
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (sqrt (- (log (- 1.0 u1)))) (cos (* (* 2.0 PI) u2))))
float code(float cosTheta_i, float u1, float u2) {
return sqrtf(-logf((1.0f - u1))) * cosf(((2.0f * ((float) M_PI)) * u2));
}
function code(cosTheta_i, u1, u2) return Float32(sqrt(Float32(-log(Float32(Float32(1.0) - u1)))) * cos(Float32(Float32(Float32(2.0) * Float32(pi)) * u2))) end
function tmp = code(cosTheta_i, u1, u2) tmp = sqrt(-log((single(1.0) - u1))) * cos(((single(2.0) * single(pi)) * u2)); end
\begin{array}{l}
\\
\sqrt{-\log \left(1 - u1\right)} \cdot \cos \left(\left(2 \cdot \pi\right) \cdot u2\right)
\end{array}
Sampling outcomes in binary32 precision:
Herbie found 12 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (sqrt (- (log (- 1.0 u1)))) (cos (* (* 2.0 PI) u2))))
float code(float cosTheta_i, float u1, float u2) {
return sqrtf(-logf((1.0f - u1))) * cosf(((2.0f * ((float) M_PI)) * u2));
}
function code(cosTheta_i, u1, u2) return Float32(sqrt(Float32(-log(Float32(Float32(1.0) - u1)))) * cos(Float32(Float32(Float32(2.0) * Float32(pi)) * u2))) end
function tmp = code(cosTheta_i, u1, u2) tmp = sqrt(-log((single(1.0) - u1))) * cos(((single(2.0) * single(pi)) * u2)); end
\begin{array}{l}
\\
\sqrt{-\log \left(1 - u1\right)} \cdot \cos \left(\left(2 \cdot \pi\right) \cdot u2\right)
\end{array}
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (sqrt (- (log1p (- u1)))) (cos (* (* 2.0 PI) u2))))
float code(float cosTheta_i, float u1, float u2) {
return sqrtf(-log1pf(-u1)) * cosf(((2.0f * ((float) M_PI)) * u2));
}
function code(cosTheta_i, u1, u2) return Float32(sqrt(Float32(-log1p(Float32(-u1)))) * cos(Float32(Float32(Float32(2.0) * Float32(pi)) * u2))) end
\begin{array}{l}
\\
\sqrt{-\mathsf{log1p}\left(-u1\right)} \cdot \cos \left(\left(2 \cdot \pi\right) \cdot u2\right)
\end{array}
Initial program 58.2%
lift-log.f32N/A
lift--.f32N/A
sub-negN/A
lower-log1p.f32N/A
lower-neg.f3299.0
Applied rewrites99.0%
(FPCore (cosTheta_i u1 u2)
:precision binary32
(let* ((t_0 (sqrt (/ 1.0 u1))) (t_1 (cos (* (* 2.0 PI) u2))))
(if (<= t_1 0.9999985098838806)
(* t_1 (sqrt u1))
(*
(fma
(* u1 u1)
(fma
u1
(fma
t_0
0.16666666666666666
(* (sqrt u1) (* 0.5 (+ 0.25 (/ -0.0625 u1)))))
(* 0.25 t_0))
(sqrt u1))
1.0))))
float code(float cosTheta_i, float u1, float u2) {
float t_0 = sqrtf((1.0f / u1));
float t_1 = cosf(((2.0f * ((float) M_PI)) * u2));
float tmp;
if (t_1 <= 0.9999985098838806f) {
tmp = t_1 * sqrtf(u1);
} else {
tmp = fmaf((u1 * u1), fmaf(u1, fmaf(t_0, 0.16666666666666666f, (sqrtf(u1) * (0.5f * (0.25f + (-0.0625f / u1))))), (0.25f * t_0)), sqrtf(u1)) * 1.0f;
}
return tmp;
}
function code(cosTheta_i, u1, u2) t_0 = sqrt(Float32(Float32(1.0) / u1)) t_1 = cos(Float32(Float32(Float32(2.0) * Float32(pi)) * u2)) tmp = Float32(0.0) if (t_1 <= Float32(0.9999985098838806)) tmp = Float32(t_1 * sqrt(u1)); else tmp = Float32(fma(Float32(u1 * u1), fma(u1, fma(t_0, Float32(0.16666666666666666), Float32(sqrt(u1) * Float32(Float32(0.5) * Float32(Float32(0.25) + Float32(Float32(-0.0625) / u1))))), Float32(Float32(0.25) * t_0)), sqrt(u1)) * Float32(1.0)); end return tmp end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \sqrt{\frac{1}{u1}}\\
