
(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 21 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 (/ 0.75 s) (/ (/ (exp (/ (/ r -3.0) s)) r) (* 6.0 (PI))) (* 0.125 (/ (exp (/ (- r) s)) (* (* (PI) s) r)))))
\begin{array}{l}
\\
\mathsf{fma}\left(\frac{0.75}{s}, \frac{\frac{e^{\frac{\frac{r}{-3}}{s}}}{r}}{6 \cdot \mathsf{PI}\left(\right)}, 0.125 \cdot \frac{e^{\frac{-r}{s}}}{\left(\mathsf{PI}\left(\right) \cdot s\right) \cdot r}\right)
\end{array}
Initial program 99.5%
lift-+.f32N/A
+-commutativeN/A
lift-/.f32N/A
lift-*.f32N/A
lift-*.f32N/A
times-fracN/A
associate-*l/N/A
lift-*.f32N/A
*-commutativeN/A
times-fracN/A
Applied rewrites99.7%
(FPCore (s r)
:precision binary32
(let* ((t_0 (* (PI) s)))
(fma
(/ (exp (/ (/ r -3.0) s)) (* (* t_0 6.0) r))
0.75
(* (/ 0.125 r) (/ (exp (/ (- r) s)) t_0)))))\begin{array}{l}
\\
\begin{array}{l}
t_0 := \mathsf{PI}\left(\right) \cdot s\\
\mathsf{fma}\left(\frac{e^{\frac{\frac{r}{-3}}{s}}}{\left(t\_0 \cdot 6\right) \cdot r}, 0.75, \frac{0.125}{r} \cdot \frac{e^{\frac{-r}{s}}}{t\_0}\right)
\end{array}
\end{array}
Initial program 99.5%
lift-+.f32N/A
+-commutativeN/A
lift-/.f32N/A
lift-*.f32N/A
lift-*.f32N/A
times-fracN/A
associate-*l/N/A
lift-*.f32N/A
*-commutativeN/A
times-fracN/A
Applied rewrites99.7%
Applied rewrites99.6%
(FPCore (s r) :precision binary32 (/ (fma (/ (exp (/ (- r) s)) (PI)) 0.125 (/ (* -0.75 (exp (/ (/ r -3.0) s))) (* -6.0 (PI)))) (* r s)))
\begin{array}{l}
\\
\frac{\mathsf{fma}\left(\frac{e^{\frac{-r}{s}}}{\mathsf{PI}\left(\right)}, 0.125, \frac{-0.75 \cdot e^{\frac{\frac{r}{-3}}{s}}}{-6 \cdot \mathsf{PI}\left(\right)}\right)}{r \cdot s}
\end{array}
Initial program 99.5%
lift-+.f32N/A
+-commutativeN/A
lift-/.f32N/A
lift-*.f32N/A
lift-*.f32N/A
times-fracN/A
associate-*l/N/A
lift-*.f32N/A
*-commutativeN/A
times-fracN/A
Applied rewrites99.7%
Applied rewrites99.6%
(FPCore (s r) :precision binary32 (/ (/ (* 0.125 (+ (exp (/ (- r) s)) (exp (/ (/ r -3.0) s)))) r) (* (PI) s)))
\begin{array}{l}
\\
\frac{\frac{0.125 \cdot \left(e^{\frac{-r}{s}} + e^{\frac{\frac{r}{-3}}{s}}\right)}{r}}{\mathsf{PI}\left(\right) \cdot s}
\end{array}
Initial program 99.5%
lift-+.f32N/A
+-commutativeN/A
lift-/.f32N/A
lift-*.f32N/A
lift-*.f32N/A
times-fracN/A
associate-*l/N/A
lift-*.f32N/A
*-commutativeN/A
times-fracN/A
Applied rewrites99.7%
Applied rewrites99.6%
Applied rewrites99.6%
(FPCore (s r) :precision binary32 (* 0.125 (/ (/ (+ (exp (/ (- r) s)) (exp (/ (/ r -3.0) s))) (PI)) (* r s))))
\begin{array}{l}
\\
0.125 \cdot \frac{\frac{e^{\frac{-r}{s}} + e^{\frac{\frac{r}{-3}}{s}}}{\mathsf{PI}\left(\right)}}{r \cdot s}
\end{array}
Initial program 99.5%
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 rewrites99.6%
lift-/.f32N/A
lift-fma.f32N/A
lift-*.f32N/A
distribute-rgt-outN/A
associate-/l*N/A
lower-*.f32N/A
lower-/.f32N/A
Applied rewrites99.6%
(FPCore (s r) :precision binary32 (/ (fma (exp (/ (- r) s)) 0.125 (* 0.125 (exp (/ (/ r -3.0) s)))) (* (* r s) (PI))))
\begin{array}{l}
\\
\frac{\mathsf{fma}\left(e^{\frac{-r}{s}}, 0.125, 0.125 \cdot e^{\frac{\frac{r}{-3}}{s}}\right)}{\left(r \cdot s\right) \cdot \mathsf{PI}\left(\right)}
