
(FPCore (s r) :precision binary32 (+ (/ (* 0.25 (exp (/ (- r) s))) (* (* (* 2.0 (PI)) s) r)) (/ (* 0.75 (exp (/ (- r) (* 3.0 s)))) (* (* (* 6.0 (PI)) s) r))))
\begin{array}{l}
\\
\frac{0.25 \cdot e^{\frac{-r}{s}}}{\left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot s\right) \cdot r} + \frac{0.75 \cdot e^{\frac{-r}{3 \cdot s}}}{\left(\left(6 \cdot \mathsf{PI}\left(\right)\right) \cdot s\right) \cdot r}
\end{array}
Sampling outcomes in binary32 precision:
Herbie found 15 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (s r) :precision binary32 (+ (/ (* 0.25 (exp (/ (- r) s))) (* (* (* 2.0 (PI)) s) r)) (/ (* 0.75 (exp (/ (- r) (* 3.0 s)))) (* (* (* 6.0 (PI)) s) r))))
\begin{array}{l}
\\
\frac{0.25 \cdot e^{\frac{-r}{s}}}{\left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot s\right) \cdot r} + \frac{0.75 \cdot e^{\frac{-r}{3 \cdot s}}}{\left(\left(6 \cdot \mathsf{PI}\left(\right)\right) \cdot s\right) \cdot r}
\end{array}
(FPCore (s r)
:precision binary32
(let* ((t_0 (sqrt (PI))))
(+
(/ 0.125 (* (exp (/ r s)) (* (* (PI) s) r)))
(/ (* 0.75 (exp (/ (- r) (* 3.0 s)))) (* (* t_0 s) (* (* t_0 r) 6.0))))))\begin{array}{l}
\\
\begin{array}{l}
t_0 := \sqrt{\mathsf{PI}\left(\right)}\\
\frac{0.125}{e^{\frac{r}{s}} \cdot \left(\left(\mathsf{PI}\left(\right) \cdot s\right) \cdot r\right)} + \frac{0.75 \cdot e^{\frac{-r}{3 \cdot s}}}{\left(t\_0 \cdot s\right) \cdot \left(\left(t\_0 \cdot r\right) \cdot 6\right)}
\end{array}
\end{array}
Initial program 99.5%
lift-*.f32N/A
lift-*.f32N/A
lift-*.f32N/A
associate-*l*N/A
associate-*l*N/A
lower-*.f32N/A
lower-*.f32N/A
lower-*.f3299.6
Applied rewrites99.6%
lift-/.f32N/A
lift-*.f32N/A
lift-*.f32N/A
times-fracN/A
lift-*.f32N/A
lift-*.f32N/A
associate-*l*N/A
lift-*.f32N/A
associate-/r*N/A
metadata-evalN/A
times-fracN/A
Applied rewrites99.6%
lift-*.f32N/A
*-commutativeN/A
lift-PI.f32N/A
add-sqr-sqrtN/A
associate-*r*N/A
lower-*.f32N/A
lower-*.f32N/A
lift-PI.f32N/A
lower-sqrt.f32N/A
lift-PI.f32N/A
lower-sqrt.f3299.6
Applied rewrites99.6%
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
lift-*.f32N/A
associate-*l*N/A
associate-*l*N/A
lower-*.f32N/A
lift-*.f32N/A
*-commutativeN/A
lower-*.f32N/A
lower-*.f32N/A
lower-*.f3299.6
Applied rewrites99.6%
(FPCore (s r)
:precision binary32
(let* ((t_0 (sqrt (PI))))
(+
(/ 0.125 (* (exp (/ r s)) (* (* (PI) s) r)))
(/ (* 0.75 (exp (/ r (* -3.0 s)))) (* 6.0 (* (* (* s t_0) t_0) r))))))\begin{array}{l}
\\
\begin{array}{l}
t_0 := \sqrt{\mathsf{PI}\left(\right)}\\
