
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (sqrt (- (log (- 1.0 u1)))) (sin (* (* 2.0 PI) u2))))
float code(float cosTheta_i, float u1, float u2) {
return sqrtf(-logf((1.0f - u1))) * sinf(((2.0f * ((float) M_PI)) * u2));
}
function code(cosTheta_i, u1, u2) return Float32(sqrt(Float32(-log(Float32(Float32(1.0) - u1)))) * sin(Float32(Float32(Float32(2.0) * Float32(pi)) * u2))) end
function tmp = code(cosTheta_i, u1, u2) tmp = sqrt(-log((single(1.0) - u1))) * sin(((single(2.0) * single(pi)) * u2)); end
\begin{array}{l}
\\
\sqrt{-\log \left(1 - u1\right)} \cdot \sin \left(\left(2 \cdot \pi\right) \cdot u2\right)
\end{array}
Sampling outcomes in binary32 precision:
Herbie found 7 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (sqrt (- (log (- 1.0 u1)))) (sin (* (* 2.0 PI) u2))))
float code(float cosTheta_i, float u1, float u2) {
return sqrtf(-logf((1.0f - u1))) * sinf(((2.0f * ((float) M_PI)) * u2));
}
function code(cosTheta_i, u1, u2) return Float32(sqrt(Float32(-log(Float32(Float32(1.0) - u1)))) * sin(Float32(Float32(Float32(2.0) * Float32(pi)) * u2))) end
function tmp = code(cosTheta_i, u1, u2) tmp = sqrt(-log((single(1.0) - u1))) * sin(((single(2.0) * single(pi)) * u2)); end
\begin{array}{l}
\\
\sqrt{-\log \left(1 - u1\right)} \cdot \sin \left(\left(2 \cdot \pi\right) \cdot u2\right)
\end{array}
(FPCore (cosTheta_i u1 u2) :precision binary32 (let* ((t_0 (sqrt (* 2.0 PI)))) (* (sqrt (- (log1p (- u1)))) (sin (* t_0 (* u2 t_0))))))
float code(float cosTheta_i, float u1, float u2) {
float t_0 = sqrtf((2.0f * ((float) M_PI)));
return sqrtf(-log1pf(-u1)) * sinf((t_0 * (u2 * t_0)));
}
function code(cosTheta_i, u1, u2) t_0 = sqrt(Float32(Float32(2.0) * Float32(pi))) return Float32(sqrt(Float32(-log1p(Float32(-u1)))) * sin(Float32(t_0 * Float32(u2 * t_0)))) end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \sqrt{2 \cdot \pi}\\
\sqrt{-\mathsf{log1p}\left(-u1\right)} \cdot \sin \left(t_0 \cdot \left(u2 \cdot t_0\right)\right)
\end{array}
\end{array}
Initial program 56.2%
sub-neg56.2%
log1p-def98.3%
Simplified98.3%
add-sqr-sqrt97.5%
pow297.5%
*-commutative97.5%
associate-*r*97.5%
Applied egg-rr97.5%
unpow297.5%
add-sqr-sqrt98.3%
associate-*l*98.3%
add-sqr-sqrt98.3%
associate-*r*98.4%
Applied egg-rr98.4%
Final simplification98.4%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (sqrt (- (log1p (- u1)))) (sin (* u2 (* 2.0 PI)))))
float code(float cosTheta_i, float u1, float u2) {
return sqrtf(-log1pf(-u1)) * sinf((u2 * (2.0f * ((float) M_PI))));
}
function code(cosTheta_i, u1, u2) return Float32(sqrt(Float32(-log1p(Float32(-u1)))) * sin(Float32(u2 * Float32(Float32(2.0) * Float32(pi))))) end
\begin{array}{l}
\\
\sqrt{-\mathsf{log1p}\left(-u1\right)} \cdot \sin \left(u2 \cdot \left(2 \cdot \pi\right)\right)
\end{array}
Initial program 56.2%
sub-neg56.2%
log1p-def98.3%
Simplified98.3%
Final simplification98.3%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (sin (* u2 (* 2.0 PI))) (sqrt (* u1 (- (- -1.0) (* u1 -0.5))))))
float code(float cosTheta_i, float u1, float u2) {
return sinf((u2 * (2.0f * ((float) M_PI)))) * sqrtf((u1 * (-(-1.0f) - (u1 * -0.5f))));
}
function code(cosTheta_i, u1, u2) return Float32(sin(Float32(u2 * Float32(Float32(2.0) * Float32(pi)))) * sqrt(Float32(u1 * Float32(Float32(-Float32(-1.0)) - Float32(u1 * Float32(-0.5)))))) end
function tmp = code(cosTheta_i, u1, u2) tmp = sin((u2 * (single(2.0) * single(pi)))) * sqrt((u1 * (-single(-1.0) - (u1 * single(-0.5))))); end
\begin{array}{l}
\\
\sin \left(u2 \cdot \left(2 \cdot \pi\right)\right) \cdot \sqrt{u1 \cdot \left(\left(--1\right) - u1 \cdot -0.5\right)}