t_1 := \cos \left(\left(2 \cdot \pi\right) \cdot u2\right)\\
\mathbf{if}\;t\_1 \leq 0.9999985098838806:\\
\;\;\;\;t\_1 \cdot \sqrt{u1}\\
\mathbf{else}:\\
\;\;\;\;\mathsf{fma}\left(u1 \cdot u1, \mathsf{fma}\left(u1, \mathsf{fma}\left(t\_0, 0.16666666666666666, \sqrt{u1} \cdot \left(0.5 \cdot \left(0.25 + \frac{-0.0625}{u1}\right)\right)\right), 0.25 \cdot t\_0\right), \sqrt{u1}\right) \cdot 1\\
\end{array}
\end{array}
if (cos.f32 (*.f32 (*.f32 #s(literal 2 binary32) (PI.f32)) u2)) < 0.99999851Initial program 61.2%
Applied rewrites54.9%
Taylor expanded in u1 around 0
lower-sqrt.f3273.7
Applied rewrites73.7%
if 0.99999851 < (cos.f32 (*.f32 (*.f32 #s(literal 2 binary32) (PI.f32)) u2)) Initial program 56.4%
Applied rewrites51.3%
Taylor expanded in u1 around 0
lower-sqrt.f3278.2
Applied rewrites78.2%
Taylor expanded in u2 around 0
Applied rewrites78.1%
Taylor expanded in u1 around 0
+-commutativeN/A
lower-fma.f32N/A
Applied rewrites94.2%
Final simplification86.9%
(FPCore (cosTheta_i u1 u2)
:precision binary32
(*
(cos (* (* 2.0 PI) u2))
(sqrt
(fma
(fma u1 0.25 0.3333333333333333)
(* u1 (* u1 u1))
(fma (* u1 u1) 0.5 u1)))))
float code(float cosTheta_i, float u1, float u2) {
return cosf(((2.0f * ((float) M_PI)) * u2)) * sqrtf(fmaf(fmaf(u1, 0.25f, 0.3333333333333333f), (u1 * (u1 * u1)), fmaf((u1 * u1), 0.5f, u1)));
}
function code(cosTheta_i, u1, u2) return Float32(cos(Float32(Float32(Float32(2.0) * Float32(pi)) * u2)) * sqrt(fma(fma(u1, Float32(0.25), Float32(0.3333333333333333)), Float32(u1 * Float32(u1 * u1)), fma(Float32(u1 * u1), Float32(0.5), u1)))) end
\begin{array}{l}
\\
\cos \left(\left(2 \cdot \pi\right) \cdot u2\right) \cdot \sqrt{\mathsf{fma}\left(\mathsf{fma}\left(u1, 0.25, 0.3333333333333333\right), u1 \cdot \left(u1 \cdot u1\right), \mathsf{fma}\left(u1 \cdot u1, 0.5, u1\right)\right)}
\end{array}
Initial program 58.2%
Applied rewrites98.9%
Taylor expanded in u1 around 0
+-commutativeN/A
distribute-lft-inN/A
associate-*r*N/A
unpow2N/A
*-rgt-identityN/A
lower-fma.f32N/A
unpow2N/A
lower-*.f32N/A
+-commutativeN/A
lower-fma.f32N/A
+-commutativeN/A
*-commutativeN/A
lower-fma.f3294.6
Applied rewrites94.6%
Applied rewrites94.6%
Final simplification94.6%
(FPCore (cosTheta_i u1 u2) :precision binary32 (if (<= (cos (* (* 2.0 PI) u2)) 0.9999985098838806) (* (sqrt u1) (fma (* PI PI) (* -2.0 (* u2 u2)) 1.0)) (* 1.0 (fma (sqrt (* u1 (* u1 u1))) 0.25 (sqrt u1)))))
float code(float cosTheta_i, float u1, float u2) {
float tmp;
if (cosf(((2.0f * ((float) M_PI)) * u2)) <= 0.9999985098838806f) {
tmp = sqrtf(u1) * fmaf((((float) M_PI) * ((float) M_PI)), (-2.0f * (u2 * u2)), 1.0f);
} else {
tmp = 1.0f * fmaf(sqrtf((u1 * (u1 * u1))), 0.25f, sqrtf(u1));
}
return tmp;
}
function code(cosTheta_i, u1, u2) tmp = Float32(0.0) if (cos(Float32(Float32(Float32(2.0) * Float32(pi)) * u2)) <= Float32(0.9999985098838806)) tmp = Float32(sqrt(u1) * fma(Float32(Float32(pi) * Float32(pi)), Float32(Float32(-2.0) * Float32(u2 * u2)), Float32(1.0))); else tmp = Float32(Float32(1.0) * fma(sqrt(Float32(u1 * Float32(u1 * u1))), Float32(0.25), sqrt(u1))); end return tmp end