\frac{0.125}{e^{\frac{r}{s}} \cdot \left(\left(\mathsf{PI}\left(\right) \cdot s\right) \cdot r\right)} + \frac{0.75 \cdot e^{\frac{r}{-3 \cdot s}}}{6 \cdot \left(\left(\left(s \cdot t\_0\right) \cdot t\_0\right) \cdot r\right)}
\end{array}
\end{array}
Initial program 99.5%
lift-*.f32N/A
lift-*.f32N/A
lift-*.f32N/A
associate-*l*N/A
associate-*l*N/A
lower-*.f32N/A
lower-*.f32N/A
lower-*.f3299.6
Applied rewrites99.6%
lift-/.f32N/A
lift-*.f32N/A
lift-*.f32N/A
times-fracN/A
lift-*.f32N/A
lift-*.f32N/A
associate-*l*N/A
lift-*.f32N/A
associate-/r*N/A
metadata-evalN/A
times-fracN/A
Applied rewrites99.6%
lift-*.f32N/A
*-commutativeN/A
lift-PI.f32N/A
add-sqr-sqrtN/A
associate-*r*N/A
lower-*.f32N/A
lower-*.f32N/A
lift-PI.f32N/A
lower-sqrt.f32N/A
lift-PI.f32N/A
lower-sqrt.f3299.6
Applied rewrites99.6%
lift-/.f32N/A
frac-2negN/A
lift-neg.f32N/A
remove-double-negN/A
lower-/.f32N/A
lift-*.f32N/A
distribute-lft-neg-inN/A
lower-*.f32N/A
metadata-eval99.6
Applied rewrites99.6%
(FPCore (s r) :precision binary32 (+ (/ 0.125 (* (exp (/ r s)) (* (* (PI) s) r))) (/ (* 0.75 (exp (/ (- r) (* 3.0 s)))) (* (* 6.0 s) (* (PI) r)))))
\begin{array}{l}
\\
\frac{0.125}{e^{\frac{r}{s}} \cdot \left(\left(\mathsf{PI}\left(\right) \cdot s\right) \cdot r\right)} + \frac{0.75 \cdot e^{\frac{-r}{3 \cdot s}}}{\left(6 \cdot s\right) \cdot \left(\mathsf{PI}\left(\right) \cdot r\right)}
\end{array}
Initial program 99.5%
lift-*.f32N/A
lift-*.f32N/A
lift-*.f32N/A
associate-*l*N/A
associate-*l*N/A
lower-*.f32N/A
lower-*.f32N/A
lower-*.f3299.6
Applied rewrites99.6%
lift-/.f32N/A
lift-*.f32N/A
lift-*.f32N/A
times-fracN/A
lift-*.f32N/A
lift-*.f32N/A
associate-*l*N/A
lift-*.f32N/A
associate-/r*N/A
metadata-evalN/A
times-fracN/A
Applied rewrites99.6%
lift-*.f32N/A
*-commutativeN/A
lift-PI.f32N/A
add-sqr-sqrtN/A
associate-*r*N/A
lower-*.f32N/A
lower-*.f32N/A
lift-PI.f32N/A
lower-sqrt.f32N/A
lift-PI.f32N/A
lower-sqrt.f3299.6
Applied rewrites99.6%
lift-*.f32N/A
lift-*.f32N/A
lift-*.f32N/A
lift-*.f32N/A
associate-*l*N/A
lift-sqrt.f32N/A
lift-sqrt.f32N/A
rem-square-sqrtN/A
associate-*r*N/A
lift-*.f32N/A
associate-*r*N/A
lower-*.f32N/A
lower-*.f3299.6
Applied rewrites99.6%
(FPCore (s r)
:precision binary32
(let* ((t_0 (* (* (PI) s) r)))
(+
(/ 0.125 (* (exp (/ r s)) t_0))
(/ (* 0.75 (exp (/ r (* -3.0 s)))) (* 6.0 t_0)))))\begin{array}{l}
\\
\begin{array}{l}
t_0 := \left(\mathsf{PI}\left(\right) \cdot s\right) \cdot r\\
\frac{0.125}{e^{\frac{r}{s}} \cdot t\_0} + \frac{0.75 \cdot e^{\frac{r}{-3 \cdot s}}}{6 \cdot t\_0}
\end{array}
\end{array}
Initial program 99.5%
lift-*.f32N/A
lift-*.f32N/A
lift-*.f32N/A
associate-*l*N/A
