
(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
(*
2.0
(+
(log alpha)
(* (pow cosTheta 2.0) (* (fma alpha alpha -1.0) (log alpha))))))))
float code(float cosTheta, float alpha) {
return fmaf(alpha, alpha, -1.0f) / (((float) M_PI) * (2.0f * (logf(alpha) + (powf(cosTheta, 2.0f) * (fmaf(alpha, alpha, -1.0f) * logf(alpha))))));
}
function code(cosTheta, alpha) return Float32(fma(alpha, alpha, Float32(-1.0)) / Float32(Float32(pi) * Float32(Float32(2.0) * Float32(log(alpha) + Float32((cosTheta ^ Float32(2.0)) * Float32(fma(alpha, alpha, Float32(-1.0)) * log(alpha))))))) end
\begin{array}{l}
\\
\frac{\mathsf{fma}\left(\alpha, \alpha, -1\right)}{\pi \cdot \left(2 \cdot \left(\log \alpha + {cosTheta}^{2} \cdot \left(\mathsf{fma}\left(\alpha, \alpha, -1\right) \cdot \log \alpha\right)\right)\right)}
\end{array}
Initial program 98.6%
associate-/r*98.6%
cancel-sign-sub98.6%
distribute-rgt-neg-out98.6%
unsub-neg98.6%
distribute-rgt-neg-out98.6%
associate-/r*98.6%
sqr-neg98.6%
sqr-neg98.6%
fma-neg98.5%
metadata-eval98.5%
associate-*l*98.6%
Simplified98.7%
Taylor expanded in cosTheta around 0 98.7%
distribute-lft-out98.7%
unpow298.7%
fma-neg98.7%
metadata-eval98.7%
Simplified98.7%
Final simplification98.7%
(FPCore (cosTheta alpha)
:precision binary32
(/
(fma alpha alpha -1.0)
(*
PI
(*
(* 2.0 (log 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) * ((2.0f * logf(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(Float32(Float32(2.0) * log(alpha)) * 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)}{\pi \cdot \left(\left(2 \cdot \log \alpha\right) \cdot \mathsf{fma}\left(\mathsf{fma}\left(\alpha, \alpha, -1\right), cosTheta \cdot cosTheta, 1\right)\right)}
\end{array}
Initial program 98.6%
associate-/r*98.6%
cancel-sign-sub98.6%
distribute-rgt-neg-out98.6%
unsub-neg98.6%
distribute-rgt-neg-out98.6%
associate-/r*98.6%
sqr-neg98.6%
sqr-neg98.6%
fma-neg98.5%
metadata-eval98.5%
associate-*l*98.6%
Simplified98.7%
Final simplification98.7%
(FPCore (cosTheta alpha)
:precision binary32
(let* ((t_0 (+ (* alpha alpha) -1.0)))
(/
t_0
(* (log (pow (pow alpha 2.0) PI)) (+ 1.0 (* cosTheta (* cosTheta t_0)))))))
float code(float cosTheta, float alpha) {
float t_0 = (alpha * alpha) + -1.0f;
return t_0 / (logf(powf(powf(alpha, 2.0f), ((float) M_PI))) * (1.0f + (cosTheta * (cosTheta * t_0))));
}
function code(cosTheta, alpha) t_0 = Float32(Float32(alpha * alpha) + Float32(-1.0)) return Float32(t_0 / Float32(log(((alpha ^ Float32(2.0)) ^ Float32(pi))) * Float32(Float32(1.0) + Float32(cosTheta * Float32(cosTheta * t_0))))) end
function tmp = code(cosTheta, alpha) t_0 = (alpha * alpha) + single(-1.0); tmp = t_0 / (log(((alpha ^ single(2.0)) ^ single(pi))) * (single(1.0) + (cosTheta * (cosTheta * t_0)))); end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \alpha \cdot \alpha + -1\\
\frac{t\_0}{\log \left({\left({\alpha}^{2}\right)}^{\pi}\right) \cdot \left(1 + cosTheta \cdot \left(cosTheta \cdot t\_0\right)\right)}
\end{array}
\end{array}
Initial program 98.6%
*-commutative98.6%
add-log-exp98.6%
exp-to-pow98.6%
pow298.6%
Applied egg-rr98.6%
Final simplification98.6%
(FPCore (cosTheta alpha)
:precision binary32
(let* ((t_0 (+ (* alpha alpha) -1.0)))
(/
t_0