\end{array}
Initial program 99.5%
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 rewrites99.6%
lift-/.f32N/A
lift-fma.f32N/A
+-commutativeN/A
div-addN/A
Applied rewrites99.5%
lift-*.f32N/A
lift-*.f32N/A
associate-*l*N/A
*-commutativeN/A
lower-*.f32N/A
*-commutativeN/A
lower-*.f3299.6
Applied rewrites99.6%
(FPCore (s r) :precision binary32 (/ (* 0.125 (+ (exp (/ (/ r -3.0) s)) (exp (/ (- r) s)))) (* (* (PI) s) r)))
\begin{array}{l}
\\
\frac{0.125 \cdot \left(e^{\frac{\frac{r}{-3}}{s}} + e^{\frac{-r}{s}}\right)}{\left(\mathsf{PI}\left(\right) \cdot s\right) \cdot r}
\end{array}
Initial program 99.5%
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 rewrites99.6%
lift-/.f32N/A
lift-fma.f32N/A
+-commutativeN/A
div-addN/A
Applied rewrites99.5%
lift-fma.f32N/A
+-commutativeN/A
lift-*.f32N/A
*-commutativeN/A
distribute-lft-outN/A
lower-*.f32N/A
lower-+.f3299.5
Applied rewrites99.5%
(FPCore (s r) :precision binary32 (/ (fma (exp (/ (- r) s)) 0.125 (* 0.125 (exp (* -0.3333333333333333 (/ r s))))) (* (* (PI) s) r)))
\begin{array}{l}
\\
\frac{\mathsf{fma}\left(e^{\frac{-r}{s}}, 0.125, 0.125 \cdot e^{-0.3333333333333333 \cdot \frac{r}{s}}\right)}{\left(\mathsf{PI}\left(\right) \cdot s\right) \cdot r}
\end{array}
Initial program 99.5%
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 rewrites99.6%
lift-/.f32N/A
lift-fma.f32N/A
+-commutativeN/A
div-addN/A
Applied rewrites99.5%
Taylor expanded in s around 0
lower-*.f32N/A
lower-/.f3299.5
Applied rewrites99.5%
(FPCore (s r)
:precision binary32
(let* ((t_0 (* (* (PI) s) r)))
(fma
(/
(fma
(fma (/ (/ 0.05555555555555555 s) s) r (/ -0.3333333333333333 s))
r
1.0)
6.0)
(/ 0.75 t_0)
(* 0.125 (/ (exp (/ (- r) s)) t_0)))))\begin{array}{l}
\\
\begin{array}{l}
t_0 := \left(\mathsf{PI}\left(\right) \cdot s\right) \cdot r\\
\mathsf{fma}\left(\frac{\mathsf{fma}\left(\mathsf{fma}\left(\frac{\frac{0.05555555555555555}{s}}{s}, r, \frac{-0.3333333333333333}{s}\right), r, 1\right)}{6}, \frac{0.75}{t\_0}, 0.125 \cdot \frac{e^{\frac{-r}{s}}}{t\_0}\right)
\end{array}
\end{array}
Initial program 99.5%
lift-+.f32N/A
+-commutativeN/A
lift-/.f32N/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
lift-*.f32N/A
lift-*.f32N/A
associate-*l*N/A
associate-*l*N/A
times-fracN/A
Applied rewrites97.6%
Taylor expanded in r around 0
+-commutativeN/A
*-commutativeN/A
lower-fma.f32N/A
Applied rewrites11.0%
(FPCore (s r)
:precision binary32
(let* ((t_0 (* (* (PI) s) r)))
(fma
(/
(-
1.0
(/ (fma 0.3333333333333333 r (* (* r (/ r s)) -0.05555555555555555)) s))
6.0)
(/ 0.75 t_0)
(* 0.125 (/ (exp (/ (- r) s)) t_0)))))\begin{array}{l}
\\
\begin{array}{l}
t_0 := \left(\mathsf{PI}\left(\right) \cdot s\right) \cdot r\\
\mathsf{fma}\left(\frac{1 - \frac{\mathsf{fma}\left(0.3333333333333333, r, \left(r \cdot \frac{r}{s}\right) \cdot -0.05555555555555555\right)}{s}}{6}, \frac{0.75}{t\_0}, 0.125 \cdot \frac{e^{\frac{-r}{s}}}{t\_0}\right)
\end{array}
\end{array}
Initial program 99.5%
lift-+.f32N/A
+-commutativeN/A
lift-/.f32N/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
lift-*.f32N/A
lift-*.f32N/A
