
(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 11 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 (/ 0.125 (* s (pow (cbrt PI) 3.0))) (/ (exp (* -0.3333333333333333 (/ r s))) r) (* (/ 0.125 (* s PI)) (/ (exp (/ (- r) s)) r))))
float code(float s, float r) {
return fmaf((0.125f / (s * powf(cbrtf(((float) M_PI)), 3.0f))), (expf((-0.3333333333333333f * (r / s))) / r), ((0.125f / (s * ((float) M_PI))) * (expf((-r / s)) / r)));
}
function code(s, r) return fma(Float32(Float32(0.125) / Float32(s * (cbrt(Float32(pi)) ^ Float32(3.0)))), Float32(exp(Float32(Float32(-0.3333333333333333) * Float32(r / s))) / r), Float32(Float32(Float32(0.125) / Float32(s * Float32(pi))) * Float32(exp(Float32(Float32(-r) / s)) / r))) end
\begin{array}{l}
\\
\mathsf{fma}\left(\frac{0.125}{s \cdot {\left(\sqrt[3]{\pi}\right)}^{3}}, \frac{e^{-0.3333333333333333 \cdot \frac{r}{s}}}{r}, \frac{0.125}{s \cdot \pi} \cdot \frac{e^{\frac{-r}{s}}}{r}\right)
\end{array}
Initial program 99.6%
+-commutative99.6%
times-frac99.6%
fma-define99.7%
associate-*l*99.7%
associate-/r*99.7%
metadata-eval99.7%
*-commutative99.7%
neg-mul-199.7%
times-frac99.7%
metadata-eval99.7%
times-frac99.6%
Simplified99.6%
add-cube-cbrt99.7%
pow399.7%
Applied egg-rr99.7%
Final simplification99.7%
(FPCore (s r) :precision binary32 (/ (+ (* 0.125 (/ (exp (/ (- r) s)) (* s PI))) (* 0.125 (/ (pow E (* -0.3333333333333333 (/ r s))) (* s PI)))) r))
float code(float s, float r) {
return ((0.125f * (expf((-r / s)) / (s * ((float) M_PI)))) + (0.125f * (powf(((float) M_E), (-0.3333333333333333f * (r / s))) / (s * ((float) M_PI))))) / r;
}
function code(s, r) return Float32(Float32(Float32(Float32(0.125) * Float32(exp(Float32(Float32(-r) / s)) / Float32(s * Float32(pi)))) + Float32(Float32(0.125) * Float32((Float32(exp(1)) ^ Float32(Float32(-0.3333333333333333) * Float32(r / s))) / Float32(s * Float32(pi))))) / r) end
function tmp = code(s, r) tmp = ((single(0.125) * (exp((-r / s)) / (s * single(pi)))) + (single(0.125) * ((single(2.71828182845904523536) ^ (single(-0.3333333333333333) * (r / s))) / (s * single(pi))))) / r; end
\begin{array}{l}
\\
\frac{0.125 \cdot \frac{e^{\frac{-r}{s}}}{s \cdot \pi} + 0.125 \cdot \frac{{e}^{\left(-0.3333333333333333 \cdot \frac{r}{s}\right)}}{s \cdot \pi}}{r}
\end{array}
Initial program 99.6%
+-commutative99.6%
times-frac99.6%
fma-define99.7%
associate-*l*99.7%
associate-/r*99.7%
metadata-eval99.7%
*-commutative99.7%
neg-mul-199.7%
times-frac99.7%
metadata-eval99.7%
times-frac99.6%
Simplified99.6%
add-cube-cbrt99.7%
pow399.7%
Applied egg-rr99.7%
Taylor expanded in r around inf 99.7%
*-un-lft-identity99.7%
exp-prod99.7%
Applied egg-rr99.7%
Final simplification99.7%
(FPCore (s r) :precision binary32 (/ (+ (* 0.125 (/ (exp (/ (- r) s)) (* s PI))) (* 0.125 (/ (exp (/ (/ r s) -3.0)) (* s PI)))) r))
float code(float s, float r) {
return ((0.125f * (expf((-r / s)) / (s * ((float) M_PI)))) + (0.125f * (expf(((r / s) / -3.0f)) / (s * ((float) M_PI))))) / r;
}
function code(s, r) return Float32(Float32(Float32(Float32(0.125) * Float32(exp(Float32(Float32(-r) / s)) / Float32(s * Float32(pi)))) + Float32(Float32(0.125) * Float32(exp(Float32(Float32(r / s) / Float32(-3.0))) / Float32(s * Float32(pi))))) / r) end
