
(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 9 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 (* PI 2.0)))) (* (sqrt (- (log1p (- u1)))) (sin (* t_0 (* u2 t_0))))))
float code(float cosTheta_i, float u1, float u2) {
float t_0 = sqrtf((((float) M_PI) * 2.0f));
return sqrtf(-log1pf(-u1)) * sinf((t_0 * (u2 * t_0)));
}
function code(cosTheta_i, u1, u2) t_0 = sqrt(Float32(Float32(pi) * Float32(2.0))) 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{\pi \cdot 2}\\
\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 60.4%
sub-neg60.4%
log1p-def98.2%
Simplified98.2%
add-cube-cbrt97.0%
pow397.0%
*-commutative97.0%
associate-*r*97.0%
Applied egg-rr97.0%
rem-cube-cbrt98.2%
associate-*l*98.2%
add-sqr-sqrt98.2%
associate-*r*98.3%
*-commutative98.3%
*-commutative98.3%
Applied egg-rr98.3%
Final simplification98.3%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (sqrt (- (log1p (- u1)))) (sin (* u2 (* PI 2.0)))))
float code(float cosTheta_i, float u1, float u2) {
return sqrtf(-log1pf(-u1)) * sinf((u2 * (((float) M_PI) * 2.0f)));
}
function code(cosTheta_i, u1, u2) return Float32(sqrt(Float32(-log1p(Float32(-u1)))) * sin(Float32(u2 * Float32(Float32(pi) * Float32(2.0))))) end
\begin{array}{l}
\\
\sqrt{-\mathsf{log1p}\left(-u1\right)} \cdot \sin \left(u2 \cdot \left(\pi \cdot 2\right)\right)
\end{array}
Initial program 60.4%
sub-neg60.4%
log1p-def98.2%
Simplified98.2%
Final simplification98.2%
(FPCore (cosTheta_i u1 u2)
:precision binary32
(let* ((t_0 (* u2 (* PI 2.0))))
(if (<= t_0 0.07999999821186066)
(*
(sqrt (- (log1p (- u1))))
(* 2.0 (/ 1.0 (+ (* 0.6666666666666666 (* u2 PI)) (/ 1.0 (* u2 PI))))))
(* (sin t_0) (sqrt (* u1 (- (* u1 (- -0.5)) -1.0)))))))
float code(float cosTheta_i, float u1, float u2) {
float t_0 = u2 * (((float) M_PI) * 2.0f);
float tmp;
if (t_0 <= 0.07999999821186066f) {
tmp = sqrtf(-log1pf(-u1)) * (2.0f * (1.0f / ((0.6666666666666666f * (u2 * ((float) M_PI))) + (1.0f / (u2 * ((float) M_PI))))));
} else {
tmp = sinf(t_0) * sqrtf((u1 * ((u1 * -(-0.5f)) - -1.0f)));
}
return tmp;
}
function code(cosTheta_i, u1, u2) t_0 = Float32(u2 * Float32(Float32(pi) * Float32(2.0))) tmp = Float32(0.0) if (t_0 <= Float32(0.07999999821186066)) tmp = Float32(sqrt(Float32(-log1p(Float32(-u1)))) * Float32(Float32(2.0) * Float32(Float32(1.0) / Float32(Float32(Float32(0.6666666666666666) * Float32(u2 * Float32(pi))) + Float32(Float32(1.0) / Float32(u2 * Float32(pi))))))); else tmp = Float32(sin(t_0) * sqrt(Float32(u1 * Float32(Float32(u1 * Float32(-Float32(-0.5))) - Float32(-1.0))))); end return tmp end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := u2 \cdot \left(\pi \cdot 2\right)\\
\mathbf{if}\;t_0 \leq 0.07999999821186066:\\
\;\;\;\;\sqrt{-\mathsf{log1p}\left(-u1\right)} \cdot \left(2 \cdot \frac{1}{0.6666666666666666 \cdot \left(u2 \cdot \pi\right) + \frac{1}{u2 \cdot \pi}}\right)\\
\mathbf{else}:\\
\;\;\;\;\sin t_0 \cdot \sqrt{u1 \cdot \left(u1 \cdot \left(--0.5\right) - -1\right)}\\