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;\cos \left(\left(2 \cdot \pi\right) \cdot u2\right) \leq 0.9999985098838806:\\
\;\;\;\;\sqrt{u1} \cdot \mathsf{fma}\left(\pi \cdot \pi, -2 \cdot \left(u2 \cdot u2\right), 1\right)\\
\mathbf{else}:\\
\;\;\;\;1 \cdot \mathsf{fma}\left(\sqrt{u1 \cdot \left(u1 \cdot u1\right)}, 0.25, \sqrt{u1}\right)\\
\end{array}
\end{array}
if (cos.f32 (*.f32 (*.f32 #s(literal 2 binary32) (PI.f32)) u2)) < 0.99999851Initial program 61.2%
Applied rewrites54.9%
Taylor expanded in u1 around 0
lower-sqrt.f3273.7
Applied rewrites73.7%
Taylor expanded in u2 around 0
+-commutativeN/A
*-commutativeN/A
associate-*r*N/A
*-commutativeN/A
associate-*l*N/A
lower-fma.f32N/A
unpow2N/A
lower-*.f32N/A
lower-PI.f32N/A
lower-PI.f32N/A
lower-*.f32N/A
unpow2N/A
lower-*.f3250.5
Applied rewrites50.5%
if 0.99999851 < (cos.f32 (*.f32 (*.f32 #s(literal 2 binary32) (PI.f32)) u2)) Initial program 56.4%
Applied rewrites51.3%
Taylor expanded in u1 around 0
+-commutativeN/A
*-commutativeN/A
lower-fma.f32N/A
lower-sqrt.f32N/A
cube-multN/A
unpow2N/A
lower-*.f32N/A
unpow2N/A
lower-*.f32N/A
lower-sqrt.f3290.6
Applied rewrites90.6%
Taylor expanded in u2 around 0
Applied rewrites90.3%
Final simplification76.0%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (cos (* (* 2.0 PI) u2)) (sqrt (- (* u1 (fma u1 (fma u1 (fma u1 -0.25 -0.3333333333333333) -0.5) -1.0))))))
float code(float cosTheta_i, float u1, float u2) {
return cosf(((2.0f * ((float) M_PI)) * u2)) * sqrtf(-(u1 * fmaf(u1, fmaf(u1, fmaf(u1, -0.25f, -0.3333333333333333f), -0.5f), -1.0f)));
}
function code(cosTheta_i, u1, u2) return Float32(cos(Float32(Float32(Float32(2.0) * Float32(pi)) * u2)) * sqrt(Float32(-Float32(u1 * fma(u1, fma(u1, fma(u1, Float32(-0.25), Float32(-0.3333333333333333)), Float32(-0.5)), Float32(-1.0)))))) end
\begin{array}{l}
\\
\cos \left(\left(2 \cdot \pi\right) \cdot u2\right) \cdot \sqrt{-u1 \cdot \mathsf{fma}\left(u1, \mathsf{fma}\left(u1, \mathsf{fma}\left(u1, -0.25, -0.3333333333333333\right), -0.5\right), -1\right)}
\end{array}
Initial program 58.2%
Taylor expanded in u1 around 0
lower-*.f32N/A
sub-negN/A
metadata-evalN/A
lower-fma.f32N/A
sub-negN/A
metadata-evalN/A
lower-fma.f32N/A
sub-negN/A
*-commutativeN/A
metadata-evalN/A
lower-fma.f3294.6
Applied rewrites94.6%
Final simplification94.6%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (cos (* (* 2.0 PI) u2)) (sqrt (fma (* u1 u1) (fma u1 (fma u1 0.25 0.3333333333333333) 0.5) u1))))
float code(float cosTheta_i, float u1, float u2) {
return cosf(((2.0f * ((float) M_PI)) * u2)) * sqrtf(fmaf((u1 * u1), fmaf(u1, fmaf(u1, 0.25f, 0.3333333333333333f), 0.5f), u1));
}
function code(cosTheta_i, u1, u2) return Float32(cos(Float32(Float32(Float32(2.0) * Float32(pi)) * u2)) * sqrt(fma(Float32(u1 * u1), fma(u1, fma(u1, Float32(0.25), Float32(0.3333333333333333)), Float32(0.5)), u1))) end
\begin{array}{l}
