
(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 17 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 (/ (- r) (* 3.0 s)))) (* (* r (* 6.0 (PI))) s))))
\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(r \cdot \left(6 \cdot \mathsf{PI}\left(\right)\right)\right) \cdot s}
\end{array}
Initial program 99.3%
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
associate-*r*N/A
lower-*.f32N/A
lower-*.f3299.3
Applied rewrites99.3%
(FPCore (s r) :precision binary32 (+ (/ (* 0.125 (exp (/ (- r) s))) (* (* (PI) r) s)) (/ (* 0.75 (exp (/ r (* -3.0 s)))) (* (* r (* 6.0 (PI))) s))))
\begin{array}{l}
\\
\frac{0.125 \cdot e^{\frac{-r}{s}}}{\left(\mathsf{PI}\left(\right) \cdot r\right) \cdot s} + \frac{0.75 \cdot e^{\frac{r}{-3 \cdot s}}}{\left(r \cdot \left(6 \cdot \mathsf{PI}\left(\right)\right)\right) \cdot s}
\end{array}
Initial program 99.3%
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
associate-*r*N/A
lower-*.f32N/A
lower-*.f3299.3
Applied rewrites99.3%
lift-/.f32N/A
lift-*.f32N/A
lift-exp.f32N/A
lift-/.f32N/A
lift-neg.f32N/A
lift-*.f32N/A
lift-*.f32N/A
lift-*.f32N/A
lift-PI.f32N/A
lift-neg.f32N/A
lift-/.f32N/A
lift-exp.f32N/A
lift-*.f32N/A
lift-PI.f32N/A
lift-*.f32N/A
lift-*.f32N/A
Applied rewrites99.3%
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
metadata-evalN/A
lower-*.f3299.3
Applied rewrites99.3%
(FPCore (s r) :precision binary32 (fma 0.125 (/ (exp (/ (/ r -3.0) s)) (* (PI) (* s r))) (* 0.125 (/ (exp (/ (- r) s)) (* (* (PI) s) r)))))
\begin{array}{l}
\\
\mathsf{fma}\left(0.125, \frac{e^{\frac{\frac{r}{-3}}{s}}}{\mathsf{PI}\left(\right) \cdot \left(s \cdot r\right)}, 0.125 \cdot \frac{e^{\frac{-r}{s}}}{\left(\mathsf{PI}\left(\right) \cdot s\right) \cdot r}\right)
\end{array}
Initial program 99.3%
lift-+.f32N/A
+-commutativeN/A
lift-/.f32N/A
lift-*.f32N/A
lift-*.f32N/A
lift-*.f32N/A
associate-*l*N/A
lift-*.f32N/A
associate-*l*N/A
times-fracN/A
metadata-evalN/A
metadata-evalN/A
Applied rewrites99.3%
(FPCore (s r) :precision binary32 (fma 0.125 (/ (exp (/ (- r) s)) (* (PI) (* s r))) (* 0.125 (/ (exp (/ (/ r -3.0) s)) (* (* (PI) s) r)))))
\begin{array}{l}
\\
\mathsf{fma}\left(0.125, \frac{e^{\frac{-r}{s}}}{\mathsf{PI}\left(\right) \cdot \left(s \cdot r\right)}, 0.125 \cdot \frac{e^{\frac{\frac{r}{-3}}{s}}}{\left(\mathsf{PI}\left(\right) \cdot s\right) \cdot r}\right)
\end{array}
Initial program 99.3%
lift-+.f32N/A
lift-/.f32N/A
lift-*.f32N/A
lift-*.f32N/A
lift-*.f32N/A
associate-*l*N/A
lift-*.f32N/A
associate-*l*N/A
times-fracN/A
lower-fma.f32N/A
Applied rewrites99.3%
(FPCore (s r) :precision binary32 (* 0.125 (/ (/ (+ (exp (/ (/ r -3.0) s)) (exp (/ (- r) s))) (PI)) (* s r))))
\begin{array}{l}
\\
0.125 \cdot \frac{\frac{e^{\frac{\frac{r}{-3}}{s}} + e^{\frac{-r}{s}}}{\mathsf{PI}\left(\right)}}{s \cdot r}
\end{array}
Initial program 99.3%
