
(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 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(Float32(2.0) * Float32(pi)) * u2))) end
\begin{array}{l}
\\
\sqrt{-\mathsf{log1p}\left(-u1\right)} \cdot \sin \left(\left(2 \cdot \pi\right) \cdot u2\right)
\end{array}
Initial program 58.7%
sub-neg58.7%
log1p-define98.5%
Simplified98.5%
Final simplification98.5%
(FPCore (cosTheta_i u1 u2)
:precision binary32
(let* ((t_0 (* (* 2.0 PI) u2)))
(if (<= t_0 0.0024999999441206455)
(* (sqrt (- (log1p (- u1)))) t_0)
(*
(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 = (2.0f * ((float) M_PI)) * u2;
float tmp;
if (t_0 <= 0.0024999999441206455f) {
tmp = sqrtf(-log1pf(-u1)) * t_0;
} 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(Float32(Float32(2.0) * Float32(pi)) * u2) tmp = Float32(0.0) if (t_0 <= Float32(0.0024999999441206455)) tmp = Float32(sqrt(Float32(-log1p(Float32(-u1)))) * t_0); 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 := \left(2 \cdot \pi\right) \cdot u2\\
\mathbf{if}\;t\_0 \leq 0.0024999999441206455:\\
\;\;\;\;\sqrt{-\mathsf{log1p}\left(-u1\right)} \cdot t\_0\\
\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) < 0.00249999994Initial program 58.0%
sub-neg58.0%
log1p-define98.7%
Simplified98.7%
add-cbrt-cube98.7%
add-cbrt-cube98.7%
cbrt-unprod98.5%
pow398.5%
pow398.5%
Applied egg-rr98.5%
Taylor expanded in u2 around 0 98.2%
*-commutative98.2%
associate-*r*98.2%
*-commutative98.2%
Simplified98.2%
if 0.00249999994 < (*.f32 (*.f32 #s(literal 2 binary32) (PI.f32)) u2) Initial program 59.9%
Taylor expanded in u1 around 0 90.8%
Final simplification95.5%
(FPCore (cosTheta_i u1 u2)
:precision binary32
(let* ((t_0 (* (* 2.0 PI) u2)))
(if (<= t_0 0.0024999999441206455)
(* (sqrt (- (log1p (- u1)))) t_0)
(* (sin t_0) (sqrt (* u1 (- 1.0 (* u1 -0.5))))))))
float code(float cosTheta_i, float u1, float u2) {
float t_0 = (2.0f * ((float) M_PI)) * u2;
float tmp;
if (t_0 <= 0.0024999999441206455f) {
tmp = sqrtf(-log1pf(-u1)) * t_0;
} else {
tmp = sinf(t_0) * sqrtf((u1 * (1.0f - (u1 * -0.5f))));
}
return tmp;
}
function code(cosTheta_i, u1, u2) t_0 = Float32(Float32(Float32(2.0) * Float32(pi)) * u2) tmp = Float32(0.0) if (t_0 <= Float32(0.0024999999441206455)) tmp = Float32(sqrt(Float32(-log1p(Float32(-u1)))) * t_0); 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 := \left(2 \cdot \pi\right) \cdot u2\\
\mathbf{if}\;t\_0 \leq 0.0024999999441206455:\\
\;\;\;\;\sqrt{-\mathsf{log1p}\left(-u1\right)} \cdot t\_0\\
\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) < 0.00249999994Initial program 58.0%
sub-neg58.0%
log1p-define98.7%
Simplified98.7%
add-cbrt-cube98.7%
add-cbrt-cube98.7%
cbrt-unprod98.5%
pow398.5%
pow398.5%
Applied egg-rr98.5%
Taylor expanded in u2 around 0 98.2%
*-commutative98.2%
associate-*r*98.2%
