
(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 8 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 (* (+ (* u1 2.0) 0.5) (PI)))
(t_1
(sin
(atan
(* (tan (+ (* (PI) 0.5) (* (* (PI) 2.0) u1))) (/ alphay alphax))))))
(/
1.0
(sqrt
(+
(/
(*
u0
(/
1.0
(+
(/ (* t_1 t_1) (* alphay alphay))
(/
(pow (cos (atan (/ (* (sin t_0) (/ alphay alphax)) (cos t_0)))) 2.0)
(* alphax alphax)))))
(- 1.0 u0))
1.0)))))\begin{array}{l}
\\
\begin{array}{l}
t_0 := \left(u1 \cdot 2 + 0.5\right) \cdot \mathsf{PI}\left(\right)\\
t_1 := \sin \tan^{-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)\\
\frac{1}{\sqrt{\frac{u0 \cdot \frac{1}{\frac{t\_1 \cdot t\_1}{alphay \cdot alphay} + \frac{{\cos \tan^{-1} \left(\frac{\sin t\_0 \cdot \frac{alphay}{alphax}}{\cos t\_0}\right)}^{2}}{alphax \cdot alphax}}}{1 - u0} + 1}}
\end{array}
\end{array}
Initial program 99.2%
Taylor expanded in alphax around 0
lower-pow.f32N/A
Applied rewrites97.1%
Applied rewrites98.4%
Applied rewrites99.2%
Final simplification99.2%
(FPCore (u0 u1 alphax alphay)
:precision binary32
(let* ((t_0 (atan (* (tan (* (+ (* u1 2.0) 0.5) (PI))) (/ alphay alphax)))))
(pow
(pow
(+
(/
(/ u0 (- 1.0 u0))
(+ (pow (/ alphax (cos t_0)) -2.0) (pow (/ (sin t_0) alphay) 2.0)))
1.0)
-0.25)
2.0)))\begin{array}{l}
\\
\begin{array}{l}
t_0 := \tan^{-1} \left(\tan \left(\left(u1 \cdot 2 + 0.5\right) \cdot \mathsf{PI}\left(\right)\right) \cdot \frac{alphay}{alphax}\right)\\
{\left({\left(\frac{\frac{u0}{1 - u0}}{{\left(\frac{alphax}{\cos t\_0}\right)}^{-2} + {\left(\frac{\sin t\_0}{alphay}\right)}^{2}} + 1\right)}^{-0.25}\right)}^{2}
\end{array}
\end{array}
Initial program 99.2%
lift-+.f32N/A
+-commutativeN/A
Applied rewrites78.5%
Applied rewrites89.7%
lift-fma.f32N/A
lift-*.f32N/A
lift-+.f3286.0
Applied rewrites86.4%
lift-fma.f32N/A
lift-*.f32N/A
lift-+.f3299.2
Applied rewrites99.2%
Final simplification99.2%
(FPCore (u0 u1 alphax alphay)
:precision binary32
(let* ((t_0 (* (+ (* u1 2.0) 0.5) (PI))))
(/
1.0
(sqrt
(+
(/
(*
(/
1.0
(+
(/
(- 1.0 (cos (* (atan (* (tan t_0) (/ alphay alphax))) 2.0)))
(* (* alphay alphay) 2.0))
(/
(pow
(cos
(atan
(/
(* (sin (* (fma u1 2.0 0.5) (PI))) (/ alphay alphax))
(cos t_0))))
2.0)
(* alphax alphax))))
u0)
(- 1.0 u0))
1.0)))))\begin{array}{l}
\\
\begin{array}{l}
t_0 := \left(u1 \cdot 2 + 0.5\right) \cdot \mathsf{PI}\left(\right)\\
\frac{1}{\sqrt{\frac{\frac{1}{\frac{1 - \cos \left(\tan^{-1} \left(\tan t\_0 \cdot \frac{alphay}{alphax}\right) \cdot 2\right)}{\left(alphay \cdot alphay\right) \cdot 2} + \frac{{\cos \tan^{-1} \left(\frac{\sin \left(\mathsf{fma}\left(u1, 2, 0.5\right) \cdot \mathsf{PI}\left(\right)\right) \cdot \frac{alphay}{alphax}}{\cos t\_0}\right)}^{2}}{alphax \cdot alphax}} \cdot u0}{1 - u0} + 1}}
\end{array}
\end{array}
Initial program 99.2%
Taylor expanded in alphax around 0
lower-pow.f32N/A
Applied rewrites97.1%
Applied rewrites98.4%
lift-/.f32N/A
Applied rewrites97.5%
lift-fma.f32N/A
lift-*.f32N/A
lift-+.f3298.4
Applied rewrites98.4%
Final simplification96.9%
(FPCore (u0 u1 alphax alphay)
:precision binary32
(let* ((t_0 (* (+ (* u1 2.0) 0.5) (PI))))
(/
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))