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
associate-*r*N/A
lower-*.f32N/A
lower-*.f3299.3
Applied rewrites99.3%
lift-/.f32N/A
lift-*.f32N/A
lift-exp.f32N/A
lift-/.f32N/A
lift-neg.f32N/A
lift-*.f32N/A
lift-*.f32N/A
lift-*.f32N/A
lift-PI.f32N/A
lift-neg.f32N/A
lift-/.f32N/A
lift-exp.f32N/A
lift-*.f32N/A
lift-PI.f32N/A
lift-*.f32N/A
lift-*.f32N/A
Applied rewrites99.3%
Applied rewrites99.2%
(FPCore (s r) :precision binary32 (/ (- (* (exp (/ (/ r -3.0) s)) 0.125) (* -0.125 (exp (/ (- r) s)))) (* (* (PI) r) s)))
\begin{array}{l}
\\
\frac{e^{\frac{\frac{r}{-3}}{s}} \cdot 0.125 - -0.125 \cdot e^{\frac{-r}{s}}}{\left(\mathsf{PI}\left(\right) \cdot r\right) \cdot s}
\end{array}
Initial program 99.3%
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
associate-*r*N/A
lower-*.f32N/A
lower-*.f3299.3
Applied rewrites99.3%
lift-/.f32N/A
lift-*.f32N/A
lift-exp.f32N/A
lift-/.f32N/A
lift-neg.f32N/A
lift-*.f32N/A
lift-*.f32N/A
lift-*.f32N/A
lift-PI.f32N/A
lift-neg.f32N/A
lift-/.f32N/A
lift-exp.f32N/A
lift-*.f32N/A
lift-PI.f32N/A
lift-*.f32N/A
lift-*.f32N/A
Applied rewrites99.3%
Applied rewrites99.2%
(FPCore (s r) :precision binary32 (fma (fma (/ (+ -0.3333333333333333 (/ (* 0.05555555555555555 r) s)) s) r 1.0) (/ 0.75 (* (* (* 6.0 (PI)) s) r)) (* 0.125 (/ (exp (/ (- r) s)) (* (* (PI) s) r)))))
\begin{array}{l}
\\
\mathsf{fma}\left(\mathsf{fma}\left(\frac{-0.3333333333333333 + \frac{0.05555555555555555 \cdot r}{s}}{s}, r, 1\right), \frac{0.75}{\left(\left(6 \cdot \mathsf{PI}\left(\right)\right) \cdot s\right) \cdot r}, 0.125 \cdot \frac{e^{\frac{-r}{s}}}{\left(\mathsf{PI}\left(\right) \cdot s\right) \cdot r}\right)
\end{array}
Initial program 99.3%
lift-+.f32N/A
+-commutativeN/A
lift-/.f32N/A
lift-*.f32N/A
*-commutativeN/A
associate-/l*N/A
lower-fma.f32N/A
Applied rewrites97.0%
Taylor expanded in r around 0
+-commutativeN/A
*-commutativeN/A
lower-fma.f32N/A
fp-cancel-sub-sign-invN/A
+-commutativeN/A
metadata-evalN/A
associate-*r/N/A
metadata-evalN/A
associate-*r/N/A
unpow2N/A
associate-/r*N/A
div-add-revN/A
lower-/.f32N/A
lower-+.f32N/A
lower-/.f32N/A
lower-*.f3210.9
Applied rewrites10.9%
(FPCore (s r) :precision binary32 (+ (/ (* 0.125 (exp (/ (- r) s))) (* (* (PI) r) s)) (/ (fma (/ (fma 0.041666666666666664 (/ r s) -0.25) s) r 0.75) (* (* r (* 6.0 (PI))) s))))
\begin{array}{l}
\\
\frac{0.125 \cdot e^{\frac{-r}{s}}}{\left(\mathsf{PI}\left(\right) \cdot r\right) \cdot s} + \frac{\mathsf{fma}\left(\frac{\mathsf{fma}\left(0.041666666666666664, \frac{r}{s}, -0.25\right)}{s}, r, 0.75\right)}{\left(r \cdot \left(6 \cdot \mathsf{PI}\left(\right)\right)\right) \cdot s}
\end{array}
Initial program 99.3%
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
associate-*r*N/A
lower-*.f32N/A
lower-*.f3299.3
Applied rewrites99.3%
lift-/.f32N/A
lift-*.f32N/A
lift-exp.f32N/A
lift-/.f32N/A
lift-neg.f32N/A
