
(FPCore (u0 u1 alphax alphay)
:precision binary32
(let* ((t_0
(atan
(* (/ alphay alphax) (tan (+ (* (* 2.0 (PI)) u1) (* 0.5 (PI)))))))
(t_1 (sin t_0))
(t_2 (cos t_0)))
(/
1.0
(sqrt
(+
1.0
(/
(*
(/
1.0
(+
(/ (* t_2 t_2) (* alphax alphax))
(/ (* t_1 t_1) (* alphay alphay))))
u0)
(- 1.0 u0)))))))\begin{array}{l}
\\
\begin{array}{l}
t_0 := \tan^{-1} \left(\frac{alphay}{alphax} \cdot \tan \left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot u1 + 0.5 \cdot \mathsf{PI}\left(\right)\right)\right)\\
t_1 := \sin t\_0\\
t_2 := \cos t\_0\\
\frac{1}{\sqrt{1 + \frac{\frac{1}{\frac{t\_2 \cdot t\_2}{alphax \cdot alphax} + \frac{t\_1 \cdot t\_1}{alphay \cdot alphay}} \cdot u0}{1 - u0}}}
\end{array}
\end{array}
Sampling outcomes in binary32 precision:
Herbie found 7 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (u0 u1 alphax alphay)
:precision binary32
(let* ((t_0
(atan
(* (/ alphay alphax) (tan (+ (* (* 2.0 (PI)) u1) (* 0.5 (PI)))))))
(t_1 (sin t_0))
(t_2 (cos t_0)))
(/
1.0
(sqrt
(+
1.0
(/
(*
(/
1.0
(+
(/ (* t_2 t_2) (* alphax alphax))
(/ (* t_1 t_1) (* alphay alphay))))
u0)
(- 1.0 u0)))))))\begin{array}{l}
\\
\begin{array}{l}
t_0 := \tan^{-1} \left(\frac{alphay}{alphax} \cdot \tan \left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot u1 + 0.5 \cdot \mathsf{PI}\left(\right)\right)\right)\\
t_1 := \sin t\_0\\
t_2 := \cos t\_0\\
\frac{1}{\sqrt{1 + \frac{\frac{1}{\frac{t\_2 \cdot t\_2}{alphax \cdot alphax} + \frac{t\_1 \cdot t\_1}{alphay \cdot alphay}} \cdot u0}{1 - u0}}}
\end{array}
\end{array}
(FPCore (u0 u1 alphax alphay)
:precision binary32
(let* ((t_0
(sin
(atan
(* (/ alphay alphax) (tan (+ (* (* 2.0 (PI)) u1) (* 0.5 (PI)))))))))
(/
1.0
(sqrt
(+
1.0
(/
(*
(/
1.0
(+
(/
(/
1.0
(+
(pow
(* (tan (+ (* (* (PI) 2.0) u1) (* (PI) 0.5))) (/ alphay alphax))
2.0)
1.0))
(* alphax alphax))
(/ (* t_0 t_0) (* alphay alphay))))
u0)
(- 1.0 u0)))))))\begin{array}{l}
\\
\begin{array}{l}
t_0 := \sin \tan^{-1} \left(\frac{alphay}{alphax} \cdot \tan \left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot u1 + 0.5 \cdot \mathsf{PI}\left(\right)\right)\right)\\
\frac{1}{\sqrt{1 + \frac{\frac{1}{\frac{\frac{1}{{\left(\tan \left(\left(\mathsf{PI}\left(\right) \cdot 2\right) \cdot u1 + \mathsf{PI}\left(\right) \cdot 0.5\right) \cdot \frac{alphay}{alphax}\right)}^{2} + 1}}{alphax \cdot alphax} + \frac{t\_0 \cdot t\_0}{alphay \cdot alphay}} \cdot u0}{1 - u0}}}
\end{array}
\end{array}
Initial program 99.4%
lift-*.f32N/A
lift-cos.f32N/A
lift-atan.f32N/A
cos-atanN/A
lift-cos.f32N/A
lift-atan.f32N/A
cos-atanN/A
Applied rewrites93.5%
lift-fma.f32N/A
lift-*.f32N/A
+-commutativeN/A
lift-*.f32N/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
lift-+.f3299.4
lift-*.f32N/A
*-commutativeN/A
lift-*.f3299.4
