
(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))))
float code(float s, float r) {
return ((0.25f * expf((-r / s))) / (((2.0f * ((float) M_PI)) * s) * r)) + ((0.75f * expf((-r / (3.0f * s)))) / (((6.0f * ((float) M_PI)) * s) * r));
}
function code(s, r) return Float32(Float32(Float32(Float32(0.25) * exp(Float32(Float32(-r) / s))) / Float32(Float32(Float32(Float32(2.0) * Float32(pi)) * s) * r)) + Float32(Float32(Float32(0.75) * exp(Float32(Float32(-r) / Float32(Float32(3.0) * s)))) / Float32(Float32(Float32(Float32(6.0) * Float32(pi)) * s) * r))) end
function tmp = code(s, r) tmp = ((single(0.25) * exp((-r / s))) / (((single(2.0) * single(pi)) * s) * r)) + ((single(0.75) * exp((-r / (single(3.0) * s)))) / (((single(6.0) * single(pi)) * s) * r)); end
\begin{array}{l}
\\
\frac{0.25 \cdot e^{\frac{-r}{s}}}{\left(\left(2 \cdot \pi\right) \cdot s\right) \cdot r} + \frac{0.75 \cdot e^{\frac{-r}{3 \cdot s}}}{\left(\left(6 \cdot \pi\right) \cdot s\right) \cdot r}
\end{array}
Sampling outcomes in binary32 precision:
Herbie found 10 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))))
float code(float s, float r) {
return ((0.25f * expf((-r / s))) / (((2.0f * ((float) M_PI)) * s) * r)) + ((0.75f * expf((-r / (3.0f * s)))) / (((6.0f * ((float) M_PI)) * s) * r));
}
function code(s, r) return Float32(Float32(Float32(Float32(0.25) * exp(Float32(Float32(-r) / s))) / Float32(Float32(Float32(Float32(2.0) * Float32(pi)) * s) * r)) + Float32(Float32(Float32(0.75) * exp(Float32(Float32(-r) / Float32(Float32(3.0) * s)))) / Float32(Float32(Float32(Float32(6.0) * Float32(pi)) * s) * r))) end
function tmp = code(s, r) tmp = ((single(0.25) * exp((-r / s))) / (((single(2.0) * single(pi)) * s) * r)) + ((single(0.75) * exp((-r / (single(3.0) * s)))) / (((single(6.0) * single(pi)) * s) * r)); end
\begin{array}{l}
\\
\frac{0.25 \cdot e^{\frac{-r}{s}}}{\left(\left(2 \cdot \pi\right) \cdot s\right) \cdot r} + \frac{0.75 \cdot e^{\frac{-r}{3 \cdot s}}}{\left(\left(6 \cdot \pi\right) \cdot s\right) \cdot r}
\end{array}
(FPCore (s r) :precision binary32 (+ (/ (* 0.25 (exp (/ r (- s)))) (* r (* s (* 2.0 PI)))) (/ (/ (* 0.75 (exp (/ r (* s -3.0)))) (* r 6.0)) (* s PI))))
float code(float s, float r) {
return ((0.25f * expf((r / -s))) / (r * (s * (2.0f * ((float) M_PI))))) + (((0.75f * expf((r / (s * -3.0f)))) / (r * 6.0f)) / (s * ((float) M_PI)));
}
function code(s, r) return Float32(Float32(Float32(Float32(0.25) * exp(Float32(r / Float32(-s)))) / Float32(r * Float32(s * Float32(Float32(2.0) * Float32(pi))))) + Float32(Float32(Float32(Float32(0.75) * exp(Float32(r / Float32(s * Float32(-3.0))))) / Float32(r * Float32(6.0))) / Float32(s * Float32(pi)))) end
