
(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 20 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 (+ (/ (* 0.125 (exp (/ (- r) s))) (* (* (PI) s) r)) (/ (* 0.75 (exp (/ (/ r s) -3.0))) (* (* s r) (* 6.0 (PI))))))
\begin{array}{l}
\\
\frac{0.125 \cdot e^{\frac{-r}{s}}}{\left(\mathsf{PI}\left(\right) \cdot s\right) \cdot r} + \frac{0.75 \cdot e^{\frac{\frac{r}{s}}{-3}}}{\left(s \cdot r\right) \cdot \left(6 \cdot \mathsf{PI}\left(\right)\right)}
\end{array}
Initial program 99.2%
lift-*.f32N/A
lift-*.f32N/A
associate-*l*N/A
*-commutativeN/A
lower-*.f32N/A
lower-*.f3299.3
Applied rewrites99.3%
lift-/.f32N/A
lift-*.f32N/A
*-commutativeN/A
associate-/r*N/A
lift-/.f32N/A
frac-2negN/A
lift-/.f32N/A
distribute-frac-neg2N/A
lift-neg.f32N/A
frac-2negN/A
lift-/.f32N/A
metadata-evalN/A
lower-/.f3299.3
Applied rewrites99.3%
lift-/.f32N/A
lift-*.f32N/A
lift-exp.f32N/A
lift-neg.f32N/A
lift-/.f32N/A
lift-*.f32N/A
lift-*.f32N/A
lift-*.f32N/A
lift-PI.f32N/A
lift-/.f32N/A
lift-neg.f32N/A
lift-exp.f32N/A
lift-PI.f32N/A
lift-*.f32N/A
lift-*.f32N/A
Applied rewrites99.3%
(FPCore (s r) :precision binary32 (+ (/ (* 0.125 (exp (/ (- r) s))) (* (* (PI) s) r)) (/ (* 0.75 (exp (/ r (* -3.0 s)))) (* (* s r) (* 6.0 (PI))))))
\begin{array}{l}
\\
\frac{0.125 \cdot 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(s \cdot r\right) \cdot \left(6 \cdot \mathsf{PI}\left(\right)\right)}
\end{array}
Initial program 99.2%
lift-*.f32N/A
lift-*.f32N/A
associate-*l*N/A
*-commutativeN/A
lower-*.f32N/A
lower-*.f3299.3
Applied rewrites99.3%
lift-/.f32N/A
lift-*.f32N/A
*-commutativeN/A
associate-/r*N/A
lift-/.f32N/A
frac-2negN/A
lift-/.f32N/A
distribute-frac-neg2N/A
lift-neg.f32N/A
frac-2negN/A
lift-/.f32N/A
metadata-evalN/A
lower-/.f3299.3
Applied rewrites99.3%
lift-/.f32N/A
lift-*.f32N/A
lift-exp.f32N/A
lift-neg.f32N/A
lift-/.f32N/A
lift-*.f32N/A
lift-*.f32N/A
lift-*.f32N/A
lift-PI.f32N/A
lift-/.f32N/A
lift-neg.f32N/A
lift-exp.f32N/A
lift-PI.f32N/A
lift-*.f32N/A
lift-*.f32N/A
Applied rewrites99.3%
lift-/.f32N/A
frac-2negN/A
lift-/.f32N/A
distribute-neg-frac2N/A
metadata-evalN/A
associate-/l/N/A
distribute-lft-neg-inN/A
*-commutativeN/A
lower-/.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) 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 99.2%
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 (fma 0.125 (/ (exp (/ (- r) s)) (* (PI) (* s r))) (* 0.125 (/ (exp (/ (/ r -3.0) s)) (* (* (PI) r) s)))))
\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 r\right) \cdot s}\right)
\end{array}
Initial program 99.2%
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%
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
associate-*r*N/A
*-commutativeN/A
lift-*.f32N/A
lower-*.f3299.3
Applied rewrites99.3%
(FPCore (s r) :precision binary32 (/ (fma (/ (exp (/ (/ r -3.0) s)) (PI)) 0.125 (* (/ (exp (/ (- r) s)) (PI)) 0.125)) (* s r)))
\begin{array}{l}
\\
\frac{\mathsf{fma}\left(\frac{e^{\frac{\frac{r}{-3}}{s}}}{\mathsf{PI}\left(\right)}, 0.125, \frac{e^{\frac{-r}{s}}}{\mathsf{PI}\left(\right)} \cdot 0.125\right)}{s \cdot r}
\end{array}
Initial program 99.2%
lift-+.f32N/A
+-commutativeN/A
lift-/.f32N/A
lift-*.f32N/A
lift-*.f32N/A
associate-*l*N/A
associate-/r*N/A
lift-/.f32N/A
lift-*.f32N/A
lift-*.f32N/A
associate-*l*N/A
associate-/r*N/A
Applied rewrites99.2%
(FPCore (s r) :precision binary32 (/ (/ (* (/ (+ (exp (/ (- r) s)) (exp (/ (/ r -3.0) s))) (PI)) 0.125) r) s))