*-commutative98.2%
Simplified98.2%
if 0.00249999994 < (*.f32 (*.f32 #s(literal 2 binary32) (PI.f32)) u2) Initial program 59.9%
Taylor expanded in u1 around 0 86.8%
Final simplification94.2%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (sin (* (* 2.0 PI) u2)) (sqrt (* u1 (+ 1.0 (* u1 (- 0.5 (* u1 (- (* u1 -0.25) 0.3333333333333333)))))))))
float code(float cosTheta_i, float u1, float u2) {
return sinf(((2.0f * ((float) M_PI)) * u2)) * sqrtf((u1 * (1.0f + (u1 * (0.5f - (u1 * ((u1 * -0.25f) - 0.3333333333333333f)))))));
}
function code(cosTheta_i, u1, u2) return Float32(sin(Float32(Float32(Float32(2.0) * Float32(pi)) * u2)) * sqrt(Float32(u1 * Float32(Float32(1.0) + Float32(u1 * Float32(Float32(0.5) - Float32(u1 * Float32(Float32(u1 * Float32(-0.25)) - Float32(0.3333333333333333))))))))) end
function tmp = code(cosTheta_i, u1, u2) tmp = sin(((single(2.0) * single(pi)) * u2)) * sqrt((u1 * (single(1.0) + (u1 * (single(0.5) - (u1 * ((u1 * single(-0.25)) - single(0.3333333333333333)))))))); end
\begin{array}{l}
\\
\sin \left(\left(2 \cdot \pi\right) \cdot u2\right) \cdot \sqrt{u1 \cdot \left(1 + u1 \cdot \left(0.5 - u1 \cdot \left(u1 \cdot -0.25 - 0.3333333333333333\right)\right)\right)}
\end{array}
Initial program 58.7%
Taylor expanded in u1 around 0 93.6%
Final simplification93.6%
(FPCore (cosTheta_i u1 u2)
:precision binary32
(let* ((t_0 (* (* 2.0 PI) u2)))
(if (<= t_0 0.005200000014156103)
(* (sqrt (- (log1p (- u1)))) t_0)
(* (sin t_0) (sqrt u1)))))
float code(float cosTheta_i, float u1, float u2) {
float t_0 = (2.0f * ((float) M_PI)) * u2;
float tmp;
if (t_0 <= 0.005200000014156103f) {
tmp = sqrtf(-log1pf(-u1)) * t_0;
} else {
tmp = sinf(t_0) * sqrtf(u1);
}
return tmp;
}
function code(cosTheta_i, u1, u2) t_0 = Float32(Float32(Float32(2.0) * Float32(pi)) * u2) tmp = Float32(0.0) if (t_0 <= Float32(0.005200000014156103)) tmp = Float32(sqrt(Float32(-log1p(Float32(-u1)))) * t_0); else tmp = Float32(sin(t_0) * sqrt(u1)); end return tmp end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \left(2 \cdot \pi\right) \cdot u2\\
\mathbf{if}\;t\_0 \leq 0.005200000014156103:\\
\;\;\;\;\sqrt{-\mathsf{log1p}\left(-u1\right)} \cdot t\_0\\
\mathbf{else}:\\
\;\;\;\;\sin t\_0 \cdot \sqrt{u1}\\
\end{array}
\end{array}
if (*.f32 (*.f32 #s(literal 2 binary32) (PI.f32)) u2) < 0.00520000001Initial program 58.4%
sub-neg58.4%
log1p-define98.7%
Simplified98.7%
add-cbrt-cube98.7%
add-cbrt-cube98.7%
cbrt-unprod98.5%
pow398.5%
pow398.5%
Applied egg-rr98.5%
Taylor expanded in u2 around 0 98.0%
*-commutative98.0%
associate-*r*98.0%
*-commutative98.0%
Simplified98.0%
if 0.00520000001 < (*.f32 (*.f32 #s(literal 2 binary32) (PI.f32)) u2) Initial program 59.2%
sub-neg59.2%
log1p-define98.2%
Simplified98.2%
add-cbrt-cube98.2%
pow1/395.6%
Applied egg-rr71.5%
unpow1/373.2%
Simplified73.2%
