
(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 60.3%
sub-neg60.3%
log1p-define98.4%
Simplified98.4%
Final simplification98.4%
(FPCore (cosTheta_i u1 u2)
:precision binary32
(let* ((t_0 (* (* 2.0 PI) u2)))
(if (<= t_0 0.0005000000237487257)
(* (sqrt (- (log1p (- u1)))) (* 2.0 (* PI u2)))
(*
(sin t_0)
(sqrt
(*
u1
(+ 1.0 (* u1 (+ 0.5 (* u1 (- 0.3333333333333333 (* u1 -0.25))))))))))))
float code(float cosTheta_i, float u1, float u2) {
float t_0 = (2.0f * ((float) M_PI)) * u2;
float tmp;
if (t_0 <= 0.0005000000237487257f) {
tmp = sqrtf(-log1pf(-u1)) * (2.0f * (((float) M_PI) * u2));
} else {
tmp = sinf(t_0) * sqrtf((u1 * (1.0f + (u1 * (0.5f + (u1 * (0.3333333333333333f - (u1 * -0.25f))))))));
}
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(0.0005000000237487257)) tmp = Float32(sqrt(Float32(-log1p(Float32(-u1)))) * Float32(Float32(2.0) * Float32(Float32(pi) * u2))); else tmp = Float32(sin(t_0) * sqrt(Float32(u1 * Float32(Float32(1.0) + Float32(u1 * Float32(Float32(0.5) + Float32(u1 * Float32(Float32(0.3333333333333333) - Float32(u1 * Float32(-0.25)))))))))); end return tmp end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \left(2 \cdot \pi\right) \cdot u2\\
\mathbf{if}\;t\_0 \leq 0.0005000000237487257:\\
\;\;\;\;\sqrt{-\mathsf{log1p}\left(-u1\right)} \cdot \left(2 \cdot \left(\pi \cdot u2\right)\right)\\
\mathbf{else}:\\
\;\;\;\;\sin t\_0 \cdot \sqrt{u1 \cdot \left(1 + u1 \cdot \left(0.5 + u1 \cdot \left(0.3333333333333333 - u1 \cdot -0.25\right)\right)\right)}\\
\end{array}
\end{array}
if (*.f32 (*.f32 #s(literal 2 binary32) (PI.f32)) u2) < 5.00000024e-4Initial program 62.4%
sub-neg62.4%
log1p-define98.6%
Simplified98.6%
add-cbrt-cube98.6%
add-cbrt-cube98.6%
cbrt-unprod98.6%
pow398.6%
pow398.6%
Applied egg-rr98.6%
Taylor expanded in u2 around 0 98.6%
if 5.00000024e-4 < (*.f32 (*.f32 #s(literal 2 binary32) (PI.f32)) u2) Initial program 57.4%
Taylor expanded in u1 around 0 93.1%
Final simplification96.3%
(FPCore (cosTheta_i u1 u2)
:precision binary32
(let* ((t_0 (* (* 2.0 PI) u2)))
(if (<= t_0 0.004000000189989805)
(* (sqrt (- (log1p (- u1)))) (* 2.0 (* PI 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 = (2.0f * ((float) M_PI)) * u2;
float tmp;
if (t_0 <= 0.004000000189989805f) {
tmp = sqrtf(-log1pf(-u1)) * (2.0f * (((float) M_PI) * 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(Float32(Float32(2.0) * Float32(pi)) * u2) tmp = Float32(0.0) if (t_0 <= Float32(0.004000000189989805)) tmp = Float32(sqrt(Float32(-log1p(Float32(-u1)))) * Float32(Float32(2.0) * Float32(Float32(pi) * 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 := \left(2 \cdot \pi\right) \cdot u2\\
\mathbf{if}\;t\_0 \leq 0.004000000189989805:\\
\;\;\;\;\sqrt{-\mathsf{log1p}\left(-u1\right)} \cdot \left(2 \cdot \left(\pi \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) < 0.00400000019Initial program 61.1%
sub-neg61.1%
log1p-define98.6%
Simplified98.6%
add-cbrt-cube98.6%
add-cbrt-cube98.6%
cbrt-unprod98.5%
pow398.5%
pow398.6%
Applied egg-rr98.6%
Taylor expanded in u2 around 0 97.9%
if 0.00400000019 < (*.f32 (*.f32 #s(literal 2 binary32) (PI.f32)) u2) Initial program 58.6%
Taylor expanded in u1 around 0 90.2%
Final simplification95.4%
(FPCore (cosTheta_i u1 u2)
:precision binary32
(let* ((t_0 (* (* 2.0 PI) u2)))
(if (<= t_0 0.012000000104308128)
(* (sqrt (- (log1p (- u1)))) (* 2.0 (* PI u2)))
(* (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 <= 0.012000000104308128f) {
tmp = sqrtf(-log1pf(-u1)) * (2.0f * (((float) M_PI) * u2));
} 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(0.012000000104308128)) tmp = Float32(sqrt(Float32(-log1p(Float32(-u1)))) * Float32(Float32(2.0) * Float32(Float32(pi) * 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 := \left(2 \cdot \pi\right) \cdot u2\\
