
(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 16 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 (+ (/ (* 0.25 (exp (/ (- r) s))) (* (* (* 2.0 (PI)) s) r)) (/ (* 0.75 (exp (/ 1.0 (* (/ -3.0 r) 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{1}{\frac{-3}{r} \cdot s}}}{\left(\left(6 \cdot \mathsf{PI}\left(\right)\right) \cdot s\right) \cdot r}
\end{array}
Initial program 99.7%
lift-/.f32N/A
clear-numN/A
lift-*.f32N/A
*-commutativeN/A
associate-/l*N/A
associate-/r*N/A
lower-/.f32N/A
lower-/.f32N/A
frac-2negN/A
lift-neg.f32N/A
remove-double-negN/A
lower-/.f32N/A
metadata-eval99.7
Applied rewrites99.7%
lift-/.f32N/A
lift-/.f32N/A
associate-/l/N/A
lower-/.f32N/A
lower-*.f3299.7
Applied rewrites99.7%
(FPCore (s r) :precision binary32 (+ (/ (/ 0.125 (exp (/ r s))) (* (* (PI) s) r)) (/ (* 0.75 (exp (/ (- r) (* 3.0 s)))) (* (* (* 6.0 (PI)) s) r))))
\begin{array}{l}
\\
\frac{\frac{0.125}{e^{\frac{r}{s}}}}{\left(\mathsf{PI}\left(\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}
Initial program 99.7%
Taylor expanded in s around 0
associate-*r/N/A
lower-/.f32N/A
mul-1-negN/A
exp-negN/A
associate-*r/N/A
metadata-evalN/A
lower-/.f32N/A
lower-exp.f32N/A
lower-/.f32N/A
*-commutativeN/A
lower-*.f32N/A
*-commutativeN/A
lower-*.f32N/A
lower-PI.f3299.7
Applied rewrites99.7%
(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{\frac{0.125}{e^{\frac{r}{s}}}}{\left(\mathsf{PI}\left(\right) \cdot s\right) \cdot r} + \frac{0.75 \cdot e^{\frac{-r}{3 \cdot s}}}{\left(\left(6 \cdot s\right) \cdot \mathsf{PI}\left(\right)\right) \cdot r}
\end{array}
Initial program 99.7%
Taylor expanded in s around 0
associate-*r/N/A
lower-/.f32N/A
mul-1-negN/A
exp-negN/A
associate-*r/N/A
metadata-evalN/A
lower-/.f32N/A
lower-exp.f32N/A
lower-/.f32N/A
*-commutativeN/A
lower-*.f32N/A
*-commutativeN/A
lower-*.f32N/A
lower-PI.f3299.7
Applied rewrites99.7%
lift-*.f32N/A
lift-*.f32N/A
associate-*l*N/A
*-commutativeN/A
associate-*r*N/A
lower-*.f32N/A
lower-*.f3299.7
Applied rewrites99.7%
(FPCore (s r) :precision binary32 (+ (* 0.125 (/ (exp (/ (- r) s)) (* (* (PI) s) r))) (/ (* 0.75 (exp (* r (/ -0.3333333333333333 s)))) (* (* (* 6.0 (PI)) s) r))))
\begin{array}{l}
\\
0.125 \cdot \frac{e^{\frac{-r}{s}}}{\left(\mathsf{PI}\left(\right) \cdot s\right) \cdot r} + \frac{0.75 \cdot e^{r \cdot \frac{-0.3333333333333333}{s}}}{\left(\left(6 \cdot \mathsf{PI}\left(\right)\right) \cdot s\right) \cdot r}
\end{array}
Initial program 99.7%
lift-/.f32N/A
frac-2negN/A
div-invN/A
lift-neg.f32N/A
remove-double-negN/A
lower-*.f32N/A
lift-*.f32N/A
distribute-lft-neg-inN/A
associate-/r*N/A
metadata-evalN/A
metadata-evalN/A
metadata-evalN/A
lower-/.f32N/A
metadata-eval99.7
Applied rewrites99.7%
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
lift-*.f32N/A
