
(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 (+ (* (/ 0.125 (* s PI)) (/ (exp (/ r (- s))) r)) (* 0.75 (/ (exp (/ r (* s (- 3.0)))) (* s (* r (* PI 6.0)))))))
float code(float s, float r) {
return ((0.125f / (s * ((float) M_PI))) * (expf((r / -s)) / r)) + (0.75f * (expf((r / (s * -3.0f))) / (s * (r * (((float) M_PI) * 6.0f)))));
}
function code(s, r) return Float32(Float32(Float32(Float32(0.125) / Float32(s * Float32(pi))) * Float32(exp(Float32(r / Float32(-s))) / r)) + Float32(Float32(0.75) * Float32(exp(Float32(r / Float32(s * Float32(-Float32(3.0))))) / Float32(s * Float32(r * Float32(Float32(pi) * Float32(6.0))))))) end
function tmp = code(s, r) tmp = ((single(0.125) / (s * single(pi))) * (exp((r / -s)) / r)) + (single(0.75) * (exp((r / (s * -single(3.0)))) / (s * (r * (single(pi) * single(6.0)))))); end
\begin{array}{l}
\\
\frac{0.125}{s \cdot \pi} \cdot \frac{e^{\frac{r}{-s}}}{r} + 0.75 \cdot \frac{e^{\frac{r}{s \cdot \left(-3\right)}}}{s \cdot \left(r \cdot \left(\pi \cdot 6\right)\right)}
\end{array}
Initial program 99.6%
times-frac99.6%
*-commutative99.6%
distribute-frac-neg99.6%
associate-/l*99.7%
*-commutative99.7%
*-commutative99.7%
associate-*l*99.6%
Simplified99.6%
Taylor expanded in s around 0 99.6%
Taylor expanded in s around 0 99.6%
*-commutative99.6%
associate-*r*99.7%
Simplified99.7%
Taylor expanded in r around 0 99.6%
*-commutative99.6%
associate-*r*99.6%
associate-*r*99.7%
*-commutative99.7%
associate-*l*99.7%
*-commutative99.7%
Simplified99.7%
Final simplification99.7%
(FPCore (s r) :precision binary32 (/ (+ (* 0.125 (/ (exp (/ r (- s))) (* PI r))) (* 0.125 (/ (exp (* (/ r s) -0.3333333333333333)) (* PI r)))) s))
float code(float s, float r) {
return ((0.125f * (expf((r / -s)) / (((float) M_PI) * r))) + (0.125f * (expf(((r / s) * -0.3333333333333333f)) / (((float) M_PI) * r)))) / s;
}
function code(s, r) return Float32(Float32(Float32(Float32(0.125) * Float32(exp(Float32(r / Float32(-s))) / Float32(Float32(pi) * r))) + Float32(Float32(0.125) * Float32(exp(Float32(Float32(r / s) * Float32(-0.3333333333333333))) / Float32(Float32(pi) * r)))) / s) end
function tmp = code(s, r) tmp = ((single(0.125) * (exp((r / -s)) / (single(pi) * r))) + (single(0.125) * (exp(((r / s) * single(-0.3333333333333333))) / (single(pi) * r)))) / s; end
\begin{array}{l}
\\
\frac{0.125 \cdot \frac{e^{\frac{r}{-s}}}{\pi \cdot r} + 0.125 \cdot \frac{e^{\frac{r}{s} \cdot -0.3333333333333333}}{\pi \cdot r}}{s}
\end{array}
Initial program 99.6%
+-commutative99.6%
times-frac99.6%
fma-define99.7%
associate-*l*99.6%
associate-/r*99.7%
metadata-eval99.7%
*-commutative99.7%
neg-mul-199.7%
times-frac99.7%
metadata-eval99.7%
times-frac99.7%
Simplified99.7%
Taylor expanded in s around 0 99.7%
Final simplification99.7%
(FPCore (s r) :precision binary32 (/ (+ (* 0.125 (/ (exp (/ r (- s))) PI)) (* 0.125 (/ (exp (* (/ r s) -0.3333333333333333)) PI))) (* s r)))
float code(float s, float r) {
return ((0.125f * (expf((r / -s)) / ((float) M_PI))) + (0.125f * (expf(((r / s) * -0.3333333333333333f)) / ((float) M_PI)))) / (s * r);
}
