
(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 14 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 (/ (fma (exp (- (log (* (* r (* PI 6.0)) (exp (- 0.0 (/ r (* s -3.0)))))))) 0.75 (/ 0.125 (* (* r PI) (exp (/ r s))))) s))
float code(float s, float r) {
return fmaf(expf(-logf(((r * (((float) M_PI) * 6.0f)) * expf((0.0f - (r / (s * -3.0f))))))), 0.75f, (0.125f / ((r * ((float) M_PI)) * expf((r / s))))) / s;
}
function code(s, r) return Float32(fma(exp(Float32(-log(Float32(Float32(r * Float32(Float32(pi) * Float32(6.0))) * exp(Float32(Float32(0.0) - Float32(r / Float32(s * Float32(-3.0))))))))), Float32(0.75), Float32(Float32(0.125) / Float32(Float32(r * Float32(pi)) * exp(Float32(r / s))))) / s) end
\begin{array}{l}
\\
\frac{\mathsf{fma}\left(e^{-\log \left(\left(r \cdot \left(\pi \cdot 6\right)\right) \cdot e^{0 - \frac{r}{s \cdot -3}}\right)}, 0.75, \frac{0.125}{\left(r \cdot \pi\right) \cdot e^{\frac{r}{s}}}\right)}{s}
\end{array}
Initial program 99.5%
Taylor expanded in s around 0
/-lowering-/.f32N/A
Simplified99.4%
+-commutativeN/A
distribute-rgt-inN/A
metadata-evalN/A
div-invN/A
associate-/r*N/A
metadata-evalN/A
times-fracN/A
*-commutativeN/A
associate-*r*N/A
associate-/l*N/A
*-commutativeN/A
Applied egg-rr99.5%
clear-numN/A
inv-powN/A
pow-to-expN/A
exp-lowering-exp.f32N/A
*-lowering-*.f32N/A
Applied egg-rr99.5%
Final simplification99.5%
(FPCore (s r) :precision binary32 (/ (fma (/ (exp (/ r (* s -3.0))) (* r (* PI 6.0))) 0.75 (/ 0.125 (* (* r PI) (exp (/ r s))))) s))
float code(float s, float r) {
return fmaf((expf((r / (s * -3.0f))) / (r * (((float) M_PI) * 6.0f))), 0.75f, (0.125f / ((r * ((float) M_PI)) * expf((r / s))))) / s;
}
function code(s, r) return Float32(fma(Float32(exp(Float32(r / Float32(s * Float32(-3.0)))) / Float32(r * Float32(Float32(pi) * Float32(6.0)))), Float32(0.75), Float32(Float32(0.125) / Float32(Float32(r * Float32(pi)) * exp(Float32(r / s))))) / s) end
\begin{array}{l}
\\
\frac{\mathsf{fma}\left(\frac{e^{\frac{r}{s \cdot -3}}}{r \cdot \left(\pi \cdot 6\right)}, 0.75, \frac{0.125}{\left(r \cdot \pi\right) \cdot e^{\frac{r}{s}}}\right)}{s}
\end{array}
Initial program 99.5%
Taylor expanded in s around 0
/-lowering-/.f32N/A
Simplified99.4%
+-commutativeN/A
distribute-rgt-inN/A
metadata-evalN/A
div-invN/A
associate-/r*N/A
metadata-evalN/A
times-fracN/A
*-commutativeN/A
associate-*r*N/A
associate-/l*N/A
*-commutativeN/A
Applied egg-rr99.5%
(FPCore (s r) :precision binary32 (/ (* 0.125 (+ (exp (/ r (* s -3.0))) (exp (/ (- r) s)))) (* r (* PI s))))
float code(float s, float r) {
return (0.125f * (expf((r / (s * -3.0f))) + expf((-r / s)))) / (r * (((float) M_PI) * s));
}
function code(s, r) return Float32(Float32(Float32(0.125) * Float32(exp(Float32(r / Float32(s * Float32(-3.0)))) + exp(Float32(Float32(-r) / s)))) / Float32(r * Float32(Float32(pi) * s))) end
function tmp = code(s, r) tmp = (single(0.125) * (exp((r / (s * single(-3.0)))) + exp((-r / s)))) / (r * (single(pi) * s)); end
\begin{array}{l}
\\
\frac{0.125 \cdot \left(e^{\frac{r}{s \cdot -3}} + e^{\frac{-r}{s}}\right)}{r \cdot \left(\pi \cdot s\right)}
\end{array}
Initial program 99.5%
Applied egg-rr99.5%
Taylor expanded in r around inf
associate-*r/N/A
/-lowering-/.f32N/A
Simplified99.4%
*-commutativeN/A
