
(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 (fma 0.125 (/ (/ 1.0 (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{\frac{1}{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 rewrites99.4%
lift-exp.f32N/A
lift-/.f32N/A
lift-/.f32N/A
frac-2negN/A
lift-neg.f32N/A
metadata-evalN/A
associate-/r*N/A
lift-neg.f32N/A
lift-neg.f32N/A
lift-*.f32N/A
lift-/.f32N/A
sinh-+-cosh-revN/A
flip-+N/A
sinh-coshN/A
sinh---cosh-revN/A
lower-/.f32N/A
lower-exp.f32N/A
lower-neg.f3299.4
Applied rewrites99.4%
Final simplification99.4%
(FPCore (s r) :precision binary32 (fma 0.125 (/ (/ 1.0 (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{\frac{1}{e^{\frac{r}{3 \cdot 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 rewrites99.4%
lift-exp.f32N/A
lift-/.f32N/A
lift-/.f32N/A
frac-2negN/A
lift-neg.f32N/A
metadata-evalN/A
associate-/r*N/A
lift-neg.f32N/A
lift-neg.f32N/A
lift-*.f32N/A
lift-/.f32N/A
sinh-+-cosh-revN/A
flip-+N/A
sinh-coshN/A
sinh---cosh-revN/A
lower-/.f32N/A
lower-exp.f32N/A
lower-neg.f3299.4
Applied rewrites99.4%
lift-neg.f32N/A
lift-/.f32N/A
distribute-neg-fracN/A
lift-/.f32N/A
distribute-neg-frac2N/A
metadata-evalN/A
associate-/r*N/A
lower-/.f32N/A
lower-*.f3299.4
Applied rewrites99.4%
(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 rewrites99.4%
(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 99.3%
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 rewrites99.4%
(FPCore (s r) :precision binary32 (fma 0.125 (/ (exp (* -0.3333333333333333 (/ r s))) (* (PI) (* s r))) (* 0.125 (/ (exp (/ (- r) s)) (* (* (PI) s) r)))))
\begin{array}{l}
\\
\mathsf{fma}\left(0.125, \frac{e^{-0.3333333333333333 \cdot \frac{r}{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 rewrites99.4%
Taylor expanded in s around 0
lower-*.f32N/A
lower-/.f3299.3
Applied rewrites99.3%
(FPCore (s r) :precision binary32 (* (/ (+ (exp (/ (/ r -3.0) s)) (exp (/ (- r) s))) (* (* s r) (PI))) 0.125))
\begin{array}{l}
\\
\frac{e^{\frac{\frac{r}{-3}}{s}} + e^{\frac{-r}{s}}}{\left(s \cdot r\right) \cdot \mathsf{PI}\left(\right)} \cdot 0.125
\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 rewrites99.4%
lift-fma.f32N/A
lift-*.f32N/A
distribute-lft-outN/A
*-commutativeN/A
lower-*.f32N/A
Applied rewrites99.3%
(FPCore (s r)
:precision binary32
(fma
0.125
(/
(/
1.0
(fma
(fma (/ r (* s s)) 0.05555555555555555 (/ 0.3333333333333333 s))
r
1.0))
(* (PI) (* s r)))
(* 0.125 (/ (exp (/ (- r) s)) (* (* (PI) s) r)))))\begin{array}{l}
\\
\mathsf{fma}\left(0.125, \frac{\frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(\frac{r}{s \cdot s}, 0.05555555555555555, \frac{0.3333333333333333}{s}\right), r, 1\right)}}{\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 rewrites99.4%
lift-exp.f32N/A
lift-/.f32N/A
lift-/.f32N/A
frac-2negN/A
lift-neg.f32N/A
metadata-evalN/A
associate-/r*N/A
lift-neg.f32N/A
lift-neg.f32N/A
lift-*.f32N/A
lift-/.f32N/A
sinh-+-cosh-revN/A
flip-+N/A
sinh-coshN/A
sinh---cosh-revN/A
lower-/.f32N/A
lower-exp.f32N/A
lower-neg.f3299.4
Applied rewrites99.4%
Taylor expanded in r around 0
+-commutativeN/A
*-commutativeN/A
lower-fma.f32N/A
*-commutativeN/A
lower-fma.f32N/A
lower-/.f32N/A
unpow2N/A
lower-*.f32N/A
associate-*r/N/A
metadata-evalN/A
lower-/.f3260.6
Applied rewrites60.6%
(FPCore (s r) :precision binary32 (fma 0.125 (/ (/ 1.0 (fma 0.3333333333333333 (/ r s) 1.0)) (* (PI) (* s r))) (* 0.125 (/ (exp (/ (- r) s)) (* (* (PI) s) r)))))
\begin{array}{l}
\\
\mathsf{fma}\left(0.125, \frac{\frac{1}{\mathsf{fma}\left(0.3333333333333333, \frac{r}{s}, 1\right)}}{\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 rewrites99.4%
lift-exp.f32N/A
lift-/.f32N/A
lift-/.f32N/A
frac-2negN/A
lift-neg.f32N/A
metadata-evalN/A
associate-/r*N/A
lift-neg.f32N/A
lift-neg.f32N/A
lift-*.f32N/A
lift-/.f32N/A
sinh-+-cosh-revN/A
flip-+N/A
sinh-coshN/A
sinh---cosh-revN/A