\end{array}
Initial program 56.2%
Taylor expanded in u1 around 0 88.4%
*-commutative88.4%
*-commutative88.4%
unpow288.4%
associate-*l*88.4%
distribute-lft-out88.4%
Simplified88.4%
Final simplification88.4%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (sqrt u1) (sin (* 2.0 (* u2 PI)))))
float code(float cosTheta_i, float u1, float u2) {
return sqrtf(u1) * sinf((2.0f * (u2 * ((float) M_PI))));
}
function code(cosTheta_i, u1, u2) return Float32(sqrt(u1) * sin(Float32(Float32(2.0) * Float32(u2 * Float32(pi))))) end
function tmp = code(cosTheta_i, u1, u2) tmp = sqrt(u1) * sin((single(2.0) * (u2 * single(pi)))); end
\begin{array}{l}
\\
\sqrt{u1} \cdot \sin \left(2 \cdot \left(u2 \cdot \pi\right)\right)
\end{array}
Initial program 56.2%
Taylor expanded in u1 around 0 77.4%
mul-1-neg77.4%
Simplified77.4%
Taylor expanded in u2 around inf 77.4%
Final simplification77.4%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* 2.0 (* u2 (* PI (sqrt u1)))))
float code(float cosTheta_i, float u1, float u2) {
return 2.0f * (u2 * (((float) M_PI) * sqrtf(u1)));
}
function code(cosTheta_i, u1, u2) return Float32(Float32(2.0) * Float32(u2 * Float32(Float32(pi) * sqrt(u1)))) end
function tmp = code(cosTheta_i, u1, u2) tmp = single(2.0) * (u2 * (single(pi) * sqrt(u1))); end
\begin{array}{l}
\\
2 \cdot \left(u2 \cdot \left(\pi \cdot \sqrt{u1}\right)\right)
\end{array}
Initial program 56.2%
Taylor expanded in u1 around 0 77.4%
mul-1-neg77.4%
Simplified77.4%
Taylor expanded in u2 around 0 67.7%
*-commutative67.7%
Simplified67.7%
Taylor expanded in u2 around 0 67.7%
associate-*r*67.9%
*-commutative67.9%
*-commutative67.9%
Simplified67.9%
Taylor expanded in u2 around 0 67.7%
associate-*r*67.9%
*-commutative67.9%
associate-*l*67.9%
Simplified67.9%
Final simplification67.9%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* 2.0 (* PI (* u2 (sqrt u1)))))
float code(float cosTheta_i, float u1, float u2) {
return 2.0f * (((float) M_PI) * (u2 * sqrtf(u1)));
}
function code(cosTheta_i, u1, u2) return Float32(Float32(2.0) * Float32(Float32(pi) * Float32(u2 * sqrt(u1)))) end
function tmp = code(cosTheta_i, u1, u2) tmp = single(2.0) * (single(pi) * (u2 * sqrt(u1))); end
\begin{array}{l}
\\
2 \cdot \left(\pi \cdot \left(u2 \cdot \sqrt{u1}\right)\right)
\end{array}
Initial program 56.2%
Taylor expanded in u1 around 0 77.4%
mul-1-neg77.4%
Simplified77.4%
Taylor expanded in u2 around 0 67.7%
*-commutative67.7%
Simplified67.7%
Taylor expanded in u2 around 0 67.7%
associate-*r*67.9%
*-commutative67.9%
*-commutative67.9%
Simplified67.9%
Final simplification67.9%
(FPCore (cosTheta_i u1 u2) :precision binary32 0.0)
float code(float cosTheta_i, float u1, float u2) {
return 0.0f;
}
real(4) function code(costheta_i, u1, u2)
real(4), intent (in) :: costheta_i
real(4), intent (in) :: u1
real(4), intent (in) :: u2
code = 0.0e0
end function
function code(cosTheta_i, u1, u2) return Float32(0.0) end
function tmp = code(cosTheta_i, u1, u2) tmp = single(0.0); end
\begin{array}{l}
\\
0
\end{array}
Initial program 56.2%
sub-neg56.2%
log1p-def98.3%
Simplified98.3%
add-cube-cbrt97.2%
pow397.3%
*-commutative97.3%
associate-*r*97.3%
Applied egg-rr97.3%
Taylor expanded in u2 around 0 7.2%
Final simplification7.2%
herbie shell --seed 2023321
(FPCore (cosTheta_i u1 u2)
:name "Beckmann Sample, near normal, slope_y"
:precision binary32
:pre (and (and (and (> cosTheta_i 0.9999) (<= cosTheta_i 1.0)) (and (<= 2.328306437e-10 u1) (<= u1 1.0))) (and (<= 2.328306437e-10 u2) (<= u2 1.0)))
(* (sqrt (- (log (- 1.0 u1)))) (sin (* (* 2.0 PI) u2))))