*-lowering-*.f32N/A
metadata-evalN/A
div-invN/A
associate-/r*N/A
+-lowering-+.f32N/A
associate-/r*N/A
div-invN/A
metadata-evalN/A
exp-lowering-exp.f32N/A
metadata-evalN/A
div-invN/A
associate-/r*N/A
/-lowering-/.f32N/A
*-lowering-*.f32N/A
exp-lowering-exp.f32N/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 s) -0.3333333333333333)))) (* r (* PI s))))
float code(float s, float r) {
return (0.125f * (expf((-r / s)) + expf(((r / s) * -0.3333333333333333f)))) / (r * (((float) M_PI) * s));
}
function code(s, r) return Float32(Float32(Float32(0.125) * Float32(exp(Float32(Float32(-r) / s)) + exp(Float32(Float32(r / s) * Float32(-0.3333333333333333))))) / Float32(r * Float32(Float32(pi) * s))) end
function tmp = code(s, r) tmp = (single(0.125) * (exp((-r / s)) + exp(((r / s) * single(-0.3333333333333333))))) / (r * (single(pi) * s)); end
\begin{array}{l}
\\
\frac{0.125 \cdot \left(e^{\frac{-r}{s}} + e^{\frac{r}{s} \cdot -0.3333333333333333}\right)}{r \cdot \left(\pi \cdot s\right)}
\end{array}
Initial program 99.5%
Applied egg-rr99.5%
Taylor expanded in r around inf
associate-*r/N/A
/-lowering-/.f32N/A
Simplified99.4%
Final simplification99.4%
(FPCore (s r) :precision binary32 (* 0.125 (/ (exp (/ (* r -0.3333333333333333) s)) (* r (* PI s)))))
float code(float s, float r) {
return 0.125f * (expf(((r * -0.3333333333333333f) / s)) / (r * (((float) M_PI) * s)));
}
function code(s, r) return Float32(Float32(0.125) * Float32(exp(Float32(Float32(r * Float32(-0.3333333333333333)) / s)) / Float32(r * Float32(Float32(pi) * s)))) end
function tmp = code(s, r) tmp = single(0.125) * (exp(((r * single(-0.3333333333333333)) / s)) / (r * (single(pi) * s))); end
\begin{array}{l}
\\
0.125 \cdot \frac{e^{\frac{r \cdot -0.3333333333333333}{s}}}{r \cdot \left(\pi \cdot s\right)}
\end{array}
Initial program 99.5%
Taylor expanded in s around 0
/-lowering-/.f32N/A
Simplified99.4%
+-commutativeN/A
distribute-rgt-inN/A
metadata-evalN/A
div-invN/A
associate-/r*N/A
metadata-evalN/A
times-fracN/A
*-commutativeN/A
associate-*r*N/A
associate-/l*N/A
*-commutativeN/A
Applied egg-rr99.5%
Taylor expanded in r around 0
+-commutativeN/A
accelerator-lowering-fma.f32N/A
accelerator-lowering-fma.f32N/A
accelerator-lowering-fma.f32N/A
/-lowering-/.f32N/A
cube-multN/A
unpow2N/A
*-lowering-*.f32N/A
unpow2N/A
*-lowering-*.f32N/A
associate-*r/N/A
metadata-evalN/A
/-lowering-/.f32N/A
unpow2N/A
*-lowering-*.f32N/A
/-lowering-/.f3274.4
Simplified74.4%
Taylor expanded in r around inf
*-lowering-*.f32N/A
/-lowering-/.f32N/A
exp-lowering-exp.f32N/A
associate-*r/N/A
/-lowering-/.f32N/A
*-commutativeN/A
*-lowering-*.f32N/A
*-lowering-*.f32N/A
*-commutativeN/A
*-lowering-*.f32N/A
PI-lowering-PI.f3292.3
Simplified92.3%
(FPCore (s r)
:precision binary32
(/
(+
1.5
(/
(-
(/
(-
(* 0.4166666666666667 (* r r))
(* (* r (* r r)) (/ 0.12962962962962962 s)))
s)
r)
s))
(* (* r (* PI 6.0)) s)))
float code(float s, float r) {
return (1.5f + (((((0.4166666666666667f * (r * r)) - ((r * (r * r)) * (0.12962962962962962f / s))) / s) - r) / s)) / ((r * (((float) M_PI) * 6.0f)) * s);
}
function code(s, r) return Float32(Float32(Float32(1.5) + Float32(Float32(Float32(Float32(Float32(Float32(0.4166666666666667) * Float32(r * r)) - Float32(Float32(r * Float32(r * r)) * Float32(Float32(0.12962962962962962) / s))) / s) - r) / s)) / Float32(Float32(r * Float32(Float32(pi) * Float32(6.0))) * s)) end
