
(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 (+ (/ (* 0.25 (exp (/ r (- s)))) (* r (* s (* 2.0 PI)))) (/ (* 0.75 (exp (/ r (* s (- 3.0))))) (* s (* PI (* r 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)))) / (s * (((float) M_PI) * (r * 6.0f))));
}
function code(s, r) return Float32(Float32(Float32(Float32(0.25) * exp(Float32(r / Float32(-s)))) / Float32(r * Float32(s * Float32(Float32(2.0) * Float32(pi))))) + Float32(Float32(Float32(0.75) * exp(Float32(r / Float32(s * Float32(-Float32(3.0)))))) / Float32(s * Float32(Float32(pi) * Float32(r * 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))))) / (s * (single(pi) * (r * 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 \left(-3\right)}}}{s \cdot \left(\pi \cdot \left(r \cdot 6\right)\right)}
\end{array}
Initial program 99.7%
Taylor expanded in s around 0 99.6%
associate-*r*99.6%
*-commutative99.6%
associate-*r*99.7%
*-commutative99.7%
associate-*l*99.7%
*-commutative99.7%
Simplified99.7%
Taylor expanded in r around 0 99.7%
Taylor expanded in r around 0 99.6%
associate-*r*99.6%
*-commutative99.6%
*-commutative99.6%
*-commutative99.6%
associate-*l*99.7%
Simplified99.7%
Final simplification99.7%
(FPCore (s r) :precision binary32 (+ (/ (* 0.25 (exp (/ r (- s)))) (* r (* s (* 2.0 PI)))) (/ (* 0.75 (exp (* r (/ -0.3333333333333333 s)))) (* s (* PI (* r 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 * (-0.3333333333333333f / s)))) / (s * (((float) M_PI) * (r * 6.0f))));
}
function code(s, r) return Float32(Float32(Float32(Float32(0.25) * exp(Float32(r / Float32(-s)))) / Float32(r * Float32(s * Float32(Float32(2.0) * Float32(pi))))) + 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 = ((single(0.25) * exp((r / -s))) / (r * (s * (single(2.0) * single(pi))))) + ((single(0.75) * exp((r * (single(-0.3333333333333333) / s)))) / (s * (single(pi) * (r * 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^{r \cdot \frac{-0.3333333333333333}{s}}}{s \cdot \left(\pi \cdot \left(r \cdot 6\right)\right)}
\end{array}
Initial program 99.7%
Taylor expanded in s around 0 99.6%
associate-*r*99.6%
*-commutative99.6%
associate-*r*99.7%
*-commutative99.7%
associate-*l*99.7%
*-commutative99.7%
Simplified99.7%
Taylor expanded in r around 0 99.7%
Taylor expanded in r around 0 99.6%
associate-*r*99.6%
*-commutative99.6%
*-commutative99.6%
*-commutative99.6%
associate-*l*99.7%
Simplified99.7%
neg-mul-199.7%
times-frac99.6%
metadata-eval99.6%
clear-num99.7%
div-inv99.6%
associate-/r/99.7%
Applied egg-rr99.7%
Final simplification99.7%
(FPCore (s r) :precision binary32 (* (/ 0.125 (* s PI)) (+ (/ (exp (/ r (- s))) r) (/ (exp (* -0.3333333333333333 (/ r s))) r))))
float code(float s, float r) {
return (0.125f / (s * ((float) M_PI))) * ((expf((r / -s)) / r) + (expf((-0.3333333333333333f * (r / 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(-0.3333333333333333) * Float32(r / s))) / r))) end
function tmp = code(s, r) tmp = (single(0.125) / (s * single(pi))) * ((exp((r / -s)) / r) + (exp((single(-0.3333333333333333) * (r / s))) / r)); end
\begin{array}{l}
\\
\frac{0.125}{s \cdot \pi} \cdot \left(\frac{e^{\frac{r}{-s}}}{r} + \frac{e^{-0.3333333333333333 \cdot \frac{r}{s}}}{r}\right)
\end{array}
Initial program 99.7%
