
(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 (* (sqrt (- (log1p (- u1)))) (sin (* 2.0 (* PI u2)))))
float code(float cosTheta_i, float u1, float u2) {
return sqrtf(-log1pf(-u1)) * sinf((2.0f * (((float) M_PI) * u2)));
}
function code(cosTheta_i, u1, u2) return Float32(sqrt(Float32(-log1p(Float32(-u1)))) * sin(Float32(Float32(2.0) * Float32(Float32(pi) * u2)))) end
\begin{array}{l}
\\
\sqrt{-\mathsf{log1p}\left(-u1\right)} \cdot \sin \left(2 \cdot \left(\pi \cdot u2\right)\right)
\end{array}
Initial program 57.8%
sub-neg57.8%
log1p-define98.2%
associate-*l*98.2%
Simplified98.2%
(FPCore (cosTheta_i u1 u2)
:precision binary32
(let* ((t_0 (* u2 (* 2.0 PI))))
(if (<= t_0 0.0005000000237487257)
(* (sqrt (- (log1p (- u1)))) (* PI (* 2.0 u2)))
(*
(sqrt
(*
u1
(+ 1.0 (* u1 (+ 0.5 (* u1 (- 0.3333333333333333 (* u1 -0.25))))))))
(sin t_0)))))
float code(float cosTheta_i, float u1, float u2) {
float t_0 = u2 * (2.0f * ((float) M_PI));
float tmp;
if (t_0 <= 0.0005000000237487257f) {
tmp = sqrtf(-log1pf(-u1)) * (((float) M_PI) * (2.0f * u2));
} else {
tmp = sqrtf((u1 * (1.0f + (u1 * (0.5f + (u1 * (0.3333333333333333f - (u1 * -0.25f)))))))) * sinf(t_0);
}
return tmp;
}
function code(cosTheta_i, u1, u2) t_0 = Float32(u2 * Float32(Float32(2.0) * Float32(pi))) tmp = Float32(0.0) if (t_0 <= Float32(0.0005000000237487257)) tmp = Float32(sqrt(Float32(-log1p(Float32(-u1)))) * Float32(Float32(pi) * Float32(Float32(2.0) * u2))); else tmp = Float32(sqrt(Float32(u1 * Float32(Float32(1.0) + Float32(u1 * Float32(Float32(0.5) + Float32(u1 * Float32(Float32(0.3333333333333333) - Float32(u1 * Float32(-0.25))))))))) * sin(t_0)); end return tmp end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := u2 \cdot \left(2 \cdot \pi\right)\\
\mathbf{if}\;t\_0 \leq 0.0005000000237487257:\\
\;\;\;\;\sqrt{-\mathsf{log1p}\left(-u1\right)} \cdot \left(\pi \cdot \left(2 \cdot u2\right)\right)\\
\mathbf{else}:\\
\;\;\;\;\sqrt{u1 \cdot \left(1 + u1 \cdot \left(0.5 + u1 \cdot \left(0.3333333333333333 - u1 \cdot -0.25\right)\right)\right)} \cdot \sin t\_0\\
\end{array}
\end{array}
if (*.f32 (*.f32 #s(literal 2 binary32) (PI.f32)) u2) < 5.00000024e-4Initial program 59.6%
sub-neg59.6%
log1p-define98.6%
associate-*l*98.6%
Simplified98.6%
add-log-exp35.2%
*-un-lft-identity35.2%
exp-prod35.2%
log-pow97.9%
Applied egg-rr97.9%
Taylor expanded in u2 around 0 98.6%
associate-*r*98.6%
*-commutative98.6%
Simplified98.6%
if 5.00000024e-4 < (*.f32 (*.f32 #s(literal 2 binary32) (PI.f32)) u2) Initial program 55.6%
Taylor expanded in u1 around 0 93.9%
Final simplification96.5%
(FPCore (cosTheta_i u1 u2)
:precision binary32
(let* ((t_0 (* u2 (* 2.0 PI))))
(if (<= t_0 0.0005000000237487257)
(* (sqrt (- (log1p (- u1)))) (* PI (* 2.0 u2)))
(*
(sin t_0)
(sqrt (* u1 (+ 1.0 (* u1 (- 0.5 (* u1 -0.3333333333333333))))))))))
float code(float cosTheta_i, float u1, float u2) {
float t_0 = u2 * (2.0f * ((float) M_PI));
float tmp;
