
(FPCore (s u) :precision binary32 (* (* 3.0 s) (log (/ 1.0 (- 1.0 (/ (- u 0.25) 0.75))))))
float code(float s, float u) {
return (3.0f * s) * logf((1.0f / (1.0f - ((u - 0.25f) / 0.75f))));
}
real(4) function code(s, u)
real(4), intent (in) :: s
real(4), intent (in) :: u
code = (3.0e0 * s) * log((1.0e0 / (1.0e0 - ((u - 0.25e0) / 0.75e0))))
end function
function code(s, u) return Float32(Float32(Float32(3.0) * s) * log(Float32(Float32(1.0) / Float32(Float32(1.0) - Float32(Float32(u - Float32(0.25)) / Float32(0.75)))))) end
function tmp = code(s, u) tmp = (single(3.0) * s) * log((single(1.0) / (single(1.0) - ((u - single(0.25)) / single(0.75))))); end
\begin{array}{l}
\\
\left(3 \cdot s\right) \cdot \log \left(\frac{1}{1 - \frac{u - 0.25}{0.75}}\right)
\end{array}
Sampling outcomes in binary32 precision:
Herbie found 8 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (s u) :precision binary32 (* (* 3.0 s) (log (/ 1.0 (- 1.0 (/ (- u 0.25) 0.75))))))
float code(float s, float u) {
return (3.0f * s) * logf((1.0f / (1.0f - ((u - 0.25f) / 0.75f))));
}
real(4) function code(s, u)
real(4), intent (in) :: s
real(4), intent (in) :: u
code = (3.0e0 * s) * log((1.0e0 / (1.0e0 - ((u - 0.25e0) / 0.75e0))))
end function
function code(s, u) return Float32(Float32(Float32(3.0) * s) * log(Float32(Float32(1.0) / Float32(Float32(1.0) - Float32(Float32(u - Float32(0.25)) / Float32(0.75)))))) end
function tmp = code(s, u) tmp = (single(3.0) * s) * log((single(1.0) / (single(1.0) - ((u - single(0.25)) / single(0.75))))); end
\begin{array}{l}
\\
\left(3 \cdot s\right) \cdot \log \left(\frac{1}{1 - \frac{u - 0.25}{0.75}}\right)
\end{array}
(FPCore (s u) :precision binary32 (* (log1p (/ (- (- -0.25) u) 0.75)) (* s -3.0)))
float code(float s, float u) {
return log1pf(((-(-0.25f) - u) / 0.75f)) * (s * -3.0f);
}
function code(s, u) return Float32(log1p(Float32(Float32(Float32(-Float32(-0.25)) - u) / Float32(0.75))) * Float32(s * Float32(-3.0))) end
\begin{array}{l}
\\
\mathsf{log1p}\left(\frac{\left(--0.25\right) - u}{0.75}\right) \cdot \left(s \cdot -3\right)
\end{array}
Initial program 95.8%
log-rec97.0%
distribute-rgt-neg-out97.0%
distribute-lft-neg-out97.0%
*-commutative97.0%
distribute-rgt-neg-in97.0%
metadata-eval97.0%
sub-neg97.0%
log1p-def98.5%
distribute-neg-frac98.5%
sub-neg98.5%
metadata-eval98.5%
Simplified98.5%
Final simplification98.5%
(FPCore (s u) :precision binary32 (* -3.0 (* s (log (- 1.3333333333333333 (* u 1.3333333333333333))))))
float code(float s, float u) {
return -3.0f * (s * logf((1.3333333333333333f - (u * 1.3333333333333333f))));
}
real(4) function code(s, u)
real(4), intent (in) :: s
real(4), intent (in) :: u
code = (-3.0e0) * (s * log((1.3333333333333333e0 - (u * 1.3333333333333333e0))))
end function
function code(s, u) return Float32(Float32(-3.0) * Float32(s * log(Float32(Float32(1.3333333333333333) - Float32(u * Float32(1.3333333333333333)))))) end
function tmp = code(s, u) tmp = single(-3.0) * (s * log((single(1.3333333333333333) - (u * single(1.3333333333333333))))); end
\begin{array}{l}
\\
-3 \cdot \left(s \cdot \log \left(1.3333333333333333 - u \cdot 1.3333333333333333\right)\right)
\end{array}
Initial program 95.8%
log-rec97.0%
div-sub96.1%
metadata-eval96.1%
Simplified96.1%
