
*-commutativeN/A
associate-*r*N/A
*-commutativeN/A
lift-log.f32N/A
lift-*.f32N/A
pow2N/A
log-pow-revN/A
lift-log.f32N/A
associate-*r*N/A
lift-*.f32N/A
lift-*.f32N/A
Applied rewrites98.6%
(FPCore (cosTheta alpha) :precision binary32 (/ (- (* alpha alpha) 1.0) (* (* (fma (* -1.0 cosTheta) cosTheta 1.0) (log (* alpha alpha))) PI)))
float code(float cosTheta, float alpha) {
return ((alpha * alpha) - 1.0f) / ((fmaf((-1.0f * cosTheta), cosTheta, 1.0f) * logf((alpha * alpha))) * ((float) M_PI));
}
function code(cosTheta, alpha) return Float32(Float32(Float32(alpha * alpha) - Float32(1.0)) / Float32(Float32(fma(Float32(Float32(-1.0) * cosTheta), cosTheta, Float32(1.0)) * log(Float32(alpha * alpha))) * Float32(pi))) end
\begin{array}{l}
\\
\frac{\alpha \cdot \alpha - 1}{\left(\mathsf{fma}\left(-1 \cdot cosTheta, cosTheta, 1\right) \cdot \log \left(\alpha \cdot \alpha\right)\right) \cdot \pi}
\end{array}
Initial program 98.5%
lift-*.f32N/A
lift-*.f32N/A
associate-*l*N/A
*-commutativeN/A
lower-*.f32N/A
Applied rewrites98.5%
Taylor expanded in alpha around 0
lower-*.f3297.5
Applied rewrites97.5%
(FPCore (cosTheta alpha) :precision binary32 (/ (fma alpha alpha -1.0) (* (fma (* -1.0 cosTheta) cosTheta 1.0) (* 2.0 (* (log alpha) PI)))))
float code(float cosTheta, float alpha) {
return fmaf(alpha, alpha, -1.0f) / (fmaf((-1.0f * cosTheta), cosTheta, 1.0f) * (2.0f * (logf(alpha) * ((float) M_PI))));
}
function code(cosTheta, alpha) return Float32(fma(alpha, alpha, Float32(-1.0)) / Float32(fma(Float32(Float32(-1.0) * cosTheta), cosTheta, Float32(1.0)) * Float32(Float32(2.0) * Float32(log(alpha) * Float32(pi))))) end
\begin{array}{l}
\\
\frac{\mathsf{fma}\left(\alpha, \alpha, -1\right)}{\mathsf{fma}\left(-1 \cdot cosTheta, cosTheta, 1\right) \cdot \left(2 \cdot \left(\log \alpha \cdot \pi\right)\right)}
\end{array}
Initial program 98.5%
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
associate-*r*N/A
lift-log.f32N/A
log-pow-revN/A
lower-log.f32N/A
*-commutativeN/A
lower-pow.f32N/A
*-commutativeN/A
lower-*.f3298.7
Applied rewrites98.7%
Applied rewrites98.6%
Taylor expanded in alpha around 0
lower-*.f3297.5
Applied rewrites97.5%
(FPCore (cosTheta alpha) :precision binary32 (/ (/ (fma alpha alpha -1.0) (* (log alpha) 1.0)) (+ PI PI)))
float code(float cosTheta, float alpha) {
return (fmaf(alpha, alpha, -1.0f) / (logf(alpha) * 1.0f)) / (((float) M_PI) + ((float) M_PI));
}
function code(cosTheta, alpha) return Float32(Float32(fma(alpha, alpha, Float32(-1.0)) / Float32(log(alpha) * Float32(1.0))) / Float32(Float32(pi) + Float32(pi))) end
\begin{array}{l}
\\
\frac{\frac{\mathsf{fma}\left(\alpha, \alpha, -1\right)}{\log \alpha \cdot 1}}{\pi + \pi}
\end{array}
Initial program 98.5%
Taylor expanded in cosTheta around 0
Applied rewrites95.2%
lift-/.f32N/A
frac-2negN/A
mult-flipN/A
metadata-evalN/A
frac-2neg-revN/A
lower-*.f32N/A
lift--.f32N/A
sub-negate-revN/A
lower--.f32N/A
lower-/.f3295.0
Applied rewrites94.9%
Applied rewrites94.8%
lift-*.f32N/A
*-commutativeN/A
lift-/.f32N/A
lift-*.f32N/A
associate-/r*N/A
associate-*r/N/A
lower-/.f32N/A
Applied rewrites95.2%
(FPCore (cosTheta alpha) :precision binary32 (/ (fma alpha alpha -1.0) (* (* (log alpha) (+ PI PI)) 1.0)))
float code(float cosTheta, float alpha) {
return fmaf(alpha, alpha, -1.0f) / ((logf(alpha) * (((float) M_PI) + ((float) M_PI))) * 1.0f);
}
function code(cosTheta, alpha) return Float32(fma(alpha, alpha, Float32(-1.0)) / Float32(Float32(log(alpha) * Float32(Float32(pi) + Float32(pi))) * Float32(1.0))) end
\begin{array}{l}
\\
\frac{\mathsf{fma}\left(\alpha, \alpha, -1\right)}{\left(\log \alpha \cdot \left(\pi + \pi\right)\right) \cdot 1}
\end{array}
Initial program 98.5%
Taylor expanded in cosTheta around 0
Applied rewrites95.2%
lift-/.f32N/A
frac-2negN/A
mult-flipN/A
metadata-evalN/A
frac-2neg-revN/A
lower-*.f32N/A
lift--.f32N/A
sub-negate-revN/A