function tmp = code(s, r) tmp = ((single(0.125) * (exp((-r / s)) / (s * single(pi)))) + (single(0.125) * (exp(((r / s) / single(-3.0))) / (s * single(pi))))) / r; end
\begin{array}{l}
\\
\frac{0.125 \cdot \frac{e^{\frac{-r}{s}}}{s \cdot \pi} + 0.125 \cdot \frac{e^{\frac{\frac{r}{s}}{-3}}}{s \cdot \pi}}{r}
\end{array}
Initial program 99.6%
+-commutative99.6%
times-frac99.6%
fma-define99.7%
associate-*l*99.7%
associate-/r*99.7%
metadata-eval99.7%
*-commutative99.7%
neg-mul-199.7%
times-frac99.7%
metadata-eval99.7%
times-frac99.6%
Simplified99.6%
add-cube-cbrt99.7%
pow399.7%
Applied egg-rr99.7%
Taylor expanded in r around inf 99.7%
metadata-eval99.7%
times-frac99.7%
neg-mul-199.7%
*-commutative99.7%
associate-/r*99.7%
frac-2neg99.7%
distribute-frac-neg299.7%
frac-2neg99.7%
metadata-eval99.7%
Applied egg-rr99.7%
Final simplification99.7%
(FPCore (s r) :precision binary32 (/ (+ (/ (/ 0.125 (exp (/ r s))) (* s PI)) (* 0.125 (/ (exp (* -0.3333333333333333 (/ r s))) (* s PI)))) r))
float code(float s, float r) {
return (((0.125f / expf((r / s))) / (s * ((float) M_PI))) + (0.125f * (expf((-0.3333333333333333f * (r / s))) / (s * ((float) M_PI))))) / r;
}
function code(s, r) return Float32(Float32(Float32(Float32(Float32(0.125) / exp(Float32(r / s))) / Float32(s * Float32(pi))) + Float32(Float32(0.125) * Float32(exp(Float32(Float32(-0.3333333333333333) * Float32(r / s))) / Float32(s * Float32(pi))))) / r) end
function tmp = code(s, r) tmp = (((single(0.125) / exp((r / s))) / (s * single(pi))) + (single(0.125) * (exp((single(-0.3333333333333333) * (r / s))) / (s * single(pi))))) / r; end
\begin{array}{l}
\\
\frac{\frac{\frac{0.125}{e^{\frac{r}{s}}}}{s \cdot \pi} + 0.125 \cdot \frac{e^{-0.3333333333333333 \cdot \frac{r}{s}}}{s \cdot \pi}}{r}
\end{array}
Initial program 99.6%
+-commutative99.6%
times-frac99.6%
fma-define99.7%
associate-*l*99.7%
associate-/r*99.7%
metadata-eval99.7%
*-commutative99.7%
neg-mul-199.7%
times-frac99.7%
metadata-eval99.7%
times-frac99.6%
Simplified99.6%
add-cube-cbrt99.7%
pow399.7%
Applied egg-rr99.7%
Taylor expanded in r around inf 99.7%
associate-*r/99.7%
associate-*r/99.7%
neg-mul-199.7%
Applied egg-rr99.7%
distribute-frac-neg99.7%
rec-exp99.7%
associate-*r/99.7%
metadata-eval99.7%
Simplified99.7%
(FPCore (s r) :precision binary32 (* -0.125 (/ (exp (* -0.3333333333333333 (/ r s))) (* r (* s PI)))))
float code(float s, float r) {
return -0.125f * (expf((-0.3333333333333333f * (r / s))) / (r * (s * ((float) M_PI))));
}
function code(s, r) return Float32(Float32(-0.125) * Float32(exp(Float32(Float32(-0.3333333333333333) * Float32(r / s))) / Float32(r * Float32(s * Float32(pi))))) end
function tmp = code(s, r) tmp = single(-0.125) * (exp((single(-0.3333333333333333) * (r / s))) / (r * (s * single(pi)))); end
\begin{array}{l}
\\
-0.125 \cdot \frac{e^{-0.3333333333333333 \cdot \frac{r}{s}}}{r \cdot \left(s \cdot \pi\right)}
\end{array}
Initial program 99.6%
times-frac99.6%
*-commutative99.6%
distribute-frac-neg99.6%
associate-/l*99.6%
*-commutative99.6%