lift-*.f32N/A
*-commutativeN/A
lower-*.f3299.4
Applied rewrites99.4%
(FPCore (u0 u1 alphax alphay)
:precision binary32
(/
1.0
(sqrt
(+
1.0
(/
(*
(/
1.0
(+
(/
(/
1.0
(+
(pow
(* (tan (+ (* (PI) 0.5) (* (* (PI) 2.0) u1))) (/ alphay alphax))
2.0)
1.0))
(* alphax alphax))
(/
(-
1.0
(cos
(*
(atan (* (tan (* (fma u1 2.0 0.5) (PI))) (/ alphay alphax)))
2.0)))
(* (* alphay alphay) 2.0))))
u0)
(- 1.0 u0))))))\begin{array}{l}
\\
\frac{1}{\sqrt{1 + \frac{\frac{1}{\frac{\frac{1}{{\left(\tan \left(\mathsf{PI}\left(\right) \cdot 0.5 + \left(\mathsf{PI}\left(\right) \cdot 2\right) \cdot u1\right) \cdot \frac{alphay}{alphax}\right)}^{2} + 1}}{alphax \cdot alphax} + \frac{1 - \cos \left(\tan^{-1} \left(\tan \left(\mathsf{fma}\left(u1, 2, 0.5\right) \cdot \mathsf{PI}\left(\right)\right) \cdot \frac{alphay}{alphax}\right) \cdot 2\right)}{\left(alphay \cdot alphay\right) \cdot 2}} \cdot u0}{1 - u0}}}
\end{array}
Initial program 99.4%
lift-*.f32N/A
lift-cos.f32N/A
lift-atan.f32N/A
cos-atanN/A
lift-cos.f32N/A
lift-atan.f32N/A
cos-atanN/A
Applied rewrites93.5%
Applied rewrites87.4%
lift-fma.f32N/A
lower-+.f32N/A
*-commutativeN/A
lower-*.f3269.9
lift-*.f32N/A
*-commutativeN/A
lower-*.f3269.6
Applied rewrites69.7%
(FPCore (u0 u1 alphax alphay)
:precision binary32
(let* ((t_0 (* (PI) (fma 2.0 u1 0.5))))
(/
1.0
(sqrt
(+
1.0
(/
(/
(* 2.0 (* (* alphay alphay) u0))
(-
1.0
(cos (* 2.0 (atan (* (/ alphay alphax) (/ (sin t_0) (cos t_0))))))))
(- 1.0 u0)))))))\begin{array}{l}
\\
\begin{array}{l}
t_0 := \mathsf{PI}\left(\right) \cdot \mathsf{fma}\left(2, u1, 0.5\right)\\
\frac{1}{\sqrt{1 + \frac{\frac{2 \cdot \left(\left(alphay \cdot alphay\right) \cdot u0\right)}{1 - \cos \left(2 \cdot \tan^{-1} \left(\frac{alphay}{alphax} \cdot \frac{\sin t\_0}{\cos t\_0}\right)\right)}}{1 - u0}}}
\end{array}
\end{array}
Initial program 99.4%
Applied rewrites51.7%
Taylor expanded in alphax around inf
associate-*r/N/A
lower-/.f32N/A
lower-*.f32N/A
lower-*.f32N/A
unpow2N/A
lower-*.f32N/A
lower--.f32N/A
lower-cos.f32N/A
Applied rewrites97.7%
(FPCore (u0 u1 alphax alphay)
:precision binary32
(let* ((t_0 (* (PI) (fma 2.0 u1 0.5))))
(-
1.0
(/
(/ (* (* alphay alphay) u0) (- 1.0 u0))
(-
1.0
(cos (* 2.0 (atan (* (/ alphay alphax) (/ (sin t_0) (cos t_0)))))))))))\begin{array}{l}
\\
\begin{array}{l}
t_0 := \mathsf{PI}\left(\right) \cdot \mathsf{fma}\left(2, u1, 0.5\right)\\
1 - \frac{\frac{\left(alphay \cdot alphay\right) \cdot u0}{1 - u0}}{1 - \cos \left(2 \cdot \tan^{-1} \left(\frac{alphay}{alphax} \cdot \frac{\sin t\_0}{\cos t\_0}\right)\right)}
\end{array}
\end{array}
Initial program 99.4%
Applied rewrites50.9%
Taylor expanded in alphay around 0
mul-1-negN/A
unsub-negN/A
lower--.f32N/A
associate-/r*N/A
Applied rewrites75.1%
(FPCore (u0 u1 alphax alphay)