associate-/l*N/A
lower-*.f32N/A
lower-/.f3299.7
Applied rewrites99.7%
(FPCore (s r) :precision binary32 (+ (/ 0.125 (* (* (* (PI) s) r) (exp (/ r s)))) (/ (* 0.75 (exp (* r (/ -0.3333333333333333 s)))) (* (* (* 6.0 (PI)) s) r))))
\begin{array}{l}
\\
\frac{0.125}{\left(\left(\mathsf{PI}\left(\right) \cdot s\right) \cdot r\right) \cdot e^{\frac{r}{s}}} + \frac{0.75 \cdot e^{r \cdot \frac{-0.3333333333333333}{s}}}{\left(\left(6 \cdot \mathsf{PI}\left(\right)\right) \cdot s\right) \cdot r}
\end{array}
Initial program 99.7%
lift-/.f32N/A
frac-2negN/A
div-invN/A
lift-neg.f32N/A
remove-double-negN/A
lower-*.f32N/A
lift-*.f32N/A
distribute-lft-neg-inN/A
associate-/r*N/A
metadata-evalN/A
metadata-evalN/A
metadata-evalN/A
lower-/.f32N/A
metadata-eval99.7
Applied rewrites99.7%
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
lift-*.f32N/A
Applied rewrites99.7%
(FPCore (s r)
:precision binary32
(/
(fma
(/ (/ r s) (* s s))
(* (/ r (PI)) -0.021604938271604937)
(-
(/ 0.25 (* (PI) r))
(/
(*
(- (/ (/ 0.16666666666666666 (PI)) r) (/ 0.06944444444444445 (* (PI) s)))
r)
s)))
s))\begin{array}{l}
\\
\frac{\mathsf{fma}\left(\frac{\frac{r}{s}}{s \cdot s}, \frac{r}{\mathsf{PI}\left(\right)} \cdot -0.021604938271604937, \frac{0.25}{\mathsf{PI}\left(\right) \cdot r} - \frac{\left(\frac{\frac{0.16666666666666666}{\mathsf{PI}\left(\right)}}{r} - \frac{0.06944444444444445}{\mathsf{PI}\left(\right) \cdot s}\right) \cdot r}{s}\right)}{s}
\end{array}
Initial program 99.7%
Taylor expanded in s around inf
Applied rewrites5.0%
Applied rewrites10.8%
Taylor expanded in r around inf
Applied rewrites11.7%
(FPCore (s r)
:precision binary32
(let* ((t_0 (/ r (PI))))
(/
(fma
(/ (/ r s) (* s s))
(* t_0 -0.021604938271604937)
(-
(/ 0.25 (* (PI) r))
(/
(+ (/ 0.16666666666666666 (PI)) (* (/ t_0 s) -0.06944444444444445))
s)))
s)))\begin{array}{l}
\\
\begin{array}{l}
t_0 := \frac{r}{\mathsf{PI}\left(\right)}\\
\frac{\mathsf{fma}\left(\frac{\frac{r}{s}}{s \cdot s}, t\_0 \cdot -0.021604938271604937, \frac{0.25}{\mathsf{PI}\left(\right) \cdot r} - \frac{\frac{0.16666666666666666}{\mathsf{PI}\left(\right)} + \frac{t\_0}{s} \cdot -0.06944444444444445}{s}\right)}{s}
\end{array}
\end{array}
Initial program 99.7%
Taylor expanded in s around inf
Applied rewrites4.5%
Applied rewrites10.8%
Applied rewrites11.3%
(FPCore (s r)
:precision binary32
(let* ((t_0 (/ r (PI))))
(/
(+
(/
(-
(/ -0.16666666666666666 (PI))
(/
(fma 0.021604938271604937 (* r (/ t_0 s)) (* -0.06944444444444445 t_0))
s))
s)
(/ 0.25 (* (PI) r)))
s)))\begin{array}{l}
\\
\begin{array}{l}
t_0 := \frac{r}{\mathsf{PI}\left(\right)}\\
\frac{\frac{\frac{-0.16666666666666666}{\mathsf{PI}\left(\right)} - \frac{\mathsf{fma}\left(0.021604938271604937, r \cdot \frac{t\_0}{s}, -0.06944444444444445 \cdot t\_0\right)}{s}}{s} + \frac{0.25}{\mathsf{PI}\left(\right) \cdot r}}{s}