associate-*l*N/A
lower-*.f32N/A
lower-*.f32N/A
lower-*.f3299.6
Applied rewrites99.6%
lift-/.f32N/A
lift-*.f32N/A
lift-*.f32N/A
times-fracN/A
lift-*.f32N/A
lift-*.f32N/A
associate-*l*N/A
lift-*.f32N/A
associate-/r*N/A
metadata-evalN/A
times-fracN/A
Applied rewrites99.6%
lift-/.f32N/A
frac-2negN/A
lift-neg.f32N/A
remove-double-negN/A
lower-/.f32N/A
lift-*.f32N/A
distribute-lft-neg-inN/A
lower-*.f32N/A
metadata-eval99.6
Applied rewrites99.6%
(FPCore (s r)
:precision binary32
(let* ((t_0 (* (* (PI) s) r)))
(+
(/ 0.125 (* (exp (/ r s)) t_0))
(/ (* (exp (* -0.3333333333333333 (/ r s))) 0.125) t_0))))\begin{array}{l}
\\
\begin{array}{l}
t_0 := \left(\mathsf{PI}\left(\right) \cdot s\right) \cdot r\\
\frac{0.125}{e^{\frac{r}{s}} \cdot t\_0} + \frac{e^{-0.3333333333333333 \cdot \frac{r}{s}} \cdot 0.125}{t\_0}
\end{array}
\end{array}
Initial program 99.5%
lift-*.f32N/A
lift-*.f32N/A
lift-*.f32N/A
associate-*l*N/A
associate-*l*N/A
lower-*.f32N/A
lower-*.f32N/A
lower-*.f3299.6
Applied rewrites99.6%
lift-/.f32N/A
lift-*.f32N/A
lift-*.f32N/A
times-fracN/A
lift-*.f32N/A
lift-*.f32N/A
associate-*l*N/A
lift-*.f32N/A
associate-/r*N/A
metadata-evalN/A
times-fracN/A
Applied rewrites99.6%
lift-/.f32N/A
lift-*.f32N/A
associate-/r*N/A
lower-/.f32N/A
Applied rewrites99.6%
(FPCore (s r)
:precision binary32
(let* ((t_0 (* (* (PI) s) r)))
(*
0.125
(+
(/ (exp (/ (- r) s)) t_0)
(/ (exp (* -0.3333333333333333 (/ r s))) t_0)))))\begin{array}{l}
\\
\begin{array}{l}
t_0 := \left(\mathsf{PI}\left(\right) \cdot s\right) \cdot r\\
0.125 \cdot \left(\frac{e^{\frac{-r}{s}}}{t\_0} + \frac{e^{-0.3333333333333333 \cdot \frac{r}{s}}}{t\_0}\right)
\end{array}
\end{array}
Initial program 99.5%
lift-*.f32N/A
lift-*.f32N/A
lift-*.f32N/A
associate-*l*N/A
associate-*l*N/A
lower-*.f32N/A
lower-*.f32N/A
lower-*.f3299.6
Applied rewrites99.6%
lift-/.f32N/A
lift-*.f32N/A
lift-*.f32N/A
times-fracN/A
lift-*.f32N/A
lift-*.f32N/A
associate-*l*N/A
lift-*.f32N/A
associate-/r*N/A
metadata-evalN/A
times-fracN/A
Applied rewrites99.6%
lift-+.f32N/A
lift-/.f32N/A
div-invN/A
lift-/.f32N/A
lift-*.f32N/A
lift-*.f32N/A
times-fracN/A
metadata-evalN/A
distribute-lft-outN/A
lower-*.f32N/A
Applied rewrites99.5%
(FPCore (s r)
:precision binary32
(let* ((t_0 (* (PI) s)))
(+
(/ 0.125 (* (exp (/ r s)) (* t_0 r)))
(/ (- (/ 0.125 (* (PI) r)) (/ 0.041666666666666664 t_0)) s))))\begin{array}{l}
\\
\begin{array}{l}
t_0 := \mathsf{PI}\left(\right) \cdot s\\
\frac{0.125}{e^{\frac{r}{s}} \cdot \left(t\_0 \cdot r\right)} + \frac{\frac{0.125}{\mathsf{PI}\left(\right) \cdot r} - \frac{0.041666666666666664}{t\_0}}{s}