if (t_0 <= 0.0005000000237487257f) {
tmp = sqrtf(-log1pf(-u1)) * (((float) M_PI) * (2.0f * u2));
} else {
tmp = sinf(t_0) * sqrtf((u1 * (1.0f + (u1 * (0.5f - (u1 * -0.3333333333333333f))))));
}
return tmp;
}
function code(cosTheta_i, u1, u2) t_0 = Float32(u2 * Float32(Float32(2.0) * Float32(pi))) tmp = Float32(0.0) if (t_0 <= Float32(0.0005000000237487257)) tmp = Float32(sqrt(Float32(-log1p(Float32(-u1)))) * Float32(Float32(pi) * Float32(Float32(2.0) * u2))); else tmp = Float32(sin(t_0) * sqrt(Float32(u1 * Float32(Float32(1.0) + Float32(u1 * Float32(Float32(0.5) - Float32(u1 * Float32(-0.3333333333333333)))))))); end return tmp end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := u2 \cdot \left(2 \cdot \pi\right)\\
\mathbf{if}\;t\_0 \leq 0.0005000000237487257:\\
\;\;\;\;\sqrt{-\mathsf{log1p}\left(-u1\right)} \cdot \left(\pi \cdot \left(2 \cdot u2\right)\right)\\
\mathbf{else}:\\
\;\;\;\;\sin t\_0 \cdot \sqrt{u1 \cdot \left(1 + u1 \cdot \left(0.5 - u1 \cdot -0.3333333333333333\right)\right)}\\
\end{array}
\end{array}
if (*.f32 (*.f32 #s(literal 2 binary32) (PI.f32)) u2) < 5.00000024e-4Initial program 59.6%
sub-neg59.6%
log1p-define98.6%
associate-*l*98.6%
Simplified98.6%
add-log-exp35.2%
*-un-lft-identity35.2%
exp-prod35.2%
log-pow97.9%
Applied egg-rr97.9%
Taylor expanded in u2 around 0 98.6%
associate-*r*98.6%
*-commutative98.6%
Simplified98.6%
if 5.00000024e-4 < (*.f32 (*.f32 #s(literal 2 binary32) (PI.f32)) u2) Initial program 55.6%
Taylor expanded in u1 around 0 92.2%
Final simplification95.7%
(FPCore (cosTheta_i u1 u2)
:precision binary32
(let* ((t_0 (* u2 (* 2.0 PI))))
(if (<= t_0 0.0028200000524520874)
(* (sqrt (- (log1p (- u1)))) (* PI (* 2.0 u2)))
(* (sin t_0) (sqrt (* u1 (- 1.0 (* u1 -0.5))))))))
float code(float cosTheta_i, float u1, float u2) {
float t_0 = u2 * (2.0f * ((float) M_PI));
float tmp;
if (t_0 <= 0.0028200000524520874f) {
tmp = sqrtf(-log1pf(-u1)) * (((float) M_PI) * (2.0f * u2));
} else {
tmp = sinf(t_0) * sqrtf((u1 * (1.0f - (u1 * -0.5f))));
}
return tmp;
}
function code(cosTheta_i, u1, u2) t_0 = Float32(u2 * Float32(Float32(2.0) * Float32(pi))) tmp = Float32(0.0) if (t_0 <= Float32(0.0028200000524520874)) tmp = Float32(sqrt(Float32(-log1p(Float32(-u1)))) * Float32(Float32(pi) * Float32(Float32(2.0) * u2))); else tmp = Float32(sin(t_0) * sqrt(Float32(u1 * Float32(Float32(1.0) - Float32(u1 * Float32(-0.5)))))); end return tmp end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := u2 \cdot \left(2 \cdot \pi\right)\\
\mathbf{if}\;t\_0 \leq 0.0028200000524520874:\\
\;\;\;\;\sqrt{-\mathsf{log1p}\left(-u1\right)} \cdot \left(\pi \cdot \left(2 \cdot u2\right)\right)\\
\mathbf{else}:\\
\;\;\;\;\sin t\_0 \cdot \sqrt{u1 \cdot \left(1 - u1 \cdot -0.5\right)}\\
\end{array}
\end{array}
if (*.f32 (*.f32 #s(literal 2 binary32) (PI.f32)) u2) < 0.0028200001Initial program 57.8%
sub-neg57.8%
log1p-define98.5%
associate-*l*98.5%
Simplified98.5%