\end{array}
\end{array}
Initial program 99.7%
Taylor expanded in s around inf
Applied rewrites4.9%
Applied rewrites10.8%
Taylor expanded in s around -inf
Applied rewrites11.2%
(FPCore (s r)
:precision binary32
(/
(-
(/ 0.25 (* (PI) r))
(/
(fma -0.06944444444444445 (/ (/ r (PI)) s) (/ 0.16666666666666666 (PI)))
s))
s))\begin{array}{l}
\\
\frac{\frac{0.25}{\mathsf{PI}\left(\right) \cdot r} - \frac{\mathsf{fma}\left(-0.06944444444444445, \frac{\frac{r}{\mathsf{PI}\left(\right)}}{s}, \frac{0.16666666666666666}{\mathsf{PI}\left(\right)}\right)}{s}}{s}
\end{array}
Initial program 99.7%
Taylor expanded in s around inf
Applied rewrites10.8%
(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 99.7%
Taylor expanded in s around inf
lower-/.f32N/A
Applied rewrites10.8%
(FPCore (s r) :precision binary32 (let* ((t_0 (sqrt (PI)))) (/ 0.25 (* (* (* s t_0) t_0) r))))
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \sqrt{\mathsf{PI}\left(\right)}\\
\frac{0.25}{\left(\left(s \cdot t\_0\right) \cdot t\_0\right) \cdot r}
\end{array}
\end{array}
Initial program 99.7%
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.f3210.4
Applied rewrites10.4%
Applied rewrites10.4%
Applied rewrites10.4%
(FPCore (s r) :precision binary32 (/ 1.0 (/ (PI) (/ 0.25 (* s r)))))
\begin{array}{l}
\\
\frac{1}{\frac{\mathsf{PI}\left(\right)}{\frac{0.25}{s \cdot r}}}
\end{array}
Initial program 99.7%
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.f3210.4
Applied rewrites10.4%
Applied rewrites10.4%
Applied rewrites10.4%
Applied rewrites10.4%
(FPCore (s r) :precision binary32 (* (/ 0.25 (* s r)) (/ 1.0 (PI))))
\begin{array}{l}
\\
\frac{0.25}{s \cdot r} \cdot \frac{1}{\mathsf{PI}\left(\right)}
\end{array}
Initial program 99.7%
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.f3210.4
Applied rewrites10.4%
Applied rewrites10.4%
Applied rewrites10.4%
Applied rewrites10.4%
(FPCore (s r) :precision binary32 (/ (/ 0.25 (PI)) (* s r)))
\begin{array}{l}
\\
\frac{\frac{0.25}{\mathsf{PI}\left(\right)}}{s \cdot r}
\end{array}
Initial program 99.7%
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.f3210.4
Applied rewrites10.4%
Applied rewrites10.4%
(FPCore (s r) :precision binary32 (/ (/ 0.25 r) (* (PI) s)))
\begin{array}{l}
\\
\frac{\frac{0.25}{r}}{\mathsf{PI}\left(\right) \cdot s}
\end{array}
Initial program 99.7%
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.f3210.4
Applied rewrites10.4%
Applied rewrites10.4%
(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 99.7%
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.f3210.4
Applied rewrites10.4%
Applied rewrites10.4%
Applied rewrites10.4%
herbie shell --seed 2024318
(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))))