lift-*.f32N/A
lift-*.f32N/A
lift-*.f32N/A
lift-PI.f32N/A
lift-neg.f32N/A
lift-/.f32N/A
lift-exp.f32N/A
lift-*.f32N/A
lift-PI.f32N/A
lift-*.f32N/A
lift-*.f32N/A
Applied rewrites99.3%
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
metadata-evalN/A
lower-*.f3299.3
Applied rewrites99.3%
Taylor expanded in r around 0
+-commutativeN/A
*-commutativeN/A
lower-fma.f32N/A
metadata-evalN/A
fp-cancel-sign-sub-invN/A
associate-*r/N/A
unpow2N/A
associate-/r*N/A
associate-*r/N/A
metadata-evalN/A
associate-*r/N/A
metadata-evalN/A
div-add-revN/A
lower-/.f32N/A
metadata-evalN/A
lower-fma.f32N/A
lower-/.f3210.9
Applied rewrites10.9%
(FPCore (s r)
:precision binary32
(+
(/
(fma
(fma (/ (+ 0.125 (/ (* -0.041666666666666664 r) s)) (* s s)) r (/ -0.25 s))
r
0.25)
(* (* (* 2.0 (PI)) s) r))
(/
(-
(/
(+
(/
(/
(fma (* r (/ r s)) 0.0007716049382716049 (* -0.006944444444444444 r))
(PI))
s)
(/ 0.041666666666666664 (PI)))
s)
(/ 0.125 (* (PI) r)))
(- s))))\begin{array}{l}
\\
\frac{\mathsf{fma}\left(\mathsf{fma}\left(\frac{0.125 + \frac{-0.041666666666666664 \cdot r}{s}}{s \cdot s}, r, \frac{-0.25}{s}\right), r, 0.25\right)}{\left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot s\right) \cdot r} + \frac{\frac{\frac{\frac{\mathsf{fma}\left(r \cdot \frac{r}{s}, 0.0007716049382716049, -0.006944444444444444 \cdot r\right)}{\mathsf{PI}\left(\right)}}{s} + \frac{0.041666666666666664}{\mathsf{PI}\left(\right)}}{s} - \frac{0.125}{\mathsf{PI}\left(\right) \cdot r}}{-s}
\end{array}
Initial program 99.3%
Taylor expanded in s around -inf
mul-1-negN/A
distribute-neg-frac2N/A
lower-/.f32N/A
Applied rewrites10.8%
Taylor expanded in r around 0
+-commutativeN/A
*-commutativeN/A
lower-fma.f32N/A
Applied rewrites10.3%
Final simplification10.3%
(FPCore (s r)
:precision binary32
(/
(-
(/
(+
(/
(/
(fma (* r (/ r s)) 0.021604938271604937 (* r -0.06944444444444445))
(PI))
s)
(/ 0.16666666666666666 (PI)))
s)
(/ 0.25 (* (PI) r)))
(- s)))\begin{array}{l}
\\
\frac{\frac{\frac{\frac{\mathsf{fma}\left(r \cdot \frac{r}{s}, 0.021604938271604937, r \cdot -0.06944444444444445\right)}{\mathsf{PI}\left(\right)}}{s} + \frac{0.16666666666666666}{\mathsf{PI}\left(\right)}}{s} - \frac{0.25}{\mathsf{PI}\left(\right) \cdot r}}{-s}
\end{array}
Initial program 99.3%
Taylor expanded in s around inf
Applied rewrites8.9%
Applied rewrites8.9%
Taylor expanded in s around inf
associate-+r+N/A
distribute-rgt-outN/A
metadata-evalN/A
*-commutativeN/A
lower-fma.f32N/A
associate-/r*N/A
lower-/.f32N/A
lower-/.f32N/A
lower-PI.f32N/A
associate-+r+N/A
Applied rewrites10.1%
Taylor expanded in s around -inf
Applied rewrites10.3%
Final simplification10.3%
(FPCore (s r)
:precision binary32
(/
(fma
(/
(fma 0.06944444444444445 (/ (/ r s) (PI)) (/ -0.16666666666666666 (PI)))
s)
r
(/ 0.25 (PI)))
(* s r)))\begin{array}{l}
\\
