
(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
(atan
(* (/ alphay alphax) (tan (+ (* 0.5 (PI)) (* (* 2.0 (PI)) u1)))))))
(/
1.0
(sqrt
(+
(/
(/ u0 (- 1.0 u0))
(+ (pow (/ (cos t_0) alphax) 2.0) (pow (/ (sin t_0) alphay) 2.0)))
1.0)))))\begin{array}{l}
\\
\begin{array}{l}
t_0 := \tan^{-1} \left(\frac{alphay}{alphax} \cdot \tan \left(0.5 \cdot \mathsf{PI}\left(\right) + \left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot u1\right)\right)\\
\frac{1}{\sqrt{\frac{\frac{u0}{1 - u0}}{{\left(\frac{\cos t\_0}{alphax}\right)}^{2} + {\left(\frac{\sin t\_0}{alphay}\right)}^{2}} + 1}}
\end{array}
\end{array}
Initial program 99.5%
Applied rewrites87.8%
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-+.f3293.0
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
lift-*.f3293.0
Applied rewrites93.0%
lift-fma.f32N/A
lift-*.f32N/A
+-commutativeN/A
lift-+.f3299.5
Applied rewrites99.5%
Final simplification99.5%
(FPCore (u0 u1 alphax alphay)
:precision binary32
(/
1.0
(sqrt
(+
(/
(*
(/
1.0
(+
(/
(-
1.0
(cos
(*
(atan (* (tan (* (fma u1 2.0 0.5) (PI))) (/ alphay alphax)))
2.0)))
(* (* alphay alphay) 2.0))
(/
(/
1.0
(+
(pow
(* (/ alphay alphax) (tan (+ (* 0.5 (PI)) (* (* 2.0 (PI)) u1))))
2.0)
1.0))
(* alphax alphax))))
u0)
(- 1.0 u0))
1.0))))\begin{array}{l}
\\
\frac{1}{\sqrt{\frac{\frac{1}{\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} + \frac{\frac{1}{{\left(\frac{alphay}{alphax} \cdot \tan \left(0.5 \cdot \mathsf{PI}\left(\right) + \left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot u1\right)\right)}^{2} + 1}}{alphax \cdot alphax}} \cdot u0}{1 - u0} + 1}}
\end{array}
Initial program 99.5%
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 rewrites92.7%
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-+.f3299.5
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
lift-*.f3299.5
Applied rewrites99.5%
lift-/.f32N/A
Applied rewrites70.8%
Final simplification98.5%
(FPCore (u0 u1 alphax alphay)
:precision binary32
(/
1.0
(sqrt
(+
(/
(/
(* (* alphay alphay) u0)
(pow
(sin
(atan
(/
(* (sin (* 0.5 (PI))) (/ alphay alphax))
(cos (* (+ (* 2.0 u1) 0.5) (PI))))))
2.0))
(- 1.0 u0))
1.0))))\begin{array}{l}
\\
\frac{1}{\sqrt{\frac{\frac{\left(alphay \cdot alphay\right) \cdot u0}{{\sin \tan^{-1} \left(\frac{\sin \left(0.5 \cdot \mathsf{PI}\left(\right)\right) \cdot \frac{alphay}{alphax}}{\cos \left(\left(2 \cdot u1 + 0.5\right) \cdot \mathsf{PI}\left(\right)\right)}\right)}^{2}}}{1 - u0} + 1}}
\end{array}
Initial program 99.5%
Taylor expanded in alphax around inf
lower-/.f32N/A
lower-*.f32N/A
unpow2N/A
lower-*.f32N/A
lower-pow.f32N/A
Applied rewrites98.2%
Applied rewrites98.7%
Taylor expanded in u1 around 0
Applied rewrites98.7%
Final simplification98.7%
(FPCore (u0 u1 alphax alphay)
:precision binary32
(pow
(+
(/
(*
(* (* alphay alphay) u0)
(pow
(sin (atan (* (tan (* (fma u1 2.0 0.5) (PI))) (/ alphay alphax))))
-2.0))
(- 1.0 u0))
1.0)
-0.5))\begin{array}{l}
\\
{\left(\frac{\left(\left(alphay \cdot alphay\right) \cdot u0\right) \cdot {\sin \tan^{-1} \left(\tan \left(\mathsf{fma}\left(u1, 2, 0.5\right) \cdot \mathsf{PI}\left(\right)\right) \cdot \frac{alphay}{alphax}\right)}^{-2}}{1 - u0} + 1\right)}^{-0.5}
\end{array}
Initial program 99.5%
Taylor expanded in alphax around inf
lower-/.f32N/A
lower-*.f32N/A
unpow2N/A
lower-*.f32N/A
lower-pow.f32N/A
Applied rewrites98.2%
Applied rewrites86.3%
Final simplification84.2%
(FPCore (u0 u1 alphax alphay)
:precision binary32
(/
1.0
(sqrt
(+
(/
(*
(pow
(sin (atan (* (tan (* (+ (* 2.0 u1) 0.5) (PI))) (/ alphay alphax))))
-2.0)
(* (* alphay alphay) u0))
(- 1.0 u0))
1.0))))\begin{array}{l}
\\
\frac{1}{\sqrt{\frac{{\sin \tan^{-1} \left(\tan \left(\left(2 \cdot u1 + 0.5\right) \cdot \mathsf{PI}\left(\right)\right) \cdot \frac{alphay}{alphax}\right)}^{-2} \cdot \left(\left(alphay \cdot alphay\right) \cdot u0\right)}{1 - u0} + 1}}
\end{array}
Initial program 99.5%
Taylor expanded in alphax around inf
lower-/.f32N/A
lower-*.f32N/A
unpow2N/A
lower-*.f32N/A
lower-pow.f32N/A
Applied rewrites98.2%
Applied rewrites98.2%
Applied rewrites98.2%
Final simplification98.2%
(FPCore (u0 u1 alphax alphay)
:precision binary32
(/
1.0
(sqrt
(+
(/
(*
(pow (sin (atan (* (tan (* 0.5 (PI))) (/ alphay alphax)))) -2.0)
(* (* alphay alphay) u0))
(- 1.0 u0))
1.0))))\begin{array}{l}
\\
\frac{1}{\sqrt{\frac{{\sin \tan^{-1} \left(\tan \left(0.5 \cdot \mathsf{PI}\left(\right)\right) \cdot \frac{alphay}{alphax}\right)}^{-2} \cdot \left(\left(alphay \cdot alphay\right) \cdot u0\right)}{1 - u0} + 1}}
\end{array}
Initial program 99.5%
Taylor expanded in alphax around inf
lower-/.f32N/A
lower-*.f32N/A
unpow2N/A
lower-*.f32N/A
lower-pow.f32N/A
Applied rewrites98.2%
Applied rewrites98.2%
Taylor expanded in u1 around 0
Applied rewrites98.2%
Final simplification98.2%
(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 99.5%
Taylor expanded in alphax around 0
Applied rewrites91.5%
herbie shell --seed 2024270
(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))))))