
(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 10 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
(* (tan (+ (* u1 (* 2.0 (PI))) (* 0.5 (PI)))) (/ alphay alphax)))))
(pow
(+
(/
(/ u0 (- 1.0 u0))
(+ (pow (/ (cos t_0) alphax) 2.0) (pow (/ (sin t_0) alphay) 2.0)))
1.0)
-0.5)))\begin{array}{l}
\\
\begin{array}{l}
t_0 := \tan^{-1} \left(\tan \left(u1 \cdot \left(2 \cdot \mathsf{PI}\left(\right)\right) + 0.5 \cdot \mathsf{PI}\left(\right)\right) \cdot \frac{alphay}{alphax}\right)\\
{\left(\frac{\frac{u0}{1 - u0}}{{\left(\frac{\cos t\_0}{alphax}\right)}^{2} + {\left(\frac{\sin t\_0}{alphay}\right)}^{2}} + 1\right)}^{-0.5}
\end{array}
\end{array}
Initial program 99.3%
Applied rewrites90.5%
lift-fma.f32N/A
lift-*.f32N/A
lift-*.f32N/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
+-commutativeN/A
lift-+.f3282.1
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
lift-*.f3283.3
Applied rewrites83.0%
lift-fma.f32N/A
lift-*.f32N/A
+-commutativeN/A
lift-+.f3299.9
lift-*.f32N/A
*-commutativeN/A
lower-*.f3299.9
lift-*.f32N/A
*-commutativeN/A
lower-*.f3299.9
Applied rewrites99.9%
Final simplification99.9%
(FPCore (u0 u1 alphax alphay)
:precision binary32
(pow
(+
(/
(/ u0 (- 1.0 u0))
(+
(pow
(/
(sin (atan (* (tan (* (fma 2.0 u1 0.5) (PI))) (/ alphay alphax))))
alphay)
2.0)
(pow
(/
(cos
(atan
(* (tan (+ (* u1 (* 2.0 (PI))) (* 0.5 (PI)))) (/ alphay alphax))))
alphax)
2.0)))
1.0)
-0.5))\begin{array}{l}
\\
{\left(\frac{\frac{u0}{1 - u0}}{{\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} + {\left(\frac{\cos \tan^{-1} \left(\tan \left(u1 \cdot \left(2 \cdot \mathsf{PI}\left(\right)\right) + 0.5 \cdot \mathsf{PI}\left(\right)\right) \cdot \frac{alphay}{alphax}\right)}{alphax}\right)}^{2}} + 1\right)}^{-0.5}
\end{array}
Initial program 99.3%
Applied rewrites90.4%
lift-fma.f32N/A
lift-*.f32N/A
lift-*.f32N/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
+-commutativeN/A
lift-+.f3284.2
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
lift-*.f3282.8
Applied rewrites83.4%
lift-fma.f32N/A
lift-*.f32N/A
lift-*.f32N/A
*-commutativeN/A
associate-*r*N/A
lift-*.f32N/A
distribute-rgt-inN/A
+-commutativeN/A
lift-*.f32N/A
lift-fma.f32N/A
*-commutativeN/A
lift-*.f3289.7
lift-fma.f32N/A
*-commutativeN/A
lift-fma.f3289.6
Applied rewrites89.6%
Final simplification89.8%
(FPCore (u0 u1 alphax alphay)
:precision binary32
(let* ((t_0 (* 0.5 (PI))))
(pow
(+
(/
(/ u0 (- 1.0 u0))
(+
(pow (/ (sin (atan (* (tan t_0) (/ alphay alphax)))) alphay) 2.0)
(pow
(/
(cos (atan (* (tan (+ (* u1 (* 2.0 (PI))) t_0)) (/ alphay alphax))))
alphax)
2.0)))
1.0)
-0.5)))\begin{array}{l}
\\
\begin{array}{l}
t_0 := 0.5 \cdot \mathsf{PI}\left(\right)\\
