
(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}
Sampling outcomes in binary32 precision:
Herbie found 10 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) PI) (* (log alpha) 2.0)) (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) * 2.0f)) / fmaf(fmaf(alpha, alpha, -1.0f), (cosTheta * cosTheta), 1.0f);
}
function code(cosTheta, alpha) return Float32(Float32(Float32(fma(alpha, alpha, Float32(-1.0)) / Float32(pi)) / Float32(log(alpha) * Float32(2.0))) / fma(fma(alpha, alpha, Float32(-1.0)), Float32(cosTheta * cosTheta), Float32(1.0))) end
\begin{array}{l}
\\
\frac{\frac{\frac{\mathsf{fma}\left(\alpha, \alpha, -1\right)}{\pi}}{\log \alpha \cdot 2}}{\mathsf{fma}\left(\mathsf{fma}\left(\alpha, \alpha, -1\right), cosTheta \cdot cosTheta, 1\right)}
\end{array}
Initial program 98.5%
associate-/r*98.5%
associate-/r*98.6%
log-prod98.5%
count-298.5%
fma-neg98.6%
metadata-eval98.6%
*-commutative98.6%
+-commutative98.6%
associate-*l*98.6%
fma-def98.6%
fma-neg98.6%
metadata-eval98.6%
Simplified98.6%
Final simplification98.6%
(FPCore (cosTheta alpha) :precision binary32 (/ (* 0.5 (/ (fma alpha alpha -1.0) (* PI (log alpha)))) (fma (fma alpha alpha -1.0) (* cosTheta cosTheta) 1.0)))
float code(float cosTheta, float alpha) {
return (0.5f * (fmaf(alpha, alpha, -1.0f) / (((float) M_PI) * logf(alpha)))) / fmaf(fmaf(alpha, alpha, -1.0f), (cosTheta * cosTheta), 1.0f);
}
function code(cosTheta, alpha) return Float32(Float32(Float32(0.5) * Float32(fma(alpha, alpha, Float32(-1.0)) / Float32(Float32(pi) * log(alpha)))) / fma(fma(alpha, alpha, Float32(-1.0)), Float32(cosTheta * cosTheta), Float32(1.0))) end
\begin{array}{l}
\\
\frac{0.5 \cdot \frac{\mathsf{fma}\left(\alpha, \alpha, -1\right)}{\pi \cdot \log \alpha}}{\mathsf{fma}\left(\mathsf{fma}\left(\alpha, \alpha, -1\right), cosTheta \cdot cosTheta, 1\right)}
\end{array}
Initial program 98.5%
associate-/r*98.5%
associate-/r*98.6%
log-prod98.5%
count-298.5%
fma-neg98.6%
metadata-eval98.6%
*-commutative98.6%
+-commutative98.6%
associate-*l*98.6%
fma-def98.6%
fma-neg98.6%
metadata-eval98.6%
Simplified98.6%
Taylor expanded in alpha around 0 98.4%
distribute-lft-out--98.4%
div-sub98.4%
unpow298.4%
fma-neg98.5%
metadata-eval98.5%
Simplified98.5%
Final simplification98.5%
(FPCore (cosTheta alpha)
:precision binary32
(let* ((t_0 (+ -1.0 (* alpha alpha))))
(/
t_0
(* (* PI (log (* alpha alpha))) (+ 1.0 (* cosTheta (* cosTheta t_0)))))))
float code(float cosTheta, float alpha) {
float t_0 = -1.0f + (alpha * alpha);
return t_0 / ((((float) M_PI) * logf((alpha * alpha))) * (1.0f + (cosTheta * (cosTheta * t_0))));
}
function code(cosTheta, alpha) t_0 = Float32(Float32(-1.0) + Float32(alpha * alpha)) return Float32(t_0 / Float32(Float32(Float32(pi) * log(Float32(alpha * alpha))) * Float32(Float32(1.0) + Float32(cosTheta * Float32(cosTheta * t_0))))) end
function tmp = code(cosTheta, alpha) t_0 = single(-1.0) + (alpha * alpha); tmp = t_0 / ((single(pi) * log((alpha * alpha))) * (single(1.0) + (cosTheta * (cosTheta * t_0)))); end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := -1 + \alpha \cdot \alpha\\
\frac{t_0}{\left(\pi \cdot \log \left(\alpha \cdot \alpha\right)\right) \cdot \left(1 + cosTheta \cdot \left(cosTheta \cdot t_0\right)\right)}
\end{array}
\end{array}
Initial program 98.5%
Final simplification98.5%
(FPCore (cosTheta alpha) :precision binary32 (/ (+ -1.0 (* alpha alpha)) (* (* PI (log (* alpha alpha))) (- 1.0 (* cosTheta cosTheta)))))
float code(float cosTheta, float alpha) {
