
(FPCore (cosTheta c)
:precision binary32
(/
1.0
(+
(+ 1.0 c)
(*
(* (/ 1.0 (sqrt (PI))) (/ (sqrt (- (- 1.0 cosTheta) cosTheta)) cosTheta))
(exp (* (- cosTheta) cosTheta))))))\begin{array}{l}
\\
\frac{1}{\left(1 + c\right) + \left(\frac{1}{\sqrt{\mathsf{PI}\left(\right)}} \cdot \frac{\sqrt{\left(1 - cosTheta\right) - cosTheta}}{cosTheta}\right) \cdot e^{\left(-cosTheta\right) \cdot cosTheta}}
\end{array}
Sampling outcomes in binary32 precision:
Herbie found 10 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (cosTheta c)
:precision binary32
(/
1.0
(+
(+ 1.0 c)
(*
(* (/ 1.0 (sqrt (PI))) (/ (sqrt (- (- 1.0 cosTheta) cosTheta)) cosTheta))
(exp (* (- cosTheta) cosTheta))))))\begin{array}{l}
\\
\frac{1}{\left(1 + c\right) + \left(\frac{1}{\sqrt{\mathsf{PI}\left(\right)}} \cdot \frac{\sqrt{\left(1 - cosTheta\right) - cosTheta}}{cosTheta}\right) \cdot e^{\left(-cosTheta\right) \cdot cosTheta}}
\end{array}
(FPCore (cosTheta c)
:precision binary32
(/
1.0
(+
(*
(exp (* (- cosTheta) cosTheta))
(*
(/ 1.0 (pow (PI) 0.16666666666666666))
(/ (/ (sqrt (- (- 1.0 cosTheta) cosTheta)) cosTheta) (cbrt (PI)))))
(+ c 1.0))))\begin{array}{l}
\\
\frac{1}{e^{\left(-cosTheta\right) \cdot cosTheta} \cdot \left(\frac{1}{{\mathsf{PI}\left(\right)}^{0.16666666666666666}} \cdot \frac{\frac{\sqrt{\left(1 - cosTheta\right) - cosTheta}}{cosTheta}}{\sqrt[3]{\mathsf{PI}\left(\right)}}\right) + \left(c + 1\right)}
\end{array}
Initial program 97.8%
lift-*.f32N/A
lift-/.f32N/A
associate-*l/N/A
*-commutativeN/A
lift-sqrt.f32N/A
pow1/2N/A
lift-PI.f32N/A
add-cube-cbrtN/A
unpow-prod-downN/A
pow2N/A
pow-powN/A
metadata-evalN/A
unpow1N/A
times-fracN/A
lower-*.f32N/A
Applied rewrites98.6%
Final simplification98.6%
(FPCore (cosTheta c)
:precision binary32
(/
1.0
(+
(*
(/ (sqrt (- (- 1.0 cosTheta) cosTheta)) (* (sqrt (PI)) cosTheta))
(exp (* (- cosTheta) cosTheta)))
(+ c 1.0))))\begin{array}{l}
\\
\frac{1}{\frac{\sqrt{\left(1 - cosTheta\right) - cosTheta}}{\sqrt{\mathsf{PI}\left(\right)} \cdot cosTheta} \cdot e^{\left(-cosTheta\right) \cdot cosTheta} + \left(c + 1\right)}
\end{array}
Initial program 97.8%
lift-*.f32N/A
lift-/.f32N/A
lift-/.f32N/A
frac-timesN/A
*-lft-identityN/A
lower-/.f32N/A
*-commutativeN/A
lower-*.f3298.5
Applied rewrites98.5%
Final simplification98.5%
(FPCore (cosTheta c)
:precision binary32
(/
1.0
(+
(*
(/ (sqrt (- (- 1.0 cosTheta) cosTheta)) (* (sqrt (PI)) cosTheta))
(exp (* (- cosTheta) cosTheta)))
1.0)))\begin{array}{l}
\\
\frac{1}{\frac{\sqrt{\left(1 - cosTheta\right) - cosTheta}}{\sqrt{\mathsf{PI}\left(\right)} \cdot cosTheta} \cdot e^{\left(-cosTheta\right) \cdot cosTheta} + 1}
