
(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 8 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 (cbrt (* (pow PI 3.0) (pow u2 3.0)))))))
float code(float cosTheta_i, float u1, float u2) {
return sqrtf(-log1pf(-u1)) * sinf((2.0f * cbrtf((powf(((float) M_PI), 3.0f) * powf(u2, 3.0f)))));
}
function code(cosTheta_i, u1, u2) return Float32(sqrt(Float32(-log1p(Float32(-u1)))) * sin(Float32(Float32(2.0) * cbrt(Float32((Float32(pi) ^ Float32(3.0)) * (u2 ^ Float32(3.0))))))) end
\begin{array}{l}
\\
\sqrt{-\mathsf{log1p}\left(-u1\right)} \cdot \sin \left(2 \cdot \sqrt[3]{{\pi}^{3} \cdot {u2}^{3}}\right)
\end{array}
Initial program 55.8%
sub-neg55.8%
log1p-define98.2%
associate-*l*98.2%
Simplified98.2%
add-cbrt-cube98.2%
add-cbrt-cube98.2%
cbrt-unprod98.2%
pow398.2%
pow398.3%
Applied egg-rr98.3%
(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 55.8%
sub-neg55.8%
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 0.001449999981559813)
(* (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 <= 0.001449999981559813f) {
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(0.001449999981559813)) 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 0.001449999981559813:\\
\;\;\;\;\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) < 0.00144999998Initial program 54.4%
sub-neg54.4%
log1p-define98.3%
associate-*l*98.3%
Simplified98.3%
add-cbrt-cube98.3%
add-cbrt-cube98.3%
cbrt-unprod98.4%
pow398.4%
pow398.5%
Applied egg-rr98.5%
Taylor expanded in u2 around 0 98.2%
associate-*r*98.2%
*-commutative98.2%
*-commutative98.2%
*-commutative98.2%
Simplified98.2%
if 0.00144999998 < (*.f32 (*.f32 #s(literal 2 binary32) (PI.f32)) u2) Initial program 58.8%
Taylor expanded in u1 around 0 94.2%
Final simplification96.8%
(FPCore (cosTheta_i u1 u2)
:precision binary32
(let* ((t_0 (* u2 (* 2.0 PI))))
(if (<= t_0 0.001449999981559813)
(* (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 <= 0.001449999981559813f) {
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(0.001449999981559813)) 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 0.001449999981559813:\\
\;\;\;\;\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) < 0.00144999998Initial program 54.4%
sub-neg54.4%
log1p-define98.3%
associate-*l*98.3%
Simplified98.3%
add-cbrt-cube98.3%
add-cbrt-cube98.3%
cbrt-unprod98.4%
pow398.4%
pow398.5%
Applied egg-rr98.5%
Taylor expanded in u2 around 0 98.2%
associate-*r*98.2%
*-commutative98.2%
*-commutative98.2%
*-commutative98.2%
Simplified98.2%
if 0.00144999998 < (*.f32 (*.f32 #s(literal 2 binary32) (PI.f32)) u2) Initial program 58.8%
Taylor expanded in u1 around 0 91.8%
Final simplification96.0%
(FPCore (cosTheta_i u1 u2)
:precision binary32
(let* ((t_0 (* u2 (* 2.0 PI))))
(if (<= t_0 0.0020000000949949026)
(* (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 <= 0.0020000000949949026f) {
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(0.0020000000949949026)) 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 0.0020000000949949026:\\
\;\;\;\;\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) < 0.00200000009Initial program 54.2%
sub-neg54.2%
log1p-define98.3%
associate-*l*98.3%
Simplified98.3%
add-cbrt-cube98.3%
add-cbrt-cube98.3%