return (-1.0f + (alpha * alpha)) / ((((float) M_PI) * logf((alpha * alpha))) * (1.0f - (cosTheta * cosTheta)));
}
function code(cosTheta, alpha) return Float32(Float32(Float32(-1.0) + Float32(alpha * alpha)) / Float32(Float32(Float32(pi) * log(Float32(alpha * alpha))) * Float32(Float32(1.0) - Float32(cosTheta * cosTheta)))) end
function tmp = code(cosTheta, alpha) tmp = (single(-1.0) + (alpha * alpha)) / ((single(pi) * log((alpha * alpha))) * (single(1.0) - (cosTheta * cosTheta))); end
\begin{array}{l}
\\
\frac{-1 + \alpha \cdot \alpha}{\left(\pi \cdot \log \left(\alpha \cdot \alpha\right)\right) \cdot \left(1 - cosTheta \cdot cosTheta\right)}
\end{array}
Initial program 98.5%
Taylor expanded in alpha around 0 97.1%
mul-1-neg96.8%
Simplified97.1%
Final simplification97.1%
(FPCore (cosTheta alpha) :precision binary32 (* 0.5 (/ (* (+ alpha 1.0) (+ alpha -1.0)) (* PI (log alpha)))))
float code(float cosTheta, float alpha) {
return 0.5f * (((alpha + 1.0f) * (alpha + -1.0f)) / (((float) M_PI) * logf(alpha)));
}
function code(cosTheta, alpha) return Float32(Float32(0.5) * Float32(Float32(Float32(alpha + Float32(1.0)) * Float32(alpha + Float32(-1.0))) / Float32(Float32(pi) * log(alpha)))) end
function tmp = code(cosTheta, alpha) tmp = single(0.5) * (((alpha + single(1.0)) * (alpha + single(-1.0))) / (single(pi) * log(alpha))); end
\begin{array}{l}
\\
0.5 \cdot \frac{\left(\alpha + 1\right) \cdot \left(\alpha + -1\right)}{\pi \cdot \log \alpha}
\end{array}
Initial program 98.5%
associate-/r*98.5%
associate-/r*98.6%
log-prod98.5%
count-298.5%
fma-neg98.6%
metadata-eval98.6%
*-commutative98.6%
+-commutative98.6%
associate-*l*98.6%
fma-def98.6%
fma-neg98.6%
metadata-eval98.6%
Simplified98.6%
metadata-eval98.6%
fma-neg98.5%
difference-of-sqr-198.4%
*-un-lft-identity98.4%
times-frac98.2%
Applied egg-rr98.2%
Taylor expanded in cosTheta around 0 94.6%
Final simplification94.6%
(FPCore (cosTheta alpha) :precision binary32 (/ -0.5 (* PI (* (log alpha) (- 1.0 (* cosTheta cosTheta))))))
float code(float cosTheta, float alpha) {
return -0.5f / (((float) M_PI) * (logf(alpha) * (1.0f - (cosTheta * cosTheta))));
}
function code(cosTheta, alpha) return Float32(Float32(-0.5) / Float32(Float32(pi) * Float32(log(alpha) * Float32(Float32(1.0) - Float32(cosTheta * cosTheta))))) end
function tmp = code(cosTheta, alpha) tmp = single(-0.5) / (single(pi) * (log(alpha) * (single(1.0) - (cosTheta * cosTheta)))); end
\begin{array}{l}
\\
\frac{-0.5}{\pi \cdot \left(\log \alpha \cdot \left(1 - cosTheta \cdot cosTheta\right)\right)}
\end{array}
Initial program 98.5%
associate-/r*98.5%
associate-/r*98.6%
log-prod98.5%
count-298.5%
fma-neg98.6%
metadata-eval98.6%
*-commutative98.6%
+-commutative98.6%
associate-*l*98.6%
fma-def98.6%
fma-neg98.6%
metadata-eval98.6%
Simplified98.6%
Taylor expanded in alpha around 0 67.9%
mul-1-neg67.9%
unsub-neg67.9%
unpow267.9%
Simplified67.9%
Final simplification67.9%
(FPCore (cosTheta alpha) :precision binary32 (/ -0.5 (* (* PI (log alpha)) (- 1.0 (* cosTheta cosTheta)))))
float code(float cosTheta, float alpha) {
return -0.5f / ((((float) M_PI) * logf(alpha)) * (1.0f - (cosTheta * cosTheta)));
}
function code(cosTheta, alpha) return Float32(Float32(-0.5) / Float32(Float32(Float32(pi) * log(alpha)) * Float32(Float32(1.0) - Float32(cosTheta * cosTheta)))) end
function tmp = code(cosTheta, alpha) tmp = single(-0.5) / ((single(pi) * log(alpha)) * (single(1.0) - (cosTheta * cosTheta))); end
\begin{array}{l}
\\
