
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (sqrt (- (log (- 1.0 u1)))) (cos (* (* 2.0 (PI)) u2))))
\begin{array}{l}
\\
\sqrt{-\log \left(1 - u1\right)} \cdot \cos \left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot u2\right)
\end{array}
Sampling outcomes in binary32 precision:
Herbie found 9 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (sqrt (- (log (- 1.0 u1)))) (cos (* (* 2.0 (PI)) u2))))
\begin{array}{l}
\\
\sqrt{-\log \left(1 - u1\right)} \cdot \cos \left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot u2\right)
\end{array}
(FPCore (cosTheta_i u1 u2)
:precision binary32
(let* ((t_0 (- (log (- 1.0 u1)))) (t_1 (cbrt (PI))))
(if (<= t_0 0.00015500000154133886)
(* (sqrt (- (- u1))) (cos (* (* (* 2.0 u2) (cbrt (* (PI) (PI)))) t_1)))
(* (sqrt t_0) (cos (* (pow t_1 2.0) (* (* t_1 u2) 2.0)))))))\begin{array}{l}
\\
\begin{array}{l}
t_0 := -\log \left(1 - u1\right)\\
t_1 := \sqrt[3]{\mathsf{PI}\left(\right)}\\
\mathbf{if}\;t\_0 \leq 0.00015500000154133886:\\
\;\;\;\;\sqrt{-\left(-u1\right)} \cdot \cos \left(\left(\left(2 \cdot u2\right) \cdot \sqrt[3]{\mathsf{PI}\left(\right) \cdot \mathsf{PI}\left(\right)}\right) \cdot t\_1\right)\\
\mathbf{else}:\\
\;\;\;\;\sqrt{t\_0} \cdot \cos \left({t\_1}^{2} \cdot \left(\left(t\_1 \cdot u2\right) \cdot 2\right)\right)\\
\end{array}
\end{array}
if (neg.f32 (log.f32 (-.f32 #s(literal 1 binary32) u1))) < 1.55000002e-4Initial program 34.1%
Taylor expanded in u1 around 0
mul-1-negN/A
lower-neg.f3293.5
Applied rewrites93.5%
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
associate-*r*N/A
lift-PI.f32N/A
add-cube-cbrtN/A
associate-*r*N/A
lower-*.f32N/A
lower-*.f32N/A
lower-*.f32N/A
pow2N/A
lower-pow.f32N/A
lift-PI.f32N/A
lower-cbrt.f32N/A
lift-PI.f32N/A
lower-cbrt.f3293.5
Applied rewrites93.5%
Taylor expanded in u2 around 0
associate-*r*N/A
lower-*.f32N/A
lower-*.f32N/A
lower-cbrt.f32N/A
unpow2N/A
lower-*.f32N/A
lower-PI.f32N/A
lower-PI.f3293.5
Applied rewrites93.5%
if 1.55000002e-4 < (neg.f32 (log.f32 (-.f32 #s(literal 1 binary32) u1))) Initial program 90.7%
lift-*.f32N/A
lift-*.f32N/A
associate-*l*N/A
*-commutativeN/A
lift-PI.f32N/A
add-cube-cbrtN/A
associate-*l*N/A
associate-*l*N/A
lower-*.f32N/A
pow2N/A
lower-pow.f32N/A
lift-PI.f32N/A
lower-cbrt.f32N/A
lower-*.f32N/A
lower-*.f32N/A
lift-PI.f32N/A
lower-cbrt.f3290.8
Applied rewrites90.8%
(FPCore (cosTheta_i u1 u2)
:precision binary32
(let* ((t_0 (- (log (- 1.0 u1)))) (t_1 (cos (* u2 (* (PI) 2.0)))))
(if (<= t_0 0.00015500000154133886)
(*
(sqrt (- (- u1)))
(cos (* (* (* 2.0 u2) (cbrt (* (PI) (PI)))) (cbrt (PI)))))
(* (sqrt t_0) (/ (- (+ t_1 1.0) (- 1.0 t_1)) 2.0)))))\begin{array}{l}
\\
\begin{array}{l}
t_0 := -\log \left(1 - u1\right)\\
t_1 := \cos \left(u2 \cdot \left(\mathsf{PI}\left(\right) \cdot 2\right)\right)\\
\mathbf{if}\;t\_0 \leq 0.00015500000154133886:\\
