
(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 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))))
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 (+ (/ (* (exp (/ r (- s))) 0.125) (* PI (* r s))) (/ (* 0.75 (exp (* r (/ -0.3333333333333333 s)))) (* s (* (pow (cbrt PI) 3.0) (* r 6.0))))))
float code(float s, float r) {
return ((expf((r / -s)) * 0.125f) / (((float) M_PI) * (r * s))) + ((0.75f * expf((r * (-0.3333333333333333f / s)))) / (s * (powf(cbrtf(((float) M_PI)), 3.0f) * (r * 6.0f))));
}
function code(s, r) return Float32(Float32(Float32(exp(Float32(r / Float32(-s))) * Float32(0.125)) / Float32(Float32(pi) * Float32(r * s))) + Float32(Float32(Float32(0.75) * exp(Float32(r * Float32(Float32(-0.3333333333333333) / s)))) / Float32(s * Float32((cbrt(Float32(pi)) ^ Float32(3.0)) * Float32(r * Float32(6.0)))))) end
\begin{array}{l}
\\
\frac{e^{\frac{r}{-s}} \cdot 0.125}{\pi \cdot \left(r \cdot s\right)} + \frac{0.75 \cdot e^{r \cdot \frac{-0.3333333333333333}{s}}}{s \cdot \left({\left(\sqrt[3]{\pi}\right)}^{3} \cdot \left(r \cdot 6\right)\right)}
\end{array}
Initial program 99.5%
lift-/.f32N/A
frac-2negN/A
div-invN/A
lift-neg.f32N/A
remove-double-negN/A
lower-*.f32N/A
lift-*.f32N/A
distribute-lft-neg-inN/A
associate-/r*N/A
metadata-evalN/A
metadata-evalN/A
metadata-evalN/A
lower-/.f32N/A
metadata-eval99.5
Applied rewrites99.5%
lift-/.f32N/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
*-commutativeN/A
times-fracN/A
lift-*.f32N/A
lift-*.f32N/A
associate-*l*N/A
*-commutativeN/A
lift-*.f32N/A
associate-/r*N/A
metadata-evalN/A
times-fracN/A
lift-*.f32N/A
associate-*r*N/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
Applied rewrites99.6%
Taylor expanded in s around 0
associate-*r*N/A
*-commutativeN/A
associate-*l*N/A
lower-*.f32N/A
lower-*.f32N/A
lower-PI.f32N/A
*-commutativeN/A
lower-*.f3299.6
Applied rewrites99.6%
Applied rewrites99.6%
(FPCore (s r) :precision binary32 (+ (/ (* (exp (/ r (- s))) 0.125) (* PI (* r s))) (/ (* 0.75 (exp (* r (/ -0.3333333333333333 s)))) (* s (* PI (* r 6.0))))))
float code(float s, float r) {
return ((expf((r / -s)) * 0.125f) / (((float) M_PI) * (r * s))) + ((0.75f * expf((r * (-0.3333333333333333f / s)))) / (s * (((float) M_PI) * (r * 6.0f))));
}
function code(s, r) return Float32(Float32(Float32(exp(Float32(r / Float32(-s))) * Float32(0.125)) / Float32(Float32(pi) * Float32(r * s))) + Float32(Float32(Float32(0.75) * exp(Float32(r * Float32(Float32(-0.3333333333333333) / s)))) / Float32(s * Float32(Float32(pi) * Float32(r * Float32(6.0)))))) end
function tmp = code(s, r) tmp = ((exp((r / -s)) * single(0.125)) / (single(pi) * (r * s))) + ((single(0.75) * exp((r * (single(-0.3333333333333333) / s)))) / (s * (single(pi) * (r * single(6.0))))); end
\begin{array}{l}
\\
\frac{e^{\frac{r}{-s}} \cdot 0.125}{\pi \cdot \left(r \cdot s\right)} + \frac{0.75 \cdot e^{r \cdot \frac{-0.3333333333333333}{s}}}{s \cdot \left(\pi \cdot \left(r \cdot 6\right)\right)}
\end{array}
Initial program 99.6%
lift-/.f32N/A
frac-2negN/A
div-invN/A
lift-neg.f32N/A
remove-double-negN/A
lower-*.f32N/A
lift-*.f32N/A
distribute-lft-neg-inN/A
associate-/r*N/A
metadata-evalN/A
metadata-evalN/A
metadata-evalN/A
lower-/.f32N/A
metadata-eval99.6
Applied rewrites99.6%
lift-/.f32N/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
*-commutativeN/A
times-fracN/A
lift-*.f32N/A
lift-*.f32N/A
associate-*l*N/A
*-commutativeN/A
lift-*.f32N/A
associate-/r*N/A
metadata-evalN/A
times-fracN/A
lift-*.f32N/A
associate-*r*N/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
Applied rewrites99.6%
Taylor expanded in s around 0
associate-*r*N/A
*-commutativeN/A
associate-*l*N/A
lower-*.f32N/A
lower-*.f32N/A
lower-PI.f32N/A
*-commutativeN/A
lower-*.f3299.5
Applied rewrites99.5%
herbie shell --seed 2024223
(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))))