\frac{-0.5}{\left(\pi \cdot \log \alpha\right) \cdot \left(1 - cosTheta \cdot cosTheta\right)}
\end{array}
Initial program 98.5%
associate-/r*98.5%
associate-/r*98.6%
log-prod98.5%
count-298.5%
fma-neg98.6%
metadata-eval98.6%
*-commutative98.6%
+-commutative98.6%
associate-*l*98.6%
fma-def98.6%
fma-neg98.6%
metadata-eval98.6%
Simplified98.6%
Taylor expanded in alpha around 0 98.4%
distribute-lft-out--98.4%
div-sub98.4%
unpow298.4%
fma-neg98.5%
metadata-eval98.5%
Simplified98.5%
div-inv98.5%
metadata-eval98.5%
fma-neg98.4%
associate-*r/98.4%
fma-neg98.5%
metadata-eval98.5%
Applied egg-rr98.5%
associate-*l/98.5%
Simplified98.5%
Taylor expanded in alpha around 0 67.9%
associate-*r*67.9%
mul-1-neg67.9%
sub-neg67.9%
unpow267.9%
Simplified67.9%
Final simplification67.9%
(FPCore (cosTheta alpha) :precision binary32 (/ (/ -0.5 PI) (* (log alpha) (- 1.0 (* cosTheta cosTheta)))))
float code(float cosTheta, float alpha) {
return (-0.5f / ((float) M_PI)) / (logf(alpha) * (1.0f - (cosTheta * cosTheta)));
}
function code(cosTheta, alpha) return Float32(Float32(Float32(-0.5) / Float32(pi)) / Float32(log(alpha) * Float32(Float32(1.0) - Float32(cosTheta * cosTheta)))) end
function tmp = code(cosTheta, alpha) tmp = (single(-0.5) / single(pi)) / (log(alpha) * (single(1.0) - (cosTheta * cosTheta))); end
\begin{array}{l}
\\
\frac{\frac{-0.5}{\pi}}{\log \alpha \cdot \left(1 - cosTheta \cdot cosTheta\right)}
\end{array}
Initial program 98.5%
associate-/r*98.5%
associate-/r*98.6%
log-prod98.5%
count-298.5%
fma-neg98.6%
metadata-eval98.6%
*-commutative98.6%
+-commutative98.6%
associate-*l*98.6%
fma-def98.6%
fma-neg98.6%
metadata-eval98.6%
Simplified98.6%
Taylor expanded in alpha around 0 98.4%
distribute-lft-out--98.4%
div-sub98.4%
unpow298.4%
fma-neg98.5%
metadata-eval98.5%
Simplified98.5%
Taylor expanded in alpha around 0 67.9%
associate-/r*67.9%
mul-1-neg67.9%
unsub-neg67.9%
unpow267.9%
Simplified67.9%
Final simplification67.9%
(FPCore (cosTheta alpha) :precision binary32 (/ (/ 0.5 PI) (- (log alpha))))
float code(float cosTheta, float alpha) {
return (0.5f / ((float) M_PI)) / -logf(alpha);
}
function code(cosTheta, alpha) return Float32(Float32(Float32(0.5) / Float32(pi)) / Float32(-log(alpha))) end
function tmp = code(cosTheta, alpha) tmp = (single(0.5) / single(pi)) / -log(alpha); end
\begin{array}{l}
\\
\frac{\frac{0.5}{\pi}}{-\log \alpha}
\end{array}
Initial program 98.5%
Taylor expanded in alpha around inf 98.2%
Taylor expanded in alpha around 0 96.8%
mul-1-neg96.8%
Simplified96.8%
Taylor expanded in alpha around 0 67.9%
Taylor expanded in cosTheta around 0 66.6%
log-rec66.6%
associate-/r*66.6%
Simplified66.6%
Final simplification66.6%
(FPCore (cosTheta alpha) :precision binary32 (/ -0.5 (* PI (log alpha))))
float code(float cosTheta, float alpha) {
return -0.5f / (((float) M_PI) * logf(alpha));
}
function code(cosTheta, alpha) return Float32(Float32(-0.5) / Float32(Float32(pi) * log(alpha))) end
function tmp = code(cosTheta, alpha) tmp = single(-0.5) / (single(pi) * log(alpha)); end
\begin{array}{l}
\\
\frac{-0.5}{\pi \cdot \log \alpha}
\end{array}
Initial program 98.5%
Taylor expanded in alpha around inf 98.2%
Taylor expanded in alpha around 0 96.8%
mul-1-neg96.8%
Simplified96.8%
Taylor expanded in alpha around 0 67.9%
Taylor expanded in cosTheta around 0 66.6%
log-rec66.6%
distribute-rgt-neg-in66.6%
neg-mul-166.6%
associate-/r*66.6%
metadata-eval66.6%
Simplified66.6%
Final simplification66.6%
herbie shell --seed 2023287
(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)))))