\mathbf{if}\;t\_0 \leq 0.012000000104308128:\\
\;\;\;\;\sqrt{-\mathsf{log1p}\left(-u1\right)} \cdot \left(2 \cdot \left(\pi \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) < 0.0120000001Initial program 61.6%
sub-neg61.6%
log1p-define98.6%
Simplified98.6%
add-cbrt-cube98.6%
add-cbrt-cube98.6%
cbrt-unprod98.5%
pow398.5%
pow398.6%
Applied egg-rr98.6%
Taylor expanded in u2 around 0 96.8%
if 0.0120000001 < (*.f32 (*.f32 #s(literal 2 binary32) (PI.f32)) u2) Initial program 57.1%
Taylor expanded in u1 around 0 88.3%
Final simplification94.4%
(FPCore (cosTheta_i u1 u2) :precision binary32 (if (<= (* (* 2.0 PI) u2) 0.012000000104308128) (* (sqrt (- (log1p (- u1)))) (* 2.0 (* PI u2))) (* (sqrt u1) (sin (* PI (* 2.0 u2))))))
float code(float cosTheta_i, float u1, float u2) {
float tmp;
if (((2.0f * ((float) M_PI)) * u2) <= 0.012000000104308128f) {
tmp = sqrtf(-log1pf(-u1)) * (2.0f * (((float) M_PI) * u2));
} else {
tmp = sqrtf(u1) * sinf((((float) M_PI) * (2.0f * u2)));
}
return tmp;
}
function code(cosTheta_i, u1, u2) tmp = Float32(0.0) if (Float32(Float32(Float32(2.0) * Float32(pi)) * u2) <= Float32(0.012000000104308128)) tmp = Float32(sqrt(Float32(-log1p(Float32(-u1)))) * Float32(Float32(2.0) * Float32(Float32(pi) * u2))); else tmp = Float32(sqrt(u1) * sin(Float32(Float32(pi) * Float32(Float32(2.0) * u2)))); end return tmp end
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;\left(2 \cdot \pi\right) \cdot u2 \leq 0.012000000104308128:\\
\;\;\;\;\sqrt{-\mathsf{log1p}\left(-u1\right)} \cdot \left(2 \cdot \left(\pi \cdot u2\right)\right)\\
\mathbf{else}:\\
\;\;\;\;\sqrt{u1} \cdot \sin \left(\pi \cdot \left(2 \cdot u2\right)\right)\\
\end{array}
\end{array}
if (*.f32 (*.f32 #s(literal 2 binary32) (PI.f32)) u2) < 0.0120000001Initial program 61.6%
sub-neg61.6%
log1p-define98.6%
Simplified98.6%
add-cbrt-cube98.6%
add-cbrt-cube98.6%
cbrt-unprod98.5%
pow398.5%
pow398.6%
Applied egg-rr98.6%
Taylor expanded in u2 around 0 96.8%
if 0.0120000001 < (*.f32 (*.f32 #s(literal 2 binary32) (PI.f32)) u2) Initial program 57.1%
add-exp-log50.8%
add-sqr-sqrt50.8%
sqrt-unprod50.8%
sqr-neg50.8%
sqrt-unprod1.4%
add-sqr-sqrt1.4%
sub-neg1.4%
log1p-undefine-0.0%
add-sqr-sqrt-0.0%
sqrt-unprod65.1%
sqr-neg65.1%
sqrt-unprod65.1%
add-sqr-sqrt65.1%
associate-*l*65.1%
Applied egg-rr65.1%
Taylor expanded in u1 around 0 77.3%
*-commutative77.3%
*-commutative77.3%
associate-*r*77.3%
Simplified77.3%
Final simplification91.3%
(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 60.3%
add-exp-log58.0%
add-sqr-sqrt58.0%
sqrt-unprod58.0%
sqr-neg58.0%
sqrt-unprod1.4%
add-sqr-sqrt1.4%
sub-neg1.4%
log1p-undefine-0.0%
add-sqr-sqrt-0.0%
sqrt-unprod68.7%
sqr-neg68.7%
sqrt-unprod68.7%
add-sqr-sqrt68.7%
associate-*l*68.7%
Applied egg-rr68.7%
Taylor expanded in u1 around 0 74.9%
*-commutative74.9%
*-commutative74.9%
associate-*r*74.9%
Simplified74.9%
Final simplification74.9%
(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(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 60.3%
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 4.6%
Final simplification4.6%
(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 60.3%
add-exp-log58.0%
add-sqr-sqrt58.0%
sqrt-unprod58.0%
sqr-neg58.0%
sqrt-unprod1.4%
add-sqr-sqrt1.4%
sub-neg1.4%
log1p-undefine-0.0%
add-sqr-sqrt-0.0%
sqrt-unprod68.7%
sqr-neg68.7%
sqrt-unprod68.7%
add-sqr-sqrt68.7%
associate-*l*68.7%
Applied egg-rr68.7%
Taylor expanded in u2 around 0 37.4%
associate-*l*37.4%
log1p-define63.6%
Simplified63.6%
Taylor expanded in u1 around 0 65.1%
Final simplification65.1%
herbie shell --seed 2024069
(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))))