Taylor expanded in s around 0 96.3%
Final simplification96.3%
(FPCore (s u) :precision binary32 (* -3.0 (* s (log1p (* 1.3333333333333333 (- 0.25 u))))))
float code(float s, float u) {
return -3.0f * (s * log1pf((1.3333333333333333f * (0.25f - u))));
}
function code(s, u) return Float32(Float32(-3.0) * Float32(s * log1p(Float32(Float32(1.3333333333333333) * Float32(Float32(0.25) - u))))) end
\begin{array}{l}
\\
-3 \cdot \left(s \cdot \mathsf{log1p}\left(1.3333333333333333 \cdot \left(0.25 - u\right)\right)\right)
\end{array}
Initial program 95.8%
log-rec97.0%
distribute-rgt-neg-out97.0%
distribute-lft-neg-out97.0%
*-commutative97.0%
distribute-rgt-neg-in97.0%
metadata-eval97.0%
sub-neg97.0%
log1p-def98.5%
distribute-neg-frac98.5%
sub-neg98.5%
metadata-eval98.5%
Simplified98.5%
Taylor expanded in s around 0 96.6%
log1p-def97.9%
Simplified97.9%
Final simplification97.9%
(FPCore (s u) :precision binary32 (* s (* -3.0 (log1p (* (+ u -0.25) -1.3333333333333333)))))
float code(float s, float u) {
return s * (-3.0f * log1pf(((u + -0.25f) * -1.3333333333333333f)));
}
function code(s, u) return Float32(s * Float32(Float32(-3.0) * log1p(Float32(Float32(u + Float32(-0.25)) * Float32(-1.3333333333333333))))) end
\begin{array}{l}
\\
s \cdot \left(-3 \cdot \mathsf{log1p}\left(\left(u + -0.25\right) \cdot -1.3333333333333333\right)\right)
\end{array}
Initial program 95.8%
*-commutative95.8%
associate-*l*95.9%
*-commutative95.9%
log-rec96.9%
distribute-lft-neg-out96.9%
distribute-rgt-neg-in96.9%
Simplified97.1%
expm1-log1p-u96.6%
expm1-udef96.2%
Applied egg-rr96.1%
expm1-def96.2%
expm1-log1p96.7%
log-pow97.1%
log1p-expm196.6%
expm1-def96.6%
rem-exp-log96.6%
fma-def96.4%
associate--l+95.4%
metadata-eval97.1%
+-commutative97.1%
metadata-eval97.1%
*-commutative97.1%
metadata-eval97.1%
distribute-lft-neg-in97.1%
distribute-rgt-neg-in97.1%
distribute-lft-in98.0%
sub-neg98.0%
log1p-def96.7%
log1p-def98.0%
sub-neg98.0%
distribute-lft-in97.1%
metadata-eval97.1%
distribute-rgt-neg-in97.1%
*-commutative97.1%
distribute-rgt-neg-in97.1%
metadata-eval97.1%
Simplified98.0%
fma-udef97.1%
metadata-eval97.1%
metadata-eval97.1%
distribute-rgt-in98.0%
sub-neg98.0%
*-commutative98.0%
sub-neg98.0%
metadata-eval98.0%
Applied egg-rr98.0%
Final simplification98.0%
(FPCore (s u) :precision binary32 (* (* s -3.0) (log1p (* 1.3333333333333333 (- 0.25 u)))))
float code(float s, float u) {
return (s * -3.0f) * log1pf((1.3333333333333333f * (0.25f - u)));
}
function code(s, u) return Float32(Float32(s * Float32(-3.0)) * log1p(Float32(Float32(1.3333333333333333) * Float32(Float32(0.25) - u)))) end
\begin{array}{l}
\\
\left(s \cdot -3\right) \cdot \mathsf{log1p}\left(1.3333333333333333 \cdot \left(0.25 - u\right)\right)
\end{array}
Initial program 95.8%
log-rec97.0%
distribute-rgt-neg-out97.0%
distribute-lft-neg-out97.0%
*-commutative97.0%
distribute-rgt-neg-in97.0%
metadata-eval97.0%
sub-neg97.0%
log1p-def98.5%
distribute-neg-frac98.5%
sub-neg98.5%
metadata-eval98.5%
Simplified98.5%
Taylor expanded in s around 0 96.6%
log1p-def97.9%
Simplified97.9%
add-sqr-sqrt97.4%
pow297.4%
associate-*r*97.4%
Applied egg-rr97.4%
unpow297.4%
add-sqr-sqrt98.1%
Applied egg-rr98.1%
Final simplification98.1%
(FPCore (s u) :precision binary32 (* (* s -3.0) (* u -1.3333333333333333)))