\;\;\;\;\sqrt{-\left(-u1\right)} \cdot \cos \left(\left(\left(2 \cdot u2\right) \cdot \sqrt[3]{\mathsf{PI}\left(\right) \cdot \mathsf{PI}\left(\right)}\right) \cdot \sqrt[3]{\mathsf{PI}\left(\right)}\right)\\
\mathbf{else}:\\
\;\;\;\;\sqrt{t\_0} \cdot \frac{\left(t\_1 + 1\right) - \left(1 - t\_1\right)}{2}\\
\end{array}
\end{array}
if (neg.f32 (log.f32 (-.f32 #s(literal 1 binary32) u1))) < 1.55000002e-4Initial program 34.1%
Taylor expanded in u1 around 0
mul-1-negN/A
lower-neg.f3293.5
Applied rewrites93.5%
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
associate-*r*N/A
lift-PI.f32N/A
add-cube-cbrtN/A
associate-*r*N/A
lower-*.f32N/A
lower-*.f32N/A
lower-*.f32N/A
pow2N/A
lower-pow.f32N/A
lift-PI.f32N/A
lower-cbrt.f32N/A
lift-PI.f32N/A
lower-cbrt.f3293.5
Applied rewrites93.5%
Taylor expanded in u2 around 0
associate-*r*N/A
lower-*.f32N/A
lower-*.f32N/A
lower-cbrt.f32N/A
unpow2N/A
lower-*.f32N/A
lower-PI.f32N/A
lower-PI.f3293.5
Applied rewrites93.5%
if 1.55000002e-4 < (neg.f32 (log.f32 (-.f32 #s(literal 1 binary32) u1))) Initial program 90.7%
lift-cos.f32N/A
lift-*.f32N/A
lift-*.f32N/A
associate-*l*N/A
cos-2N/A
cos-multN/A
sin-multN/A
sub-divN/A
lower-/.f32N/A
Applied rewrites90.7%
(FPCore (cosTheta_i u1 u2)
:precision binary32
(let* ((t_0 (sqrt (- (log (- 1.0 u1))))) (t_1 (cos (* (* 2.0 (PI)) u2))))
(if (<= (* t_0 t_1) 0.012600000016391277)
(* (pow (* u1 u1) 0.25) t_1)
(* t_0 1.0))))\begin{array}{l}
\\
\begin{array}{l}
t_0 := \sqrt{-\log \left(1 - u1\right)}\\
t_1 := \cos \left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot u2\right)\\
\mathbf{if}\;t\_0 \cdot t\_1 \leq 0.012600000016391277:\\
\;\;\;\;{\left(u1 \cdot u1\right)}^{0.25} \cdot t\_1\\
\mathbf{else}:\\
\;\;\;\;t\_0 \cdot 1\\
\end{array}
\end{array}
if (*.f32 (sqrt.f32 (neg.f32 (log.f32 (-.f32 #s(literal 1 binary32) u1)))) (cos.f32 (*.f32 (*.f32 #s(literal 2 binary32) (PI.f32)) u2))) < 0.0126Initial program 36.6%
Taylor expanded in u1 around 0
mul-1-negN/A
lower-neg.f3291.5
Applied rewrites91.5%
lift-sqrt.f32N/A
pow1/2N/A
sqr-powN/A
pow-prod-downN/A
lower-pow.f32N/A
lower-*.f32N/A
metadata-eval91.5
Applied rewrites91.5%
Taylor expanded in u1 around 0
unpow2N/A
lower-*.f3291.5
Applied rewrites91.5%
if 0.0126 < (*.f32 (sqrt.f32 (neg.f32 (log.f32 (-.f32 #s(literal 1 binary32) u1)))) (cos.f32 (*.f32 (*.f32 #s(literal 2 binary32) (PI.f32)) u2))) Initial program 91.2%
Taylor expanded in u2 around 0
Applied rewrites80.1%
(FPCore (cosTheta_i u1 u2)
:precision binary32
(let* ((t_0 (- (log (- 1.0 u1)))))
(if (<= t_0 0.00015500000154133886)
(*
(sqrt (- (- u1)))
(cos (* (* (* 2.0 u2) (cbrt (* (PI) (PI)))) (cbrt (PI)))))
(* (sqrt t_0) (cos (* (* 2.0 (PI)) u2))))))\begin{array}{l}
\\
\begin{array}{l}
t_0 := -\log \left(1 - u1\right)\\
\mathbf{if}\;t\_0 \leq 0.00015500000154133886:\\
\;\;\;\;\sqrt{-\left(-u1\right)} \cdot \cos \left(\left(\left(2 \cdot u2\right) \cdot \sqrt[3]{\mathsf{PI}\left(\right) \cdot \mathsf{PI}\left(\right)}\right) \cdot \sqrt[3]{\mathsf{PI}\left(\right)}\right)\\
\mathbf{else}:\\