add-log-exp40.7%
*-un-lft-identity40.7%
exp-prod40.7%
log-pow97.9%
Applied egg-rr97.9%
Taylor expanded in u2 around 0 97.9%
associate-*r*97.9%
*-commutative97.9%
Simplified97.9%
if 0.0028200001 < (*.f32 (*.f32 #s(literal 2 binary32) (PI.f32)) u2) Initial program 58.0%
Taylor expanded in u1 around 0 87.6%
Final simplification94.3%
(FPCore (cosTheta_i u1 u2)
:precision binary32
(let* ((t_0 (* PI (* 2.0 u2))))
(if (<= (* u2 (* 2.0 PI)) 0.008999999612569809)
(* (sqrt (- (log1p (- u1)))) t_0)
(* (sqrt u1) (sin t_0)))))
float code(float cosTheta_i, float u1, float u2) {
float t_0 = ((float) M_PI) * (2.0f * u2);
float tmp;
if ((u2 * (2.0f * ((float) M_PI))) <= 0.008999999612569809f) {
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(pi) * Float32(Float32(2.0) * u2)) tmp = Float32(0.0) if (Float32(u2 * Float32(Float32(2.0) * Float32(pi))) <= Float32(0.008999999612569809)) 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 := \pi \cdot \left(2 \cdot u2\right)\\
\mathbf{if}\;u2 \cdot \left(2 \cdot \pi\right) \leq 0.008999999612569809:\\
\;\;\;\;\sqrt{-\mathsf{log1p}\left(-u1\right)} \cdot t\_0\\
\mathbf{else}:\\
\;\;\;\;\sqrt{u1} \cdot \sin t\_0\\
\end{array}
\end{array}
if (*.f32 (*.f32 #s(literal 2 binary32) (PI.f32)) u2) < 0.00899999961Initial program 57.9%
sub-neg57.9%
log1p-define98.6%
associate-*l*98.6%
Simplified98.6%
add-log-exp43.4%
*-un-lft-identity43.4%
exp-prod43.4%
log-pow97.9%
Applied egg-rr97.9%
Taylor expanded in u2 around 0 96.8%
associate-*r*96.8%
*-commutative96.8%
Simplified96.8%
if 0.00899999961 < (*.f32 (*.f32 #s(literal 2 binary32) (PI.f32)) u2) Initial program 57.6%
Taylor expanded in u1 around 0 76.9%
mul-1-neg76.9%
Simplified76.9%
Taylor expanded in u1 around 0 76.9%
associate-*r*76.9%
*-commutative76.9%
Simplified76.9%
Final simplification90.8%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (sqrt u1) (sin (* PI (* 2.0 u2)))))
float code(float cosTheta_i, float u1, float u2) {
return sqrtf(u1) * sinf((((float) M_PI) * (2.0f * u2)));
}
function code(cosTheta_i, u1, u2) return Float32(sqrt(u1) * sin(Float32(Float32(pi) * Float32(Float32(2.0) * u2)))) end
function tmp = code(cosTheta_i, u1, u2) tmp = sqrt(u1) * sin((single(pi) * (single(2.0) * u2))); end
\begin{array}{l}
\\
\sqrt{u1} \cdot \sin \left(\pi \cdot \left(2 \cdot u2\right)\right)
\end{array}
Initial program 57.8%
Taylor expanded in u1 around 0 77.0%
mul-1-neg77.0%
Simplified77.0%
Taylor expanded in u1 around 0 77.0%
associate-*r*77.0%
*-commutative77.0%
Simplified77.0%
(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(Float32(pi) * 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(\left(\pi \cdot u2\right) \cdot \sqrt{u1}\right)
\end{array}
Initial program 57.8%
Taylor expanded in u1 around 0 77.0%
mul-1-neg77.0%
Simplified77.0%
Taylor expanded in u2 around 0 66.1%
Final simplification66.1%
herbie shell --seed 2024096
(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))))