
(FPCore (s u) :precision binary32 (* s (log (/ 1.0 (- 1.0 (* 4.0 u))))))
float code(float s, float u) {
return s * logf((1.0f / (1.0f - (4.0f * u))));
}
real(4) function code(s, u)
real(4), intent (in) :: s
real(4), intent (in) :: u
code = s * log((1.0e0 / (1.0e0 - (4.0e0 * u))))
end function
function code(s, u) return Float32(s * log(Float32(Float32(1.0) / Float32(Float32(1.0) - Float32(Float32(4.0) * u))))) end
function tmp = code(s, u) tmp = s * log((single(1.0) / (single(1.0) - (single(4.0) * u)))); end
\begin{array}{l}
\\
s \cdot \log \left(\frac{1}{1 - 4 \cdot u}\right)
\end{array}
Sampling outcomes in binary32 precision:
Herbie found 15 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (s u) :precision binary32 (* s (log (/ 1.0 (- 1.0 (* 4.0 u))))))
float code(float s, float u) {
return s * logf((1.0f / (1.0f - (4.0f * u))));
}
real(4) function code(s, u)
real(4), intent (in) :: s
real(4), intent (in) :: u
code = s * log((1.0e0 / (1.0e0 - (4.0e0 * u))))
end function
function code(s, u) return Float32(s * log(Float32(Float32(1.0) / Float32(Float32(1.0) - Float32(Float32(4.0) * u))))) end
function tmp = code(s, u) tmp = s * log((single(1.0) / (single(1.0) - (single(4.0) * u)))); end
\begin{array}{l}
\\
s \cdot \log \left(\frac{1}{1 - 4 \cdot u}\right)
\end{array}
(FPCore (s u) :precision binary32 (* (log1p (* u -4.0)) (- s)))
float code(float s, float u) {
return log1pf((u * -4.0f)) * -s;
}
function code(s, u) return Float32(log1p(Float32(u * Float32(-4.0))) * Float32(-s)) end
\begin{array}{l}
\\
\mathsf{log1p}\left(u \cdot -4\right) \cdot \left(-s\right)
\end{array}
Initial program 59.9%
Taylor expanded in s around 0
*-commutativeN/A
log-recN/A
distribute-lft-neg-outN/A
distribute-rgt-neg-inN/A
*-lowering-*.f32N/A
cancel-sign-sub-invN/A
metadata-evalN/A
accelerator-lowering-log1p.f32N/A
*-commutativeN/A
*-lowering-*.f32N/A
neg-lowering-neg.f3299.4
Simplified99.4%
(FPCore (s u)
:precision binary32
(/
(*
u
(fma
s
-16.0
(*
(* u u)
(fma
u
(fma s 341.3333333333333 (* u (* s 967.1111111111111)))
(* s 64.0)))))
(fma u (fma u (fma u 64.0 21.333333333333332) 8.0) -4.0)))
float code(float s, float u) {
return (u * fmaf(s, -16.0f, ((u * u) * fmaf(u, fmaf(s, 341.3333333333333f, (u * (s * 967.1111111111111f))), (s * 64.0f))))) / fmaf(u, fmaf(u, fmaf(u, 64.0f, 21.333333333333332f), 8.0f), -4.0f);
}
function code(s, u) return Float32(Float32(u * fma(s, Float32(-16.0), Float32(Float32(u * u) * fma(u, fma(s, Float32(341.3333333333333), Float32(u * Float32(s * Float32(967.1111111111111)))), Float32(s * Float32(64.0)))))) / fma(u, fma(u, fma(u, Float32(64.0), Float32(21.333333333333332)), Float32(8.0)), Float32(-4.0))) end
\begin{array}{l}
\\
\frac{u \cdot \mathsf{fma}\left(s, -16, \left(u \cdot u\right) \cdot \mathsf{fma}\left(u, \mathsf{fma}\left(s, 341.3333333333333, u \cdot \left(s \cdot 967.1111111111111\right)\right), s \cdot 64\right)\right)}{\mathsf{fma}\left(u, \mathsf{fma}\left(u, \mathsf{fma}\left(u, 64, 21.333333333333332\right), 8\right), -4\right)}
\end{array}
Initial program 59.9%
Taylor expanded in u around 0
*-lowering-*.f32N/A
+-commutativeN/A
accelerator-lowering-fma.f32N/A
+-commutativeN/A
accelerator-lowering-fma.f32N/A
+-commutativeN/A
*-commutativeN/A
accelerator-lowering-fma.f3294.2
Simplified94.2%
associate-*r*N/A
*-commutativeN/A
flip-+N/A
associate-*r/N/A
/-lowering-/.f32N/A
Applied egg-rr94.1%
Taylor expanded in u around 0
*-lowering-*.f32N/A
+-commutativeN/A
*-commutativeN/A
accelerator-lowering-fma.f3294.6
Simplified94.6%
Taylor expanded in u around 0
*-lowering-*.f32N/A
*-commutativeN/A
accelerator-lowering-fma.f32N/A
*-lowering-*.f32N/A
