
(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 13 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 (* (* (/ 0.16666666666666666 (* s PI)) 0.75) (+ (/ (pow E (/ (* r -0.3333333333333333) s)) r) (/ (exp (/ r (- s))) r))))
float code(float s, float r) {
return ((0.16666666666666666f / (s * ((float) M_PI))) * 0.75f) * ((powf(((float) M_E), ((r * -0.3333333333333333f) / s)) / r) + (expf((r / -s)) / r));
}
function code(s, r) return Float32(Float32(Float32(Float32(0.16666666666666666) / Float32(s * Float32(pi))) * Float32(0.75)) * Float32(Float32((Float32(exp(1)) ^ Float32(Float32(r * Float32(-0.3333333333333333)) / s)) / r) + Float32(exp(Float32(r / Float32(-s))) / r))) end
function tmp = code(s, r) tmp = ((single(0.16666666666666666) / (s * single(pi))) * single(0.75)) * (((single(2.71828182845904523536) ^ ((r * single(-0.3333333333333333)) / s)) / r) + (exp((r / -s)) / r)); end
\begin{array}{l}
\\
\left(\frac{0.16666666666666666}{s \cdot \pi} \cdot 0.75\right) \cdot \left(\frac{{e}^{\left(\frac{r \cdot -0.3333333333333333}{s}\right)}}{r} + \frac{e^{\frac{r}{-s}}}{r}\right)
\end{array}
Initial program 99.4%
+-commutativeN/A
times-fracN/A
times-fracN/A
associate-*l*N/A
associate-/r*N/A
metadata-evalN/A
metadata-evalN/A
associate-/r*N/A
associate-*l*N/A
distribute-lft-outN/A
*-lowering-*.f32N/A
Applied egg-rr99.4%
*-commutativeN/A
associate-/r*N/A
/-lowering-/.f32N/A
/-lowering-/.f3299.4
Applied egg-rr99.4%
clear-numN/A
div-invN/A
clear-numN/A
div-invN/A
metadata-evalN/A
associate-*l/N/A
exp-prodN/A
pow-lowering-pow.f32N/A
exp-1-eN/A
E-lowering-E.f32N/A
associate-*l/N/A
metadata-evalN/A
div-invN/A
/-lowering-/.f32N/A
div-invN/A
metadata-evalN/A
*-lowering-*.f3299.6
Applied egg-rr99.6%
metadata-evalN/A
associate-*l/N/A
*-lowering-*.f32N/A
/-lowering-/.f32N/A
*-lowering-*.f32N/A
PI-lowering-PI.f3299.6
Applied egg-rr99.6%
(FPCore (s r) :precision binary32 (* (+ (/ (pow E (/ (* r -0.3333333333333333) s)) r) (/ (exp (/ r (- s))) r)) (/ 0.125 (* s PI))))
float code(float s, float r) {
return ((powf(((float) M_E), ((r * -0.3333333333333333f) / s)) / r) + (expf((r / -s)) / r)) * (0.125f / (s * ((float) M_PI)));
}
function code(s, r) return Float32(Float32(Float32((Float32(exp(1)) ^ Float32(Float32(r * Float32(-0.3333333333333333)) / s)) / r) + Float32(exp(Float32(r / Float32(-s))) / r)) * Float32(Float32(0.125) / Float32(s * Float32(pi)))) end
function tmp = code(s, r) tmp = (((single(2.71828182845904523536) ^ ((r * single(-0.3333333333333333)) / s)) / r) + (exp((r / -s)) / r)) * (single(0.125) / (s * single(pi))); end
\begin{array}{l}
\\
\left(\frac{{e}^{\left(\frac{r \cdot -0.3333333333333333}{s}\right)}}{r} + \frac{e^{\frac{r}{-s}}}{r}\right) \cdot \frac{0.125}{s \cdot \pi}
\end{array}
Initial program 99.4%
+-commutativeN/A
times-fracN/A
times-fracN/A
associate-*l*N/A
associate-/r*N/A
metadata-evalN/A
metadata-evalN/A
associate-/r*N/A
associate-*l*N/A