function code(s, r) return Float32(Float32(Float32(Float32(0.125) * Float32(exp(Float32(r / Float32(-s))) / Float32(pi))) + Float32(Float32(0.125) * Float32(exp(Float32(Float32(r / s) * Float32(-0.3333333333333333))) / Float32(pi)))) / Float32(s * r)) end
function tmp = code(s, r) tmp = ((single(0.125) * (exp((r / -s)) / single(pi))) + (single(0.125) * (exp(((r / s) * single(-0.3333333333333333))) / single(pi)))) / (s * r); end
\begin{array}{l}
\\
\frac{0.125 \cdot \frac{e^{\frac{r}{-s}}}{\pi} + 0.125 \cdot \frac{e^{\frac{r}{s} \cdot -0.3333333333333333}}{\pi}}{s \cdot r}
\end{array}
Initial program 99.6%
+-commutative99.6%
times-frac99.6%
fma-define99.7%
associate-*l*99.6%
associate-/r*99.7%
metadata-eval99.7%
*-commutative99.7%
neg-mul-199.7%
times-frac99.7%
metadata-eval99.7%
times-frac99.7%
Simplified99.7%
Taylor expanded in s around 0 99.7%
Taylor expanded in r around inf 99.7%
Final simplification99.7%
(FPCore (s r) :precision binary32 (/ 0.25 (log1p (expm1 (* s (* PI r))))))
float code(float s, float r) {
return 0.25f / log1pf(expm1f((s * (((float) M_PI) * r))));
}
function code(s, r) return Float32(Float32(0.25) / log1p(expm1(Float32(s * Float32(Float32(pi) * r))))) end
\begin{array}{l}
\\
\frac{0.25}{\mathsf{log1p}\left(\mathsf{expm1}\left(s \cdot \left(\pi \cdot r\right)\right)\right)}
\end{array}
Initial program 99.6%
+-commutative99.6%
times-frac99.6%
fma-define99.7%
associate-*l*99.6%
associate-/r*99.7%
metadata-eval99.7%
*-commutative99.7%
neg-mul-199.7%
times-frac99.7%
metadata-eval99.7%
times-frac99.7%
Simplified99.7%
Taylor expanded in s around inf 8.1%
*-commutative8.1%
associate-*l*8.1%
Simplified8.1%
log1p-expm1-u9.4%
*-commutative9.4%
*-commutative9.4%
Applied egg-rr9.4%
Final simplification9.4%
(FPCore (s r)
:precision binary32
(/
(+
(* 0.125 (/ (exp (* (/ r s) -0.3333333333333333)) (* PI r)))
(*
0.125
(+ (/ (- (/ -1.0 PI) (* -0.5 (/ r (* s PI)))) s) (/ 1.0 (* PI r)))))
s))
float code(float s, float r) {
return ((0.125f * (expf(((r / s) * -0.3333333333333333f)) / (((float) M_PI) * r))) + (0.125f * ((((-1.0f / ((float) M_PI)) - (-0.5f * (r / (s * ((float) M_PI))))) / s) + (1.0f / (((float) M_PI) * r))))) / s;
}
function code(s, r) return Float32(Float32(Float32(Float32(0.125) * Float32(exp(Float32(Float32(r / s) * Float32(-0.3333333333333333))) / Float32(Float32(pi) * r))) + Float32(Float32(0.125) * Float32(Float32(Float32(Float32(Float32(-1.0) / Float32(pi)) - Float32(Float32(-0.5) * Float32(r / Float32(s * Float32(pi))))) / s) + Float32(Float32(1.0) / Float32(Float32(pi) * r))))) / s) end
function tmp = code(s, r) tmp = ((single(0.125) * (exp(((r / s) * single(-0.3333333333333333))) / (single(pi) * r))) + (single(0.125) * ((((single(-1.0) / single(pi)) - (single(-0.5) * (r / (s * single(pi))))) / s) + (single(1.0) / (single(pi) * r))))) / s; end
\begin{array}{l}
\\
\frac{0.125 \cdot \frac{e^{\frac{r}{s} \cdot -0.3333333333333333}}{\pi \cdot r} + 0.125 \cdot \left(\frac{\frac{-1}{\pi} - -0.5 \cdot \frac{r}{s \cdot \pi}}{s} + \frac{1}{\pi \cdot r}\right)}{s}
\end{array}
Initial program 99.6%
+-commutative99.6%
times-frac99.6%
fma-define99.7%
associate-*l*99.6%
associate-/r*99.7%
metadata-eval99.7%