function tmp = code(s, r) tmp = ((single(0.25) * exp((r / -s))) / (r * (s * (single(2.0) * single(pi))))) + (((single(0.75) * exp((r / (s * single(-3.0))))) / (r * single(6.0))) / (s * single(pi))); end
\begin{array}{l}
\\
\frac{0.25 \cdot e^{\frac{r}{-s}}}{r \cdot \left(s \cdot \left(2 \cdot \pi\right)\right)} + \frac{\frac{0.75 \cdot e^{\frac{r}{s \cdot -3}}}{r \cdot 6}}{s \cdot \pi}
\end{array}
Initial program 99.7%
lift-*.f32N/A
lift-neg.f32N/A
lift-/.f32N/A
lift-exp.f32N/A
lift-PI.f32N/A
lift-*.f32N/A
lift-*.f32N/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
lift-*.f32N/A
associate-*l*N/A
associate-*r*N/A
associate-/r*N/A
lower-/.f32N/A
Applied rewrites99.7%
Final simplification99.7%
(FPCore (s r) :precision binary32 (+ (/ (* 0.125 (exp (/ r (- s)))) (* r (* s PI))) (/ 0.75 (/ (* r (* s (* PI 6.0))) (exp (/ r (* s -3.0)))))))
float code(float s, float r) {
return ((0.125f * expf((r / -s))) / (r * (s * ((float) M_PI)))) + (0.75f / ((r * (s * (((float) M_PI) * 6.0f))) / expf((r / (s * -3.0f)))));
}
function code(s, r) return Float32(Float32(Float32(Float32(0.125) * exp(Float32(r / Float32(-s)))) / Float32(r * Float32(s * Float32(pi)))) + Float32(Float32(0.75) / Float32(Float32(r * Float32(s * Float32(Float32(pi) * Float32(6.0)))) / exp(Float32(r / Float32(s * Float32(-3.0))))))) end
function tmp = code(s, r) tmp = ((single(0.125) * exp((r / -s))) / (r * (s * single(pi)))) + (single(0.75) / ((r * (s * (single(pi) * single(6.0)))) / exp((r / (s * single(-3.0)))))); end
\begin{array}{l}
\\
\frac{0.125 \cdot e^{\frac{r}{-s}}}{r \cdot \left(s \cdot \pi\right)} + \frac{0.75}{\frac{r \cdot \left(s \cdot \left(\pi \cdot 6\right)\right)}{e^{\frac{r}{s \cdot -3}}}}
\end{array}
Initial program 99.7%
lift-*.f32N/A
lift-neg.f32N/A
lift-/.f32N/A
lift-exp.f32N/A
lift-PI.f32N/A
lift-*.f32N/A
lift-*.f32N/A
lift-*.f32N/A
associate-/l*N/A
clear-numN/A
un-div-invN/A
lower-/.f32N/A
Applied rewrites99.7%
lift-neg.f32N/A
lift-/.f32N/A
lift-exp.f32N/A
lift-PI.f32N/A
lift-*.f32N/A
lift-*.f32N/A
times-fracN/A
lift-/.f32N/A
lift-neg.f32N/A
distribute-frac-negN/A
distribute-frac-neg2N/A
lift-neg.f32N/A
lift-/.f32N/A
Applied rewrites99.7%
(FPCore (s r) :precision binary32 (+ (/ (* 0.125 (exp (/ r (- s)))) (* r (* s PI))) (/ 0.75 (* r (* (* s (* PI 6.0)) (exp (/ r (* -3.0 (- s)))))))))
float code(float s, float r) {
return ((0.125f * expf((r / -s))) / (r * (s * ((float) M_PI)))) + (0.75f / (r * ((s * (((float) M_PI) * 6.0f)) * expf((r / (-3.0f * -s))))));
}
function code(s, r) return Float32(Float32(Float32(Float32(0.125) * exp(Float32(r / Float32(-s)))) / Float32(r * Float32(s * Float32(pi)))) + Float32(Float32(0.75) / Float32(r * Float32(Float32(s * Float32(Float32(pi) * Float32(6.0))) * exp(Float32(r / Float32(Float32(-3.0) * Float32(-s)))))))) end