(/
(pow (cos (atan (/ (* (sin t_0) (/ alphay alphax)) (cos t_0)))) 2.0)
(* alphax alphax))))
u0)
(- 1.0 u0))
1.0)))))\begin{array}{l}
\\
\begin{array}{l}
t_0 := \left(u1 \cdot 2 + 0.5\right) \cdot \mathsf{PI}\left(\right)\\
\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{{\cos \tan^{-1} \left(\frac{\sin t\_0 \cdot \frac{alphay}{alphax}}{\cos t\_0}\right)}^{2}}{alphax \cdot alphax}} \cdot u0}{1 - u0} + 1}}
\end{array}
\end{array}
Initial program 99.2%
Taylor expanded in alphax around 0
lower-pow.f32N/A
Applied rewrites97.1%
Applied rewrites98.3%
lift-/.f32N/A
Applied rewrites97.4%
Applied rewrites62.1%
Final simplification98.0%
(FPCore (u0 u1 alphax alphay)
:precision binary32
(/
1.0
(sqrt
(+
(/
(*
(/
(* alphay alphay)
(pow
(sin
(atan
(*
(/ alphay (cos (* (+ (* u1 2.0) 0.5) (PI))))
(/ (sin (* (fma u1 2.0 0.5) (PI))) alphax))))
2.0))
u0)
(- 1.0 u0))
1.0))))\begin{array}{l}
\\
\frac{1}{\sqrt{\frac{\frac{alphay \cdot alphay}{{\sin \tan^{-1} \left(\frac{alphay}{\cos \left(\left(u1 \cdot 2 + 0.5\right) \cdot \mathsf{PI}\left(\right)\right)} \cdot \frac{\sin \left(\mathsf{fma}\left(u1, 2, 0.5\right) \cdot \mathsf{PI}\left(\right)\right)}{alphax}\right)}^{2}} \cdot u0}{1 - u0} + 1}}
\end{array}
Initial program 99.2%
lift-+.f32N/A
+-commutativeN/A
Applied rewrites78.4%
Taylor expanded in alphax around inf
lower-/.f32N/A
unpow2N/A
lower-*.f32N/A
lower-pow.f32N/A
Applied rewrites96.9%
Applied rewrites97.7%
Final simplification62.9%
(FPCore (u0 u1 alphax alphay)
:precision binary32
(/
1.0
(sqrt
(+
(/
(*
(/
(* alphay alphay)
(pow
(sin
(atan
(*
(/ alphay (cos (* (fma 2.0 u1 0.5) (PI))))
(/ (sin (* (fma u1 2.0 0.5) (PI))) alphax))))
2.0))
u0)
(- 1.0 u0))
1.0))))\begin{array}{l}
\\
\frac{1}{\sqrt{\frac{\frac{alphay \cdot alphay}{{\sin \tan^{-1} \left(\frac{alphay}{\cos \left(\mathsf{fma}\left(2, u1, 0.5\right) \cdot \mathsf{PI}\left(\right)\right)} \cdot \frac{\sin \left(\mathsf{fma}\left(u1, 2, 0.5\right) \cdot \mathsf{PI}\left(\right)\right)}{alphax}\right)}^{2}} \cdot u0}{1 - u0} + 1}}
\end{array}
Initial program 99.2%
lift-+.f32N/A
+-commutativeN/A
Applied rewrites78.6%
Taylor expanded in alphax around inf
lower-/.f32N/A
unpow2N/A
lower-*.f32N/A
lower-pow.f32N/A
Applied rewrites97.0%
Applied rewrites87.0%
Final simplification97.0%
(FPCore (u0 u1 alphax alphay)
:precision binary32
(/
1.0
(sqrt
(+
(*
(pow
(/
(sin (atan (* (tan (* (fma u1 2.0 0.5) (PI))) (/ alphay alphax))))
alphay)
-2.0)
(/ u0 (- 1.0 u0)))
1.0))))\begin{array}{l}
\\
\frac{1}{\sqrt{{\left(\frac{\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)}{alphay}\right)}^{-2} \cdot \frac{u0}{1 - u0} + 1}}
\end{array}
Initial program 99.2%
lift-+.f32N/A
+-commutativeN/A
Applied rewrites78.5%
Taylor expanded in alphax around inf
lower-/.f32N/A
unpow2N/A
lower-*.f32N/A
lower-pow.f32N/A
Applied rewrites96.9%
Applied rewrites6.7%
lift-fma.f32N/A
lift-*.f32N/A
Applied rewrites97.0%
(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 99.2%
Taylor expanded in alphax around 0
Applied rewrites90.4%
herbie shell --seed 2024264
(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))))))