Simplified99.4%
Taylor expanded in r around inf 99.6%
Final simplification99.6%
(FPCore (s r) :precision binary32 (/ 0.25 (log1p (expm1 (* PI (* r s))))))
float code(float s, float r) {
return 0.25f / log1pf(expm1f((((float) M_PI) * (r * s))));
}
function code(s, r) return Float32(Float32(0.25) / log1p(expm1(Float32(Float32(pi) * Float32(r * s))))) end
\begin{array}{l}
\\
\frac{0.25}{\mathsf{log1p}\left(\mathsf{expm1}\left(\pi \cdot \left(r \cdot s\right)\right)\right)}
\end{array}
Initial program 99.7%
Simplified99.4%
Taylor expanded in r around 0 10.6%
Taylor expanded in s around inf 10.0%
associate-*r*10.0%
add-sqr-sqrt10.0%
sqrt-unprod9.8%
sqr-neg9.8%
sqrt-unprod-0.0%
add-sqr-sqrt4.5%
distribute-rgt-neg-in4.5%
distribute-lft-neg-in4.5%
associate-*r*4.5%
log1p-expm1-u7.4%
associate-*r*7.4%
distribute-lft-neg-in7.4%
distribute-rgt-neg-in7.4%
add-sqr-sqrt-0.0%
sqrt-unprod12.3%
sqr-neg12.3%
sqrt-unprod12.5%
add-sqr-sqrt12.5%
*-commutative12.5%
Applied egg-rr12.5%
Final simplification12.5%
(FPCore (s r)
:precision binary32
(*
(/ 0.125 (* s PI))
(+
(/ (exp (/ r (- s))) r)
(/
(+
1.0
(* r (+ (/ -0.3333333333333333 s) (* (/ r s) (/ 0.05555555555555555 s)))))
r))))
float code(float s, float r) {
return (0.125f / (s * ((float) M_PI))) * ((expf((r / -s)) / r) + ((1.0f + (r * ((-0.3333333333333333f / s) + ((r / s) * (0.05555555555555555f / 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(Float32(Float32(1.0) + Float32(r * Float32(Float32(Float32(-0.3333333333333333) / s) + Float32(Float32(r / s) * Float32(Float32(0.05555555555555555) / s))))) / r))) end
function tmp = code(s, r) tmp = (single(0.125) / (s * single(pi))) * ((exp((r / -s)) / r) + ((single(1.0) + (r * ((single(-0.3333333333333333) / s) + ((r / s) * (single(0.05555555555555555) / s))))) / r)); end
\begin{array}{l}
\\
\frac{0.125}{s \cdot \pi} \cdot \left(\frac{e^{\frac{r}{-s}}}{r} + \frac{1 + r \cdot \left(\frac{-0.3333333333333333}{s} + \frac{r}{s} \cdot \frac{0.05555555555555555}{s}\right)}{r}\right)
\end{array}
Initial program 99.7%
Simplified99.4%
Taylor expanded in r around 0 12.1%
cancel-sign-sub-inv12.1%
associate-*r/12.1%
metadata-eval12.1%
associate-*r/12.1%
metadata-eval12.1%
Simplified12.1%
*-commutative12.1%
unpow212.1%
times-frac12.1%
Applied egg-rr12.1%
Final simplification12.1%
(FPCore (s r)
:precision binary32
(*
(/ 0.125 (* s PI))
(+
(/ (exp (/ r (- s))) r)
(-
(/ 1.0 r)
(/ (+ 0.3333333333333333 (* (/ r s) -0.05555555555555555)) s)))))
float code(float s, float r) {
return (0.125f / (s * ((float) M_PI))) * ((expf((r / -s)) / r) + ((1.0f / r) - ((0.3333333333333333f + ((r / s) * -0.05555555555555555f)) / s)));
}
function code(s, r) return Float32(Float32(Float32(0.125) / Float32(s * Float32(pi))) * Float32(Float32(exp(Float32(r / Float32(-s))) / r) + Float32(Float32(Float32(1.0) / r) - Float32(Float32(Float32(0.3333333333333333) + Float32(Float32(r / s) * Float32(-0.05555555555555555))) / s)))) end
function tmp = code(s, r) tmp = (single(0.125) / (s * single(pi))) * ((exp((r / -s)) / r) + ((single(1.0) / r) - ((single(0.3333333333333333) + ((r / s) * single(-0.05555555555555555))) / s))); end
\begin{array}{l}
\\