float code(float s, float u) {
return (s * -3.0f) * (u * -1.3333333333333333f);
}
real(4) function code(s, u)
real(4), intent (in) :: s
real(4), intent (in) :: u
code = (s * (-3.0e0)) * (u * (-1.3333333333333333e0))
end function
function code(s, u) return Float32(Float32(s * Float32(-3.0)) * Float32(u * Float32(-1.3333333333333333))) end
function tmp = code(s, u) tmp = (s * single(-3.0)) * (u * single(-1.3333333333333333)); end
\begin{array}{l}
\\
\left(s \cdot -3\right) \cdot \left(u \cdot -1.3333333333333333\right)
\end{array}
Initial program 95.8%
log-rec97.0%
distribute-rgt-neg-out97.0%
distribute-lft-neg-out97.0%
*-commutative97.0%
distribute-rgt-neg-in97.0%
metadata-eval97.0%
sub-neg97.0%
log1p-def98.5%
neg-mul-198.5%
associate-*r/98.5%
associate-/l*98.2%
associate-/r/98.1%
sub-neg98.1%
distribute-lft-in97.2%
metadata-eval97.2%
metadata-eval97.2%
metadata-eval97.2%
metadata-eval97.2%
Simplified97.2%
Taylor expanded in u around inf 19.8%
*-commutative19.8%
Simplified19.8%
Taylor expanded in u around 0 29.7%
*-commutative29.7%
Simplified29.7%
Final simplification29.7%
(FPCore (s u) :precision binary32 (* 4.0 (* s u)))
float code(float s, float u) {
return 4.0f * (s * u);
}
real(4) function code(s, u)
real(4), intent (in) :: s
real(4), intent (in) :: u
code = 4.0e0 * (s * u)
end function
function code(s, u) return Float32(Float32(4.0) * Float32(s * u)) end
function tmp = code(s, u) tmp = single(4.0) * (s * u); end
\begin{array}{l}
\\
4 \cdot \left(s \cdot u\right)
\end{array}
Initial program 95.8%
log-rec97.0%
distribute-rgt-neg-out97.0%
distribute-lft-neg-out97.0%
*-commutative97.0%
distribute-rgt-neg-in97.0%
metadata-eval97.0%
sub-neg97.0%
log1p-def98.5%
neg-mul-198.5%
associate-*r/98.5%
associate-/l*98.2%
associate-/r/98.1%
sub-neg98.1%
distribute-lft-in97.2%
metadata-eval97.2%
metadata-eval97.2%
metadata-eval97.2%
metadata-eval97.2%
Simplified97.2%
Taylor expanded in u around inf 19.8%
*-commutative19.8%
Simplified19.8%
Taylor expanded in u around 0 29.7%
Final simplification29.7%
(FPCore (s u) :precision binary32 (* u (* s 4.0)))
float code(float s, float u) {
return u * (s * 4.0f);
}
real(4) function code(s, u)
real(4), intent (in) :: s
real(4), intent (in) :: u
code = u * (s * 4.0e0)
end function
function code(s, u) return Float32(u * Float32(s * Float32(4.0))) end
function tmp = code(s, u) tmp = u * (s * single(4.0)); end
\begin{array}{l}
\\
u \cdot \left(s \cdot 4\right)
\end{array}
Initial program 95.8%
log-rec97.0%
distribute-rgt-neg-out97.0%
distribute-lft-neg-out97.0%
*-commutative97.0%
distribute-rgt-neg-in97.0%
metadata-eval97.0%
sub-neg97.0%
log1p-def98.5%
neg-mul-198.5%
associate-*r/98.5%
associate-/l*98.2%
associate-/r/98.1%
sub-neg98.1%
distribute-lft-in97.2%
metadata-eval97.2%
metadata-eval97.2%
metadata-eval97.2%
metadata-eval97.2%
Simplified97.2%
Taylor expanded in u around inf 19.8%
*-commutative19.8%
Simplified19.8%
Taylor expanded in u around 0 29.7%
associate-*r*29.7%
Simplified29.7%
Final simplification29.7%
herbie shell --seed 2024020
(FPCore (s u)
:name "Disney BSSRDF, sample scattering profile, upper"
:precision binary32
:pre (and (and (<= 0.0 s) (<= s 256.0)) (and (<= 0.25 u) (<= u 1.0)))
(* (* 3.0 s) (log (/ 1.0 (- 1.0 (/ (- u 0.25) 0.75))))))