:precision binary32
(sqrt
(-
1.0
(*
(/ u0 (- 1.0 u0))
(pow
(/
(sin (atan (* (tan (* (fma 2.0 u1 0.5) (PI))) (/ alphay alphax))))
alphay)
-2.0)))))\begin{array}{l}
\\
\sqrt{1 - \frac{u0}{1 - u0} \cdot {\left(\frac{\sin \tan^{-1} \left(\tan \left(\mathsf{fma}\left(2, u1, 0.5\right) \cdot \mathsf{PI}\left(\right)\right) \cdot \frac{alphay}{alphax}\right)}{alphay}\right)}^{-2}}
\end{array}
Initial program 99.4%
Taylor expanded in u1 around 0
Applied rewrites98.1%
Taylor expanded in alphay around 0
Applied rewrites96.7%
Applied rewrites96.7%
Applied rewrites96.7%
(FPCore (u0 u1 alphax alphay)
:precision binary32
(/
1.0
(sqrt
(+
1.0
(/
(*
(/
1.0
(+
(/ 1.0 (* alphax alphax))
(/
(-
1.0
(cos
(*
(atan (* (tan (* (fma u1 2.0 0.5) (PI))) (/ alphay alphax)))
2.0)))
(* (* alphay alphay) 2.0))))
u0)
(- 1.0 u0))))))\begin{array}{l}
\\
\frac{1}{\sqrt{1 + \frac{\frac{1}{\frac{1}{alphax \cdot alphax} + \frac{1 - \cos \left(\tan^{-1} \left(\tan \left(\mathsf{fma}\left(u1, 2, 0.5\right) \cdot \mathsf{PI}\left(\right)\right) \cdot \frac{alphay}{alphax}\right) \cdot 2\right)}{\left(alphay \cdot alphay\right) \cdot 2}} \cdot u0}{1 - u0}}}
\end{array}
Initial program 99.4%
lift-*.f32N/A
lift-cos.f32N/A
lift-atan.f32N/A
cos-atanN/A
lift-cos.f32N/A
lift-atan.f32N/A
cos-atanN/A
Applied rewrites93.5%
Applied rewrites87.5%
Taylor expanded in alphax around inf
lower-/.f32N/A
unpow2N/A
lower-*.f3292.8
Applied rewrites92.8%
(FPCore (u0 u1 alphax alphay) :precision binary32 1.0)
float code(float u0, float u1, float alphax, float alphay) {
return 1.0f;
}
real(4) function code(u0, u1, alphax, alphay)
real(4), intent (in) :: u0
real(4), intent (in) :: u1
real(4), intent (in) :: alphax
real(4), intent (in) :: alphay
code = 1.0e0
end function
function code(u0, u1, alphax, alphay) return Float32(1.0) end
function tmp = code(u0, u1, alphax, alphay) tmp = single(1.0); end
\begin{array}{l}
\\
1
\end{array}
Initial program 99.4%
Taylor expanded in u0 around 0
Applied rewrites91.9%
herbie shell --seed 2024298
(FPCore (u0 u1 alphax alphay)
:name "Trowbridge-Reitz Sample, sample surface normal, cosTheta"
:precision binary32
:pre (and (and (and (and (<= 2.328306437e-10 u0) (<= u0 1.0)) (and (<= 2.328306437e-10 u1) (<= u1 0.5))) (and (<= 0.0001 alphax) (<= alphax 1.0))) (and (<= 0.0001 alphay) (<= alphay 1.0)))
(/ 1.0 (sqrt (+ 1.0 (/ (* (/ 1.0 (+ (/ (* (cos (atan (* (/ alphay alphax) (tan (+ (* (* 2.0 (PI)) u1) (* 0.5 (PI))))))) (cos (atan (* (/ alphay alphax) (tan (+ (* (* 2.0 (PI)) u1) (* 0.5 (PI)))))))) (* alphax alphax)) (/ (* (sin (atan (* (/ alphay alphax) (tan (+ (* (* 2.0 (PI)) u1) (* 0.5 (PI))))))) (sin (atan (* (/ alphay alphax) (tan (+ (* (* 2.0 (PI)) u1) (* 0.5 (PI)))))))) (* alphay alphay)))) u0) (- 1.0 u0))))))