
(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 10 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 (* (cos (* PI (* u2 -2.0))) (sqrt (- (log1p (- u1))))))
float code(float cosTheta_i, float u1, float u2) {
return cosf((((float) M_PI) * (u2 * -2.0f))) * sqrtf(-log1pf(-u1));
}
function code(cosTheta_i, u1, u2) return Float32(cos(Float32(Float32(pi) * Float32(u2 * Float32(-2.0)))) * sqrt(Float32(-log1p(Float32(-u1))))) end
\begin{array}{l}
\\
\cos \left(\pi \cdot \left(u2 \cdot -2\right)\right) \cdot \sqrt{-\mathsf{log1p}\left(-u1\right)}
\end{array}
Initial program 55.6%
cos-neg55.6%
distribute-rgt-neg-out55.6%
sub-neg55.6%
log1p-define99.2%
*-commutative99.2%
associate-*r*99.2%
*-commutative99.2%
distribute-lft-neg-out99.2%
distribute-rgt-neg-in99.2%
metadata-eval99.2%
Simplified99.2%
Final simplification99.2%
(FPCore (cosTheta_i u1 u2)
:precision binary32
(let* ((t_0 (cos (* u2 (* PI 2.0)))))
(if (<= t_0 0.999998927116394)
(* t_0 (sqrt (* u1 (+ 1.0 (* u1 0.5)))))
(sqrt (- (log1p (- u1)))))))
float code(float cosTheta_i, float u1, float u2) {
float t_0 = cosf((u2 * (((float) M_PI) * 2.0f)));
float tmp;
if (t_0 <= 0.999998927116394f) {
tmp = t_0 * sqrtf((u1 * (1.0f + (u1 * 0.5f))));
} else {
tmp = sqrtf(-log1pf(-u1));
}
return tmp;
}
function code(cosTheta_i, u1, u2) t_0 = cos(Float32(u2 * Float32(Float32(pi) * Float32(2.0)))) tmp = Float32(0.0) if (t_0 <= Float32(0.999998927116394)) tmp = Float32(t_0 * sqrt(Float32(u1 * Float32(Float32(1.0) + Float32(u1 * Float32(0.5)))))); else tmp = sqrt(Float32(-log1p(Float32(-u1)))); end return tmp end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \cos \left(u2 \cdot \left(\pi \cdot 2\right)\right)\\
\mathbf{if}\;t\_0 \leq 0.999998927116394:\\
\;\;\;\;t\_0 \cdot \sqrt{u1 \cdot \left(1 + u1 \cdot 0.5\right)}\\
\mathbf{else}:\\
\;\;\;\;\sqrt{-\mathsf{log1p}\left(-u1\right)}\\
\end{array}
\end{array}
if (cos.f32 (*.f32 (*.f32 #s(literal 2 binary32) (PI.f32)) u2)) < 0.999998927Initial program 58.6%
Taylor expanded in u1 around 0 87.7%
if 0.999998927 < (cos.f32 (*.f32 (*.f32 #s(literal 2 binary32) (PI.f32)) u2)) Initial program 54.1%
cos-neg54.1%
distribute-rgt-neg-out54.1%
sub-neg54.1%
log1p-define99.6%
*-commutative99.6%
associate-*r*99.6%
*-commutative99.6%
distribute-lft-neg-out99.6%
distribute-rgt-neg-in99.6%
metadata-eval99.6%
Simplified99.6%
Taylor expanded in u2 around 0 99.2%
Final simplification95.3%
(FPCore (cosTheta_i u1 u2)
:precision binary32
(let* ((t_0 (cos (* u2 (* PI 2.0)))))
(if (<= t_0 0.999904990196228)
(* t_0 (sqrt u1))
(sqrt (- (log1p (- u1)))))))
float code(float cosTheta_i, float u1, float u2) {
float t_0 = cosf((u2 * (((float) M_PI) * 2.0f)));
float tmp;
if (t_0 <= 0.999904990196228f) {
tmp = t_0 * sqrtf(u1);
} else {
tmp = sqrtf(-log1pf(-u1));
}
return tmp;
}