\end{array}
\end{array}
Initial program 99.5%
lift-*.f32N/A
lift-*.f32N/A
lift-*.f32N/A
associate-*l*N/A
associate-*l*N/A
lower-*.f32N/A
lower-*.f32N/A
lower-*.f3299.6
Applied rewrites99.6%
lift-/.f32N/A
lift-*.f32N/A
lift-*.f32N/A
times-fracN/A
lift-*.f32N/A
lift-*.f32N/A
associate-*l*N/A
lift-*.f32N/A
associate-/r*N/A
metadata-evalN/A
times-fracN/A
Applied rewrites99.6%
Taylor expanded in s around inf
lower-/.f32N/A
lower--.f32N/A
associate-*r/N/A
metadata-evalN/A
lower-/.f32N/A
*-commutativeN/A
lower-*.f32N/A
lower-PI.f32N/A
associate-*r/N/A
metadata-evalN/A
lower-/.f32N/A
*-commutativeN/A
lower-*.f32N/A
lower-PI.f3212.0
Applied rewrites12.0%
(FPCore (s r) :precision binary32 (let* ((t_0 (* (PI) s))) (+ (/ 0.125 (* (exp (/ r s)) (* t_0 r))) (/ (/ 0.125 t_0) r))))
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \mathsf{PI}\left(\right) \cdot s\\
\frac{0.125}{e^{\frac{r}{s}} \cdot \left(t\_0 \cdot r\right)} + \frac{\frac{0.125}{t\_0}}{r}
\end{array}
\end{array}
Initial program 99.5%
lift-*.f32N/A
lift-*.f32N/A
lift-*.f32N/A
associate-*l*N/A
associate-*l*N/A
lower-*.f32N/A
lower-*.f32N/A
lower-*.f3299.6
Applied rewrites99.6%
lift-/.f32N/A
lift-*.f32N/A
lift-*.f32N/A
times-fracN/A
lift-*.f32N/A
lift-*.f32N/A
associate-*l*N/A
lift-*.f32N/A
associate-/r*N/A
metadata-evalN/A
times-fracN/A
Applied rewrites99.6%
Taylor expanded in s around inf
*-commutativeN/A
associate-/r*N/A
metadata-evalN/A
associate-*r/N/A
lower-/.f32N/A
associate-*r/N/A
metadata-evalN/A
lower-/.f32N/A
*-commutativeN/A
lower-*.f32N/A
lower-PI.f3211.4
Applied rewrites11.4%
(FPCore (s r) :precision binary32 (let* ((t_0 (* (* (PI) s) r))) (+ (/ 0.125 (* (exp (/ r s)) t_0)) (/ 0.75 (* 6.0 t_0)))))
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \left(\mathsf{PI}\left(\right) \cdot s\right) \cdot r\\
\frac{0.125}{e^{\frac{r}{s}} \cdot t\_0} + \frac{0.75}{6 \cdot t\_0}
\end{array}
\end{array}
Initial program 99.5%
lift-*.f32N/A
lift-*.f32N/A
lift-*.f32N/A
associate-*l*N/A
associate-*l*N/A
lower-*.f32N/A
lower-*.f32N/A
lower-*.f3299.6
Applied rewrites99.6%
lift-/.f32N/A
lift-*.f32N/A
lift-*.f32N/A
times-fracN/A
lift-*.f32N/A
lift-*.f32N/A
associate-*l*N/A
lift-*.f32N/A
associate-/r*N/A
metadata-evalN/A
times-fracN/A
Applied rewrites99.6%
Taylor expanded in s around inf
Applied rewrites11.3%
(FPCore (s r) :precision binary32 (/ (- (/ -0.16666666666666666 (* (PI) s)) (/ -0.25 (* (PI) r))) s))
\begin{array}{l}
\\
\frac{\frac{-0.16666666666666666}{\mathsf{PI}\left(\right) \cdot s} - \frac{-0.25}{\mathsf{PI}\left(\right) \cdot r}}{s}