\\
\cos \left(\left(2 \cdot \pi\right) \cdot u2\right) \cdot \sqrt{\mathsf{fma}\left(u1 \cdot u1, \mathsf{fma}\left(u1, \mathsf{fma}\left(u1, 0.25, 0.3333333333333333\right), 0.5\right), u1\right)}
\end{array}
Initial program 58.2%
Taylor expanded in u1 around 0
+-commutativeN/A
distribute-lft-inN/A
associate-*r*N/A
unpow2N/A
*-rgt-identityN/A
lower-fma.f32N/A
unpow2N/A
lower-*.f32N/A
+-commutativeN/A
lower-fma.f32N/A
+-commutativeN/A
*-commutativeN/A
lower-fma.f3294.6
Applied rewrites94.6%
Final simplification94.6%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (cos (* (* 2.0 PI) u2)) (sqrt (- (* u1 (fma u1 (fma u1 -0.3333333333333333 -0.5) -1.0))))))
float code(float cosTheta_i, float u1, float u2) {
return cosf(((2.0f * ((float) M_PI)) * u2)) * sqrtf(-(u1 * fmaf(u1, fmaf(u1, -0.3333333333333333f, -0.5f), -1.0f)));
}
function code(cosTheta_i, u1, u2) return Float32(cos(Float32(Float32(Float32(2.0) * Float32(pi)) * u2)) * sqrt(Float32(-Float32(u1 * fma(u1, fma(u1, Float32(-0.3333333333333333), Float32(-0.5)), Float32(-1.0)))))) end
\begin{array}{l}
\\
\cos \left(\left(2 \cdot \pi\right) \cdot u2\right) \cdot \sqrt{-u1 \cdot \mathsf{fma}\left(u1, \mathsf{fma}\left(u1, -0.3333333333333333, -0.5\right), -1\right)}
\end{array}
Initial program 58.2%
Taylor expanded in u1 around 0
lower-*.f32N/A
sub-negN/A
metadata-evalN/A
lower-fma.f32N/A
sub-negN/A
*-commutativeN/A
metadata-evalN/A
lower-fma.f3293.0
Applied rewrites93.0%
Final simplification93.0%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (cos (* (* 2.0 PI) u2)) (sqrt (fma (* u1 u1) (fma u1 0.3333333333333333 0.5) u1))))
float code(float cosTheta_i, float u1, float u2) {
return cosf(((2.0f * ((float) M_PI)) * u2)) * sqrtf(fmaf((u1 * u1), fmaf(u1, 0.3333333333333333f, 0.5f), u1));
}
function code(cosTheta_i, u1, u2) return Float32(cos(Float32(Float32(Float32(2.0) * Float32(pi)) * u2)) * sqrt(fma(Float32(u1 * u1), fma(u1, Float32(0.3333333333333333), Float32(0.5)), u1))) end
\begin{array}{l}
\\
\cos \left(\left(2 \cdot \pi\right) \cdot u2\right) \cdot \sqrt{\mathsf{fma}\left(u1 \cdot u1, \mathsf{fma}\left(u1, 0.3333333333333333, 0.5\right), u1\right)}
\end{array}
Initial program 58.2%
Taylor expanded in u1 around 0
+-commutativeN/A
distribute-lft-inN/A
associate-*r*N/A
unpow2N/A
*-rgt-identityN/A
lower-fma.f32N/A
unpow2N/A
lower-*.f32N/A
+-commutativeN/A
*-commutativeN/A
lower-fma.f3293.0
Applied rewrites93.0%
Final simplification93.0%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (cos (* (* 2.0 PI) u2)) (sqrt (fma u1 (* u1 0.5) u1))))
float code(float cosTheta_i, float u1, float u2) {
return cosf(((2.0f * ((float) M_PI)) * u2)) * sqrtf(fmaf(u1, (u1 * 0.5f), u1));
}
function code(cosTheta_i, u1, u2) return Float32(cos(Float32(Float32(Float32(2.0) * Float32(pi)) * u2)) * sqrt(fma(u1, Float32(u1 * Float32(0.5)), u1))) end
\begin{array}{l}
\\
\cos \left(\left(2 \cdot \pi\right) \cdot u2\right) \cdot \sqrt{\mathsf{fma}\left(u1, u1 \cdot 0.5, u1\right)}
\end{array}
Initial program 58.2%
Taylor expanded in u1 around 0
+-commutativeN/A