function code(cosTheta_i, u1, u2) t_0 = cos(Float32(u2 * Float32(Float32(pi) * Float32(2.0)))) tmp = Float32(0.0) if (t_0 <= Float32(0.999904990196228)) tmp = Float32(t_0 * sqrt(u1)); else tmp = sqrt(Float32(-log1p(Float32(-u1)))); end return tmp end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \cos \left(u2 \cdot \left(\pi \cdot 2\right)\right)\\
\mathbf{if}\;t\_0 \leq 0.999904990196228:\\
\;\;\;\;t\_0 \cdot \sqrt{u1}\\
\mathbf{else}:\\
\;\;\;\;\sqrt{-\mathsf{log1p}\left(-u1\right)}\\
\end{array}
\end{array}
if (cos.f32 (*.f32 (*.f32 #s(literal 2 binary32) (PI.f32)) u2)) < 0.99990499Initial program 57.2%
Taylor expanded in u1 around 0 76.4%
if 0.99990499 < (cos.f32 (*.f32 (*.f32 #s(literal 2 binary32) (PI.f32)) u2)) Initial program 55.0%
cos-neg55.0%
distribute-rgt-neg-out55.0%
sub-neg55.0%
log1p-define99.5%
*-commutative99.5%
associate-*r*99.5%
*-commutative99.5%
distribute-lft-neg-out99.5%
distribute-rgt-neg-in99.5%
metadata-eval99.5%
Simplified99.5%
Taylor expanded in u2 around 0 97.3%
Final simplification91.8%
(FPCore (cosTheta_i u1 u2)
:precision binary32
(let* ((t_0 (* u2 (* PI 2.0))))
(if (<= t_0 0.001449999981559813)
(sqrt (- (log1p (- u1))))
(*
(sqrt
(* u1 (+ 1.0 (* u1 (+ 0.5 (* u1 (+ 0.3333333333333333 (* u1 0.25))))))))
(cos t_0)))))
float code(float cosTheta_i, float u1, float u2) {
float t_0 = u2 * (((float) M_PI) * 2.0f);
float tmp;
if (t_0 <= 0.001449999981559813f) {
tmp = sqrtf(-log1pf(-u1));
} else {
tmp = sqrtf((u1 * (1.0f + (u1 * (0.5f + (u1 * (0.3333333333333333f + (u1 * 0.25f)))))))) * cosf(t_0);
}
return tmp;
}
function code(cosTheta_i, u1, u2) t_0 = Float32(u2 * Float32(Float32(pi) * Float32(2.0))) tmp = Float32(0.0) if (t_0 <= Float32(0.001449999981559813)) tmp = sqrt(Float32(-log1p(Float32(-u1)))); 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))))))))) * cos(t_0)); end return tmp end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := u2 \cdot \left(\pi \cdot 2\right)\\
\mathbf{if}\;t\_0 \leq 0.001449999981559813:\\
\;\;\;\;\sqrt{-\mathsf{log1p}\left(-u1\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 \cos t\_0\\
\end{array}
\end{array}
if (*.f32 (*.f32 #s(literal 2 binary32) (PI.f32)) u2) < 0.00144999998Initial program 54.1%
cos-neg54.1%
distribute-rgt-neg-out54.1%
sub-neg54.1%
log1p-define99.6%
*-commutative99.6%
associate-*r*99.6%
*-commutative99.6%
distribute-lft-neg-out99.6%
distribute-rgt-neg-in99.6%
metadata-eval99.6%
Simplified99.6%
Taylor expanded in u2 around 0 99.2%
if 0.00144999998 < (*.f32 (*.f32 #s(literal 2 binary32) (PI.f32)) u2) Initial program 58.6%
Taylor expanded in u1 around 0 94.3%
Final simplification97.5%
(FPCore (cosTheta_i u1 u2)
:precision binary32
(let* ((t_0 (* u2 (* PI 2.0))))
(if (<= t_0 0.001449999981559813)
(sqrt (- (log1p (- u1))))
(*
(cos 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 * (((float) M_PI) * 2.0f);
float tmp;
