
(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 7 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 (- (* alpha alpha) 1.0)) (t_1 (log (pow (pow alpha PI) 2.0)))) (/ t_0 (fma t_1 1.0 (* t_1 (* (* cosTheta cosTheta) t_0))))))
float code(float cosTheta, float alpha) {
float t_0 = (alpha * alpha) - 1.0f;
float t_1 = logf(powf(powf(alpha, ((float) M_PI)), 2.0f));
return t_0 / fmaf(t_1, 1.0f, (t_1 * ((cosTheta * cosTheta) * t_0)));
}
function code(cosTheta, alpha) t_0 = Float32(Float32(alpha * alpha) - Float32(1.0)) t_1 = log(((alpha ^ Float32(pi)) ^ Float32(2.0))) return Float32(t_0 / fma(t_1, Float32(1.0), Float32(t_1 * Float32(Float32(cosTheta * cosTheta) * t_0)))) end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \alpha \cdot \alpha - 1\\
t_1 := \log \left({\left({\alpha}^{\pi}\right)}^{2}\right)\\
\frac{t\_0}{\mathsf{fma}\left(t\_1, 1, t\_1 \cdot \left(\left(cosTheta \cdot cosTheta\right) \cdot t\_0\right)\right)}
\end{array}
\end{array}
Initial program 98.5%
Applied rewrites98.6%
(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 98.5%
lift-PI.f32N/A
lift-*.f32N/A
lift-log.f32N/A
log-pow-revN/A
lift-*.f32N/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 (/ (fma alpha alpha -1.0) (* (* (* (log alpha) PI) 2.0) (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)) * 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(Float32(log(alpha) * Float32(pi)) * 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)}{\left(\left(\log \alpha \cdot \pi\right) \cdot 2\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-PI.f32N/A
lift-*.f32N/A
lift-log.f32N/A
lift-*.f32N/A
pow2N/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%
lift-*.f32N/A
lift-fma.f32N/A
lift--.f32N/A
lift-*.f32N/A
pow2N/A
associate-*l*N/A
*-commutativeN/A
pow2N/A
*-commutativeN/A
lift-*.f32N/A
lift--.f32N/A
lift-*.f32N/A
lift-fma.f3298.5
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%
Applied rewrites98.5%
(FPCore (cosTheta alpha)
:precision binary32
(/
(fma alpha alpha -1.0)
(*
PI
(*
(log (* alpha alpha))
(fma (* (fma alpha alpha -1.0) cosTheta) cosTheta 1.0)))))
float code(float cosTheta, float alpha) {
return fmaf(alpha, alpha, -1.0f) / (((float) M_PI) * (logf((alpha * alpha)) * fmaf((fmaf(alpha, alpha, -1.0f) * cosTheta), cosTheta, 1.0f)));
}
function code(cosTheta, alpha) return Float32(fma(alpha, alpha, Float32(-1.0)) / Float32(Float32(pi) * Float32(log(Float32(alpha * alpha)) * fma(Float32(fma(alpha, alpha, Float32(-1.0)) * cosTheta), cosTheta, Float32(1.0))))) end
\begin{array}{l}
\\
\frac{\mathsf{fma}\left(\alpha, \alpha, -1\right)}{\pi \cdot \left(\log \left(\alpha \cdot \alpha\right) \cdot \mathsf{fma}\left(\mathsf{fma}\left(\alpha, \alpha, -1\right) \cdot cosTheta, cosTheta, 1\right)\right)}
\end{array}
Initial program 98.5%
lift-*.f32N/A
lift-PI.f32N/A
lift-*.f32N/A
lift-log.f32N/A
lift-*.f32N/A
pow2N/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%
lift-*.f32N/A
lift-fma.f32N/A
lift--.f32N/A
lift-*.f32N/A
pow2N/A
associate-*l*N/A
*-commutativeN/A
pow2N/A
*-commutativeN/A
lift-*.f32N/A
lift--.f32N/A
lift-*.f32N/A
lift-fma.f3298.5
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%
lift--.f32N/A
lift-*.f32N/A
difference-of-sqr-1N/A
difference-of-sqr--1N/A
lift-fma.f3298.4
Applied rewrites98.4%
(FPCore (cosTheta alpha) :precision binary32 (/ (fma alpha alpha -1.0) (* (* (* (log alpha) PI) 2.0) (fma (- cosTheta) cosTheta 1.0))))
float code(float cosTheta, float alpha) {
return fmaf(alpha, alpha, -1.0f) / (((logf(alpha) * ((float) M_PI)) * 2.0f) * fmaf(-cosTheta, cosTheta, 1.0f));
}
function code(cosTheta, alpha) return Float32(fma(alpha, alpha, Float32(-1.0)) / Float32(Float32(Float32(log(alpha) * Float32(pi)) * Float32(2.0)) * fma(Float32(-cosTheta), cosTheta, Float32(1.0)))) end
\begin{array}{l}
\\
\frac{\mathsf{fma}\left(\alpha, \alpha, -1\right)}{\left(\left(\log \alpha \cdot \pi\right) \cdot 2\right) \cdot \mathsf{fma}\left(-cosTheta, cosTheta, 1\right)}
\end{array}
Initial program 98.5%
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-*.f3298.5
Applied rewrites98.5%
Taylor expanded in alpha around 0
mul-1-negN/A
lower-neg.f3297.6
Applied rewrites97.6%
lift--.f32N/A
lift-*.f32N/A
difference-of-sqr-1N/A
difference-of-sqr--1N/A
lift-fma.f3297.5
lift-PI.f32N/A
lift-*.f32N/A
lift-*.f32N/A
lift-log.f32N/A
log-pow-revN/A
unpow-prod-downN/A
pow2N/A
log-pow-revN/A
log-pow-revN/A
*-commutativeN/A
*-commutativeN/A
lift-log.f32N/A
lift-*.f32N/A
lift-PI.f32N/A
lift-*.f3297.6
Applied rewrites97.6%
(FPCore (cosTheta alpha) :precision binary32 (/ (* 0.5 (fma alpha alpha -1.0)) (* (log alpha) PI)))
float code(float cosTheta, float alpha) {
return (0.5f * fmaf(alpha, alpha, -1.0f)) / (logf(alpha) * ((float) M_PI));
}
function code(cosTheta, alpha) return Float32(Float32(Float32(0.5) * fma(alpha, alpha, Float32(-1.0))) / Float32(log(alpha) * Float32(pi))) end
\begin{array}{l}
\\
\frac{0.5 \cdot \mathsf{fma}\left(\alpha, \alpha, -1\right)}{\log \alpha \cdot \pi}
\end{array}
Initial program 98.5%
Taylor expanded in cosTheta around 0
Applied rewrites95.6%
Taylor expanded in alpha around 0
Applied rewrites65.8%
lift-PI.f32N/A
lift-*.f32N/A
lift-log.f32N/A
log-pow-revN/A
lift-*.f32N/A
unpow-prod-downN/A
unpow2N/A
log-powN/A
log-pow-revN/A
*-commutativeN/A
lower-*.f32N/A
*-commutativeN/A
lower-*.f32N/A
lower-log.f32N/A
lift-PI.f3265.8
Applied rewrites65.8%
Taylor expanded in cosTheta around 0
Applied rewrites95.6%
(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 rewrites95.6%
Taylor expanded in alpha around 0
Applied rewrites65.8%
herbie shell --seed 2025096
(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)))))