(* (+ 1.0 (* cosTheta (* cosTheta t_0))) (* PI (log (* alpha alpha)))))))
float code(float cosTheta, float alpha) {
float t_0 = (alpha * alpha) + -1.0f;
return t_0 / ((1.0f + (cosTheta * (cosTheta * t_0))) * (((float) M_PI) * logf((alpha * alpha))));
}
function code(cosTheta, alpha) t_0 = Float32(Float32(alpha * alpha) + Float32(-1.0)) return Float32(t_0 / Float32(Float32(Float32(1.0) + Float32(cosTheta * Float32(cosTheta * t_0))) * Float32(Float32(pi) * log(Float32(alpha * alpha))))) end
function tmp = code(cosTheta, alpha) t_0 = (alpha * alpha) + single(-1.0); tmp = t_0 / ((single(1.0) + (cosTheta * (cosTheta * t_0))) * (single(pi) * log((alpha * alpha)))); end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \alpha \cdot \alpha + -1\\
\frac{t\_0}{\left(1 + cosTheta \cdot \left(cosTheta \cdot t\_0\right)\right) \cdot \left(\pi \cdot \log \left(\alpha \cdot \alpha\right)\right)}
\end{array}
\end{array}
Initial program 98.6%
Final simplification98.6%
(FPCore (cosTheta alpha) :precision binary32 (/ (+ (* alpha alpha) -1.0) (* (* PI (log (* alpha alpha))) (- 1.0 (* cosTheta cosTheta)))))
float code(float cosTheta, float alpha) {
return ((alpha * alpha) + -1.0f) / ((((float) M_PI) * logf((alpha * alpha))) * (1.0f - (cosTheta * cosTheta)));
}
function code(cosTheta, alpha) return Float32(Float32(Float32(alpha * alpha) + Float32(-1.0)) / Float32(Float32(Float32(pi) * log(Float32(alpha * alpha))) * Float32(Float32(1.0) - Float32(cosTheta * cosTheta)))) end
function tmp = code(cosTheta, alpha) tmp = ((alpha * alpha) + single(-1.0)) / ((single(pi) * log((alpha * alpha))) * (single(1.0) - (cosTheta * cosTheta))); end
\begin{array}{l}
\\
\frac{\alpha \cdot \alpha + -1}{\left(\pi \cdot \log \left(\alpha \cdot \alpha\right)\right) \cdot \left(1 - cosTheta \cdot cosTheta\right)}
\end{array}
Initial program 98.6%
Taylor expanded in alpha around 0 98.0%
mul-1-neg98.0%
Simplified98.0%
Final simplification98.0%
(FPCore (cosTheta alpha) :precision binary32 (/ 1.0 (* 2.0 (* (/ PI (+ alpha 1.0)) (/ (log alpha) (+ alpha -1.0))))))
float code(float cosTheta, float alpha) {
return 1.0f / (2.0f * ((((float) M_PI) / (alpha + 1.0f)) * (logf(alpha) / (alpha + -1.0f))));
}
function code(cosTheta, alpha) return Float32(Float32(1.0) / Float32(Float32(2.0) * Float32(Float32(Float32(pi) / Float32(alpha + Float32(1.0))) * Float32(log(alpha) / Float32(alpha + Float32(-1.0)))))) end
function tmp = code(cosTheta, alpha) tmp = single(1.0) / (single(2.0) * ((single(pi) / (alpha + single(1.0))) * (log(alpha) / (alpha + single(-1.0))))); end
\begin{array}{l}
\\
\frac{1}{2 \cdot \left(\frac{\pi}{\alpha + 1} \cdot \frac{\log \alpha}{\alpha + -1}\right)}
\end{array}
Initial program 98.6%
Taylor expanded in alpha around 0 98.0%
mul-1-neg98.0%
Simplified98.0%
fma-neg97.9%
metadata-eval97.9%
clear-num97.8%
inv-pow97.8%
Applied egg-rr95.7%
unpow-195.7%
associate-*r*95.7%
associate-*r*95.7%
*-commutative95.7%
associate-*r*95.7%
Simplified95.7%
Taylor expanded in cosTheta around 0 95.9%
pow295.9%
difference-of-sqr-195.6%
add-exp-log95.6%
expm1-udef95.6%
times-frac95.8%
expm1-udef95.8%
add-exp-log95.8%
Applied egg-rr95.8%
Final simplification95.8%
