
(FPCore (ux uy maxCos) :precision binary32 (let* ((t_0 (+ (- 1.0 ux) (* ux maxCos)))) (* (cos (* (* uy 2.0) PI)) (sqrt (- 1.0 (* t_0 t_0))))))
float code(float ux, float uy, float maxCos) {
float t_0 = (1.0f - ux) + (ux * maxCos);
return cosf(((uy * 2.0f) * ((float) M_PI))) * sqrtf((1.0f - (t_0 * t_0)));
}
function code(ux, uy, maxCos) t_0 = Float32(Float32(Float32(1.0) - ux) + Float32(ux * maxCos)) return Float32(cos(Float32(Float32(uy * Float32(2.0)) * Float32(pi))) * sqrt(Float32(Float32(1.0) - Float32(t_0 * t_0)))) end
function tmp = code(ux, uy, maxCos) t_0 = (single(1.0) - ux) + (ux * maxCos); tmp = cos(((uy * single(2.0)) * single(pi))) * sqrt((single(1.0) - (t_0 * t_0))); end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \left(1 - ux\right) + ux \cdot maxCos\\
\cos \left(\left(uy \cdot 2\right) \cdot \pi\right) \cdot \sqrt{1 - t\_0 \cdot t\_0}
\end{array}
\end{array}
Sampling outcomes in binary32 precision:
Herbie found 4 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (ux uy maxCos) :precision binary32 (let* ((t_0 (+ (- 1.0 ux) (* ux maxCos)))) (* (cos (* (* uy 2.0) PI)) (sqrt (- 1.0 (* t_0 t_0))))))
float code(float ux, float uy, float maxCos) {
float t_0 = (1.0f - ux) + (ux * maxCos);
return cosf(((uy * 2.0f) * ((float) M_PI))) * sqrtf((1.0f - (t_0 * t_0)));
}
function code(ux, uy, maxCos) t_0 = Float32(Float32(Float32(1.0) - ux) + Float32(ux * maxCos)) return Float32(cos(Float32(Float32(uy * Float32(2.0)) * Float32(pi))) * sqrt(Float32(Float32(1.0) - Float32(t_0 * t_0)))) end
function tmp = code(ux, uy, maxCos) t_0 = (single(1.0) - ux) + (ux * maxCos); tmp = cos(((uy * single(2.0)) * single(pi))) * sqrt((single(1.0) - (t_0 * t_0))); end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \left(1 - ux\right) + ux \cdot maxCos\\
\cos \left(\left(uy \cdot 2\right) \cdot \pi\right) \cdot \sqrt{1 - t\_0 \cdot t\_0}
\end{array}
\end{array}
(FPCore (ux uy maxCos) :precision binary32 (* (cos (* uy (* 2.0 (* (log E) PI)))) (sqrt (fma (fma ux maxCos (- 1.0 ux)) (- -1.0 (* ux (+ maxCos -1.0))) 1.0))))
float code(float ux, float uy, float maxCos) {
return cosf((uy * (2.0f * (logf(((float) M_E)) * ((float) M_PI))))) * sqrtf(fmaf(fmaf(ux, maxCos, (1.0f - ux)), (-1.0f - (ux * (maxCos + -1.0f))), 1.0f));
}
function code(ux, uy, maxCos) return Float32(cos(Float32(uy * Float32(Float32(2.0) * Float32(log(Float32(exp(1))) * Float32(pi))))) * sqrt(fma(fma(ux, maxCos, Float32(Float32(1.0) - ux)), Float32(Float32(-1.0) - Float32(ux * Float32(maxCos + Float32(-1.0)))), Float32(1.0)))) end
\begin{array}{l}
\\
\cos \left(uy \cdot \left(2 \cdot \left(\log e \cdot \pi\right)\right)\right) \cdot \sqrt{\mathsf{fma}\left(\mathsf{fma}\left(ux, maxCos, 1 - ux\right), -1 - ux \cdot \left(maxCos + -1\right), 1\right)}
\end{array}
Initial program 55.5%
associate-*l*55.5%
sub-neg55.5%
+-commutative55.5%
distribute-rgt-neg-in55.5%
fma-def55.5%
Simplified55.5%
log1p-expm1-u55.5%
expm1-udef55.5%
*-un-lft-identity55.5%
exp-prod55.6%
pow-to-exp55.6%
expm1-def55.6%
log1p-expm1-u55.6%
exp-1-e55.6%
Applied egg-rr55.6%
Final simplification55.6%
(FPCore (ux uy maxCos) :precision binary32 (* (sqrt (fma (fma ux maxCos (- 1.0 ux)) (- -1.0 (* ux (+ maxCos -1.0))) 1.0)) (cos (* uy (* 2.0 PI)))))
float code(float ux, float uy, float maxCos) {