Taylor expanded in u1 around 0 75.2%
associate-*r*75.2%
*-commutative75.2%
*-commutative75.2%
*-commutative75.2%
associate-*r*75.2%
Simplified75.2%
Final simplification90.1%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (sin (* (* 2.0 PI) u2)) (sqrt u1)))
float code(float cosTheta_i, float u1, float u2) {
return sinf(((2.0f * ((float) M_PI)) * u2)) * sqrtf(u1);
}
function code(cosTheta_i, u1, u2) return Float32(sin(Float32(Float32(Float32(2.0) * Float32(pi)) * u2)) * sqrt(u1)) end
function tmp = code(cosTheta_i, u1, u2) tmp = sin(((single(2.0) * single(pi)) * u2)) * sqrt(u1); end
\begin{array}{l}
\\
\sin \left(\left(2 \cdot \pi\right) \cdot u2\right) \cdot \sqrt{u1}
\end{array}
Initial program 58.7%
sub-neg58.7%
log1p-define98.5%
Simplified98.5%
add-cbrt-cube98.5%
pow1/395.9%
Applied egg-rr72.3%
unpow1/374.1%
Simplified74.1%
Taylor expanded in u1 around 0 76.2%
associate-*r*76.2%
*-commutative76.2%
*-commutative76.2%
*-commutative76.2%
associate-*r*76.2%
Simplified76.2%
Final simplification76.2%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (* (sqrt u1) (* PI u2)) -2.0))
float code(float cosTheta_i, float u1, float u2) {
return (sqrtf(u1) * (((float) M_PI) * u2)) * -2.0f;
}
function code(cosTheta_i, u1, u2) return Float32(Float32(sqrt(u1) * Float32(Float32(pi) * u2)) * Float32(-2.0)) end
function tmp = code(cosTheta_i, u1, u2) tmp = (sqrt(u1) * (single(pi) * u2)) * single(-2.0); end
\begin{array}{l}
\\
\left(\sqrt{u1} \cdot \left(\pi \cdot u2\right)\right) \cdot -2
\end{array}
Initial program 58.7%
Taylor expanded in u1 around 0 -0.0%
associate-*r*-0.0%
unpow2-0.0%
rem-square-sqrt4.0%
*-commutative4.0%
associate-*l*4.0%
*-commutative4.0%
mul-1-neg4.0%
Simplified4.0%
Taylor expanded in u2 around 0 4.7%
Final simplification4.7%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* 2.0 (* (sqrt u1) (* PI u2))))
float code(float cosTheta_i, float u1, float u2) {
return 2.0f * (sqrtf(u1) * (((float) M_PI) * u2));
}
function code(cosTheta_i, u1, u2) return Float32(Float32(2.0) * Float32(sqrt(u1) * Float32(Float32(pi) * u2))) end
function tmp = code(cosTheta_i, u1, u2) tmp = single(2.0) * (sqrt(u1) * (single(pi) * u2)); end
\begin{array}{l}
\\
2 \cdot \left(\sqrt{u1} \cdot \left(\pi \cdot u2\right)\right)
\end{array}
Initial program 58.7%
Taylor expanded in u1 around 0 -0.0%
associate-*r*-0.0%
unpow2-0.0%
rem-square-sqrt4.0%
*-commutative4.0%
associate-*l*4.0%
*-commutative4.0%
mul-1-neg4.0%
Simplified4.0%
add-cube-cbrt4.0%
pow34.0%
*-commutative4.0%
associate-*l*4.0%
*-commutative4.0%
associate-*r*4.0%
add-sqr-sqrt-0.0%
sqrt-unprod75.8%
sqr-neg75.8%
add-sqr-sqrt75.8%
Applied egg-rr75.8%
Taylor expanded in u2 around 0 65.1%
Final simplification65.1%
herbie shell --seed 2024130
(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))))