
(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 15 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 (* s (* PI 6.0))))))
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 * (s * (((float) M_PI) * 6.0f))));
}
function code(s, r) return Float32(Float32(Float32(Float32(0.25) * exp(Float32(Float32(-r) / s))) / Float32(r * Float32(s * Float32(Float32(2.0) * Float32(pi))))) + Float32(Float32(Float32(0.75) * exp(Float32(Float32(-r) / Float32(s * Float32(3.0))))) / Float32(r * Float32(s * Float32(Float32(pi) * Float32(6.0)))))) 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 * (s * (single(pi) * single(6.0))))); end
\begin{array}{l}
\\
\frac{0.25 \cdot e^{\frac{-r}{s}}}{r \cdot \left(s \cdot \left(2 \cdot \pi\right)\right)} + \frac{0.75 \cdot e^{\frac{-r}{s \cdot 3}}}{r \cdot \left(s \cdot \left(\pi \cdot 6\right)\right)}
\end{array}
Initial program 99.6%
Final simplification99.6%
(FPCore (s r) :precision binary32 (* 0.125 (/ (+ (exp (/ (- r) s)) (exp (* (/ r s) -0.3333333333333333))) (* r (* s PI)))))
float code(float s, float r) {
return 0.125f * ((expf((-r / s)) + expf(((r / s) * -0.3333333333333333f))) / (r * (s * ((float) M_PI))));
}
function code(s, r) return Float32(Float32(0.125) * Float32(Float32(exp(Float32(Float32(-r) / s)) + exp(Float32(Float32(r / s) * Float32(-0.3333333333333333)))) / Float32(r * Float32(s * Float32(pi))))) end
function tmp = code(s, r) tmp = single(0.125) * ((exp((-r / s)) + exp(((r / s) * single(-0.3333333333333333)))) / (r * (s * single(pi)))); end
\begin{array}{l}
\\
0.125 \cdot \frac{e^{\frac{-r}{s}} + e^{\frac{r}{s} \cdot -0.3333333333333333}}{r \cdot \left(s \cdot \pi\right)}
\end{array}
Initial program 99.6%
Simplified98.9%
Taylor expanded in r around inf 99.5%
mul-1-neg99.5%
exp-neg99.5%
Applied egg-rr99.5%
rec-exp99.5%
distribute-neg-frac99.5%
Simplified99.5%
Final simplification99.5%
(FPCore (s r) :precision binary32 (* 0.125 (/ (+ (exp (/ (- r) s)) (exp (/ (/ r s) -3.0))) (* r (* s PI)))))
float code(float s, float r) {
return 0.125f * ((expf((-r / s)) + expf(((r / s) / -3.0f))) / (r * (s * ((float) M_PI))));
}
function code(s, r) return Float32(Float32(0.125) * Float32(Float32(exp(Float32(Float32(-r) / s)) + exp(Float32(Float32(r / s) / Float32(-3.0)))) / Float32(r * Float32(s * Float32(pi))))) end
function tmp = code(s, r) tmp = single(0.125) * ((exp((-r / s)) + exp(((r / s) / single(-3.0)))) / (r * (s * single(pi)))); end
\begin{array}{l}
\\
0.125 \cdot \frac{e^{\frac{-r}{s}} + e^{\frac{\frac{r}{s}}{-3}}}{r \cdot \left(s \cdot \pi\right)}
\end{array}
Initial program 99.6%
Simplified98.9%
Taylor expanded in r around inf 99.5%
metadata-eval99.5%
times-frac99.6%
neg-mul-199.6%
*-commutative99.6%
associate-/r*99.6%
frac-2neg99.6%
add-sqr-sqrt-0.0%
sqrt-unprod10.0%
sqr-neg10.0%
sqrt-unprod10.0%
add-sqr-sqrt10.0%
distribute-frac-neg10.0%
add-sqr-sqrt-0.0%
sqrt-unprod99.6%
sqr-neg99.6%
sqrt-unprod99.5%
add-sqr-sqrt99.6%
metadata-eval99.6%
Applied egg-rr99.6%
mul-1-neg99.5%
exp-neg99.5%
Applied egg-rr99.6%
rec-exp99.5%
distribute-neg-frac99.5%
Simplified99.6%
Final simplification99.6%
(FPCore (s r) :precision binary32 (/ 0.25 (log1p (expm1 (* s (* r PI))))))
float code(float s, float r) {
return 0.25f / log1pf(expm1f((s * (r * ((float) M_PI)))));
}