function tmp = code(s, r) tmp = ((single(0.125) * exp((r / -s))) / (r * (s * single(pi)))) + (single(0.75) / (r * ((s * (single(pi) * single(6.0))) * exp((r / (single(-3.0) * -s)))))); end
\begin{array}{l}
\\
\frac{0.125 \cdot e^{\frac{r}{-s}}}{r \cdot \left(s \cdot \pi\right)} + \frac{0.75}{r \cdot \left(\left(s \cdot \left(\pi \cdot 6\right)\right) \cdot e^{\frac{r}{-3 \cdot \left(-s\right)}}\right)}
\end{array}
Initial program 99.7%
lift-*.f32N/A
lift-neg.f32N/A
lift-/.f32N/A
lift-exp.f32N/A
lift-PI.f32N/A
lift-*.f32N/A
lift-*.f32N/A
lift-*.f32N/A
associate-/l*N/A
clear-numN/A
un-div-invN/A
lower-/.f32N/A
Applied rewrites99.7%
lift-neg.f32N/A
lift-/.f32N/A
lift-exp.f32N/A
lift-PI.f32N/A
lift-*.f32N/A
lift-*.f32N/A
times-fracN/A
lift-/.f32N/A
lift-neg.f32N/A
distribute-frac-negN/A
distribute-frac-neg2N/A
lift-neg.f32N/A
lift-/.f32N/A
Applied rewrites99.7%
lift-PI.f32N/A
lift-*.f32N/A
lift-*.f32N/A
lift-*.f32N/A
lift-*.f32N/A
lift-/.f32N/A
lift-exp.f32N/A
lift-/.f32N/A
lift-/.f3299.7
lift-/.f32N/A
lift-*.f32N/A
associate-/l*N/A
lower-*.f32N/A
div-invN/A
lower-*.f32N/A
Applied rewrites99.7%
Final simplification99.7%
(FPCore (s r) :precision binary32 (* (/ 0.125 (* s PI)) (+ (/ (exp (/ r (* s -3.0))) r) (/ (exp (/ r (- s))) r))))
float code(float s, float r) {
return (0.125f / (s * ((float) M_PI))) * ((expf((r / (s * -3.0f))) / r) + (expf((r / -s)) / r));
}
function code(s, r) return Float32(Float32(Float32(0.125) / Float32(s * Float32(pi))) * Float32(Float32(exp(Float32(r / Float32(s * Float32(-3.0)))) / r) + Float32(exp(Float32(r / Float32(-s))) / r))) end
function tmp = code(s, r) tmp = (single(0.125) / (s * single(pi))) * ((exp((r / (s * single(-3.0)))) / r) + (exp((r / -s)) / r)); end
\begin{array}{l}
\\
\frac{0.125}{s \cdot \pi} \cdot \left(\frac{e^{\frac{r}{s \cdot -3}}}{r} + \frac{e^{\frac{r}{-s}}}{r}\right)
\end{array}
Initial program 99.7%
Applied rewrites99.6%
(FPCore (s r)
:precision binary32
(+
(/ (* 0.25 (exp (/ r (- s)))) (* r (* s (* 2.0 PI))))
(/
(fma
r
(/ 0.006944444444444444 (* s (* s PI)))
(+ (/ 0.125 (* r PI)) (/ -0.041666666666666664 (* s PI))))
s)))
float code(float s, float r) {
return ((0.25f * expf((r / -s))) / (r * (s * (2.0f * ((float) M_PI))))) + (fmaf(r, (0.006944444444444444f / (s * (s * ((float) M_PI)))), ((0.125f / (r * ((float) M_PI))) + (-0.041666666666666664f / (s * ((float) M_PI))))) / s);
}
function code(s, r) return Float32(Float32(Float32(Float32(0.25) * exp(Float32(r / Float32(-s)))) / Float32(r * Float32(s * Float32(Float32(2.0) * Float32(pi))))) + Float32(fma(r, Float32(Float32(0.006944444444444444) / Float32(s * Float32(s * Float32(pi)))), Float32(Float32(Float32(0.125) / Float32(r * Float32(pi))) + Float32(Float32(-0.041666666666666664) / Float32(s * Float32(pi))))) / s)) end
\begin{array}{l}
\\