\end{array}
Initial program 97.8%
lift-*.f32N/A
lift-/.f32N/A
associate-*l/N/A
*-commutativeN/A
lift-sqrt.f32N/A
pow1/2N/A
lift-PI.f32N/A
add-cube-cbrtN/A
unpow-prod-downN/A
pow2N/A
pow-powN/A
metadata-evalN/A
unpow1N/A
times-fracN/A
lower-*.f32N/A
Applied rewrites98.6%
lift-*.f32N/A
lift-/.f32N/A
un-div-invN/A
lift-/.f32N/A
associate-/r*N/A
lift-/.f32N/A
lift-cbrt.f32N/A
pow1/3N/A
lift-pow.f32N/A
pow-prod-upN/A
metadata-evalN/A
pow1/2N/A
lift-sqrt.f32N/A
associate-/r*N/A
lift-*.f32N/A
lower-/.f3298.5
lift-*.f32N/A
*-commutativeN/A
Applied rewrites98.5%
Taylor expanded in c around 0
Applied rewrites98.2%
Final simplification98.2%
(FPCore (cosTheta c)
:precision binary32
(/
1.0
(+
(*
(/ (sqrt (/ (- (- 1.0 cosTheta) cosTheta) (PI))) cosTheta)
(exp (* (- cosTheta) cosTheta)))
(+ c 1.0))))\begin{array}{l}
\\
\frac{1}{\frac{\sqrt{\frac{\left(1 - cosTheta\right) - cosTheta}{\mathsf{PI}\left(\right)}}}{cosTheta} \cdot e^{\left(-cosTheta\right) \cdot cosTheta} + \left(c + 1\right)}
\end{array}
Initial program 97.8%
lift-*.f32N/A
lift-/.f32N/A
associate-*r/N/A
lower-/.f32N/A
lift-/.f32N/A
associate-*l/N/A
*-lft-identityN/A
lift-sqrt.f32N/A
lift-sqrt.f32N/A
sqrt-undivN/A
lower-sqrt.f32N/A
lower-/.f3298.0
Applied rewrites98.0%
Final simplification98.0%
(FPCore (cosTheta c)
:precision binary32
(/
1.0
(+
(*
(/ (sqrt (/ (- (- 1.0 cosTheta) cosTheta) (PI))) cosTheta)
(exp (* (- cosTheta) cosTheta)))
1.0)))\begin{array}{l}
\\
\frac{1}{\frac{\sqrt{\frac{\left(1 - cosTheta\right) - cosTheta}{\mathsf{PI}\left(\right)}}}{cosTheta} \cdot e^{\left(-cosTheta\right) \cdot cosTheta} + 1}
\end{array}
Initial program 97.8%
lift-*.f32N/A
lift-/.f32N/A
associate-*r/N/A
lower-/.f32N/A
lift-/.f32N/A
associate-*l/N/A
*-lft-identityN/A
lift-sqrt.f32N/A
lift-sqrt.f32N/A
sqrt-undivN/A
lower-sqrt.f32N/A
lower-/.f3298.0
Applied rewrites98.0%
Taylor expanded in c around 0
Applied rewrites97.6%
Final simplification97.6%
(FPCore (cosTheta c)
:precision binary32
(/
1.0
(+
(*
(/ (- 1.0 cosTheta) (* (sqrt (PI)) cosTheta))
(exp (* (- cosTheta) cosTheta)))
(+ c 1.0))))\begin{array}{l}
\\
\frac{1}{\frac{1 - cosTheta}{\sqrt{\mathsf{PI}\left(\right)} \cdot cosTheta} \cdot e^{\left(-cosTheta\right) \cdot cosTheta} + \left(c + 1\right)}
\end{array}
Initial program 97.8%
Taylor expanded in cosTheta around 0
associate-*r*N/A
lower-/.f32N/A
mul-1-negN/A
cancel-sign-sub-invN/A
*-lft-identityN/A
distribute-rgt-out--N/A
lower-*.f32N/A
lower-sqrt.f32N/A
lower-/.f32N/A
lower-PI.f32N/A
lower--.f3294.5
Applied rewrites94.5%
Applied rewrites95.2%