function code(s, r) return Float32(Float32(0.25) / log1p(expm1(Float32(s * Float32(r * Float32(pi)))))) end
\begin{array}{l}
\\
\frac{0.25}{\mathsf{log1p}\left(\mathsf{expm1}\left(s \cdot \left(r \cdot \pi\right)\right)\right)}
\end{array}
Initial program 99.6%
Simplified98.9%
Taylor expanded in s around inf 11.1%
add-sqr-sqrt11.1%
sqrt-unprod11.1%
sqr-neg11.1%
sqrt-unprod-0.0%
add-sqr-sqrt4.4%
distribute-lft-neg-in4.4%
log1p-expm1-u7.8%
distribute-lft-neg-in7.8%
add-sqr-sqrt-0.0%
sqrt-unprod13.4%
sqr-neg13.4%
sqrt-unprod13.4%
add-sqr-sqrt13.4%
*-commutative13.4%
associate-*l*13.4%
Applied egg-rr13.4%
Final simplification13.4%
(FPCore (s r) :precision binary32 (/ 0.25 (* s (log1p (expm1 (* r PI))))))
float code(float s, float r) {
return 0.25f / (s * log1pf(expm1f((r * ((float) M_PI)))));
}
function code(s, r) return Float32(Float32(0.25) / Float32(s * log1p(expm1(Float32(r * Float32(pi)))))) end
\begin{array}{l}
\\
\frac{0.25}{s \cdot \mathsf{log1p}\left(\mathsf{expm1}\left(r \cdot \pi\right)\right)}
\end{array}
Initial program 99.6%
Simplified98.9%
Taylor expanded in s around inf 11.1%
expm1-log1p-u11.1%
expm1-udef9.4%
*-commutative9.4%
associate-*l*9.4%
Applied egg-rr9.4%
expm1-def11.1%
expm1-log1p11.1%
Simplified11.1%
log1p-expm1-u46.9%
*-commutative46.9%
Applied egg-rr46.9%
Final simplification46.9%
(FPCore (s r) :precision binary32 (* 0.125 (/ (+ (exp (* (/ r s) -0.3333333333333333)) (- 1.0 (/ r s))) (* r (* s PI)))))
float code(float s, float r) {
return 0.125f * ((expf(((r / s) * -0.3333333333333333f)) + (1.0f - (r / s))) / (r * (s * ((float) M_PI))));
}
function code(s, r) return Float32(Float32(0.125) * Float32(Float32(exp(Float32(Float32(r / s) * Float32(-0.3333333333333333))) + Float32(Float32(1.0) - Float32(r / s))) / Float32(r * Float32(s * Float32(pi))))) end
function tmp = code(s, r) tmp = single(0.125) * ((exp(((r / s) * single(-0.3333333333333333))) + (single(1.0) - (r / s))) / (r * (s * single(pi)))); end
\begin{array}{l}
\\
0.125 \cdot \frac{e^{\frac{r}{s} \cdot -0.3333333333333333} + \left(1 - \frac{r}{s}\right)}{r \cdot \left(s \cdot \pi\right)}
\end{array}
Initial program 99.6%
Simplified98.9%
Taylor expanded in r around inf 99.5%
Taylor expanded in r around 0 11.4%
mul-1-neg11.4%
unsub-neg11.4%
Simplified11.4%
Final simplification11.4%
(FPCore (s r) :precision binary32 (* 0.125 (/ (+ (exp (/ (/ r s) -3.0)) (- 1.0 (/ r s))) (* r (* s PI)))))
float code(float s, float r) {
return 0.125f * ((expf(((r / s) / -3.0f)) + (1.0f - (r / s))) / (r * (s * ((float) M_PI))));
}
function code(s, r) return Float32(Float32(0.125) * Float32(Float32(exp(Float32(Float32(r / s) / Float32(-3.0))) + Float32(Float32(1.0) - Float32(r / s))) / Float32(r * Float32(s * Float32(pi))))) end
function tmp = code(s, r) tmp = single(0.125) * ((exp(((r / s) / single(-3.0))) + (single(1.0) - (r / s))) / (r * (s * single(pi)))); end
\begin{array}{l}
\\
0.125 \cdot \frac{e^{\frac{\frac{r}{s}}{-3}} + \left(1 - \frac{r}{s}\right)}{r \cdot \left(s \cdot \pi\right)}
\end{array}
Initial program 99.6%
Simplified98.9%
Taylor expanded in r around inf 99.5%
metadata-eval99.5%
times-frac99.6%
neg-mul-199.6%
*-commutative99.6%
associate-/r*99.6%
frac-2neg99.6%
add-sqr-sqrt-0.0%
sqrt-unprod10.0%
sqr-neg10.0%
sqrt-unprod10.0%
add-sqr-sqrt10.0%