*-commutative99.6%
associate-*l*99.6%
Simplified99.6%
Applied egg-rr99.7%
Taylor expanded in r around 0 18.7%
associate-/l*18.7%
Simplified18.7%
add-sqr-sqrt18.7%
sqrt-unprod8.8%
sqr-neg8.8%
sqrt-unprod-0.0%
add-sqr-sqrt13.8%
distribute-rgt-neg-in13.8%
*-commutative13.8%
neg-sub013.8%
Applied egg-rr13.8%
neg-sub013.8%
distribute-lft-neg-in13.8%
Simplified13.8%
Taylor expanded in s around 0 90.2%
(FPCore (s r)
:precision binary32
(/
(+
(/
(-
(* 0.16666666666666666 (/ -1.0 PI))
(/ (+ (* -0.0625 (/ r PI)) (* (/ r PI) -0.006944444444444444)) s))
s)
(* 0.25 (/ 1.0 (* PI r))))
s))
float code(float s, float r) {
return ((((0.16666666666666666f * (-1.0f / ((float) M_PI))) - (((-0.0625f * (r / ((float) M_PI))) + ((r / ((float) M_PI)) * -0.006944444444444444f)) / s)) / s) + (0.25f * (1.0f / (((float) M_PI) * r)))) / s;
}
function code(s, r) return Float32(Float32(Float32(Float32(Float32(Float32(0.16666666666666666) * Float32(Float32(-1.0) / Float32(pi))) - Float32(Float32(Float32(Float32(-0.0625) * Float32(r / Float32(pi))) + Float32(Float32(r / Float32(pi)) * Float32(-0.006944444444444444))) / s)) / s) + Float32(Float32(0.25) * Float32(Float32(1.0) / Float32(Float32(pi) * r)))) / s) end
function tmp = code(s, r) tmp = ((((single(0.16666666666666666) * (single(-1.0) / single(pi))) - (((single(-0.0625) * (r / single(pi))) + ((r / single(pi)) * single(-0.006944444444444444))) / s)) / s) + (single(0.25) * (single(1.0) / (single(pi) * r)))) / s; end
\begin{array}{l}
\\
\frac{\frac{0.16666666666666666 \cdot \frac{-1}{\pi} - \frac{-0.0625 \cdot \frac{r}{\pi} + \frac{r}{\pi} \cdot -0.006944444444444444}{s}}{s} + 0.25 \cdot \frac{1}{\pi \cdot r}}{s}
\end{array}
Initial program 99.6%
+-commutative99.6%
times-frac99.6%
fma-define99.7%
associate-*l*99.7%
associate-/r*99.7%
metadata-eval99.7%
*-commutative99.7%
neg-mul-199.7%
times-frac99.7%
metadata-eval99.7%
times-frac99.6%
Simplified99.6%
add-cube-cbrt99.7%
pow399.7%
Applied egg-rr99.7%
Taylor expanded in s around -inf 9.1%
Final simplification9.1%
(FPCore (s r)
:precision binary32
(/
(-
(/ 0.25 (* PI r))
(/
(+ (/ (* (/ r PI) -0.06944444444444445) s) (/ 0.16666666666666666 PI))
s))
s))
float code(float s, float r) {
return ((0.25f / (((float) M_PI) * r)) - (((((r / ((float) M_PI)) * -0.06944444444444445f) / s) + (0.16666666666666666f / ((float) M_PI))) / s)) / s;
}
function code(s, r) return Float32(Float32(Float32(Float32(0.25) / Float32(Float32(pi) * r)) - Float32(Float32(Float32(Float32(Float32(r / Float32(pi)) * Float32(-0.06944444444444445)) / s) + Float32(Float32(0.16666666666666666) / Float32(pi))) / s)) / s) end
function tmp = code(s, r) tmp = ((single(0.25) / (single(pi) * r)) - (((((r / single(pi)) * single(-0.06944444444444445)) / s) + (single(0.16666666666666666) / single(pi))) / s)) / s; end
\begin{array}{l}
\\
\frac{\frac{0.25}{\pi \cdot r} - \frac{\frac{\frac{r}{\pi} \cdot -0.06944444444444445}{s} + \frac{0.16666666666666666}{\pi}}{s}}{s}
\end{array}
Initial program 99.6%
+-commutative99.6%
times-frac99.6%
fma-define99.7%
associate-*l*99.7%
associate-/r*99.7%
metadata-eval99.7%
*-commutative99.7%
neg-mul-199.7%
times-frac99.7%