distribute-lft-outN/A
*-lowering-*.f32N/A
Applied egg-rr99.4%
*-commutativeN/A
associate-/r*N/A
/-lowering-/.f32N/A
/-lowering-/.f3299.4
Applied egg-rr99.4%
clear-numN/A
div-invN/A
clear-numN/A
div-invN/A
metadata-evalN/A
associate-*l/N/A
exp-prodN/A
pow-lowering-pow.f32N/A
exp-1-eN/A
E-lowering-E.f32N/A
associate-*l/N/A
metadata-evalN/A
div-invN/A
/-lowering-/.f32N/A
div-invN/A
metadata-evalN/A
*-lowering-*.f3299.6
Applied egg-rr99.6%
Final simplification99.6%
(FPCore (s r) :precision binary32 (* (/ 0.125 (* s PI)) (+ (/ (exp (/ r (- s))) r) (/ (exp (/ (* r -0.3333333333333333) s)) r))))
float code(float s, float r) {
return (0.125f / (s * ((float) M_PI))) * ((expf((r / -s)) / r) + (expf(((r * -0.3333333333333333f) / s)) / r));
}
function code(s, r) return Float32(Float32(Float32(0.125) / Float32(s * Float32(pi))) * Float32(Float32(exp(Float32(r / Float32(-s))) / r) + Float32(exp(Float32(Float32(r * Float32(-0.3333333333333333)) / s)) / r))) end
function tmp = code(s, r) tmp = (single(0.125) / (s * single(pi))) * ((exp((r / -s)) / r) + (exp(((r * single(-0.3333333333333333)) / s)) / r)); end
\begin{array}{l}
\\
\frac{0.125}{s \cdot \pi} \cdot \left(\frac{e^{\frac{r}{-s}}}{r} + \frac{e^{\frac{r \cdot -0.3333333333333333}{s}}}{r}\right)
\end{array}
Initial program 99.4%
+-commutativeN/A
times-fracN/A
times-fracN/A
associate-*l*N/A
associate-/r*N/A
metadata-evalN/A
metadata-evalN/A
associate-/r*N/A
associate-*l*N/A
distribute-lft-outN/A
*-lowering-*.f32N/A
Applied egg-rr99.4%
div-invN/A
*-commutativeN/A
associate-/r*N/A
metadata-evalN/A
associate-/l*N/A
/-lowering-/.f32N/A
*-lowering-*.f3299.4
Applied egg-rr99.4%
Final simplification99.4%
(FPCore (s r) :precision binary32 (/ (* 0.125 (+ (exp (/ r (- s))) (exp (/ (* r -0.3333333333333333) s)))) (* (* s PI) r)))
float code(float s, float r) {
return (0.125f * (expf((r / -s)) + expf(((r * -0.3333333333333333f) / s)))) / ((s * ((float) M_PI)) * r);
}
function code(s, r) return Float32(Float32(Float32(0.125) * Float32(exp(Float32(r / Float32(-s))) + exp(Float32(Float32(r * Float32(-0.3333333333333333)) / s)))) / Float32(Float32(s * Float32(pi)) * r)) end
function tmp = code(s, r) tmp = (single(0.125) * (exp((r / -s)) + exp(((r * single(-0.3333333333333333)) / s)))) / ((s * single(pi)) * r); end
\begin{array}{l}
\\
\frac{0.125 \cdot \left(e^{\frac{r}{-s}} + e^{\frac{r \cdot -0.3333333333333333}{s}}\right)}{\left(s \cdot \pi\right) \cdot r}
\end{array}
Initial program 99.4%
+-commutativeN/A
times-fracN/A
times-fracN/A
associate-*l*N/A
associate-/r*N/A
metadata-evalN/A
metadata-evalN/A
associate-/r*N/A
associate-*l*N/A
distribute-lft-outN/A
*-lowering-*.f32N/A
Applied egg-rr99.4%
*-commutativeN/A
associate-/r*N/A
/-lowering-/.f32N/A
/-lowering-/.f3299.4
Applied egg-rr99.4%
clear-numN/A
div-invN/A
clear-numN/A
div-invN/A
metadata-evalN/A
associate-*l/N/A
exp-prodN/A
pow-lowering-pow.f32N/A
exp-1-eN/A
E-lowering-E.f32N/A
associate-*l/N/A