if (t_0 <= 0.001449999981559813f) {
tmp = sqrtf(-log1pf(-u1));
} else {
tmp = cosf(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(pi) * Float32(2.0))) tmp = Float32(0.0) if (t_0 <= Float32(0.001449999981559813)) tmp = sqrt(Float32(-log1p(Float32(-u1)))); else tmp = Float32(cos(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(\pi \cdot 2\right)\\
\mathbf{if}\;t\_0 \leq 0.001449999981559813:\\
\;\;\;\;\sqrt{-\mathsf{log1p}\left(-u1\right)}\\
\mathbf{else}:\\
\;\;\;\;\cos 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 54.1%
cos-neg54.1%
distribute-rgt-neg-out54.1%
sub-neg54.1%
log1p-define99.6%
*-commutative99.6%
associate-*r*99.6%
*-commutative99.6%
distribute-lft-neg-out99.6%
distribute-rgt-neg-in99.6%
metadata-eval99.6%
Simplified99.6%
Taylor expanded in u2 around 0 99.2%
if 0.00144999998 < (*.f32 (*.f32 #s(literal 2 binary32) (PI.f32)) u2) Initial program 58.6%
Taylor expanded in u1 around 0 92.1%
Final simplification96.8%
(FPCore (cosTheta_i u1 u2) :precision binary32 (sqrt (- (log1p (- u1)))))
float code(float cosTheta_i, float u1, float u2) {
return sqrtf(-log1pf(-u1));
}
function code(cosTheta_i, u1, u2) return sqrt(Float32(-log1p(Float32(-u1)))) end
\begin{array}{l}
\\
\sqrt{-\mathsf{log1p}\left(-u1\right)}
\end{array}
Initial program 55.6%
cos-neg55.6%
distribute-rgt-neg-out55.6%
sub-neg55.6%
log1p-define99.2%
*-commutative99.2%
associate-*r*99.2%
*-commutative99.2%
distribute-lft-neg-out99.2%
distribute-rgt-neg-in99.2%
metadata-eval99.2%
Simplified99.2%
Taylor expanded in u2 around 0 82.3%
Final simplification82.3%
(FPCore (cosTheta_i u1 u2) :precision binary32 (sqrt (* u1 (+ 1.0 (* u1 (+ 0.5 (* u1 (+ 0.3333333333333333 (* u1 0.25)))))))))
float code(float cosTheta_i, float u1, float u2) {
return sqrtf((u1 * (1.0f + (u1 * (0.5f + (u1 * (0.3333333333333333f + (u1 * 0.25f))))))));
}
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 + (u1 * (0.5e0 + (u1 * (0.3333333333333333e0 + (u1 * 0.25e0))))))))
end function
function code(cosTheta_i, u1, u2) return 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
function tmp = code(cosTheta_i, u1, u2) tmp = sqrt((u1 * (single(1.0) + (u1 * (single(0.5) + (u1 * (single(0.3333333333333333) + (u1 * single(0.25))))))))); end
\begin{array}{l}
\\
\sqrt{u1 \cdot \left(1 + u1 \cdot \left(0.5 + u1 \cdot \left(0.3333333333333333 + u1 \cdot 0.25\right)\right)\right)}
\end{array}
Initial program 55.6%
cos-neg55.6%
distribute-rgt-neg-out55.6%
sub-neg55.6%
log1p-define99.2%
*-commutative99.2%
associate-*r*99.2%
*-commutative99.2%
distribute-lft-neg-out99.2%
distribute-rgt-neg-in99.2%
metadata-eval99.2%
Simplified99.2%
Taylor expanded in u2 around 0 82.3%
Taylor expanded in u1 around 0 78.4%
*-commutative78.4%
Simplified78.4%
Final simplification78.4%
(FPCore (cosTheta_i u1 u2) :precision binary32 (sqrt (* u1 (+ 1.0 (* u1 (+ 0.5 (* u1 0.3333333333333333)))))))