lower-/.f32N/A
lower-exp.f32N/A
lower-neg.f3299.4
Applied rewrites99.4%
Taylor expanded in s around inf
+-commutativeN/A
lower-fma.f32N/A
lower-/.f3214.9
Applied rewrites14.9%
(FPCore (s r) :precision binary32 (/ (fma (/ r (* (* s s) (PI))) 0.06944444444444445 (/ (fma -0.16666666666666666 (/ 1.0 s) (/ 0.25 r)) (PI))) s))
\begin{array}{l}
\\
\frac{\mathsf{fma}\left(\frac{r}{\left(s \cdot s\right) \cdot \mathsf{PI}\left(\right)}, 0.06944444444444445, \frac{\mathsf{fma}\left(-0.16666666666666666, \frac{1}{s}, \frac{0.25}{r}\right)}{\mathsf{PI}\left(\right)}\right)}{s}
\end{array}
Initial program 99.3%
Taylor expanded in s around inf
lower-/.f32N/A
Applied rewrites10.0%
(FPCore (s r) :precision binary32 (/ (- (fma (/ r (* (* s s) (PI))) 0.06944444444444445 (/ 0.25 (* (PI) r))) (/ 0.16666666666666666 (* (PI) s))) s))
\begin{array}{l}
\\
\frac{\mathsf{fma}\left(\frac{r}{\left(s \cdot s\right) \cdot \mathsf{PI}\left(\right)}, 0.06944444444444445, \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%
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.f328.8
Applied rewrites8.8%
Applied rewrites8.8%
Taylor expanded in s around inf
lower-/.f32N/A
Applied rewrites10.0%
(FPCore (s r) :precision binary32 (/ (/ (fma -0.25 (/ 1.0 r) (/ 0.16666666666666666 s)) (PI)) (- s)))
\begin{array}{l}
\\
\frac{\frac{\mathsf{fma}\left(-0.25, \frac{1}{r}, \frac{0.16666666666666666}{s}\right)}{\mathsf{PI}\left(\right)}}{-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 rewrites9.2%
(FPCore (s r) :precision binary32 (/ (/ (fma -0.16666666666666666 (/ 1.0 s) (/ 0.25 r)) (PI)) s))
\begin{array}{l}
\\
\frac{\frac{\mathsf{fma}\left(-0.16666666666666666, \frac{1}{s}, \frac{0.25}{r}\right)}{\mathsf{PI}\left(\right)}}{s}
\end{array}
Initial program 99.3%
Taylor expanded in s around inf
lower-/.f32N/A
fp-cancel-sub-sign-invN/A
+-commutativeN/A
metadata-evalN/A
associate-/r*N/A
associate-*r/N/A
associate-*r/N/A
metadata-evalN/A
associate-/r*N/A
div-add-revN/A
lower-/.f32N/A
lower-fma.f32N/A
lower-/.f32N/A
lower-/.f32N/A
lower-PI.f329.2
Applied rewrites9.2%
(FPCore (s r) :precision binary32 (/ (- (/ 0.25 (* (PI) r)) (/ 0.16666666666666666 (* (PI) s))) s))
\begin{array}{l}
\\
\frac{\frac{0.25}{\mathsf{PI}\left(\right) \cdot r} - \frac{0.16666666666666666}{\mathsf{PI}\left(\right) \cdot s}}{s}
\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 rewrites99.4%
lift-exp.f32N/A
lift-/.f32N/A
lift-/.f32N/A
frac-2negN/A
lift-neg.f32N/A
metadata-evalN/A
associate-/r*N/A
lift-neg.f32N/A
lift-neg.f32N/A
lift-*.f32N/A
lift-/.f32N/A
sinh-+-cosh-revN/A
flip-+N/A
sinh-coshN/A
sinh---cosh-revN/A
lower-/.f32N/A
lower-exp.f32N/A
lower-neg.f3299.4
Applied rewrites99.4%
Taylor expanded in s around inf
associate-*r/N/A
metadata-evalN/A
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
lower-/.f32N/A
*-commutativeN/A
lower-*.f32N/A
lower-PI.f329.2
Applied rewrites9.2%
(FPCore (s r) :precision binary32 (/ (/ 0.25 s) (* (PI) r)))
\begin{array}{l}
\\
\frac{\frac{0.25}{s}}{\mathsf{PI}\left(\right) \cdot 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.f328.8
Applied rewrites8.8%
Applied rewrites8.8%
Applied rewrites8.8%
(FPCore (s r) :precision binary32 (/ -0.25 (* s (* (- r) (PI)))))
\begin{array}{l}
\\
\frac{-0.25}{s \cdot \left(\left(-r\right) \cdot \mathsf{PI}\left(\right)\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.f328.8
Applied rewrites8.8%
Applied rewrites8.8%
Applied rewrites8.8%
(FPCore (s r) :precision binary32 (/ 0.25 (* (* (PI) s) r)))
\begin{array}{l}
\\
\frac{0.25}{\left(\mathsf{PI}\left(\right) \cdot s\right) \cdot 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.f328.8
Applied rewrites8.8%
Applied rewrites8.8%
Taylor expanded in s around 0
Applied rewrites8.8%
herbie shell --seed 2024351
(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))))