\begin{array}{l}
\\
\frac{\frac{\frac{e^{\frac{-r}{s}} + e^{\frac{\frac{r}{-3}}{s}}}{\mathsf{PI}\left(\right)} \cdot 0.125}{r}}{s}
\end{array}
Initial program 99.2%
lift-*.f32N/A
lift-*.f32N/A
associate-*l*N/A
*-commutativeN/A
lower-*.f32N/A
lower-*.f3299.3
Applied rewrites99.3%
Applied rewrites99.2%
(FPCore (s r) :precision binary32 (/ (* (/ (+ (exp (/ (- r) s)) (exp (/ (/ r -3.0) s))) (PI)) 0.125) (* s r)))
\begin{array}{l}
\\
\frac{\frac{e^{\frac{-r}{s}} + e^{\frac{\frac{r}{-3}}{s}}}{\mathsf{PI}\left(\right)} \cdot 0.125}{s \cdot r}
\end{array}
Initial program 99.2%
lift-*.f32N/A
lift-*.f32N/A
associate-*l*N/A
*-commutativeN/A
lower-*.f32N/A
lower-*.f3299.3
Applied rewrites99.3%
Applied rewrites99.2%
(FPCore (s r) :precision binary32 (* (/ (+ (exp (/ (- r) s)) (exp (/ (/ r -3.0) s))) (* (* (PI) s) r)) 0.125))
\begin{array}{l}
\\
\frac{e^{\frac{-r}{s}} + e^{\frac{\frac{r}{-3}}{s}}}{\left(\mathsf{PI}\left(\right) \cdot s\right) \cdot r} \cdot 0.125
\end{array}
Initial program 99.2%
lift-*.f32N/A
lift-*.f32N/A
associate-*l*N/A
*-commutativeN/A
lower-*.f32N/A
lower-*.f3299.3
Applied rewrites99.3%
lift-/.f32N/A
lift-*.f32N/A
*-commutativeN/A
associate-/r*N/A
lift-/.f32N/A
frac-2negN/A
lift-/.f32N/A
distribute-frac-neg2N/A
lift-neg.f32N/A
frac-2negN/A
lift-/.f32N/A
metadata-evalN/A
lower-/.f3299.3
Applied rewrites99.3%
Applied rewrites99.2%
(FPCore (s r)
:precision binary32
(+
(/ (* 0.125 (exp (/ (- r) s))) (* (* (PI) s) r))
(/
(+
(/ 0.125 (* (PI) r))
(/ (/ (fma (/ r s) 0.006944444444444444 -0.041666666666666664) (PI)) s))
s)))\begin{array}{l}
\\
\frac{0.125 \cdot e^{\frac{-r}{s}}}{\left(\mathsf{PI}\left(\right) \cdot s\right) \cdot r} + \frac{\frac{0.125}{\mathsf{PI}\left(\right) \cdot r} + \frac{\frac{\mathsf{fma}\left(\frac{r}{s}, 0.006944444444444444, -0.041666666666666664\right)}{\mathsf{PI}\left(\right)}}{s}}{s}
\end{array}
Initial program 99.2%
lift-*.f32N/A
lift-*.f32N/A
associate-*l*N/A
*-commutativeN/A
lower-*.f32N/A
lower-*.f3299.3
Applied rewrites99.3%
lift-/.f32N/A
lift-*.f32N/A
*-commutativeN/A
associate-/r*N/A
lift-/.f32N/A
frac-2negN/A
lift-/.f32N/A
distribute-frac-neg2N/A
lift-neg.f32N/A
frac-2negN/A
lift-/.f32N/A
metadata-evalN/A
lower-/.f3299.3
Applied rewrites99.3%
lift-/.f32N/A
lift-*.f32N/A
lift-exp.f32N/A
lift-neg.f32N/A
lift-/.f32N/A
lift-*.f32N/A
lift-*.f32N/A
lift-*.f32N/A
lift-PI.f32N/A
lift-/.f32N/A
lift-neg.f32N/A
lift-exp.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 rewrites12.2%
(FPCore (s r) :precision binary32 (+ (/ (* 0.125 (exp (/ (- r) s))) (* (* (PI) s) r)) (/ (fma (/ (+ -0.25 (/ (* 0.041666666666666664 r) s)) s) r 0.75) (* (* s r) (* 6.0 (PI))))))
\begin{array}{l}
\\
\frac{0.125 \cdot e^{\frac{-r}{s}}}{\left(\mathsf{PI}\left(\right) \cdot s\right) \cdot r} + \frac{\mathsf{fma}\left(\frac{-0.25 + \frac{0.041666666666666664 \cdot r}{s}}{s}, r, 0.75\right)}{\left(s \cdot r\right) \cdot \left(6 \cdot \mathsf{PI}\left(\right)\right)}
\end{array}
Initial program 99.2%
lift-*.f32N/A
lift-*.f32N/A
associate-*l*N/A
*-commutativeN/A
lower-*.f32N/A
lower-*.f3299.3
Applied rewrites99.3%
lift-/.f32N/A
lift-*.f32N/A
*-commutativeN/A
associate-/r*N/A
lift-/.f32N/A
frac-2negN/A
lift-/.f32N/A
distribute-frac-neg2N/A
lift-neg.f32N/A
frac-2negN/A
lift-/.f32N/A
metadata-evalN/A
lower-/.f3299.3
Applied rewrites99.3%
lift-/.f32N/A
lift-*.f32N/A
lift-exp.f32N/A
lift-neg.f32N/A
lift-/.f32N/A
lift-*.f32N/A
lift-*.f32N/A