float code(float cosTheta_i, float u1, float u2) {
return sqrtf((u1 * (1.0f + (u1 * (0.5f + (u1 * 0.3333333333333333f))))));
}
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 + (u1 * (0.5e0 + (u1 * 0.3333333333333333e0))))))
end function
function code(cosTheta_i, u1, u2) return sqrt(Float32(u1 * Float32(Float32(1.0) + Float32(u1 * Float32(Float32(0.5) + Float32(u1 * Float32(0.3333333333333333))))))) end
function tmp = code(cosTheta_i, u1, u2) tmp = sqrt((u1 * (single(1.0) + (u1 * (single(0.5) + (u1 * single(0.3333333333333333))))))); end
\begin{array}{l}
\\
\sqrt{u1 \cdot \left(1 + u1 \cdot \left(0.5 + u1 \cdot 0.3333333333333333\right)\right)}
\end{array}
Initial program 55.6%
cos-neg55.6%
distribute-rgt-neg-out55.6%
sub-neg55.6%
log1p-define99.2%
*-commutative99.2%
associate-*r*99.2%
*-commutative99.2%
distribute-lft-neg-out99.2%
distribute-rgt-neg-in99.2%
metadata-eval99.2%
Simplified99.2%
Taylor expanded in u2 around 0 82.3%
Taylor expanded in u1 around 0 77.4%
Final simplification77.4%
(FPCore (cosTheta_i u1 u2) :precision binary32 (sqrt (* u1 (+ 1.0 (* u1 0.5)))))
float code(float cosTheta_i, float u1, float u2) {
return sqrtf((u1 * (1.0f + (u1 * 0.5f))));
}
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 + (u1 * 0.5e0))))
end function
function code(cosTheta_i, u1, u2) return sqrt(Float32(u1 * Float32(Float32(1.0) + Float32(u1 * Float32(0.5))))) end
function tmp = code(cosTheta_i, u1, u2) tmp = sqrt((u1 * (single(1.0) + (u1 * single(0.5))))); end
\begin{array}{l}
\\
\sqrt{u1 \cdot \left(1 + u1 \cdot 0.5\right)}
\end{array}
Initial program 55.6%
cos-neg55.6%
distribute-rgt-neg-out55.6%
sub-neg55.6%
log1p-define99.2%
*-commutative99.2%
associate-*r*99.2%
*-commutative99.2%
distribute-lft-neg-out99.2%
distribute-rgt-neg-in99.2%
metadata-eval99.2%
Simplified99.2%
add-log-exp97.5%
*-commutative97.5%
associate-*l*97.5%
Applied egg-rr97.5%
Taylor expanded in u1 around 0 87.5%
*-commutative87.5%
Simplified87.5%
Taylor expanded in u2 around 0 75.2%
Final simplification75.2%
(FPCore (cosTheta_i u1 u2) :precision binary32 (sqrt u1))
float code(float cosTheta_i, float u1, float u2) {
return sqrtf(u1);
}
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)
end function
function code(cosTheta_i, u1, u2) return sqrt(u1) end
function tmp = code(cosTheta_i, u1, u2) tmp = sqrt(u1); end
\begin{array}{l}
\\
\sqrt{u1}
\end{array}
Initial program 55.6%
cos-neg55.6%
distribute-rgt-neg-out55.6%
sub-neg55.6%
log1p-define99.2%
*-commutative99.2%
associate-*r*99.2%
*-commutative99.2%
distribute-lft-neg-out99.2%
distribute-rgt-neg-in99.2%
metadata-eval99.2%
Simplified99.2%
Taylor expanded in u2 around 0 82.3%
Taylor expanded in u1 around 0 67.3%
Taylor expanded in u1 around 0 67.3%
herbie shell --seed 2024170
(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))))