\frac{\mathsf{fma}\left(\frac{\mathsf{fma}\left(0.06944444444444445, \frac{\frac{r}{s}}{\mathsf{PI}\left(\right)}, \frac{-0.16666666666666666}{\mathsf{PI}\left(\right)}\right)}{s}, r, \frac{0.25}{\mathsf{PI}\left(\right)}\right)}{s \cdot r}
\end{array}
Initial program 99.3%
Taylor expanded in s around inf
Applied rewrites8.9%
Applied rewrites8.9%
Taylor expanded in r around 0
Applied rewrites10.2%
(FPCore (s r) :precision binary32 (/ (- (fma 0.06944444444444445 (/ r (* (* s s) (PI))) (/ 0.25 (* (PI) r))) (/ 0.16666666666666666 (* (PI) s))) s))
\begin{array}{l}
\\
\frac{\mathsf{fma}\left(0.06944444444444445, \frac{r}{\left(s \cdot s\right) \cdot \mathsf{PI}\left(\right)}, \frac{0.25}{\mathsf{PI}\left(\right) \cdot r}\right) - \frac{0.16666666666666666}{\mathsf{PI}\left(\right) \cdot s}}{s}
\end{array}
Initial program 99.3%
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
associate-*r*N/A
lower-*.f32N/A
lower-*.f3299.3
Applied rewrites99.3%
lift-/.f32N/A
lift-*.f32N/A
lift-exp.f32N/A
lift-/.f32N/A
lift-neg.f32N/A
lift-*.f32N/A
lift-*.f32N/A
lift-*.f32N/A
lift-PI.f32N/A
lift-neg.f32N/A
lift-/.f32N/A
lift-exp.f32N/A
lift-*.f32N/A
lift-PI.f32N/A
lift-*.f32N/A
lift-*.f32N/A
Applied rewrites99.3%
Taylor expanded in s around inf
lower-/.f32N/A
Applied rewrites10.2%
(FPCore (s r) :precision binary32 (/ (/ (fma (/ r s) -0.16666666666666666 0.25) (PI)) (* s r)))
\begin{array}{l}
\\
\frac{\frac{\mathsf{fma}\left(\frac{r}{s}, -0.16666666666666666, 0.25\right)}{\mathsf{PI}\left(\right)}}{s \cdot r}
\end{array}
Initial program 99.3%
Taylor expanded in s around inf
Applied rewrites8.9%
Applied rewrites8.9%
Taylor expanded in s around inf
associate-+r+N/A
distribute-rgt-outN/A
metadata-evalN/A
*-commutativeN/A
lower-fma.f32N/A
associate-/r*N/A
lower-/.f32N/A
lower-/.f32N/A
lower-PI.f32N/A
associate-+r+N/A
Applied rewrites10.1%
Taylor expanded in s around inf
associate-+r+N/A
distribute-rgt-outN/A
associate-/r*N/A
metadata-evalN/A
associate-*l/N/A
associate-*r/N/A
metadata-evalN/A
div-add-revN/A
lower-/.f32N/A
lower-fma.f32N/A
lower-/.f32N/A
lower-PI.f328.9
Applied rewrites8.9%
(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 99.3%
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.f328.7
Applied rewrites8.7%
Applied rewrites8.7%
(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 99.3%
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.f328.7
Applied rewrites8.7%
Applied rewrites8.7%
(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 99.3%
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.f328.7
Applied rewrites8.7%
Applied rewrites8.7%
(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 99.3%
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.f328.7
Applied rewrites8.7%
Applied rewrites8.7%
Applied rewrites8.7%
herbie shell --seed 2024366
(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))))