\;\;\;\;\sqrt{t\_0} \cdot \cos \left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot u2\right)\\
\end{array}
\end{array}
if (neg.f32 (log.f32 (-.f32 #s(literal 1 binary32) u1))) < 1.55000002e-4Initial program 34.1%
Taylor expanded in u1 around 0
mul-1-negN/A
lower-neg.f3293.5
Applied rewrites93.5%
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
associate-*r*N/A
lift-PI.f32N/A
add-cube-cbrtN/A
associate-*r*N/A
lower-*.f32N/A
lower-*.f32N/A
lower-*.f32N/A
pow2N/A
lower-pow.f32N/A
lift-PI.f32N/A
lower-cbrt.f32N/A
lift-PI.f32N/A
lower-cbrt.f3293.5
Applied rewrites93.5%
Taylor expanded in u2 around 0
associate-*r*N/A
lower-*.f32N/A
lower-*.f32N/A
lower-cbrt.f32N/A
unpow2N/A
lower-*.f32N/A
lower-PI.f32N/A
lower-PI.f3293.5
Applied rewrites93.5%
if 1.55000002e-4 < (neg.f32 (log.f32 (-.f32 #s(literal 1 binary32) u1))) Initial program 90.7%
(FPCore (cosTheta_i u1 u2)
:precision binary32
(let* ((t_0 (cos (* (* 2.0 (PI)) u2))) (t_1 (- (log (- 1.0 u1)))))
(if (<= t_1 0.00015500000154133886)
(* (sqrt (/ (pow (- (- u1)) 3.0) (* (- u1) (- u1)))) t_0)
(* (sqrt t_1) t_0))))\begin{array}{l}
\\
\begin{array}{l}
t_0 := \cos \left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot u2\right)\\
t_1 := -\log \left(1 - u1\right)\\
\mathbf{if}\;t\_1 \leq 0.00015500000154133886:\\
\;\;\;\;\sqrt{\frac{{\left(-\left(-u1\right)\right)}^{3}}{\left(-u1\right) \cdot \left(-u1\right)}} \cdot t\_0\\
\mathbf{else}:\\
\;\;\;\;\sqrt{t\_1} \cdot t\_0\\
\end{array}
\end{array}
if (neg.f32 (log.f32 (-.f32 #s(literal 1 binary32) u1))) < 1.55000002e-4Initial program 34.1%
Taylor expanded in u1 around 0
mul-1-negN/A
lower-neg.f3293.5
Applied rewrites93.5%
+-lft-identityN/A
metadata-evalN/A
flip3-+N/A
lower-/.f32N/A
metadata-evalN/A
metadata-evalN/A
metadata-evalN/A
lower-+.f32N/A
metadata-evalN/A
lower-pow.f32N/A
Applied rewrites93.5%
if 1.55000002e-4 < (neg.f32 (log.f32 (-.f32 #s(literal 1 binary32) u1))) Initial program 90.7%
Final simplification92.4%
(FPCore (cosTheta_i u1 u2) :precision binary32 (let* ((t_0 (sqrt (- (log (- 1.0 u1))))) (t_1 (cos (* (* 2.0 (PI)) u2)))) (if (<= (* t_0 t_1) 0.012600000016391277) (* (sqrt u1) t_1) (* t_0 1.0))))
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \sqrt{-\log \left(1 - u1\right)}\\
t_1 := \cos \left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot u2\right)\\
\mathbf{if}\;t\_0 \cdot t\_1 \leq 0.012600000016391277:\\
\;\;\;\;\sqrt{u1} \cdot t\_1\\
\mathbf{else}:\\
\;\;\;\;t\_0 \cdot 1\\
\end{array}
\end{array}
if (*.f32 (sqrt.f32 (neg.f32 (log.f32 (-.f32 #s(literal 1 binary32) u1)))) (cos.f32 (*.f32 (*.f32 #s(literal 2 binary32) (PI.f32)) u2))) < 0.0126Initial program 36.6%
Applied rewrites49.3%
Taylor expanded in u1 around 0
lower-sqrt.f3291.5
Applied rewrites91.5%
if 0.0126 < (*.f32 (sqrt.f32 (neg.f32 (log.f32 (-.f32 #s(literal 1 binary32) u1)))) (cos.f32 (*.f32 (*.f32 #s(literal 2 binary32) (PI.f32)) u2))) Initial program 91.2%
Taylor expanded in u2 around 0
Applied rewrites80.1%