metadata-evalN/A
div-invN/A
/-lowering-/.f32N/A
div-invN/A
metadata-evalN/A
*-lowering-*.f3299.6
Applied egg-rr99.6%
Taylor expanded in r around inf
associate-*r/N/A
metadata-evalN/A
associate-*r*N/A
distribute-lft-outN/A
/-lowering-/.f32N/A
Simplified99.4%
Final simplification99.4%
(FPCore (s r) :precision binary32 (/ (* 0.125 (+ (exp (/ r (- s))) (exp (* r (/ -0.3333333333333333 s))))) (* (* s PI) r)))
float code(float s, float r) {
return (0.125f * (expf((r / -s)) + expf((r * (-0.3333333333333333f / s))))) / ((s * ((float) M_PI)) * r);
}
function code(s, r) return Float32(Float32(Float32(0.125) * Float32(exp(Float32(r / Float32(-s))) + exp(Float32(r * Float32(Float32(-0.3333333333333333) / s))))) / Float32(Float32(s * Float32(pi)) * r)) end
function tmp = code(s, r) tmp = (single(0.125) * (exp((r / -s)) + exp((r * (single(-0.3333333333333333) / s))))) / ((s * single(pi)) * r); end
\begin{array}{l}
\\
\frac{0.125 \cdot \left(e^{\frac{r}{-s}} + e^{r \cdot \frac{-0.3333333333333333}{s}}\right)}{\left(s \cdot \pi\right) \cdot r}
\end{array}
Initial program 99.4%
+-commutativeN/A
times-fracN/A
times-fracN/A
associate-*l*N/A
associate-/r*N/A
metadata-evalN/A
metadata-evalN/A
associate-/r*N/A
associate-*l*N/A
distribute-lft-outN/A
*-lowering-*.f32N/A
Applied egg-rr99.4%
*-commutativeN/A
associate-/r*N/A
/-lowering-/.f32N/A
/-lowering-/.f3299.4
Applied egg-rr99.4%
Taylor expanded in r around inf
associate-*r/N/A
metadata-evalN/A
associate-*r*N/A
distribute-lft-outN/A
/-lowering-/.f32N/A
Simplified99.4%
Final simplification99.4%
(FPCore (s r)
:precision binary32
(*
(/ 0.125 (* s PI))
(+
(/ (exp (/ r (- s))) r)
(/
(fma
r
(fma r (/ 0.05555555555555555 (* s s)) (/ -0.3333333333333333 s))
1.0)
r))))
float code(float s, float r) {
return (0.125f / (s * ((float) M_PI))) * ((expf((r / -s)) / r) + (fmaf(r, fmaf(r, (0.05555555555555555f / (s * s)), (-0.3333333333333333f / s)), 1.0f) / r));
}
function code(s, r) return Float32(Float32(Float32(0.125) / Float32(s * Float32(pi))) * Float32(Float32(exp(Float32(r / Float32(-s))) / r) + Float32(fma(r, fma(r, Float32(Float32(0.05555555555555555) / Float32(s * s)), Float32(Float32(-0.3333333333333333) / s)), Float32(1.0)) / r))) end
\begin{array}{l}
\\
\frac{0.125}{s \cdot \pi} \cdot \left(\frac{e^{\frac{r}{-s}}}{r} + \frac{\mathsf{fma}\left(r, \mathsf{fma}\left(r, \frac{0.05555555555555555}{s \cdot s}, \frac{-0.3333333333333333}{s}\right), 1\right)}{r}\right)
\end{array}
Initial program 99.4%
+-commutativeN/A
times-fracN/A
times-fracN/A
associate-*l*N/A
associate-/r*N/A
metadata-evalN/A
metadata-evalN/A
associate-/r*N/A
associate-*l*N/A
distribute-lft-outN/A
*-lowering-*.f32N/A
Applied egg-rr99.4%
Taylor expanded in r around 0
+-commutativeN/A
accelerator-lowering-fma.f32N/A
sub-negN/A
*-commutativeN/A
associate-*l/N/A
associate-*r/N/A
metadata-evalN/A
associate-*r/N/A
accelerator-lowering-fma.f32N/A
associate-*r/N/A
metadata-evalN/A