distribute-frac-neg10.0%
add-sqr-sqrt-0.0%
sqrt-unprod99.6%
sqr-neg99.6%
sqrt-unprod99.5%
add-sqr-sqrt99.6%
metadata-eval99.6%
Applied egg-rr99.6%
Taylor expanded in r around 0 11.4%
mul-1-neg11.4%
unsub-neg11.4%
Simplified11.4%
Final simplification11.4%
(FPCore (s r) :precision binary32 (* 0.125 (/ (+ (exp (/ (/ r s) -3.0)) (- 1.0 (/ r s))) (* s (* r PI)))))
float code(float s, float r) {
return 0.125f * ((expf(((r / s) / -3.0f)) + (1.0f - (r / s))) / (s * (r * ((float) M_PI))));
}
function code(s, r) return Float32(Float32(0.125) * Float32(Float32(exp(Float32(Float32(r / s) / Float32(-3.0))) + Float32(Float32(1.0) - Float32(r / s))) / Float32(s * Float32(r * Float32(pi))))) end
function tmp = code(s, r) tmp = single(0.125) * ((exp(((r / s) / single(-3.0))) + (single(1.0) - (r / s))) / (s * (r * single(pi)))); end
\begin{array}{l}
\\
0.125 \cdot \frac{e^{\frac{\frac{r}{s}}{-3}} + \left(1 - \frac{r}{s}\right)}{s \cdot \left(r \cdot \pi\right)}
\end{array}
Initial program 99.6%
Simplified98.9%
Taylor expanded in r around inf 99.5%
metadata-eval99.5%
times-frac99.6%
neg-mul-199.6%
*-commutative99.6%
associate-/r*99.6%
frac-2neg99.6%
add-sqr-sqrt-0.0%
sqrt-unprod10.0%
sqr-neg10.0%
sqrt-unprod10.0%
add-sqr-sqrt10.0%
distribute-frac-neg10.0%
add-sqr-sqrt-0.0%
sqrt-unprod99.6%
sqr-neg99.6%
sqrt-unprod99.5%
add-sqr-sqrt99.6%
metadata-eval99.6%
Applied egg-rr99.6%
Taylor expanded in r around 0 11.4%
mul-1-neg11.4%
unsub-neg11.4%
Simplified11.4%
expm1-log1p-u11.1%
expm1-udef9.4%
*-commutative9.4%
associate-*l*9.4%
Applied egg-rr9.2%
expm1-def11.1%
expm1-log1p11.1%
Simplified11.4%
Final simplification11.4%
(FPCore (s r) :precision binary32 (* 0.125 (/ (+ (exp (* (/ r s) -0.3333333333333333)) 1.0) (* r (* s PI)))))
float code(float s, float r) {
return 0.125f * ((expf(((r / s) * -0.3333333333333333f)) + 1.0f) / (r * (s * ((float) M_PI))));
}
function code(s, r) return Float32(Float32(0.125) * Float32(Float32(exp(Float32(Float32(r / s) * Float32(-0.3333333333333333))) + Float32(1.0)) / Float32(r * Float32(s * Float32(pi))))) end
function tmp = code(s, r) tmp = single(0.125) * ((exp(((r / s) * single(-0.3333333333333333))) + single(1.0)) / (r * (s * single(pi)))); end
\begin{array}{l}
\\
0.125 \cdot \frac{e^{\frac{r}{s} \cdot -0.3333333333333333} + 1}{r \cdot \left(s \cdot \pi\right)}
\end{array}
Initial program 99.6%
Simplified98.9%
Taylor expanded in r around inf 99.5%
Taylor expanded in r around 0 11.3%
Final simplification11.3%
(FPCore (s r) :precision binary32 (* 0.125 (/ (+ (exp (* (/ r s) -0.3333333333333333)) 1.0) (* s (* r PI)))))
float code(float s, float r) {
return 0.125f * ((expf(((r / s) * -0.3333333333333333f)) + 1.0f) / (s * (r * ((float) M_PI))));
}
function code(s, r) return Float32(Float32(0.125) * Float32(Float32(exp(Float32(Float32(r / s) * Float32(-0.3333333333333333))) + Float32(1.0)) / Float32(s * Float32(r * Float32(pi))))) end
function tmp = code(s, r) tmp = single(0.125) * ((exp(((r / s) * single(-0.3333333333333333))) + single(1.0)) / (s * (r * single(pi)))); end
\begin{array}{l}
\\
0.125 \cdot \frac{e^{\frac{r}{s} \cdot -0.3333333333333333} + 1}{s \cdot \left(r \cdot \pi\right)}
\end{array}
Initial program 99.6%
Simplified98.9%
Taylor expanded in r around inf 99.5%
Taylor expanded in r around 0 11.3%