*-commutative99.7%
neg-mul-199.7%
times-frac99.7%
metadata-eval99.7%
times-frac99.7%
Simplified99.7%
Taylor expanded in s around 0 99.7%
Taylor expanded in s around -inf 9.2%
Final simplification9.2%
(FPCore (s r) :precision binary32 (/ (+ (* (/ (/ r PI) (pow s 2.0)) 0.06944444444444445) (/ (+ (/ 0.25 r) (/ -0.16666666666666666 s)) PI)) s))
float code(float s, float r) {
return ((((r / ((float) M_PI)) / powf(s, 2.0f)) * 0.06944444444444445f) + (((0.25f / r) + (-0.16666666666666666f / s)) / ((float) M_PI))) / s;
}
function code(s, r) return Float32(Float32(Float32(Float32(Float32(r / Float32(pi)) / (s ^ Float32(2.0))) * Float32(0.06944444444444445)) + Float32(Float32(Float32(Float32(0.25) / r) + Float32(Float32(-0.16666666666666666) / s)) / Float32(pi))) / s) end
function tmp = code(s, r) tmp = ((((r / single(pi)) / (s ^ single(2.0))) * single(0.06944444444444445)) + (((single(0.25) / r) + (single(-0.16666666666666666) / s)) / single(pi))) / s; end
\begin{array}{l}
\\
\frac{\frac{\frac{r}{\pi}}{{s}^{2}} \cdot 0.06944444444444445 + \frac{\frac{0.25}{r} + \frac{-0.16666666666666666}{s}}{\pi}}{s}
\end{array}
Initial program 99.6%
+-commutative99.6%
times-frac99.6%
fma-define99.7%
associate-*l*99.6%
associate-/r*99.7%
metadata-eval99.7%
*-commutative99.7%
neg-mul-199.7%
times-frac99.7%
metadata-eval99.7%
times-frac99.7%
Simplified99.7%
Taylor expanded in s around 0 99.7%
Taylor expanded in s around inf 9.2%
Simplified9.2%
(FPCore (s r) :precision binary32 (/ (+ (/ (- (* (/ r (* s PI)) 0.06944444444444445) (/ 0.16666666666666666 PI)) s) (/ 0.25 (* PI r))) s))
float code(float s, float r) {
return (((((r / (s * ((float) M_PI))) * 0.06944444444444445f) - (0.16666666666666666f / ((float) M_PI))) / s) + (0.25f / (((float) M_PI) * r))) / s;
}
function code(s, r) return Float32(Float32(Float32(Float32(Float32(Float32(r / Float32(s * Float32(pi))) * Float32(0.06944444444444445)) - Float32(Float32(0.16666666666666666) / Float32(pi))) / s) + Float32(Float32(0.25) / Float32(Float32(pi) * r))) / s) end
function tmp = code(s, r) tmp = (((((r / (s * single(pi))) * single(0.06944444444444445)) - (single(0.16666666666666666) / single(pi))) / s) + (single(0.25) / (single(pi) * r))) / s; end
\begin{array}{l}
\\
\frac{\frac{\frac{r}{s \cdot \pi} \cdot 0.06944444444444445 - \frac{0.16666666666666666}{\pi}}{s} + \frac{0.25}{\pi \cdot r}}{s}
\end{array}
Initial program 99.6%
+-commutative99.6%
times-frac99.6%
fma-define99.7%
associate-*l*99.6%
associate-/r*99.7%
metadata-eval99.7%
*-commutative99.7%
neg-mul-199.7%
times-frac99.7%
metadata-eval99.7%
times-frac99.7%
Simplified99.7%
Taylor expanded in s around 0 99.7%
Taylor expanded in s around -inf 9.2%
mul-1-neg9.2%
Simplified9.2%
Final simplification9.2%
(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*99.6%
associate-/r*99.7%
metadata-eval99.7%
*-commutative99.7%
neg-mul-199.7%
times-frac99.7%
metadata-eval99.7%
times-frac99.7%
Simplified99.7%
Taylor expanded in r around inf 99.6%
Taylor expanded in s around -inf 9.2%
associate-*r/9.2%
Simplified9.2%
Final simplification9.2%
(FPCore (s r) :precision binary32 (* (/ (- (/ 0.25 r) (/ 0.16666666666666666 s)) PI) (/ 1.0 s)))