\frac{0.25 \cdot e^{\frac{r}{-s}}}{r \cdot \left(s \cdot \left(2 \cdot \pi\right)\right)} + \frac{\mathsf{fma}\left(r, \frac{0.006944444444444444}{s \cdot \left(s \cdot \pi\right)}, \frac{0.125}{r \cdot \pi} + \frac{-0.041666666666666664}{s \cdot \pi}\right)}{s}
\end{array}
Initial program 99.7%
lift-*.f32N/A
lift-neg.f32N/A
lift-/.f32N/A
lift-exp.f32N/A
lift-PI.f32N/A
lift-*.f32N/A
lift-*.f32N/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
lift-*.f32N/A
associate-*l*N/A
associate-*r*N/A
associate-/r*N/A
lower-/.f32N/A
Applied rewrites99.7%
Taylor expanded in s around inf
Applied rewrites8.6%
Final simplification8.6%
(FPCore (s r)
:precision binary32
(+
(/ (* 0.25 (exp (/ r (- s)))) (* r (* s (* 2.0 PI))))
(/
(-
(/ 0.125 r)
(/ (fma (/ r s) -0.006944444444444444 0.041666666666666664) s))
(* s PI))))
float code(float s, float r) {
return ((0.25f * expf((r / -s))) / (r * (s * (2.0f * ((float) M_PI))))) + (((0.125f / r) - (fmaf((r / s), -0.006944444444444444f, 0.041666666666666664f) / s)) / (s * ((float) M_PI)));
}
function code(s, r) return Float32(Float32(Float32(Float32(0.25) * exp(Float32(r / Float32(-s)))) / Float32(r * Float32(s * Float32(Float32(2.0) * Float32(pi))))) + Float32(Float32(Float32(Float32(0.125) / r) - Float32(fma(Float32(r / s), Float32(-0.006944444444444444), Float32(0.041666666666666664)) / s)) / Float32(s * Float32(pi)))) end
\begin{array}{l}
\\
\frac{0.25 \cdot e^{\frac{r}{-s}}}{r \cdot \left(s \cdot \left(2 \cdot \pi\right)\right)} + \frac{\frac{0.125}{r} - \frac{\mathsf{fma}\left(\frac{r}{s}, -0.006944444444444444, 0.041666666666666664\right)}{s}}{s \cdot \pi}
\end{array}
Initial program 99.7%
lift-*.f32N/A
lift-neg.f32N/A
lift-/.f32N/A
lift-exp.f32N/A
lift-PI.f32N/A
lift-*.f32N/A
lift-*.f32N/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
lift-*.f32N/A
associate-*l*N/A
associate-*r*N/A
associate-/r*N/A
lower-/.f32N/A
Applied rewrites99.7%
Taylor expanded in s around -inf
+-commutativeN/A
mul-1-negN/A
unsub-negN/A
lower--.f32N/A
associate-*r/N/A
metadata-evalN/A
lower-/.f32N/A
lower-/.f32N/A
+-commutativeN/A
*-commutativeN/A
lower-fma.f32N/A
lower-/.f328.6
Applied rewrites8.6%
Final simplification8.6%
(FPCore (s r)
:precision binary32
(/
(+
(/ 0.25 (* r PI))
(fma
r
(/ 0.06944444444444445 (* s (* s PI)))
(/ -0.16666666666666666 (* s PI))))
s))
float code(float s, float r) {
return ((0.25f / (r * ((float) M_PI))) + fmaf(r, (0.06944444444444445f / (s * (s * ((float) M_PI)))), (-0.16666666666666666f / (s * ((float) M_PI))))) / s;
}
function code(s, r) return Float32(Float32(Float32(Float32(0.25) / Float32(r * Float32(pi))) + fma(r, Float32(Float32(0.06944444444444445) / Float32(s * Float32(s * Float32(pi)))), Float32(Float32(-0.16666666666666666) / Float32(s * Float32(pi))))) / s) end
\begin{array}{l}
\\