(FPCore (cosTheta_i u1 u2)
:precision binary32
(let* ((t_0 (sqrt (- (log (- 1.0 u1))))))
(if (<= (* t_0 (cos (* (* 2.0 (PI)) u2))) 0.012600000016391277)
(* (sqrt (- (- u1))) 1.0)
(* t_0 1.0))))\begin{array}{l}
\\
\begin{array}{l}
t_0 := \sqrt{-\log \left(1 - u1\right)}\\
\mathbf{if}\;t\_0 \cdot \cos \left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot u2\right) \leq 0.012600000016391277:\\
\;\;\;\;\sqrt{-\left(-u1\right)} \cdot 1\\
\mathbf{else}:\\
\;\;\;\;t\_0 \cdot 1\\
\end{array}
\end{array}
if (*.f32 (sqrt.f32 (neg.f32 (log.f32 (-.f32 #s(literal 1 binary32) u1)))) (cos.f32 (*.f32 (*.f32 #s(literal 2 binary32) (PI.f32)) u2))) < 0.0126Initial program 36.6%
Taylor expanded in u1 around 0
mul-1-negN/A
lower-neg.f3291.5
Applied rewrites91.5%
Taylor expanded in u2 around 0
+-commutativeN/A
associate-*r*N/A
lower-fma.f32N/A
lower-*.f32N/A
unpow2N/A
lower-*.f32N/A
unpow2N/A
lower-*.f32N/A
lower-PI.f32N/A
lower-PI.f3274.2
Applied rewrites73.9%
Taylor expanded in u2 around 0
Applied rewrites74.2%
if 0.0126 < (*.f32 (sqrt.f32 (neg.f32 (log.f32 (-.f32 #s(literal 1 binary32) u1)))) (cos.f32 (*.f32 (*.f32 #s(literal 2 binary32) (PI.f32)) u2))) Initial program 91.2%
Taylor expanded in u2 around 0
Applied rewrites80.1%
(FPCore (cosTheta_i u1 u2)
:precision binary32
(let* ((t_0 (- (log (- 1.0 u1)))) (t_1 (cos (* (* 2.0 (PI)) u2))))
(if (<= t_0 0.00015500000154133886)
(* (pow (* u1 u1) 0.25) t_1)
(* (sqrt t_0) t_1))))\begin{array}{l}
\\
\begin{array}{l}
t_0 := -\log \left(1 - u1\right)\\
t_1 := \cos \left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot u2\right)\\
\mathbf{if}\;t\_0 \leq 0.00015500000154133886:\\
\;\;\;\;{\left(u1 \cdot u1\right)}^{0.25} \cdot t\_1\\
\mathbf{else}:\\
\;\;\;\;\sqrt{t\_0} \cdot t\_1\\
\end{array}
\end{array}
if (neg.f32 (log.f32 (-.f32 #s(literal 1 binary32) u1))) < 1.55000002e-4Initial program 34.1%
Taylor expanded in u1 around 0
mul-1-negN/A
lower-neg.f3293.5
Applied rewrites93.5%
lift-sqrt.f32N/A
pow1/2N/A
sqr-powN/A
pow-prod-downN/A
lower-pow.f32N/A
lower-*.f32N/A
metadata-eval93.5
Applied rewrites93.5%
Taylor expanded in u1 around 0
unpow2N/A
lower-*.f3293.5
Applied rewrites93.5%
if 1.55000002e-4 < (neg.f32 (log.f32 (-.f32 #s(literal 1 binary32) u1))) Initial program 90.7%
(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(Float32(-Float32(-u1))) * Float32(1.0)) end
function tmp = code(cosTheta_i, u1, u2) tmp = sqrt(-(-u1)) * single(1.0); end
\begin{array}{l}
\\
\sqrt{-\left(-u1\right)} \cdot 1
\end{array}
Initial program 57.3%
Taylor expanded in u1 around 0
mul-1-negN/A
lower-neg.f3275.6
Applied rewrites75.6%
Taylor expanded in u2 around 0
+-commutativeN/A
associate-*r*N/A
lower-fma.f32N/A
lower-*.f32N/A
unpow2N/A
lower-*.f32N/A
unpow2N/A
lower-*.f32N/A
lower-PI.f32N/A
lower-PI.f3264.4
Applied rewrites64.2%
Taylor expanded in u2 around 0
Applied rewrites64.4%
herbie shell --seed 2024313
(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))))