{\left(\frac{\frac{u0}{1 - u0}}{{\left(\frac{\sin \tan^{-1} \left(\tan t\_0 \cdot \frac{alphay}{alphax}\right)}{alphay}\right)}^{2} + {\left(\frac{\cos \tan^{-1} \left(\tan \left(u1 \cdot \left(2 \cdot \mathsf{PI}\left(\right)\right) + t\_0\right) \cdot \frac{alphay}{alphax}\right)}{alphax}\right)}^{2}} + 1\right)}^{-0.5}
\end{array}
\end{array}
Initial program 99.3%
Applied rewrites90.4%
lift-fma.f32N/A
lift-*.f32N/A
lift-*.f32N/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
+-commutativeN/A
lift-+.f3284.1
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
lift-*.f3283.8
Applied rewrites84.1%
Taylor expanded in u1 around 0
*-commutativeN/A
lower-*.f32N/A
lower-PI.f3298.5
Applied rewrites98.5%
Final simplification98.5%
(FPCore (u0 u1 alphax alphay)
:precision binary32
(pow
(+
(/
(/ u0 (- 1.0 u0))
(+
(/
(+
(cos
(* (atan (* (tan (* (fma u1 2.0 0.5) (PI))) (/ alphay alphax))) 2.0))
1.0)
(* (* alphax alphax) 2.0))
(pow
(/
(sin
(atan
(* (tan (+ (* u1 (* 2.0 (PI))) (* 0.5 (PI)))) (/ alphay alphax))))
alphay)
2.0)))
1.0)
-0.5))\begin{array}{l}
\\
{\left(\frac{\frac{u0}{1 - u0}}{\frac{\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) + 1}{\left(alphax \cdot alphax\right) \cdot 2} + {\left(\frac{\sin \tan^{-1} \left(\tan \left(u1 \cdot \left(2 \cdot \mathsf{PI}\left(\right)\right) + 0.5 \cdot \mathsf{PI}\left(\right)\right) \cdot \frac{alphay}{alphax}\right)}{alphay}\right)}^{2}} + 1\right)}^{-0.5}
\end{array}
Initial program 99.3%
Applied rewrites90.5%
lift-fma.f32N/A
lift-*.f32N/A
lift-*.f32N/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
+-commutativeN/A
lift-+.f3282.9
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
lift-*.f3284.5
Applied rewrites85.3%
lift-fma.f32N/A
lift-*.f32N/A
+-commutativeN/A
lift-+.f3299.9
lift-*.f32N/A
*-commutativeN/A
lower-*.f3299.9
lift-*.f32N/A
*-commutativeN/A
lower-*.f3299.9
Applied rewrites99.9%
Applied rewrites93.3%
Final simplification94.0%
(FPCore (u0 u1 alphax alphay)
:precision binary32
(let* ((t_0 (atan (* (tan (* (fma 2.0 u1 0.5) (PI))) (/ alphay alphax)))))
(sqrt
(/
1.0
(+
(/
(/ 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(\tan \left(\mathsf{fma}\left(2, u1, 0.5\right) \cdot \mathsf{PI}\left(\right)\right) \cdot \frac{alphay}{alphax}\right)\\
\sqrt{\frac{1}{\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 99.3%
Applied rewrites90.4%
lift-fma.f32N/A
lift-*.f32N/A
lift-*.f32N/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
+-commutativeN/A
lift-+.f3283.4
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
lift-*.f3283.1
Applied rewrites82.3%
Applied rewrites97.9%
Final simplification97.9%
(FPCore (u0 u1 alphax alphay)
:precision binary32
(let* ((t_0 (* (fma u1 2.0 0.5) (PI))))
(pow
(+
(*
(/
(* alphay alphay)
(pow (sin (atan (* (/ (sin t_0) (cos t_0)) (/ alphay alphax)))) 2.0))
(/ u0 (- 1.0 u0)))
1.0)
