
(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 8 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 (/ (fma alpha alpha -1.0) (* (log (pow alpha (+ PI PI))) (fma (fma alpha alpha -1.0) (* cosTheta cosTheta) 1.0))))
float code(float cosTheta, float alpha) {
return fmaf(alpha, alpha, -1.0f) / (logf(powf(alpha, (((float) M_PI) + ((float) M_PI)))) * fmaf(fmaf(alpha, alpha, -1.0f), (cosTheta * cosTheta), 1.0f));
}
function code(cosTheta, alpha) return Float32(fma(alpha, alpha, Float32(-1.0)) / Float32(log((alpha ^ Float32(Float32(pi) + Float32(pi)))) * fma(fma(alpha, alpha, Float32(-1.0)), Float32(cosTheta * cosTheta), Float32(1.0)))) end
\begin{array}{l}
\\
\frac{\mathsf{fma}\left(\alpha, \alpha, -1\right)}{\log \left({\alpha}^{\left(\pi + \pi\right)}\right) \cdot \mathsf{fma}\left(\mathsf{fma}\left(\alpha, \alpha, -1\right), cosTheta \cdot cosTheta, 1\right)}
\end{array}
Initial program 98.5%
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
lift-*.f32N/A
lift-*.f32N/A
lift-*.f32N/A
pow2N/A
lower--.f32N/A
associate-*l*N/A
pow2N/A
*-commutativeN/A
+-commutativeN/A
*-commutativeN/A
lower-fma.f32N/A
pow2N/A
difference-of-sqr-1-revN/A
difference-of-sqr--1-revN/A
lower-fma.f32N/A
pow2N/A
lift-*.f3298.7
Applied rewrites98.7%
lift-*.f32N/A
lift--.f32N/A
difference-of-sqr-1N/A
difference-of-sqr--1N/A
lift-fma.f3298.6
Applied rewrites98.6%
lift-*.f32N/A
lift-PI.f32N/A
lift-pow.f32N/A
unpow-prod-downN/A
pow-prod-upN/A
lower-pow.f32N/A
lower-+.f32N/A
lift-PI.f32N/A
lift-PI.f3298.7
Applied rewrites98.7%
(FPCore (cosTheta alpha)
:precision binary32
(/
(fma alpha alpha -1.0)
(*
(*
(* (log alpha) 2.0)
(fma (* (fma alpha alpha -1.0) cosTheta) cosTheta 1.0))
PI)))
float code(float cosTheta, float alpha) {
return fmaf(alpha, alpha, -1.0f) / (((logf(alpha) * 2.0f) * fmaf((fmaf(alpha, alpha, -1.0f) * cosTheta), cosTheta, 1.0f)) * ((float) M_PI));
}
function code(cosTheta, alpha) return Float32(fma(alpha, alpha, Float32(-1.0)) / Float32(Float32(Float32(log(alpha) * Float32(2.0)) * fma(Float32(fma(alpha, alpha, Float32(-1.0)) * cosTheta), cosTheta, Float32(1.0))) * Float32(pi))) end
\begin{array}{l}
\\
\frac{\mathsf{fma}\left(\alpha, \alpha, -1\right)}{\left(\left(\log \alpha \cdot 2\right) \cdot \mathsf{fma}\left(\mathsf{fma}\left(\alpha, \alpha, -1\right) \cdot cosTheta, cosTheta, 1\right)\right) \cdot \pi}
\end{array}
Initial program 98.5%
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
lift-*.f32N/A
lift-*.f32N/A
lift-*.f32N/A
pow2N/A
lower--.f32N/A
associate-*l*N/A
pow2N/A
*-commutativeN/A
+-commutativeN/A
*-commutativeN/A
lower-fma.f32N/A
pow2N/A
difference-of-sqr-1-revN/A
difference-of-sqr--1-revN/A
lower-fma.f32N/A
pow2N/A
lift-*.f3298.7
Applied rewrites98.7%
lift-*.f32N/A
lift--.f32N/A
difference-of-sqr-1N/A
difference-of-sqr--1N/A
lift-fma.f3298.6
Applied rewrites98.6%
Applied rewrites98.5%
(FPCore (cosTheta alpha)
:precision binary32
(/
(fma alpha alpha -1.0)
(*
PI
(*
(* (log alpha) 2.0)
(fma (* cosTheta cosTheta) (fma alpha alpha -1.0) 1.0)))))
float code(float cosTheta, float alpha) {