/-lowering-/.f32N/A
unpow2N/A
*-lowering-*.f32N/A
associate-*r/N/A
metadata-evalN/A
distribute-neg-fracN/A
metadata-evalN/A
/-lowering-/.f327.7
Simplified7.7%
Final simplification7.7%
(FPCore (s r) :precision binary32 (* (/ 0.125 (* s PI)) (+ (/ (exp (/ r (- s))) r) (/ 1.0 r))))
float code(float s, float r) {
return (0.125f / (s * ((float) M_PI))) * ((expf((r / -s)) / r) + (1.0f / r));
}
function code(s, r) return Float32(Float32(Float32(0.125) / Float32(s * Float32(pi))) * Float32(Float32(exp(Float32(r / Float32(-s))) / r) + Float32(Float32(1.0) / r))) end
function tmp = code(s, r) tmp = (single(0.125) / (s * single(pi))) * ((exp((r / -s)) / r) + (single(1.0) / r)); end
\begin{array}{l}
\\
\frac{0.125}{s \cdot \pi} \cdot \left(\frac{e^{\frac{r}{-s}}}{r} + \frac{1}{r}\right)
\end{array}
Initial program 99.4%
+-commutativeN/A
times-fracN/A
times-fracN/A
associate-*l*N/A
associate-/r*N/A
metadata-evalN/A
metadata-evalN/A
associate-/r*N/A
associate-*l*N/A
distribute-lft-outN/A
*-lowering-*.f32N/A
Applied egg-rr99.4%
Taylor expanded in r around 0
Simplified7.5%
Final simplification7.5%
(FPCore (s r)
:precision binary32
(/
(fma
r
(/
(fma 0.06944444444444445 (/ r (* s PI)) (/ -0.16666666666666666 PI))
(* s s))
(/ 0.25 (* s PI)))
r))
float code(float s, float r) {
return fmaf(r, (fmaf(0.06944444444444445f, (r / (s * ((float) M_PI))), (-0.16666666666666666f / ((float) M_PI))) / (s * s)), (0.25f / (s * ((float) M_PI)))) / r;
}
function code(s, r) return Float32(fma(r, 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(s * Float32(pi)))) / r) end
\begin{array}{l}
\\
\frac{\mathsf{fma}\left(r, \frac{\mathsf{fma}\left(0.06944444444444445, \frac{r}{s \cdot \pi}, \frac{-0.16666666666666666}{\pi}\right)}{s \cdot s}, \frac{0.25}{s \cdot \pi}\right)}{r}
\end{array}
Initial program 99.4%
Taylor expanded in r around 0
Simplified7.4%
(FPCore (s r) :precision binary32 (+ (/ (fma 0.06944444444444445 (/ r (* s PI)) (/ -0.16666666666666666 PI)) (* s s)) (/ 0.25 (* (* s PI) r))))
float code(float s, float r) {
return (fmaf(0.06944444444444445f, (r / (s * ((float) M_PI))), (-0.16666666666666666f / ((float) M_PI))) / (s * s)) + (0.25f / ((s * ((float) M_PI)) * r));
}
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(Float32(s * Float32(pi)) * r))) 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}{\left(s \cdot \pi\right) \cdot r}
\end{array}
Initial program 99.4%
Taylor expanded in s around inf
Simplified7.4%
Final simplification7.4%
(FPCore (s r) :precision binary32 (/ (/ 0.25 (sqrt PI)) (* s (* r (sqrt PI)))))
float code(float s, float r) {
return (0.25f / sqrtf(((float) M_PI))) / (s * (r * sqrtf(((float) M_PI))));
}
function code(s, r) return Float32(Float32(Float32(0.25) / sqrt(Float32(pi))) / Float32(s * Float32(r * sqrt(Float32(pi))))) end
function tmp = code(s, r) tmp = (single(0.25) / sqrt(single(pi))) / (s * (r * sqrt(single(pi)))); end
\begin{array}{l}
\\