expm1-log1p-u11.1%
expm1-udef9.4%
*-commutative9.4%
associate-*l*9.4%
Applied egg-rr9.5%
expm1-def11.1%
expm1-log1p11.1%
Simplified11.3%
Final simplification11.3%
(FPCore (s r) :precision binary32 (+ (/ 0.25 (* PI (* r s))) (/ -0.16666666666666666 (* PI (pow s 2.0)))))
float code(float s, float r) {
return (0.25f / (((float) M_PI) * (r * s))) + (-0.16666666666666666f / (((float) M_PI) * powf(s, 2.0f)));
}
function code(s, r) return Float32(Float32(Float32(0.25) / Float32(Float32(pi) * Float32(r * s))) + Float32(Float32(-0.16666666666666666) / Float32(Float32(pi) * (s ^ Float32(2.0))))) end
function tmp = code(s, r) tmp = (single(0.25) / (single(pi) * (r * s))) + (single(-0.16666666666666666) / (single(pi) * (s ^ single(2.0)))); end
\begin{array}{l}
\\
\frac{0.25}{\pi \cdot \left(r \cdot s\right)} + \frac{-0.16666666666666666}{\pi \cdot {s}^{2}}
\end{array}
Initial program 99.6%
Simplified98.9%
Taylor expanded in r around inf 99.5%
associate-*r/99.5%
*-commutative99.5%
times-frac99.1%
mul-1-neg99.1%
distribute-neg-frac99.1%
associate-*r/99.1%
associate-/l*99.2%
Simplified99.2%
Taylor expanded in s around inf 11.2%
sub-neg11.2%
associate-*r/11.2%
metadata-eval11.2%
associate-/r*11.2%
associate-/r*11.2%
associate-*r*11.2%
*-commutative11.2%
associate-*r/11.2%
metadata-eval11.2%
distribute-neg-frac11.2%
metadata-eval11.2%
*-commutative11.2%
Simplified11.2%
Final simplification11.2%
(FPCore (s r) :precision binary32 (- (/ 0.25 (* r (* s PI))) (/ 0.16666666666666666 (* PI (pow s 2.0)))))
float code(float s, float r) {
return (0.25f / (r * (s * ((float) M_PI)))) - (0.16666666666666666f / (((float) M_PI) * powf(s, 2.0f)));
}
function code(s, r) return Float32(Float32(Float32(0.25) / Float32(r * Float32(s * Float32(pi)))) - Float32(Float32(0.16666666666666666) / Float32(Float32(pi) * (s ^ Float32(2.0))))) end
function tmp = code(s, r) tmp = (single(0.25) / (r * (s * single(pi)))) - (single(0.16666666666666666) / (single(pi) * (s ^ single(2.0)))); end
\begin{array}{l}
\\
\frac{0.25}{r \cdot \left(s \cdot \pi\right)} - \frac{0.16666666666666666}{\pi \cdot {s}^{2}}
\end{array}
Initial program 99.6%
Simplified98.9%
Taylor expanded in s around inf 11.2%
associate-*r/11.2%
metadata-eval11.2%
associate-*r/11.2%
metadata-eval11.2%
*-commutative11.2%
Simplified11.2%
Final simplification11.2%
(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%
Simplified98.9%
Taylor expanded in s around inf 11.1%
Final simplification11.1%
(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 99.6%
Simplified98.9%
Taylor expanded in s around inf 11.1%
expm1-log1p-u11.1%
expm1-udef9.4%
*-commutative9.4%
associate-*l*9.4%
Applied egg-rr9.4%
expm1-def11.1%
expm1-log1p11.1%
Simplified11.1%
Taylor expanded in s around 0 11.1%
associate-*r*11.1%
*-commutative11.1%
Simplified11.1%
Final simplification11.1%
(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%
Simplified98.9%
Taylor expanded in s around inf 11.1%
expm1-log1p-u11.1%
expm1-udef9.4%
*-commutative9.4%
associate-*l*9.4%
Applied egg-rr9.4%
expm1-def11.1%
expm1-log1p11.1%
Simplified11.1%
Taylor expanded in s around 0 11.1%
associate-/r*11.1%
Simplified11.1%
Final simplification11.1%
herbie shell --seed 2024040
(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))))