\end{array}
\end{array}
if (*.f32 (*.f32 2 (PI.f32)) u2) < 0.0799999982Initial program 60.0%
sub-neg60.0%
log1p-def98.4%
Simplified98.4%
associate-*l*98.4%
sin-298.4%
Applied egg-rr98.4%
sin-cos-mult98.4%
clear-num98.2%
+-commutative98.2%
count-298.2%
*-commutative98.2%
*-commutative98.2%
associate-*r*98.2%
+-inverses98.2%
Applied egg-rr98.2%
Taylor expanded in u2 around 0 98.0%
if 0.0799999982 < (*.f32 (*.f32 2 (PI.f32)) u2) Initial program 62.0%
Taylor expanded in u1 around 0 86.4%
unpow286.4%
associate-*r*86.4%
distribute-rgt-out86.2%
Simplified86.2%
Final simplification95.9%
(FPCore (cosTheta_i u1 u2)
:precision binary32
(let* ((t_0 (* u2 (* PI 2.0))))
(if (<= t_0 0.001500000013038516)
(* (sqrt (- (log1p (- u1)))) (* 2.0 (* u2 PI)))
(* (sin t_0) (sqrt (* u1 (- (* u1 (- -0.5)) -1.0)))))))
float code(float cosTheta_i, float u1, float u2) {
float t_0 = u2 * (((float) M_PI) * 2.0f);
float tmp;
if (t_0 <= 0.001500000013038516f) {
tmp = sqrtf(-log1pf(-u1)) * (2.0f * (u2 * ((float) M_PI)));
} else {
tmp = sinf(t_0) * sqrtf((u1 * ((u1 * -(-0.5f)) - -1.0f)));
}
return tmp;
}
function code(cosTheta_i, u1, u2) t_0 = Float32(u2 * Float32(Float32(pi) * Float32(2.0))) tmp = Float32(0.0) if (t_0 <= Float32(0.001500000013038516)) tmp = Float32(sqrt(Float32(-log1p(Float32(-u1)))) * Float32(Float32(2.0) * Float32(u2 * Float32(pi)))); else tmp = Float32(sin(t_0) * sqrt(Float32(u1 * Float32(Float32(u1 * Float32(-Float32(-0.5))) - Float32(-1.0))))); end return tmp end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := u2 \cdot \left(\pi \cdot 2\right)\\
\mathbf{if}\;t_0 \leq 0.001500000013038516:\\
\;\;\;\;\sqrt{-\mathsf{log1p}\left(-u1\right)} \cdot \left(2 \cdot \left(u2 \cdot \pi\right)\right)\\
\mathbf{else}:\\
\;\;\;\;\sin t_0 \cdot \sqrt{u1 \cdot \left(u1 \cdot \left(--0.5\right) - -1\right)}\\
\end{array}
\end{array}
if (*.f32 (*.f32 2 (PI.f32)) u2) < 0.00150000001Initial program 59.9%
sub-neg59.9%
log1p-def98.4%
Simplified98.4%
add-exp-log93.8%
*-commutative93.8%
associate-*r*93.8%
Applied egg-rr93.8%
Taylor expanded in u2 around 0 98.0%
if 0.00150000001 < (*.f32 (*.f32 2 (PI.f32)) u2) Initial program 61.1%
Taylor expanded in u1 around 0 85.5%
unpow285.5%
associate-*r*85.5%
distribute-rgt-out85.4%
Simplified85.4%
Final simplification93.6%
(FPCore (cosTheta_i u1 u2)
:precision binary32
(let* ((t_0 (* 2.0 (* u2 PI))))
(if (<= (* u2 (* PI 2.0)) 0.023499999195337296)
(* (sqrt (- (log1p (- u1)))) t_0)
(* (sqrt u1) (sin t_0)))))
float code(float cosTheta_i, float u1, float u2) {
float t_0 = 2.0f * (u2 * ((float) M_PI));
float tmp;
if ((u2 * (((float) M_PI) * 2.0f)) <= 0.023499999195337296f) {
tmp = sqrtf(-log1pf(-u1)) * t_0;
} else {
tmp = sqrtf(u1) * sinf(t_0);
}
return tmp;
}