Applied rewrites95.2%
Final simplification95.2%
(FPCore (cosTheta c) :precision binary32 (/ 1.0 (+ (+ (/ (* (sqrt (/ 1.0 (PI))) (- 1.0 cosTheta)) cosTheta) 1.0) c)))
\begin{array}{l}
\\
\frac{1}{\left(\frac{\sqrt{\frac{1}{\mathsf{PI}\left(\right)}} \cdot \left(1 - cosTheta\right)}{cosTheta} + 1\right) + c}
\end{array}
Initial program 97.8%
lift-+.f32N/A
lift-+.f32N/A
+-commutativeN/A
associate-+l+N/A
lower-+.f32N/A
lower-+.f3297.8
lift-*.f32N/A
lift-*.f32N/A
lift-/.f32N/A
associate-*r/N/A
associate-*l/N/A
Applied rewrites97.9%
lift-/.f32N/A
lift-/.f32N/A
associate-/l/N/A
lower-/.f32N/A
*-commutativeN/A
lower-*.f3297.9
Applied rewrites97.9%
Taylor expanded in cosTheta around 0
associate-*r*N/A
lower-/.f32N/A
Applied rewrites94.1%
Final simplification94.1%
(FPCore (cosTheta c) :precision binary32 (/ 1.0 (+ (/ (+ (* (sqrt (/ 1.0 (PI))) (- 1.0 cosTheta)) cosTheta) cosTheta) c)))
\begin{array}{l}
\\
\frac{1}{\frac{\sqrt{\frac{1}{\mathsf{PI}\left(\right)}} \cdot \left(1 - cosTheta\right) + cosTheta}{cosTheta} + c}
\end{array}
Initial program 97.8%
lift-+.f32N/A
lift-+.f32N/A
+-commutativeN/A
associate-+l+N/A
lower-+.f32N/A
lower-+.f3297.8
lift-*.f32N/A
lift-*.f32N/A
lift-/.f32N/A
associate-*r/N/A
associate-*l/N/A
Applied rewrites97.9%
lift-/.f32N/A
lift-/.f32N/A
associate-/l/N/A
lower-/.f32N/A
*-commutativeN/A
lower-*.f3297.9
Applied rewrites97.9%
Taylor expanded in cosTheta around 0
lower-/.f32N/A
Applied rewrites94.1%
Final simplification94.1%
(FPCore (cosTheta c) :precision binary32 (* (sqrt (PI)) cosTheta))
\begin{array}{l}
\\
\sqrt{\mathsf{PI}\left(\right)} \cdot cosTheta
\end{array}
Initial program 97.8%
Taylor expanded in cosTheta around 0
*-commutativeN/A
lower-*.f32N/A
lower-sqrt.f32N/A
lower-PI.f3292.0
Applied rewrites92.0%
(FPCore (cosTheta c) :precision binary32 (/ 1.0 c))
float code(float cosTheta, float c) {
return 1.0f / c;
}
real(4) function code(costheta, c)
real(4), intent (in) :: costheta
real(4), intent (in) :: c
code = 1.0e0 / c
end function
function code(cosTheta, c) return Float32(Float32(1.0) / c) end
function tmp = code(cosTheta, c) tmp = single(1.0) / c; end
\begin{array}{l}
\\
\frac{1}{c}
\end{array}
Initial program 97.8%
Taylor expanded in c around inf
lower-/.f325.0
Applied rewrites5.0%
herbie shell --seed 2024270
(FPCore (cosTheta c)
:name "Beckmann Sample, normalization factor"
:precision binary32
:pre (and (and (< 0.0 cosTheta) (< cosTheta 0.9999)) (and (< -1.0 c) (< c 1.0)))
(/ 1.0 (+ (+ 1.0 c) (* (* (/ 1.0 (sqrt (PI))) (/ (sqrt (- (- 1.0 cosTheta) cosTheta)) cosTheta)) (exp (* (- cosTheta) cosTheta))))))