associate-*l*N/A
associate-*l*N/A
times-fracN/A
Applied rewrites97.6%
Taylor expanded in s around inf
associate-+r+N/A
fp-cancel-sign-sub-invN/A
associate-+l-N/A
metadata-evalN/A
associate-*r/N/A
associate-*r/N/A
unpow2N/A
associate-/r*N/A
div-subN/A
associate-/l*N/A
metadata-evalN/A
fp-cancel-sign-sub-invN/A
+-commutativeN/A
lower--.f32N/A
lower-/.f32N/A
Applied rewrites11.0%
(FPCore (s r)
:precision binary32
(let* ((t_0 (* (* (PI) s) r)))
(fma
(-
0.16666666666666666
(/ (fma (* r (/ r s)) -0.009259259259259259 (* 0.05555555555555555 r)) s))
(/ 0.75 t_0)
(* 0.125 (/ (exp (/ (- r) s)) t_0)))))\begin{array}{l}
\\
\begin{array}{l}
t_0 := \left(\mathsf{PI}\left(\right) \cdot s\right) \cdot r\\
\mathsf{fma}\left(0.16666666666666666 - \frac{\mathsf{fma}\left(r \cdot \frac{r}{s}, -0.009259259259259259, 0.05555555555555555 \cdot r\right)}{s}, \frac{0.75}{t\_0}, 0.125 \cdot \frac{e^{\frac{-r}{s}}}{t\_0}\right)
\end{array}
\end{array}
Initial program 99.5%
lift-+.f32N/A
+-commutativeN/A
lift-/.f32N/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
lift-*.f32N/A
lift-*.f32N/A
associate-*l*N/A
associate-*l*N/A
times-fracN/A
Applied rewrites97.6%
Taylor expanded in s around inf
associate-+r+N/A
fp-cancel-sign-sub-invN/A
associate-+l-N/A
metadata-evalN/A
associate-*r/N/A
associate-*r/N/A
unpow2N/A
associate-/r*N/A
div-subN/A
associate-/l*N/A
metadata-evalN/A
fp-cancel-sign-sub-invN/A
+-commutativeN/A
lower--.f32N/A
lower-/.f32N/A
Applied rewrites10.9%
(FPCore (s r)
:precision binary32
(/
(fma
(/
(-
1.0
(/ (fma 0.3333333333333333 r (* (* r (/ r s)) -0.05555555555555555)) s))
(PI))
0.125
(* (/ (exp (/ (- r) s)) (PI)) 0.125))
(* s r)))\begin{array}{l}
\\
\frac{\mathsf{fma}\left(\frac{1 - \frac{\mathsf{fma}\left(0.3333333333333333, r, \left(r \cdot \frac{r}{s}\right) \cdot -0.05555555555555555\right)}{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 99.5%
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 rewrites99.6%
Taylor expanded in s around inf
associate-+r+N/A
fp-cancel-sign-sub-invN/A
associate-+l-N/A
metadata-evalN/A
associate-*r/N/A
associate-*r/N/A
unpow2N/A
associate-/r*N/A
div-subN/A
associate-/l*N/A
metadata-evalN/A
fp-cancel-sign-sub-invN/A
+-commutativeN/A
lower--.f32N/A
lower-/.f32N/A
Applied rewrites10.9%
(FPCore (s r) :precision binary32 (/ (- 0.25 (/ (fma 0.16666666666666666 r (/ (* (* r r) 0.06944444444444445) (- s))) s)) (* (* (PI) s) r)))
\begin{array}{l}
\\
\frac{0.25 - \frac{\mathsf{fma}\left(0.16666666666666666, r, \frac{\left(r \cdot r\right) \cdot 0.06944444444444445}{-s}\right)}{s}}{\left(\mathsf{PI}\left(\right) \cdot s\right) \cdot r}
\end{array}
Initial program 99.5%
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 rewrites99.6%
lift-/.f32N/A
lift-fma.f32N/A
+-commutativeN/A
div-addN/A
Applied rewrites99.5%
Taylor expanded in s around -inf
fp-cancel-sign-sub-invN/A
metadata-evalN/A
*-lft-identityN/A
lower--.f32N/A
lower-/.f32N/A
Applied rewrites10.3%
(FPCore (s r) :precision binary32 (/ (fma (/ (+ -0.16666666666666666 (/ (* 0.06944444444444445 r) s)) s) r 0.25) (* (* (PI) s) r)))
\begin{array}{l}