function code(cosTheta_i, u1, u2) t_0 = Float32(Float32(2.0) * Float32(u2 * Float32(pi))) tmp = Float32(0.0) if (Float32(u2 * Float32(Float32(pi) * Float32(2.0))) <= Float32(0.023499999195337296)) tmp = Float32(sqrt(Float32(-log1p(Float32(-u1)))) * t_0); else tmp = Float32(sqrt(u1) * sin(t_0)); end return tmp end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := 2 \cdot \left(u2 \cdot \pi\right)\\
\mathbf{if}\;u2 \cdot \left(\pi \cdot 2\right) \leq 0.023499999195337296:\\
\;\;\;\;\sqrt{-\mathsf{log1p}\left(-u1\right)} \cdot t_0\\
\mathbf{else}:\\
\;\;\;\;\sqrt{u1} \cdot \sin t_0\\
\end{array}
\end{array}
if (*.f32 (*.f32 2 (PI.f32)) u2) < 0.0234999992Initial program 60.1%
sub-neg60.1%
log1p-def98.5%
Simplified98.5%
add-exp-log94.1%
*-commutative94.1%
associate-*r*94.1%
Applied egg-rr94.1%
Taylor expanded in u2 around 0 95.7%
if 0.0234999992 < (*.f32 (*.f32 2 (PI.f32)) u2) Initial program 61.2%
Taylor expanded in u1 around 0 73.9%
mul-1-neg73.9%
Simplified73.9%
Taylor expanded in u2 around inf 73.9%
Final simplification90.2%
(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 60.4%
Taylor expanded in u1 around 0 74.2%
mul-1-neg74.2%
Simplified74.2%
Taylor expanded in u2 around inf 74.2%
Final simplification74.2%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (* u2 PI) (* 2.0 (sqrt u1))))
float code(float cosTheta_i, float u1, float u2) {
return (u2 * ((float) M_PI)) * (2.0f * sqrtf(u1));
}
function code(cosTheta_i, u1, u2) return Float32(Float32(u2 * Float32(pi)) * Float32(Float32(2.0) * sqrt(u1))) end
function tmp = code(cosTheta_i, u1, u2) tmp = (u2 * single(pi)) * (single(2.0) * sqrt(u1)); end
\begin{array}{l}
\\
\left(u2 \cdot \pi\right) \cdot \left(2 \cdot \sqrt{u1}\right)
\end{array}
Initial program 60.4%
Taylor expanded in u1 around 0 74.2%
mul-1-neg74.2%
Simplified74.2%
Taylor expanded in u2 around 0 65.7%
Simplified65.7%
Final simplification65.7%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (* PI 2.0) (* u2 (sqrt u1))))
float code(float cosTheta_i, float u1, float u2) {
return (((float) M_PI) * 2.0f) * (u2 * sqrtf(u1));
}
function code(cosTheta_i, u1, u2) return Float32(Float32(Float32(pi) * Float32(2.0)) * Float32(u2 * sqrt(u1))) end
function tmp = code(cosTheta_i, u1, u2) tmp = (single(pi) * single(2.0)) * (u2 * sqrt(u1)); end
\begin{array}{l}
\\
\left(\pi \cdot 2\right) \cdot \left(u2 \cdot \sqrt{u1}\right)
\end{array}
Initial program 60.4%
Taylor expanded in u1 around 0 74.2%
mul-1-neg74.2%
Simplified74.2%
Taylor expanded in u2 around 0 65.7%
Simplified65.7%
expm1-log1p-u65.7%
expm1-udef28.6%
associate-*r*28.6%
*-commutative28.6%
associate-*l*28.6%
Applied egg-rr28.6%
expm1-def65.8%
expm1-log1p65.8%
associate-*r*65.8%
*-commutative65.8%
Simplified65.8%
Final simplification65.8%
(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 60.4%
sub-neg60.4%
log1p-def98.2%
Simplified98.2%
add-cube-cbrt97.0%
pow397.0%
*-commutative97.0%
associate-*r*97.0%
Applied egg-rr97.0%
Taylor expanded in u2 around 0 7.1%
Final simplification7.1%
herbie shell --seed 2024019
(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))))