return fmaf(alpha, alpha, -1.0f) / (((float) M_PI) * ((logf(alpha) * 2.0f) * fmaf((cosTheta * cosTheta), fmaf(alpha, alpha, -1.0f), 1.0f)));
}
function code(cosTheta, alpha) return Float32(fma(alpha, alpha, Float32(-1.0)) / Float32(Float32(pi) * Float32(Float32(log(alpha) * Float32(2.0)) * 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)}{\pi \cdot \left(\left(\log \alpha \cdot 2\right) \cdot \mathsf{fma}\left(cosTheta \cdot cosTheta, \mathsf{fma}\left(\alpha, \alpha, -1\right), 1\right)\right)}
\end{array}
Initial program 98.5%
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 rewrites98.4%
lift-*.f32N/A
lift--.f32N/A
difference-of-sqr-1-revN/A
difference-of-sqr--1-revN/A
lower-fma.f3298.5
Applied rewrites98.5%
lift-*.f32N/A
lift--.f32N/A
difference-of-sqr-1-revN/A
difference-of-sqr--1-revN/A
lower-fma.f3298.5
Applied rewrites98.5%
(FPCore (cosTheta alpha) :precision binary32 (/ (/ (fma alpha alpha -1.0) PI) (* (* (log alpha) (fma (- cosTheta) cosTheta 1.0)) 2.0)))
float code(float cosTheta, float alpha) {
return (fmaf(alpha, alpha, -1.0f) / ((float) M_PI)) / ((logf(alpha) * fmaf(-cosTheta, cosTheta, 1.0f)) * 2.0f);
}
function code(cosTheta, alpha) return Float32(Float32(fma(alpha, alpha, Float32(-1.0)) / Float32(pi)) / Float32(Float32(log(alpha) * fma(Float32(-cosTheta), cosTheta, Float32(1.0))) * Float32(2.0))) end
\begin{array}{l}
\\
\frac{\frac{\mathsf{fma}\left(\alpha, \alpha, -1\right)}{\pi}}{\left(\log \alpha \cdot \mathsf{fma}\left(-cosTheta, cosTheta, 1\right)\right) \cdot 2}
\end{array}
Initial program 98.5%
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 rewrites98.4%
Taylor expanded in alpha around 0
associate-*r*N/A
log-powN/A
lower-*.f32N/A
log-powN/A
*-commutativeN/A
lift-log.f32N/A
lift-*.f32N/A
mul-1-negN/A
+-commutativeN/A
lower-+.f32N/A
lower-neg.f32N/A
pow2N/A
lift-*.f3297.5
Applied rewrites97.5%
lift-/.f32N/A
lift-*.f32N/A
lift--.f32N/A
difference-of-sqr-1N/A
difference-of-sqr--1N/A
lift-fma.f32N/A
lift-PI.f32N/A
lift-*.f32N/A
associate-/r*N/A
lower-/.f32N/A
Applied rewrites97.5%
(FPCore (cosTheta alpha) :precision binary32 (/ (fma alpha alpha -1.0) (* PI (* (* (log alpha) (fma (- cosTheta) cosTheta 1.0)) 2.0))))
float code(float cosTheta, float alpha) {
return fmaf(alpha, alpha, -1.0f) / (((float) M_PI) * ((logf(alpha) * fmaf(-cosTheta, cosTheta, 1.0f)) * 2.0f));
}
function code(cosTheta, alpha) return Float32(fma(alpha, alpha, Float32(-1.0)) / Float32(Float32(pi) * Float32(Float32(log(alpha) * fma(Float32(-cosTheta), cosTheta, Float32(1.0))) * Float32(2.0)))) end
\begin{array}{l}
\\
\frac{\mathsf{fma}\left(\alpha, \alpha, -1\right)}{\pi \cdot \left(\left(\log \alpha \cdot \mathsf{fma}\left(-cosTheta, cosTheta, 1\right)\right) \cdot 2\right)}
\end{array}
Initial program 98.5%
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 rewrites98.4%
Taylor expanded in alpha around 0
associate-*r*N/A
log-powN/A
lower-*.f32N/A
log-powN/A
*-commutativeN/A
lift-log.f32N/A
lift-*.f32N/A
mul-1-negN/A
+-commutativeN/A
lower-+.f32N/A
lower-neg.f32N/A
pow2N/A
lift-*.f3297.5
Applied rewrites97.5%
lift-*.f32N/A
lift--.f32N/A
difference-of-sqr-1N/A