metadata-eval99.7%
times-frac99.6%
Simplified99.6%
add-cube-cbrt99.7%
pow399.7%
Applied egg-rr99.7%
Taylor expanded in s around -inf 9.1%
mul-1-neg9.1%
Simplified9.1%
Final simplification9.1%
(FPCore (s r) :precision binary32 (/ (- (/ 0.25 (* PI r)) (/ 0.16666666666666666 (* s PI))) s))
float code(float s, float r) {
return ((0.25f / (((float) M_PI) * r)) - (0.16666666666666666f / (s * ((float) M_PI)))) / s;
}
function code(s, r) return Float32(Float32(Float32(Float32(0.25) / Float32(Float32(pi) * r)) - Float32(Float32(0.16666666666666666) / Float32(s * Float32(pi)))) / s) end
function tmp = code(s, r) tmp = ((single(0.25) / (single(pi) * r)) - (single(0.16666666666666666) / (s * single(pi)))) / s; end
\begin{array}{l}
\\
\frac{\frac{0.25}{\pi \cdot r} - \frac{0.16666666666666666}{s \cdot \pi}}{s}
\end{array}
Initial program 99.6%
+-commutative99.6%
times-frac99.6%
fma-define99.7%
associate-*l*99.7%
associate-/r*99.7%
metadata-eval99.7%
*-commutative99.7%
neg-mul-199.7%
times-frac99.7%
metadata-eval99.7%
times-frac99.6%
Simplified99.6%
add-cube-cbrt99.7%
pow399.7%
Applied egg-rr99.7%
Taylor expanded in s around inf 8.3%
associate-*r/8.3%
metadata-eval8.3%
*-commutative8.3%
associate-*r/8.3%
metadata-eval8.3%
Simplified8.3%
(FPCore (s r) :precision binary32 (* (/ 0.25 r) (/ 1.0 (* s PI))))
float code(float s, float r) {
return (0.25f / r) * (1.0f / (s * ((float) M_PI)));
}
function code(s, r) return Float32(Float32(Float32(0.25) / r) * Float32(Float32(1.0) / Float32(s * Float32(pi)))) end
function tmp = code(s, r) tmp = (single(0.25) / r) * (single(1.0) / (s * single(pi))); end
\begin{array}{l}
\\
\frac{0.25}{r} \cdot \frac{1}{s \cdot \pi}
\end{array}
Initial program 99.6%
+-commutative99.6%
times-frac99.6%
fma-define99.7%
associate-*l*99.7%
associate-/r*99.7%
metadata-eval99.7%
*-commutative99.7%
neg-mul-199.7%
times-frac99.7%
metadata-eval99.7%
times-frac99.6%
Simplified99.6%
add-cube-cbrt99.7%
pow399.7%
Applied egg-rr99.7%
Taylor expanded in s around inf 8.3%
associate-/r*8.3%
div-inv8.3%
Applied egg-rr8.3%
(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(0.25) / r) / Float32(s * Float32(pi))) end
function tmp = code(s, r) tmp = (single(0.25) / r) / (s * single(pi)); end
\begin{array}{l}
\\
\frac{\frac{0.25}{r}}{s \cdot \pi}
\end{array}
Initial program 99.6%
+-commutative99.6%
times-frac99.6%
fma-define99.7%
associate-*l*99.7%
associate-/r*99.7%
metadata-eval99.7%
*-commutative99.7%
neg-mul-199.7%
times-frac99.7%
metadata-eval99.7%
times-frac99.6%
Simplified99.6%
add-cube-cbrt99.7%
pow399.7%
Applied egg-rr99.7%
Taylor expanded in s around inf 8.3%
associate-/r*8.3%
Simplified8.3%
(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(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 99.6%
+-commutative99.6%
times-frac99.6%
fma-define99.7%
associate-*l*99.7%
associate-/r*99.7%
metadata-eval99.7%
*-commutative99.7%
neg-mul-199.7%
times-frac99.7%
metadata-eval99.7%
times-frac99.6%
Simplified99.6%
add-cube-cbrt99.7%
pow399.7%
Applied egg-rr99.7%
Taylor expanded in s around inf 8.3%
herbie shell --seed 2024112
(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))))