function tmp = code(s, r) tmp = (single(1.5) + (((((single(0.4166666666666667) * (r * r)) - ((r * (r * r)) * (single(0.12962962962962962) / s))) / s) - r) / s)) / ((r * (single(pi) * single(6.0))) * s); end
\begin{array}{l}
\\
\frac{1.5 + \frac{\frac{0.4166666666666667 \cdot \left(r \cdot r\right) - \left(r \cdot \left(r \cdot r\right)\right) \cdot \frac{0.12962962962962962}{s}}{s} - r}{s}}{\left(r \cdot \left(\pi \cdot 6\right)\right) \cdot s}
\end{array}
Initial program 99.5%
Applied egg-rr99.5%
Taylor expanded in s around -inf
mul-1-negN/A
unsub-negN/A
--lowering--.f32N/A
/-lowering-/.f32N/A
Simplified10.3%
Final simplification10.3%
(FPCore (s r) :precision binary32 (/ (+ 1.5 (/ (- (/ (* 0.4166666666666667 (* r r)) s) r) s)) (* (* r (* PI 6.0)) s)))
float code(float s, float r) {
return (1.5f + ((((0.4166666666666667f * (r * r)) / s) - r) / s)) / ((r * (((float) M_PI) * 6.0f)) * s);
}
function code(s, r) return Float32(Float32(Float32(1.5) + Float32(Float32(Float32(Float32(Float32(0.4166666666666667) * Float32(r * r)) / s) - r) / s)) / Float32(Float32(r * Float32(Float32(pi) * Float32(6.0))) * s)) end
function tmp = code(s, r) tmp = (single(1.5) + ((((single(0.4166666666666667) * (r * r)) / s) - r) / s)) / ((r * (single(pi) * single(6.0))) * s); end
\begin{array}{l}
\\
\frac{1.5 + \frac{\frac{0.4166666666666667 \cdot \left(r \cdot r\right)}{s} - r}{s}}{\left(r \cdot \left(\pi \cdot 6\right)\right) \cdot s}
\end{array}
Initial program 99.5%
Applied egg-rr99.5%
Taylor expanded in s around -inf
mul-1-negN/A
unsub-negN/A
--lowering--.f32N/A
/-lowering-/.f32N/A
Simplified10.2%
Final simplification10.2%
(FPCore (s r) :precision binary32 (/ (fma r (fma r (/ 0.06944444444444445 (* s s)) (/ -0.16666666666666666 s)) 0.25) (* r (* PI s))))
float code(float s, float r) {
return fmaf(r, fmaf(r, (0.06944444444444445f / (s * s)), (-0.16666666666666666f / s)), 0.25f) / (r * (((float) M_PI) * s));
}
function code(s, r) return Float32(fma(r, fma(r, Float32(Float32(0.06944444444444445) / Float32(s * s)), Float32(Float32(-0.16666666666666666) / s)), Float32(0.25)) / Float32(r * Float32(Float32(pi) * s))) end
\begin{array}{l}
\\
\frac{\mathsf{fma}\left(r, \mathsf{fma}\left(r, \frac{0.06944444444444445}{s \cdot s}, \frac{-0.16666666666666666}{s}\right), 0.25\right)}{r \cdot \left(\pi \cdot s\right)}
\end{array}
Initial program 99.5%
Applied egg-rr99.5%
Taylor expanded in r around inf
associate-*r/N/A
/-lowering-/.f32N/A
Simplified99.4%
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-/.f3210.2
Simplified10.2%
Final simplification10.2%
(FPCore (s r) :precision binary32 (/ 0.25 (* r (* (sqrt PI) (* s (sqrt PI))))))
float code(float s, float r) {
return 0.25f / (r * (sqrtf(((float) M_PI)) * (s * sqrtf(((float) M_PI)))));
}
function code(s, r) return Float32(Float32(0.25) / Float32(r * Float32(sqrt(Float32(pi)) * Float32(s * sqrt(Float32(pi)))))) end
function tmp = code(s, r) tmp = single(0.25) / (r * (sqrt(single(pi)) * (s * sqrt(single(pi))))); end
\begin{array}{l}
\\
\frac{0.25}{r \cdot \left(\sqrt{\pi} \cdot \left(s \cdot \sqrt{\pi}\right)\right)}
\end{array}
Initial program 99.5%
Taylor expanded in r around 0