lift-*.f32N/A
lift-PI.f32N/A
lift-/.f32N/A
lift-neg.f32N/A
lift-exp.f32N/A
lift-PI.f32N/A
lift-*.f32N/A
lift-*.f32N/A
Applied rewrites99.3%
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-*.f3212.1
Applied rewrites12.1%
(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 99.2%
lift-*.f32N/A
lift-*.f32N/A
associate-*l*N/A
*-commutativeN/A
lower-*.f32N/A
lower-*.f3299.3
Applied rewrites99.3%
Taylor expanded in s around inf
lower-/.f32N/A
Applied rewrites11.4%
Final simplification11.4%
(FPCore (s r) :precision binary32 (/ (+ (/ (/ (fma 0.06944444444444445 (/ r s) -0.16666666666666666) (PI)) s) (/ 0.25 (* (PI) r))) s))
\begin{array}{l}
\\
\frac{\frac{\frac{\mathsf{fma}\left(0.06944444444444445, \frac{r}{s}, -0.16666666666666666\right)}{\mathsf{PI}\left(\right)}}{s} + \frac{0.25}{\mathsf{PI}\left(\right) \cdot r}}{s}
\end{array}
Initial program 99.2%
Applied rewrites99.2%
Taylor expanded in s around -inf
mul-1-negN/A
distribute-neg-frac2N/A
lower-/.f32N/A
Applied rewrites11.4%
Applied rewrites11.4%
Final simplification11.4%
(FPCore (s r) :precision binary32 (/ (/ (- 1.5 (/ r s)) s) (* (* 6.0 (PI)) r)))
\begin{array}{l}
\\
\frac{\frac{1.5 - \frac{r}{s}}{s}}{\left(6 \cdot \mathsf{PI}\left(\right)\right) \cdot r}
\end{array}
Initial program 99.2%
Taylor expanded in s around inf
+-commutativeN/A
lower-fma.f32N/A
lower-/.f3210.2
Applied rewrites10.2%
Applied rewrites10.1%
Taylor expanded in s around inf
lower-/.f32N/A
distribute-rgt-outN/A
metadata-evalN/A
*-commutativeN/A
fp-cancel-sign-sub-invN/A
metadata-evalN/A
*-lft-identityN/A
lower--.f32N/A
lower-/.f3210.2
Applied rewrites10.2%
(FPCore (s r) :precision binary32 (/ (/ (fma -0.16666666666666666 (/ r s) 0.25) s) (* (PI) r)))
\begin{array}{l}
\\
\frac{\frac{\mathsf{fma}\left(-0.16666666666666666, \frac{r}{s}, 0.25\right)}{s}}{\mathsf{PI}\left(\right) \cdot r}
\end{array}
Initial program 99.2%
Taylor expanded in r around 0
lower-/.f32N/A
Applied rewrites10.1%
Applied rewrites10.1%
(FPCore (s r) :precision binary32 (/ (/ (fma (/ s r) 0.25 -0.16666666666666666) (PI)) (* s s)))
\begin{array}{l}
\\
\frac{\frac{\mathsf{fma}\left(\frac{s}{r}, 0.25, -0.16666666666666666\right)}{\mathsf{PI}\left(\right)}}{s \cdot s}
\end{array}
Initial program 99.2%
Taylor expanded in r around 0
lower-/.f32N/A
Applied rewrites10.1%
Taylor expanded in s around 0
Applied rewrites10.1%
(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 99.2%
Applied rewrites99.2%
Taylor expanded in s around inf
lower-/.f32N/A
lower-PI.f329.9
Applied rewrites9.9%
(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 99.2%
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.f329.9
Applied rewrites9.9%
(FPCore (s r) :precision binary32 (/ (/ 0.25 (* s r)) (PI)))
\begin{array}{l}
\\
\frac{\frac{0.25}{s \cdot r}}{\mathsf{PI}\left(\right)}
\end{array}
Initial program 99.2%
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.f329.9
Applied rewrites9.9%
Applied rewrites9.9%
Applied rewrites9.9%
(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 99.2%
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.f329.9
Applied rewrites9.9%
Applied rewrites9.9%
Applied rewrites9.9%
(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 99.2%
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.f329.9
Applied rewrites9.9%
Applied rewrites9.9%
Applied rewrites9.9%
herbie shell --seed 2024364
(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))))