distribute-lft-inN/A
*-rgt-identityN/A
lower-fma.f32N/A
*-commutativeN/A
lower-*.f3289.5
Applied rewrites89.5%
Final simplification89.5%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (fma (sqrt (* u1 (* u1 u1))) 0.25 (sqrt u1)) (fma (* PI PI) (* -2.0 (* u2 u2)) 1.0)))
float code(float cosTheta_i, float u1, float u2) {
return fmaf(sqrtf((u1 * (u1 * u1))), 0.25f, sqrtf(u1)) * fmaf((((float) M_PI) * ((float) M_PI)), (-2.0f * (u2 * u2)), 1.0f);
}
function code(cosTheta_i, u1, u2) return Float32(fma(sqrt(Float32(u1 * Float32(u1 * u1))), Float32(0.25), sqrt(u1)) * fma(Float32(Float32(pi) * Float32(pi)), Float32(Float32(-2.0) * Float32(u2 * u2)), Float32(1.0))) end
\begin{array}{l}
\\
\mathsf{fma}\left(\sqrt{u1 \cdot \left(u1 \cdot u1\right)}, 0.25, \sqrt{u1}\right) \cdot \mathsf{fma}\left(\pi \cdot \pi, -2 \cdot \left(u2 \cdot u2\right), 1\right)
\end{array}
Initial program 58.2%
Applied rewrites52.6%
Taylor expanded in u1 around 0
+-commutativeN/A
*-commutativeN/A
lower-fma.f32N/A
lower-sqrt.f32N/A
cube-multN/A
unpow2N/A
lower-*.f32N/A
unpow2N/A
lower-*.f32N/A
lower-sqrt.f3289.6
Applied rewrites89.6%
Taylor expanded in u2 around 0
+-commutativeN/A
*-commutativeN/A
associate-*r*N/A
*-commutativeN/A
associate-*l*N/A
lower-fma.f32N/A
unpow2N/A
lower-*.f32N/A
lower-PI.f32N/A
lower-PI.f32N/A
lower-*.f32N/A
unpow2N/A
lower-*.f3278.2
Applied rewrites78.2%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (sqrt u1) (fma (* PI PI) (* -2.0 (* u2 u2)) 1.0)))
float code(float cosTheta_i, float u1, float u2) {
return sqrtf(u1) * fmaf((((float) M_PI) * ((float) M_PI)), (-2.0f * (u2 * u2)), 1.0f);
}
function code(cosTheta_i, u1, u2) return Float32(sqrt(u1) * fma(Float32(Float32(pi) * Float32(pi)), Float32(Float32(-2.0) * Float32(u2 * u2)), Float32(1.0))) end
\begin{array}{l}
\\
\sqrt{u1} \cdot \mathsf{fma}\left(\pi \cdot \pi, -2 \cdot \left(u2 \cdot u2\right), 1\right)
\end{array}
Initial program 58.2%
Applied rewrites52.6%
Taylor expanded in u1 around 0
lower-sqrt.f3276.6
Applied rewrites76.6%
Taylor expanded in u2 around 0
+-commutativeN/A
*-commutativeN/A
associate-*r*N/A
*-commutativeN/A
associate-*l*N/A
lower-fma.f32N/A
unpow2N/A
lower-*.f32N/A
lower-PI.f32N/A
lower-PI.f32N/A
lower-*.f32N/A
unpow2N/A
lower-*.f3268.3
Applied rewrites68.3%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (sqrt u1) 1.0))
float code(float cosTheta_i, float u1, float u2) {
return sqrtf(u1) * 1.0f;
}
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 = sqrt(u1) * 1.0e0
end function
function code(cosTheta_i, u1, u2) return Float32(sqrt(u1) * Float32(1.0)) end
function tmp = code(cosTheta_i, u1, u2) tmp = sqrt(u1) * single(1.0); end
\begin{array}{l}
\\
\sqrt{u1} \cdot 1
\end{array}
Initial program 58.2%
Applied rewrites52.6%
Taylor expanded in u1 around 0
lower-sqrt.f3276.6
Applied rewrites76.6%
Taylor expanded in u2 around 0
Applied rewrites63.7%
herbie shell --seed 2024221
(FPCore (cosTheta_i u1 u2)
:name "Beckmann Sample, near normal, slope_x"
: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)))) (cos (* (* 2.0 PI) u2))))