\end{array}
Initial program 99.5%
Taylor expanded in s around inf
lower-/.f32N/A
Applied rewrites11.3%
(FPCore (s r) :precision binary32 (/ (/ (/ 0.25 (PI)) s) r))
\begin{array}{l}
\\
\frac{\frac{\frac{0.25}{\mathsf{PI}\left(\right)}}{s}}{r}
\end{array}
Initial program 99.5%
Taylor expanded in s around inf
associate-/l/N/A
metadata-evalN/A
associate-*r/N/A
lower-/.f32N/A
associate-*r/N/A
metadata-evalN/A
lower-/.f32N/A
*-commutativeN/A
lower-*.f32N/A
lower-PI.f3210.8
Applied rewrites10.8%
Applied rewrites10.8%
(FPCore (s r) :precision binary32 (* (/ 0.25 (* (PI) r)) (/ 1.0 s)))
\begin{array}{l}
\\
\frac{0.25}{\mathsf{PI}\left(\right) \cdot r} \cdot \frac{1}{s}
\end{array}
Initial program 99.5%
Taylor expanded in s around inf
associate-/l/N/A
metadata-evalN/A
associate-*r/N/A
lower-/.f32N/A
associate-*r/N/A
metadata-evalN/A
lower-/.f32N/A
*-commutativeN/A
lower-*.f32N/A
lower-PI.f3210.8
Applied rewrites10.8%
Applied rewrites10.8%
(FPCore (s r) :precision binary32 (/ (/ 0.25 (* (PI) s)) r))
\begin{array}{l}
\\
\frac{\frac{0.25}{\mathsf{PI}\left(\right) \cdot s}}{r}
\end{array}
Initial program 99.5%
Taylor expanded in s around inf
associate-/l/N/A
metadata-evalN/A
associate-*r/N/A
lower-/.f32N/A
associate-*r/N/A
metadata-evalN/A
lower-/.f32N/A
*-commutativeN/A
lower-*.f32N/A
lower-PI.f3210.8
Applied rewrites10.8%
(FPCore (s r) :precision binary32 (/ 0.25 (* (* (PI) r) s)))
\begin{array}{l}
\\
\frac{0.25}{\left(\mathsf{PI}\left(\right) \cdot r\right) \cdot s}
\end{array}
Initial program 99.5%
Taylor expanded in s around inf
associate-/l/N/A
metadata-evalN/A
associate-*r/N/A
lower-/.f32N/A
associate-*r/N/A
metadata-evalN/A
lower-/.f32N/A
*-commutativeN/A
lower-*.f32N/A
lower-PI.f3210.8
Applied rewrites10.8%
Applied rewrites10.8%
Applied rewrites10.8%
(FPCore (s r) :precision binary32 (/ 0.25 (* (* s r) (PI))))
\begin{array}{l}
\\
\frac{0.25}{\left(s \cdot r\right) \cdot \mathsf{PI}\left(\right)}
\end{array}
Initial program 99.5%
Taylor expanded in s around inf
associate-/l/N/A
metadata-evalN/A
associate-*r/N/A
lower-/.f32N/A
associate-*r/N/A
metadata-evalN/A
lower-/.f32N/A
*-commutativeN/A
lower-*.f32N/A
lower-PI.f3210.8
Applied rewrites10.8%
Applied rewrites10.8%
Applied rewrites10.8%
herbie shell --seed 2024324
(FPCore (s r)
:name "Disney BSSRDF, PDF of scattering profile"
:precision binary32
:pre (and (and (<= 0.0 s) (<= s 256.0)) (and (< 1e-6 r) (< r 1000000.0)))
(+ (/ (* 0.25 (exp (/ (- r) s))) (* (* (* 2.0 (PI)) s) r)) (/ (* 0.75 (exp (/ (- r) (* 3.0 s)))) (* (* (* 6.0 (PI)) s) r))))