return sqrtf(fmaf(fmaf(ux, maxCos, (1.0f - ux)), (-1.0f - (ux * (maxCos + -1.0f))), 1.0f)) * cosf((uy * (2.0f * ((float) M_PI))));
}
function code(ux, uy, maxCos) return Float32(sqrt(fma(fma(ux, maxCos, Float32(Float32(1.0) - ux)), Float32(Float32(-1.0) - Float32(ux * Float32(maxCos + Float32(-1.0)))), Float32(1.0))) * cos(Float32(uy * Float32(Float32(2.0) * Float32(pi))))) end
\begin{array}{l}
\\
\sqrt{\mathsf{fma}\left(\mathsf{fma}\left(ux, maxCos, 1 - ux\right), -1 - ux \cdot \left(maxCos + -1\right), 1\right)} \cdot \cos \left(uy \cdot \left(2 \cdot \pi\right)\right)
\end{array}
Initial program 55.5%
associate-*l*55.5%
sub-neg55.5%
+-commutative55.5%
distribute-rgt-neg-in55.5%
fma-def55.5%
Simplified55.5%
Final simplification55.5%
(FPCore (ux uy maxCos) :precision binary32 (let* ((t_0 (+ (- 1.0 ux) (* ux maxCos)))) (* (cos (* (* (log E) PI) (* uy 2.0))) (sqrt (- 1.0 (* t_0 t_0))))))
float code(float ux, float uy, float maxCos) {
float t_0 = (1.0f - ux) + (ux * maxCos);
return cosf(((logf(((float) M_E)) * ((float) M_PI)) * (uy * 2.0f))) * sqrtf((1.0f - (t_0 * t_0)));
}
function code(ux, uy, maxCos) t_0 = Float32(Float32(Float32(1.0) - ux) + Float32(ux * maxCos)) return Float32(cos(Float32(Float32(log(Float32(exp(1))) * Float32(pi)) * Float32(uy * Float32(2.0)))) * sqrt(Float32(Float32(1.0) - Float32(t_0 * t_0)))) end
function tmp = code(ux, uy, maxCos) t_0 = (single(1.0) - ux) + (ux * maxCos); tmp = cos(((log(single(2.71828182845904523536)) * single(pi)) * (uy * single(2.0)))) * sqrt((single(1.0) - (t_0 * t_0))); end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \left(1 - ux\right) + ux \cdot maxCos\\
\cos \left(\left(\log e \cdot \pi\right) \cdot \left(uy \cdot 2\right)\right) \cdot \sqrt{1 - t\_0 \cdot t\_0}
\end{array}
\end{array}
Initial program 55.5%
log1p-expm1-u55.5%
expm1-udef55.5%
*-un-lft-identity55.5%
exp-prod55.6%
pow-to-exp55.6%
expm1-def55.6%
log1p-expm1-u55.6%
exp-1-e55.6%
Applied egg-rr55.5%
Final simplification55.5%
(FPCore (ux uy maxCos) :precision binary32 (let* ((t_0 (+ (- 1.0 ux) (* ux maxCos)))) (* (sqrt (- 1.0 (* t_0 t_0))) (cos (* PI (* uy 2.0))))))
float code(float ux, float uy, float maxCos) {
float t_0 = (1.0f - ux) + (ux * maxCos);
return sqrtf((1.0f - (t_0 * t_0))) * cosf((((float) M_PI) * (uy * 2.0f)));
}
function code(ux, uy, maxCos) t_0 = Float32(Float32(Float32(1.0) - ux) + Float32(ux * maxCos)) return Float32(sqrt(Float32(Float32(1.0) - Float32(t_0 * t_0))) * cos(Float32(Float32(pi) * Float32(uy * Float32(2.0))))) end
function tmp = code(ux, uy, maxCos) t_0 = (single(1.0) - ux) + (ux * maxCos); tmp = sqrt((single(1.0) - (t_0 * t_0))) * cos((single(pi) * (uy * single(2.0)))); end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \left(1 - ux\right) + ux \cdot maxCos\\
\sqrt{1 - t\_0 \cdot t\_0} \cdot \cos \left(\pi \cdot \left(uy \cdot 2\right)\right)
\end{array}
\end{array}
Initial program 55.5%
Final simplification55.5%
herbie shell --seed 2024039
(FPCore (ux uy maxCos)
:name "UniformSampleCone, x"
:precision binary32
:pre (and (and (and (<= 2.328306437e-10 ux) (<= ux 1.0)) (and (<= 2.328306437e-10 uy) (<= uy 1.0))) (and (<= 0.0 maxCos) (<= maxCos 1.0)))
(* (cos (* (* uy 2.0) PI)) (sqrt (- 1.0 (* (+ (- 1.0 ux) (* ux maxCos)) (+ (- 1.0 ux) (* ux maxCos)))))))