-0.5)))\begin{array}{l}
\\
\begin{array}{l}
t_0 := \mathsf{fma}\left(u1, 2, 0.5\right) \cdot \mathsf{PI}\left(\right)\\
{\left(\frac{alphay \cdot alphay}{{\sin \tan^{-1} \left(\frac{\sin t\_0}{\cos t\_0} \cdot \frac{alphay}{alphax}\right)}^{2}} \cdot \frac{u0}{1 - u0} + 1\right)}^{-0.5}
\end{array}
\end{array}
Initial program 99.3%
Applied rewrites90.4%
Taylor expanded in alphax around inf
times-fracN/A
lower-*.f32N/A
Applied rewrites88.3%
Final simplification88.5%
(FPCore (u0 u1 alphax alphay)
:precision binary32
(let* ((t_0 (* (fma 2.0 u1 0.5) (PI))))
(/
1.0
(sqrt
(+
(/
(/
(* (* alphay alphay) u0)
(pow (sin (atan (/ (* (sin t_0) (/ alphay alphax)) (cos t_0)))) 2.0))
(- 1.0 u0))
1.0)))))\begin{array}{l}
\\
\begin{array}{l}
t_0 := \mathsf{fma}\left(2, u1, 0.5\right) \cdot \mathsf{PI}\left(\right)\\
\frac{1}{\sqrt{\frac{\frac{\left(alphay \cdot alphay\right) \cdot u0}{{\sin \tan^{-1} \left(\frac{\sin t\_0 \cdot \frac{alphay}{alphax}}{\cos t\_0}\right)}^{2}}}{1 - u0} + 1}}
\end{array}
\end{array}
Initial program 99.3%
Taylor expanded in alphax around inf
lower-/.f32N/A
lower-*.f32N/A
unpow2N/A
lower-*.f32N/A
lower-pow.f32N/A
Applied rewrites97.4%
Final simplification97.4%
(FPCore (u0 u1 alphax alphay)
:precision binary32
(let* ((t_0 (* (fma u1 2.0 0.5) (PI))))
(sqrt
(-
1.0
(*
(/
(* alphay alphay)
(pow (sin (atan (* (/ (sin t_0) (cos t_0)) (/ alphay alphax)))) 2.0))
(/ u0 (- 1.0 u0)))))))\begin{array}{l}
\\
\begin{array}{l}
t_0 := \mathsf{fma}\left(u1, 2, 0.5\right) \cdot \mathsf{PI}\left(\right)\\
\sqrt{1 - \frac{alphay \cdot alphay}{{\sin \tan^{-1} \left(\frac{\sin t\_0}{\cos t\_0} \cdot \frac{alphay}{alphax}\right)}^{2}} \cdot \frac{u0}{1 - u0}}
\end{array}
\end{array}
Initial program 99.3%
Taylor expanded in u1 around 0
Applied rewrites97.9%
Taylor expanded in alphay around 0
Applied rewrites95.1%
Final simplification95.3%
(FPCore (u0 u1 alphax alphay)
:precision binary32
(let* ((t_0 (* (fma u1 2.0 0.5) (PI))))
(sqrt
(-
1.0
(/
(* (* alphay alphay) u0)
(pow (sin (atan (* (/ (sin t_0) (cos t_0)) (/ alphay alphax)))) 2.0))))))\begin{array}{l}
\\
\begin{array}{l}
t_0 := \mathsf{fma}\left(u1, 2, 0.5\right) \cdot \mathsf{PI}\left(\right)\\
\sqrt{1 - \frac{\left(alphay \cdot alphay\right) \cdot u0}{{\sin \tan^{-1} \left(\frac{\sin t\_0}{\cos t\_0} \cdot \frac{alphay}{alphax}\right)}^{2}}}
\end{array}
\end{array}
Initial program 99.3%
Taylor expanded in u1 around 0
Applied rewrites97.9%
Taylor expanded in u0 around 0
Applied rewrites94.5%
Taylor expanded in alphax around inf
Applied rewrites94.5%
Final simplification93.3%
(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 99.3%
Taylor expanded in alphax around 0
Applied rewrites91.1%
herbie shell --seed 2024271
(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))))))