float code(float s, float r) {
return (((0.25f / r) - (0.16666666666666666f / s)) / ((float) M_PI)) * (1.0f / s);
}
function code(s, r) return Float32(Float32(Float32(Float32(Float32(0.25) / r) - Float32(Float32(0.16666666666666666) / s)) / Float32(pi)) * Float32(Float32(1.0) / s)) end
function tmp = code(s, r) tmp = (((single(0.25) / r) - (single(0.16666666666666666) / s)) / single(pi)) * (single(1.0) / s); end
\begin{array}{l}
\\
\frac{\frac{0.25}{r} - \frac{0.16666666666666666}{s}}{\pi} \cdot \frac{1}{s}
\end{array}
Initial program 99.6%
+-commutative99.6%
times-frac99.6%
fma-define99.7%
associate-*l*99.6%
associate-/r*99.7%
metadata-eval99.7%
*-commutative99.7%
neg-mul-199.7%
times-frac99.7%
metadata-eval99.7%
times-frac99.7%
Simplified99.7%
Taylor expanded in s around inf 8.5%
associate-*r/8.5%
metadata-eval8.5%
associate-/r*8.5%
associate-*r/8.5%
metadata-eval8.5%
associate-/r*8.5%
Simplified8.5%
div-inv8.5%
sub-div8.5%
Applied egg-rr8.5%
(FPCore (s r) :precision binary32 (/ (- (/ 0.25 r) (/ 0.16666666666666666 s)) (* s PI)))
float code(float s, float r) {
return ((0.25f / r) - (0.16666666666666666f / s)) / (s * ((float) M_PI));
}
function code(s, r) return Float32(Float32(Float32(Float32(0.25) / r) - Float32(Float32(0.16666666666666666) / s)) / Float32(s * Float32(pi))) end
function tmp = code(s, r) tmp = ((single(0.25) / r) - (single(0.16666666666666666) / s)) / (s * single(pi)); end
\begin{array}{l}
\\
\frac{\frac{0.25}{r} - \frac{0.16666666666666666}{s}}{s \cdot \pi}
\end{array}
Initial program 99.6%
+-commutative99.6%
times-frac99.6%
fma-define99.7%
associate-*l*99.6%
associate-/r*99.7%
metadata-eval99.7%
*-commutative99.7%
neg-mul-199.7%
times-frac99.7%
metadata-eval99.7%
times-frac99.7%
Simplified99.7%
Taylor expanded in s around 0 99.7%
Taylor expanded in s around inf 8.5%
associate-*r/8.5%
metadata-eval8.5%
associate-/r*8.5%
associate-*r/8.5%
metadata-eval8.5%
associate-/r*8.5%
div-sub8.5%
associate-/l/8.5%
Simplified8.5%
(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*99.6%
associate-/r*99.7%
metadata-eval99.7%
*-commutative99.7%
neg-mul-199.7%
times-frac99.7%
metadata-eval99.7%
times-frac99.7%
Simplified99.7%
Taylor expanded in s around inf 8.1%
*-commutative8.1%
Simplified8.1%
Taylor expanded in s around 0 8.1%
associate-/r*8.1%
Simplified8.1%
(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 99.6%
+-commutative99.6%
times-frac99.6%
fma-define99.7%
associate-*l*99.6%
associate-/r*99.7%
metadata-eval99.7%
*-commutative99.7%
neg-mul-199.7%
times-frac99.7%
metadata-eval99.7%
times-frac99.7%
Simplified99.7%
Taylor expanded in s around inf 8.1%
*-commutative8.1%
Simplified8.1%
(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 99.6%
+-commutative99.6%
times-frac99.6%
fma-define99.7%
associate-*l*99.6%
associate-/r*99.7%
metadata-eval99.7%
*-commutative99.7%
neg-mul-199.7%
times-frac99.7%
metadata-eval99.7%
times-frac99.7%
Simplified99.7%
Taylor expanded in s around inf 8.1%
*-commutative8.1%
associate-*l*8.1%
Simplified8.1%
herbie shell --seed 2024087
(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))))