\\
\frac{\mathsf{fma}\left(\frac{-0.16666666666666666 + \frac{0.06944444444444445 \cdot r}{s}}{s}, r, 0.25\right)}{\left(\mathsf{PI}\left(\right) \cdot s\right) \cdot r}
\end{array}
Initial program 99.5%
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 rewrites99.6%
lift-/.f32N/A
lift-fma.f32N/A
+-commutativeN/A
div-addN/A
Applied rewrites99.5%
lift-/.f32N/A
lift-/.f32N/A
associate-/l/N/A
metadata-evalN/A
distribute-lft-neg-inN/A
lower-/.f32N/A
distribute-lft-neg-inN/A
metadata-evalN/A
lower-*.f3299.5
Applied rewrites99.5%
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-*.f3210.3
Applied rewrites10.3%
Final simplification10.3%
(FPCore (s r) :precision binary32 (/ (fma (/ (fma 0.06944444444444445 (/ r s) -0.16666666666666666) s) r 0.25) (* (* (PI) s) r)))
\begin{array}{l}
\\
\frac{\mathsf{fma}\left(\frac{\mathsf{fma}\left(0.06944444444444445, \frac{r}{s}, -0.16666666666666666\right)}{s}, r, 0.25\right)}{\left(\mathsf{PI}\left(\right) \cdot s\right) \cdot r}
\end{array}
Initial program 99.5%
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 rewrites99.6%
lift-/.f32N/A
lift-fma.f32N/A
+-commutativeN/A
div-addN/A
Applied rewrites99.5%
Taylor expanded in r around 0
+-commutativeN/A
*-commutativeN/A
lower-fma.f32N/A
fp-cancel-sub-sign-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
lower-fma.f32N/A
lower-/.f3210.3
Applied rewrites10.3%
(FPCore (s r) :precision binary32 (/ (/ (/ (fma -0.16666666666666666 (/ r s) 0.25) s) (PI)) r))
\begin{array}{l}
\\
\frac{\frac{\frac{\mathsf{fma}\left(-0.16666666666666666, \frac{r}{s}, 0.25\right)}{s}}{\mathsf{PI}\left(\right)}}{r}
\end{array}
Initial program 99.5%
Taylor expanded in r around 0
lower-/.f32N/A
Applied rewrites9.1%
Applied rewrites9.1%
(FPCore (s r) :precision binary32 (/ (fma -0.16666666666666666 (/ r s) 0.25) (* (* (PI) s) r)))
\begin{array}{l}
\\
\frac{\mathsf{fma}\left(-0.16666666666666666, \frac{r}{s}, 0.25\right)}{\left(\mathsf{PI}\left(\right) \cdot s\right) \cdot r}
\end{array}
Initial program 99.5%
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 rewrites99.6%
lift-/.f32N/A
lift-fma.f32N/A
+-commutativeN/A
div-addN/A
Applied rewrites99.5%
Taylor expanded in s around inf
+-commutativeN/A
distribute-rgt-outN/A
metadata-evalN/A
*-commutativeN/A
lower-fma.f32N/A
lower-/.f329.1
Applied rewrites9.1%
(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 99.5%
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%
(FPCore (s r) :precision binary32 (/ (/ (/ 0.25 s) (PI)) r))
\begin{array}{l}
\\
\frac{\frac{\frac{0.25}{s}}{\mathsf{PI}\left(\right)}}{r}
\end{array}
Initial program 99.5%
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%
(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
*-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%
(FPCore (s r) :precision binary32 (/ 0.25 (* (* r s) (PI))))
\begin{array}{l}
\\
\frac{0.25}{\left(r \cdot s\right) \cdot \mathsf{PI}\left(\right)}
\end{array}
Initial program 99.5%
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%
herbie shell --seed 2024359
(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))))