\frac{\frac{0.25}{r \cdot \pi} + \mathsf{fma}\left(r, \frac{0.06944444444444445}{s \cdot \left(s \cdot \pi\right)}, \frac{-0.16666666666666666}{s \cdot \pi}\right)}{s}
\end{array}
Initial program 99.7%
lift-*.f32N/A
lift-neg.f32N/A
lift-/.f32N/A
lift-exp.f32N/A
lift-PI.f32N/A
lift-*.f32N/A
lift-*.f32N/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
lift-*.f32N/A
associate-*l*N/A
associate-*r*N/A
associate-/r*N/A
lower-/.f32N/A
Applied rewrites99.7%
Taylor expanded in s around inf
Applied rewrites8.0%
(FPCore (s r) :precision binary32 (+ (/ (fma 0.06944444444444445 (/ r (* s PI)) (/ -0.16666666666666666 PI)) (* s s)) (/ 0.25 (* r (* s PI)))))
float code(float s, float r) {
return (fmaf(0.06944444444444445f, (r / (s * ((float) M_PI))), (-0.16666666666666666f / ((float) M_PI))) / (s * s)) + (0.25f / (r * (s * ((float) M_PI))));
}
function code(s, r) return Float32(Float32(fma(Float32(0.06944444444444445), Float32(r / Float32(s * Float32(pi))), Float32(Float32(-0.16666666666666666) / Float32(pi))) / Float32(s * s)) + Float32(Float32(0.25) / Float32(r * Float32(s * Float32(pi))))) end
\begin{array}{l}
\\
\frac{\mathsf{fma}\left(0.06944444444444445, \frac{r}{s \cdot \pi}, \frac{-0.16666666666666666}{\pi}\right)}{s \cdot s} + \frac{0.25}{r \cdot \left(s \cdot \pi\right)}
\end{array}
Initial program 99.7%
Taylor expanded in s around inf
Applied rewrites8.0%
(FPCore (s r) :precision binary32 (/ 1.0 (/ PI (/ 0.25 (* r s)))))
float code(float s, float r) {
return 1.0f / (((float) M_PI) / (0.25f / (r * s)));
}
function code(s, r) return Float32(Float32(1.0) / Float32(Float32(pi) / Float32(Float32(0.25) / Float32(r * s)))) end
function tmp = code(s, r) tmp = single(1.0) / (single(pi) / (single(0.25) / (r * s))); end
\begin{array}{l}
\\
\frac{1}{\frac{\pi}{\frac{0.25}{r \cdot s}}}
\end{array}
Initial program 99.7%
Taylor expanded in r around 0
lower-/.f32N/A
lower-*.f32N/A
lower-*.f32N/A
lower-PI.f327.6
Applied rewrites7.6%
lift-PI.f32N/A
associate-*r*N/A
lift-*.f32N/A
lower-*.f327.6
Applied rewrites7.6%
lift-*.f32N/A
lift-PI.f32N/A
associate-/r*N/A
clear-numN/A
lower-/.f32N/A
lower-/.f32N/A
lower-/.f327.6
Applied rewrites7.6%
(FPCore (s r) :precision binary32 (/ 0.25 (* r (* s PI))))
float code(float s, float r) {
return 0.25f / (r * (s * ((float) M_PI)));
}
function code(s, r) return Float32(Float32(0.25) / Float32(r * Float32(s * Float32(pi)))) end
function tmp = code(s, r) tmp = single(0.25) / (r * (s * single(pi))); end
\begin{array}{l}
\\
\frac{0.25}{r \cdot \left(s \cdot \pi\right)}
\end{array}
Initial program 99.7%
Taylor expanded in r around 0
lower-/.f32N/A
lower-*.f32N/A
lower-*.f32N/A
lower-PI.f327.6
Applied rewrites7.6%
herbie shell --seed 2024216
(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))))