(FPCore (cosTheta alpha) :precision binary32 (* (* (+ alpha 1.0) (/ (+ alpha -1.0) PI)) (/ 0.5 (log alpha))))
float code(float cosTheta, float alpha) {
return ((alpha + 1.0f) * ((alpha + -1.0f) / ((float) M_PI))) * (0.5f / logf(alpha));
}
function code(cosTheta, alpha) return Float32(Float32(Float32(alpha + Float32(1.0)) * Float32(Float32(alpha + Float32(-1.0)) / Float32(pi))) * Float32(Float32(0.5) / log(alpha))) end
function tmp = code(cosTheta, alpha) tmp = ((alpha + single(1.0)) * ((alpha + single(-1.0)) / single(pi))) * (single(0.5) / log(alpha)); end
\begin{array}{l}
\\
\left(\left(\alpha + 1\right) \cdot \frac{\alpha + -1}{\pi}\right) \cdot \frac{0.5}{\log \alpha}
\end{array}
Initial program 98.6%
Taylor expanded in alpha around 0 98.0%
mul-1-neg98.0%
Simplified98.0%
Taylor expanded in cosTheta around 0 96.1%
unpow296.1%
fma-neg96.0%
metadata-eval96.0%
*-rgt-identity96.0%
log-pow96.1%
/-rgt-identity96.1%
times-frac95.7%
/-rgt-identity95.7%
associate-/r*95.7%
metadata-eval95.7%
Simplified95.7%
metadata-eval95.7%
fma-neg95.7%
difference-of-sqr-195.5%
add-exp-log95.5%
expm1-udef95.5%
*-un-lft-identity95.5%
times-frac95.5%
expm1-udef95.5%
add-exp-log95.4%
Applied egg-rr95.4%
Final simplification95.4%
(FPCore (cosTheta alpha) :precision binary32 (/ (/ (/ -0.5 (log alpha)) PI) (- 1.0 (* cosTheta cosTheta))))
float code(float cosTheta, float alpha) {
return ((-0.5f / logf(alpha)) / ((float) M_PI)) / (1.0f - (cosTheta * cosTheta));
}
function code(cosTheta, alpha) return Float32(Float32(Float32(Float32(-0.5) / log(alpha)) / Float32(pi)) / Float32(Float32(1.0) - Float32(cosTheta * cosTheta))) end
function tmp = code(cosTheta, alpha) tmp = ((single(-0.5) / log(alpha)) / single(pi)) / (single(1.0) - (cosTheta * cosTheta)); end
\begin{array}{l}
\\
\frac{\frac{\frac{-0.5}{\log \alpha}}{\pi}}{1 - cosTheta \cdot cosTheta}
\end{array}
Initial program 98.6%
associate-/r*98.6%
sqr-neg98.6%
sqr-neg98.6%
fma-neg98.6%
metadata-eval98.6%
*-commutative98.6%
cancel-sign-sub98.6%
cancel-sign-sub-inv98.6%
remove-double-neg98.6%
sqr-neg98.6%
sqr-neg98.6%
fma-neg98.6%
metadata-eval98.6%
Simplified98.6%
associate-/r*98.3%
div-inv98.2%
pow298.2%
log-pow98.3%
*-commutative98.3%
Applied egg-rr98.3%
Taylor expanded in alpha around 0 97.7%
mul-1-neg97.7%
Simplified97.7%
associate-*l/97.9%
*-commutative97.9%
Applied egg-rr97.9%
Taylor expanded in alpha around 0 68.4%
Final simplification68.4%
(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 98.6%
Taylor expanded in alpha around 0 68.3%
associate-*r*68.3%
mul-1-neg68.3%
unsub-neg68.3%
Simplified68.3%
Taylor expanded in cosTheta around 0 67.4%
Final simplification67.4%
(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)) / 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 98.6%
Taylor expanded in alpha around 0 98.0%
mul-1-neg98.0%
Simplified98.0%
Taylor expanded in cosTheta around 0 96.1%
unpow296.1%
fma-neg96.0%
metadata-eval96.0%
*-rgt-identity96.0%
log-pow96.1%
/-rgt-identity96.1%
times-frac95.7%
/-rgt-identity95.7%
associate-/r*95.7%
metadata-eval95.7%
Simplified95.7%
Taylor expanded in alpha around 0 67.4%
associate-/r*67.5%
Simplified67.5%
Final simplification67.5%
herbie shell --seed 2024026
(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)))))