\frac{0.125}{s \cdot \pi} \cdot \left(\frac{e^{\frac{r}{-s}}}{r} + \left(\frac{1}{r} - \frac{0.3333333333333333 + \frac{r}{s} \cdot -0.05555555555555555}{s}\right)\right)
\end{array}
Initial program 99.7%
Simplified99.4%
Taylor expanded in r around 0 12.1%
cancel-sign-sub-inv12.1%
associate-*r/12.1%
metadata-eval12.1%
associate-*r/12.1%
metadata-eval12.1%
Simplified12.1%
Taylor expanded in s around -inf 12.1%
Final simplification12.1%
(FPCore (s r) :precision binary32 (* (* (/ 0.125 s) (/ 1.0 PI)) (+ (/ (exp (/ r (- s))) r) (/ (+ 1.0 (/ -0.3333333333333333 (/ s r))) r))))
float code(float s, float r) {
return ((0.125f / s) * (1.0f / ((float) M_PI))) * ((expf((r / -s)) / r) + ((1.0f + (-0.3333333333333333f / (s / r))) / r));
}
function code(s, r) return Float32(Float32(Float32(Float32(0.125) / s) * Float32(Float32(1.0) / Float32(pi))) * Float32(Float32(exp(Float32(r / Float32(-s))) / r) + Float32(Float32(Float32(1.0) + Float32(Float32(-0.3333333333333333) / Float32(s / r))) / r))) end
function tmp = code(s, r) tmp = ((single(0.125) / s) * (single(1.0) / single(pi))) * ((exp((r / -s)) / r) + ((single(1.0) + (single(-0.3333333333333333) / (s / r))) / r)); end
\begin{array}{l}
\\
\left(\frac{0.125}{s} \cdot \frac{1}{\pi}\right) \cdot \left(\frac{e^{\frac{r}{-s}}}{r} + \frac{1 + \frac{-0.3333333333333333}{\frac{s}{r}}}{r}\right)
\end{array}
Initial program 99.7%
Simplified99.4%
Taylor expanded in r around 0 11.1%
associate-*r/11.1%
associate-*l/11.1%
associate-/r/11.1%
Simplified11.1%
associate-/r*11.1%
div-inv11.1%
Applied egg-rr11.1%
Final simplification11.1%
(FPCore (s r) :precision binary32 (* (/ 0.125 (* s PI)) (+ (/ (exp (/ r (- s))) r) (- (/ 1.0 r) (/ 0.3333333333333333 s)))))
float code(float s, float r) {
return (0.125f / (s * ((float) M_PI))) * ((expf((r / -s)) / r) + ((1.0f / r) - (0.3333333333333333f / s)));
}
function code(s, r) return Float32(Float32(Float32(0.125) / Float32(s * Float32(pi))) * Float32(Float32(exp(Float32(r / Float32(-s))) / r) + Float32(Float32(Float32(1.0) / r) - Float32(Float32(0.3333333333333333) / s)))) end
function tmp = code(s, r) tmp = (single(0.125) / (s * single(pi))) * ((exp((r / -s)) / r) + ((single(1.0) / r) - (single(0.3333333333333333) / s))); end
\begin{array}{l}
\\
\frac{0.125}{s \cdot \pi} \cdot \left(\frac{e^{\frac{r}{-s}}}{r} + \left(\frac{1}{r} - \frac{0.3333333333333333}{s}\right)\right)
\end{array}
Initial program 99.7%
Simplified99.4%
Taylor expanded in r around 0 11.1%
associate-*r/11.1%
associate-*l/11.1%
associate-/r/11.1%
Simplified11.1%
Taylor expanded in s around inf 11.0%
associate-*r/11.0%
metadata-eval11.0%
Simplified11.0%
Final simplification11.0%
(FPCore (s r) :precision binary32 (* (/ 0.125 (* s PI)) (+ (/ (exp (/ r (- s))) r) (/ (- (/ s r) 0.3333333333333333) s))))
float code(float s, float r) {
return (0.125f / (s * ((float) M_PI))) * ((expf((r / -s)) / r) + (((s / r) - 0.3333333333333333f) / s));
}
function code(s, r) return Float32(Float32(Float32(0.125) / Float32(s * Float32(pi))) * Float32(Float32(exp(Float32(r / Float32(-s))) / r) + Float32(Float32(Float32(s / r) - Float32(0.3333333333333333)) / s))) end
function tmp = code(s, r) tmp = (single(0.125) / (s * single(pi))) * ((exp((r / -s)) / r) + (((s / r) - single(0.3333333333333333)) / s)); end
\begin{array}{l}
\\