lower--.f32N/A
lower-/.f3295.0
Applied rewrites94.9%
lift-*.f32N/A
lift-/.f32N/A
frac-2negN/A
metadata-evalN/A
mult-flip-revN/A
lift--.f32N/A
sub-negate-revN/A
lift--.f32N/A
lift-*.f32N/A
distribute-lft-neg-inN/A
Applied rewrites95.2%
(FPCore (cosTheta alpha) :precision binary32 (/ (- (* alpha alpha) 1.0) (* 2.0 (* PI (log alpha)))))
float code(float cosTheta, float alpha) {
return ((alpha * alpha) - 1.0f) / (2.0f * (((float) M_PI) * logf(alpha)));
}
function code(cosTheta, alpha) return Float32(Float32(Float32(alpha * alpha) - Float32(1.0)) / Float32(Float32(2.0) * Float32(Float32(pi) * log(alpha)))) end
function tmp = code(cosTheta, alpha) tmp = ((alpha * alpha) - single(1.0)) / (single(2.0) * (single(pi) * log(alpha))); end
\begin{array}{l}
\\
\frac{\alpha \cdot \alpha - 1}{2 \cdot \left(\pi \cdot \log \alpha\right)}
\end{array}
Initial program 98.5%
lift-log.f32N/A
lift-*.f32N/A
pow2N/A
log-powN/A
lower-special-*.f32N/A
lower-special-log.f3298.5
Applied rewrites98.5%
Taylor expanded in cosTheta around 0
lower-*.f32N/A
lower-*.f32N/A
lower-PI.f32N/A
lower-log.f3295.1
Applied rewrites95.1%
(FPCore (cosTheta alpha) :precision binary32 (* (- 1.0 (* alpha alpha)) (/ -0.5 (* PI (log alpha)))))
float code(float cosTheta, float alpha) {
return (1.0f - (alpha * alpha)) * (-0.5f / (((float) M_PI) * logf(alpha)));
}
function code(cosTheta, alpha) return Float32(Float32(Float32(1.0) - Float32(alpha * alpha)) * Float32(Float32(-0.5) / Float32(Float32(pi) * log(alpha)))) end
function tmp = code(cosTheta, alpha) tmp = (single(1.0) - (alpha * alpha)) * (single(-0.5) / (single(pi) * log(alpha))); end
\begin{array}{l}
\\
\left(1 - \alpha \cdot \alpha\right) \cdot \frac{-0.5}{\pi \cdot \log \alpha}
\end{array}
Initial program 98.5%
Taylor expanded in cosTheta around 0
Applied rewrites95.2%
lift-/.f32N/A
frac-2negN/A
mult-flipN/A
metadata-evalN/A
frac-2neg-revN/A
lower-*.f32N/A
lift--.f32N/A
sub-negate-revN/A
lower--.f32N/A
lower-/.f3295.0
Applied rewrites94.9%
Taylor expanded in cosTheta around 0
lower-/.f32N/A
lower-*.f32N/A
lower-PI.f32N/A
lower-log.f3294.9
Applied rewrites94.9%
(FPCore (cosTheta alpha) :precision binary32 (/ -1.0 (* (* PI (log (* alpha alpha))) 1.0)))
float code(float cosTheta, float alpha) {
return -1.0f / ((((float) M_PI) * logf((alpha * alpha))) * 1.0f);
}
function code(cosTheta, alpha) return Float32(Float32(-1.0) / Float32(Float32(Float32(pi) * log(Float32(alpha * alpha))) * Float32(1.0))) end
function tmp = code(cosTheta, alpha) tmp = single(-1.0) / ((single(pi) * log((alpha * alpha))) * single(1.0)); end
\begin{array}{l}
\\
\frac{-1}{\left(\pi \cdot \log \left(\alpha \cdot \alpha\right)\right) \cdot 1}
\end{array}
Initial program 98.5%
Taylor expanded in cosTheta around 0
Applied rewrites95.2%
Taylor expanded in alpha around 0
Applied rewrites65.3%
(FPCore (cosTheta alpha) :precision binary32 (/ -1.0 (* 2.0 (* PI (log alpha)))))
float code(float cosTheta, float alpha) {
return -1.0f / (2.0f * (((float) M_PI) * logf(alpha)));
}
function code(cosTheta, alpha) return Float32(Float32(-1.0) / Float32(Float32(2.0) * Float32(Float32(pi) * log(alpha)))) end
function tmp = code(cosTheta, alpha) tmp = single(-1.0) / (single(2.0) * (single(pi) * log(alpha))); end
\begin{array}{l}
\\
\frac{-1}{2 \cdot \left(\pi \cdot \log \alpha\right)}
\end{array}
Initial program 98.5%
Taylor expanded in cosTheta around 0
Applied rewrites95.2%
Taylor expanded in alpha around 0
Applied rewrites65.3%
lift-*.f32N/A
lift-log.f32N/A
lift-*.f32N/A
sum-logN/A
lift-log.f32N/A
lift-log.f32N/A
distribute-lft-outN/A
distribute-rgt-outN/A
lower-*.f32N/A
lower-+.f3265.3
Applied rewrites65.3%
Taylor expanded in cosTheta around 0
lower-*.f32N/A
lower-*.f32N/A
lower-PI.f32N/A
lower-log.f3265.3
Applied rewrites65.3%
herbie shell --seed 2025150
(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)))))