cbrt-unprod98.5%
pow398.5%
pow398.5%
Applied egg-rr98.5%
Taylor expanded in u2 around 0 97.9%
associate-*r*97.9%
*-commutative97.9%
*-commutative97.9%
*-commutative97.9%
Simplified97.9%
if 0.00200000009 < (*.f32 (*.f32 #s(literal 2 binary32) (PI.f32)) u2) Initial program 59.5%
Taylor expanded in u1 around 0 87.3%
Final simplification94.6%
(FPCore (cosTheta_i u1 u2)
:precision binary32
(let* ((t_0 (* u2 (* 2.0 PI))))
(if (<= t_0 0.013799999840557575)
(* (sqrt (- (log1p (- u1)))) (* PI (* 2.0 u2)))
(* (sin t_0) (sqrt u1)))))
float code(float cosTheta_i, float u1, float u2) {
float t_0 = u2 * (2.0f * ((float) M_PI));
float tmp;
if (t_0 <= 0.013799999840557575f) {
tmp = sqrtf(-log1pf(-u1)) * (((float) M_PI) * (2.0f * u2));
} else {
tmp = sinf(t_0) * sqrtf(u1);
}
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(0.013799999840557575)) tmp = Float32(sqrt(Float32(-log1p(Float32(-u1)))) * Float32(Float32(pi) * Float32(Float32(2.0) * u2))); else tmp = Float32(sin(t_0) * sqrt(u1)); end return tmp end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := u2 \cdot \left(2 \cdot \pi\right)\\
\mathbf{if}\;t\_0 \leq 0.013799999840557575:\\
\;\;\;\;\sqrt{-\mathsf{log1p}\left(-u1\right)} \cdot \left(\pi \cdot \left(2 \cdot u2\right)\right)\\
\mathbf{else}:\\
\;\;\;\;\sin t\_0 \cdot \sqrt{u1}\\
\end{array}
\end{array}
if (*.f32 (*.f32 #s(literal 2 binary32) (PI.f32)) u2) < 0.0137999998Initial program 55.3%
sub-neg55.3%
log1p-define98.3%
associate-*l*98.3%
Simplified98.3%
add-cbrt-cube98.3%
add-cbrt-cube98.3%
cbrt-unprod98.4%
pow398.4%
pow398.5%
Applied egg-rr98.5%
Taylor expanded in u2 around 0 96.9%
associate-*r*96.9%
*-commutative96.9%
*-commutative96.9%
*-commutative96.9%
Simplified96.9%
if 0.0137999998 < (*.f32 (*.f32 #s(literal 2 binary32) (PI.f32)) u2) Initial program 57.4%
Taylor expanded in u1 around 0 76.2%
Final simplification91.5%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (sin (* u2 (* 2.0 PI))) (sqrt u1)))
float code(float cosTheta_i, float u1, float u2) {
return sinf((u2 * (2.0f * ((float) M_PI)))) * sqrtf(u1);
}
function code(cosTheta_i, u1, u2) return Float32(sin(Float32(u2 * Float32(Float32(2.0) * Float32(pi)))) * sqrt(u1)) end
function tmp = code(cosTheta_i, u1, u2) tmp = sin((u2 * (single(2.0) * single(pi)))) * sqrt(u1); end
\begin{array}{l}
\\
\sin \left(u2 \cdot \left(2 \cdot \pi\right)\right) \cdot \sqrt{u1}
\end{array}
Initial program 55.8%
Taylor expanded in u1 around 0 77.5%
Final simplification77.5%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (* PI u2) (* 2.0 (sqrt u1))))
float code(float cosTheta_i, float u1, float u2) {
return (((float) M_PI) * u2) * (2.0f * sqrtf(u1));
}
function code(cosTheta_i, u1, u2) return Float32(Float32(Float32(pi) * u2) * Float32(Float32(2.0) * sqrt(u1))) end
function tmp = code(cosTheta_i, u1, u2) tmp = (single(pi) * u2) * (single(2.0) * sqrt(u1)); end
\begin{array}{l}
\\
\left(\pi \cdot u2\right) \cdot \left(2 \cdot \sqrt{u1}\right)
\end{array}
Initial program 55.8%
Taylor expanded in u1 around 0 77.5%
Taylor expanded in u2 around 0 68.5%
associate-*r*68.5%
Simplified68.5%
Final simplification68.5%
herbie shell --seed 2024170
(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))))