\frac{0.125}{s \cdot \pi} \cdot \left(\frac{e^{\frac{r}{-s}}}{r} + \frac{\frac{s}{r} - 0.3333333333333333}{s}\right)
\end{array}
Initial program 99.7%
Simplified99.4%
Taylor expanded in r around 0 11.1%
associate-*r/11.1%
associate-*l/11.1%
associate-/r/11.1%
Simplified11.1%
Taylor expanded in s around 0 11.1%
Final simplification11.1%
(FPCore (s r) :precision binary32 (* 0.125 (/ (+ (/ (exp (/ r (- s))) r) (/ 1.0 r)) (* s PI))))
float code(float s, float r) {
return 0.125f * (((expf((r / -s)) / r) + (1.0f / r)) / (s * ((float) M_PI)));
}
function code(s, r) return Float32(Float32(0.125) * Float32(Float32(Float32(exp(Float32(r / Float32(-s))) / r) + Float32(Float32(1.0) / r)) / Float32(s * Float32(pi)))) end
function tmp = code(s, r) tmp = single(0.125) * (((exp((r / -s)) / r) + (single(1.0) / r)) / (s * single(pi))); end
\begin{array}{l}
\\
0.125 \cdot \frac{\frac{e^{\frac{r}{-s}}}{r} + \frac{1}{r}}{s \cdot \pi}
\end{array}
Initial program 99.7%
Simplified99.4%
Taylor expanded in r around 0 10.6%
Taylor expanded in s around 0 10.6%
associate-*r/10.6%
mul-1-neg10.6%
Simplified10.6%
Final simplification10.6%
(FPCore (s r) :precision binary32 (/ (+ 0.125 (/ 0.125 (exp (/ r s)))) (* r (* s PI))))
float code(float s, float r) {
return (0.125f + (0.125f / expf((r / s)))) / (r * (s * ((float) M_PI)));
}
function code(s, r) return Float32(Float32(Float32(0.125) + Float32(Float32(0.125) / exp(Float32(r / s)))) / Float32(r * Float32(s * Float32(pi)))) end
function tmp = code(s, r) tmp = (single(0.125) + (single(0.125) / exp((r / s)))) / (r * (s * single(pi))); end
\begin{array}{l}
\\
\frac{0.125 + \frac{0.125}{e^{\frac{r}{s}}}}{r \cdot \left(s \cdot \pi\right)}
\end{array}
Initial program 99.7%
Simplified99.4%
Taylor expanded in r around 0 10.6%
Taylor expanded in r around inf 10.6%
associate-*r/10.6%
distribute-lft-in10.6%
metadata-eval10.6%
mul-1-neg10.6%
distribute-neg-frac210.6%
Simplified10.6%
Taylor expanded in r around inf 10.6%
mul-1-neg10.6%
rec-exp10.6%
associate-*r/10.6%
metadata-eval10.6%
Simplified10.6%
Final simplification10.6%
(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 99.7%
Simplified99.4%
Taylor expanded in r around 0 10.6%
Taylor expanded in s around inf 10.0%
Final simplification10.0%
(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 99.7%
Simplified99.4%
Taylor expanded in r around 0 10.6%
Taylor expanded in r around inf 10.6%
associate-*r/10.6%
distribute-lft-in10.6%
metadata-eval10.6%
mul-1-neg10.6%
distribute-neg-frac210.6%
Simplified10.6%
Taylor expanded in r around 0 10.0%
associate-*r*10.0%
*-commutative10.0%
Simplified10.0%
Final simplification10.0%
(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(Float32(Float32(0.25) / Float32(pi)) / r) / s) end
function tmp = code(s, r) tmp = ((single(0.25) / single(pi)) / r) / s; end
\begin{array}{l}
\\
\frac{\frac{\frac{0.25}{\pi}}{r}}{s}
\end{array}
Initial program 99.7%
Simplified99.4%
Taylor expanded in r around 0 10.6%
Taylor expanded in s around inf 10.0%
associate-*r*10.0%
*-commutative10.0%
associate-*l*10.0%
*-commutative10.0%
associate-/l/10.0%
associate-/r*10.0%
Simplified10.0%
Final simplification10.0%
herbie shell --seed 2024080
(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))))