difference-of-sqr--1N/A
lift-fma.f3297.5
lift-*.f32N/A
lift-*.f32N/A
lift-log.f32N/A
*-commutativeN/A
lift-+.f32N/A
lift-*.f32N/A
lift-neg.f32N/A
+-commutativeN/A
pow2N/A
mul-1-negN/A
associate-*r*N/A
Applied rewrites97.5%
(FPCore (cosTheta alpha) :precision binary32 (/ (fma alpha alpha -1.0) (* (* (log alpha) PI) 2.0)))
float code(float cosTheta, float alpha) {
return fmaf(alpha, alpha, -1.0f) / ((logf(alpha) * ((float) M_PI)) * 2.0f);
}
function code(cosTheta, alpha) return Float32(fma(alpha, alpha, Float32(-1.0)) / Float32(Float32(log(alpha) * Float32(pi)) * Float32(2.0))) end
\begin{array}{l}
\\
\frac{\mathsf{fma}\left(\alpha, \alpha, -1\right)}{\left(\log \alpha \cdot \pi\right) \cdot 2}
\end{array}
Initial program 98.5%
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 cosTheta around 0
log-powN/A
lower-/.f32N/A
pow2N/A
difference-of-sqr-1-revN/A
difference-of-sqr--1-revN/A
lower-fma.f32N/A
log-powN/A
pow-powN/A
log-powN/A
associate-*r*N/A
*-commutativeN/A
lower-*.f32N/A
*-commutativeN/A
lower-*.f32N/A
lift-log.f32N/A
lift-PI.f3295.4
Applied rewrites95.4%
(FPCore (cosTheta alpha) :precision binary32 (/ (/ -1.0 PI) (* (log alpha) 2.0)))
float code(float cosTheta, float alpha) {
return (-1.0f / ((float) M_PI)) / (logf(alpha) * 2.0f);
}
function code(cosTheta, alpha) return Float32(Float32(Float32(-1.0) / Float32(pi)) / Float32(log(alpha) * Float32(2.0))) end
function tmp = code(cosTheta, alpha) tmp = (single(-1.0) / single(pi)) / (log(alpha) * single(2.0)); end
\begin{array}{l}
\\
\frac{\frac{-1}{\pi}}{\log \alpha \cdot 2}
\end{array}
Initial program 98.5%
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 rewrites98.4%
Taylor expanded in alpha around 0
Applied rewrites66.6%
Taylor expanded in alpha around 0
Applied rewrites66.6%
Taylor expanded in cosTheta around 0
*-commutativeN/A
lift-log.f32N/A
lift-*.f3265.4
Applied rewrites65.4%
lift-/.f32N/A
lift-PI.f32N/A
lift-*.f32N/A
associate-/r*N/A
lower-/.f32N/A
lower-/.f32N/A
difference-of-sqr-1N/A
difference-of-sqr--1N/A
difference-of-sqr--1N/A
Applied rewrites65.5%
(FPCore (cosTheta alpha) :precision binary32 (/ -1.0 (* PI (log (* alpha alpha)))))
float code(float cosTheta, float alpha) {
return -1.0f / (((float) M_PI) * logf((alpha * alpha)));
}
function code(cosTheta, alpha) return Float32(Float32(-1.0) / Float32(Float32(pi) * log(Float32(alpha * alpha)))) end
function tmp = code(cosTheta, alpha) tmp = single(-1.0) / (single(pi) * log((alpha * alpha))); end
\begin{array}{l}
\\
\frac{-1}{\pi \cdot \log \left(\alpha \cdot \alpha\right)}
\end{array}
Initial program 98.5%
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 rewrites98.4%
Taylor expanded in alpha around 0
Applied rewrites66.6%
Taylor expanded in alpha around 0
Applied rewrites66.6%
Taylor expanded in cosTheta around 0
*-commutativeN/A
lift-log.f32N/A
lift-*.f3265.4
Applied rewrites65.4%
lift-*.f32N/A
lift-log.f32N/A
*-commutativeN/A
log-pow-revN/A
lower-log.f32N/A
pow2N/A
lift-*.f3265.4
Applied rewrites65.4%
herbie shell --seed 2025133
(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)))))