\frac{\frac{0.25}{\sqrt{\pi}}}{s \cdot \left(r \cdot \sqrt{\pi}\right)}
\end{array}
Initial program 99.4%
Taylor expanded in r around 0
/-lowering-/.f32N/A
*-lowering-*.f32N/A
*-lowering-*.f32N/A
PI-lowering-PI.f327.2
Simplified7.2%
associate-*r*N/A
*-lowering-*.f32N/A
*-lowering-*.f32N/A
PI-lowering-PI.f327.2
Applied egg-rr7.2%
*-commutativeN/A
associate-*r*N/A
*-commutativeN/A
*-lowering-*.f32N/A
*-commutativeN/A
*-lowering-*.f32N/A
PI-lowering-PI.f327.2
Applied egg-rr7.2%
associate-*r*N/A
add-sqr-sqrtN/A
*-commutativeN/A
associate-*r*N/A
*-commutativeN/A
associate-/r*N/A
/-lowering-/.f32N/A
/-lowering-/.f32N/A
sqrt-lowering-sqrt.f32N/A
PI-lowering-PI.f32N/A
associate-*l*N/A
*-lowering-*.f32N/A
*-lowering-*.f32N/A
sqrt-lowering-sqrt.f32N/A
PI-lowering-PI.f327.2
Applied egg-rr7.2%
(FPCore (s r) :precision binary32 (* (/ 1.0 (* s PI)) (/ 0.25 r)))
float code(float s, float r) {
return (1.0f / (s * ((float) M_PI))) * (0.25f / r);
}
function code(s, r) return Float32(Float32(Float32(1.0) / Float32(s * Float32(pi))) * Float32(Float32(0.25) / r)) end
function tmp = code(s, r) tmp = (single(1.0) / (s * single(pi))) * (single(0.25) / r); end
\begin{array}{l}
\\
\frac{1}{s \cdot \pi} \cdot \frac{0.25}{r}
\end{array}
Initial program 99.4%
Taylor expanded in r around 0
/-lowering-/.f32N/A
*-lowering-*.f32N/A
*-lowering-*.f32N/A
PI-lowering-PI.f327.2
Simplified7.2%
clear-numN/A
inv-powN/A
*-commutativeN/A
associate-/l*N/A
unpow-prod-downN/A
inv-powN/A
inv-powN/A
clear-numN/A
*-lowering-*.f32N/A
/-lowering-/.f32N/A
*-lowering-*.f32N/A
PI-lowering-PI.f32N/A
/-lowering-/.f327.2
Applied egg-rr7.2%
(FPCore (s r) :precision binary32 (/ 0.25 (* s (* PI r))))
float code(float s, float r) {
return 0.25f / (s * (((float) M_PI) * r));
}
function code(s, r) return Float32(Float32(0.25) / Float32(s * Float32(Float32(pi) * r))) end
function tmp = code(s, r) tmp = single(0.25) / (s * (single(pi) * r)); end
\begin{array}{l}
\\
\frac{0.25}{s \cdot \left(\pi \cdot r\right)}
\end{array}
Initial program 99.4%
Taylor expanded in r around 0
/-lowering-/.f32N/A
*-lowering-*.f32N/A
*-lowering-*.f32N/A
PI-lowering-PI.f327.2
Simplified7.2%
*-commutativeN/A
associate-*r*N/A
*-lowering-*.f32N/A
*-lowering-*.f32N/A
PI-lowering-PI.f327.2
Applied egg-rr7.2%
Final simplification7.2%
(FPCore (s r) :precision binary32 (/ 0.25 (* (* s PI) r)))
float code(float s, float r) {
return 0.25f / ((s * ((float) M_PI)) * r);
}
function code(s, r) return Float32(Float32(0.25) / Float32(Float32(s * Float32(pi)) * r)) end
function tmp = code(s, r) tmp = single(0.25) / ((s * single(pi)) * r); end
\begin{array}{l}
\\
\frac{0.25}{\left(s \cdot \pi\right) \cdot r}
\end{array}
Initial program 99.4%
Taylor expanded in r around 0
/-lowering-/.f32N/A
*-lowering-*.f32N/A
*-lowering-*.f32N/A
PI-lowering-PI.f327.2
Simplified7.2%
Final simplification7.2%
herbie shell --seed 2024198
(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))))