/-lowering-/.f32N/A
*-lowering-*.f32N/A
*-lowering-*.f32N/A
PI-lowering-PI.f329.3
Simplified9.3%
add-sqr-sqrtN/A
associate-*r*N/A
*-lowering-*.f32N/A
*-lowering-*.f32N/A
sqrt-lowering-sqrt.f32N/A
PI-lowering-PI.f32N/A
sqrt-lowering-sqrt.f32N/A
PI-lowering-PI.f329.3
Applied egg-rr9.3%
Final simplification9.3%
(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(Float32(Float32(0.25) / r) / s) / Float32(pi)) end
function tmp = code(s, r) tmp = ((single(0.25) / r) / s) / single(pi); end
\begin{array}{l}
\\
\frac{\frac{\frac{0.25}{r}}{s}}{\pi}
\end{array}
Initial program 99.5%
Taylor expanded in r around 0
/-lowering-/.f32N/A
*-lowering-*.f32N/A
*-lowering-*.f32N/A
PI-lowering-PI.f329.3
Simplified9.3%
associate-/r*N/A
associate-/r*N/A
/-lowering-/.f32N/A
/-lowering-/.f32N/A
/-lowering-/.f32N/A
PI-lowering-PI.f329.3
Applied egg-rr9.3%
(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(Float32(1.0) / 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}{\pi} \cdot \frac{0.25}{r \cdot s}
\end{array}
Initial program 99.5%
Taylor expanded in r around 0
/-lowering-/.f32N/A
*-lowering-*.f32N/A
*-lowering-*.f32N/A
PI-lowering-PI.f329.3
Simplified9.3%
associate-*r*N/A
*-lowering-*.f32N/A
*-lowering-*.f32N/A
PI-lowering-PI.f329.3
Applied egg-rr9.3%
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
PI-lowering-PI.f32N/A
/-lowering-/.f32N/A
*-lowering-*.f329.3
Applied egg-rr9.3%
(FPCore (s r) :precision binary32 (/ 1.5 (* (* r (* PI 6.0)) s)))
float code(float s, float r) {
return 1.5f / ((r * (((float) M_PI) * 6.0f)) * s);
}
function code(s, r) return Float32(Float32(1.5) / Float32(Float32(r * Float32(Float32(pi) * Float32(6.0))) * s)) end
function tmp = code(s, r) tmp = single(1.5) / ((r * (single(pi) * single(6.0))) * s); end
\begin{array}{l}
\\
\frac{1.5}{\left(r \cdot \left(\pi \cdot 6\right)\right) \cdot s}
\end{array}
Initial program 99.5%
Applied egg-rr99.5%
Taylor expanded in r around 0
Simplified9.3%
Final simplification9.3%
(FPCore (s r) :precision binary32 (/ 0.25 (* PI (* r s))))
float code(float s, float r) {
return 0.25f / (((float) M_PI) * (r * s));
}
function code(s, r) return Float32(Float32(0.25) / Float32(Float32(pi) * Float32(r * s))) end
function tmp = code(s, r) tmp = single(0.25) / (single(pi) * (r * s)); end
\begin{array}{l}
\\
\frac{0.25}{\pi \cdot \left(r \cdot s\right)}
\end{array}
Initial program 99.5%
Taylor expanded in r around 0
/-lowering-/.f32N/A
*-lowering-*.f32N/A
*-lowering-*.f32N/A
PI-lowering-PI.f329.3
Simplified9.3%
associate-*r*N/A
*-lowering-*.f32N/A
*-lowering-*.f32N/A
PI-lowering-PI.f329.3
Applied egg-rr9.3%
Final simplification9.3%
(FPCore (s r) :precision binary32 (/ 0.25 (* r (* PI s))))
float code(float s, float r) {
return 0.25f / (r * (((float) M_PI) * s));
}
function code(s, r) return Float32(Float32(0.25) / Float32(r * Float32(Float32(pi) * s))) end
function tmp = code(s, r) tmp = single(0.25) / (r * (single(pi) * s)); end
\begin{array}{l}
\\
\frac{0.25}{r \cdot \left(\pi \cdot s\right)}
\end{array}
Initial program 99.5%
Taylor expanded in r around 0
/-lowering-/.f32N/A
*-lowering-*.f32N/A
*-lowering-*.f32N/A
PI-lowering-PI.f329.3
Simplified9.3%
Final simplification9.3%
herbie shell --seed 2024196
(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))))