unpow2N/A
*-lowering-*.f32N/A
+-commutativeN/A
accelerator-lowering-fma.f32N/A
*-commutativeN/A
accelerator-lowering-fma.f32N/A
associate-*r*N/A
*-commutativeN/A
*-lowering-*.f32N/A
*-commutativeN/A
*-lowering-*.f32N/A
*-commutativeN/A
*-lowering-*.f3295.0
Simplified95.0%
(FPCore (s u)
:precision binary32
(/
(*
(* u s)
(fma
(* u u)
(fma u (fma u 967.1111111111111 341.3333333333333) 64.0)
-16.0))
(fma u (fma u (fma u 64.0 21.333333333333332) 8.0) -4.0)))
float code(float s, float u) {
return ((u * s) * fmaf((u * u), fmaf(u, fmaf(u, 967.1111111111111f, 341.3333333333333f), 64.0f), -16.0f)) / fmaf(u, fmaf(u, fmaf(u, 64.0f, 21.333333333333332f), 8.0f), -4.0f);
}
function code(s, u) return Float32(Float32(Float32(u * s) * fma(Float32(u * u), fma(u, fma(u, Float32(967.1111111111111), Float32(341.3333333333333)), Float32(64.0)), Float32(-16.0))) / fma(u, fma(u, fma(u, Float32(64.0), Float32(21.333333333333332)), Float32(8.0)), Float32(-4.0))) end
\begin{array}{l}
\\
\frac{\left(u \cdot s\right) \cdot \mathsf{fma}\left(u \cdot u, \mathsf{fma}\left(u, \mathsf{fma}\left(u, 967.1111111111111, 341.3333333333333\right), 64\right), -16\right)}{\mathsf{fma}\left(u, \mathsf{fma}\left(u, \mathsf{fma}\left(u, 64, 21.333333333333332\right), 8\right), -4\right)}
\end{array}
Initial program 59.9%
Taylor expanded in u around 0
*-lowering-*.f32N/A
+-commutativeN/A
accelerator-lowering-fma.f32N/A
+-commutativeN/A
accelerator-lowering-fma.f32N/A
+-commutativeN/A
*-commutativeN/A
accelerator-lowering-fma.f3294.2
Simplified94.2%
associate-*r*N/A
*-commutativeN/A
flip-+N/A
associate-*r/N/A
/-lowering-/.f32N/A
Applied egg-rr94.1%
Taylor expanded in u around 0
*-lowering-*.f32N/A
+-commutativeN/A
*-commutativeN/A
accelerator-lowering-fma.f3294.6
Simplified94.6%
Taylor expanded in u around 0
sub-negN/A
metadata-evalN/A
accelerator-lowering-fma.f32N/A
unpow2N/A
*-lowering-*.f32N/A
+-commutativeN/A
accelerator-lowering-fma.f32N/A
+-commutativeN/A
*-commutativeN/A
accelerator-lowering-fma.f3294.8
Simplified94.8%
(FPCore (s u) :precision binary32 (* u (fma s 4.0 (* (fma u (fma u 64.0 21.333333333333332) 8.0) (* u s)))))
float code(float s, float u) {
return u * fmaf(s, 4.0f, (fmaf(u, fmaf(u, 64.0f, 21.333333333333332f), 8.0f) * (u * s)));
}
function code(s, u) return Float32(u * fma(s, Float32(4.0), Float32(fma(u, fma(u, Float32(64.0), Float32(21.333333333333332)), Float32(8.0)) * Float32(u * s)))) end
\begin{array}{l}
\\
u \cdot \mathsf{fma}\left(s, 4, \mathsf{fma}\left(u, \mathsf{fma}\left(u, 64, 21.333333333333332\right), 8\right) \cdot \left(u \cdot s\right)\right)
\end{array}
Initial program 59.9%
Taylor expanded in u around 0
*-lowering-*.f32N/A
+-commutativeN/A
accelerator-lowering-fma.f32N/A
+-commutativeN/A
accelerator-lowering-fma.f32N/A
+-commutativeN/A
*-commutativeN/A
accelerator-lowering-fma.f3294.2
Simplified94.2%
associate-*r*N/A
*-commutativeN/A
distribute-rgt-inN/A
accelerator-lowering-fma.f32N/A
*-lowering-*.f32N/A
accelerator-lowering-fma.f32N/A
accelerator-lowering-fma.f32N/A
*-lowering-*.f32N/A
associate-*r*N/A
*-commutativeN/A
*-lowering-*.f32N/A
*-commutativeN/A
*-lowering-*.f3294.6
Applied egg-rr94.6%
+-commutativeN/A
*-commutativeN/A
associate-*l*N/A
associate-*l*N/A
distribute-lft-outN/A
*-lowering-*.f32N/A
*-commutativeN/A
accelerator-lowering-fma.f32N/A
*-lowering-*.f32N/A
accelerator-lowering-fma.f32N/A
accelerator-lowering-fma.f32N/A
*-lowering-*.f3294.6
Applied egg-rr94.6%
(FPCore (s u) :precision binary32 (* s (fma (fma u (fma u 64.0 21.333333333333332) 8.0) (* u u) (* u 4.0))))
float code(float s, float u) {
return s * fmaf(fmaf(u, fmaf(u, 64.0f, 21.333333333333332f), 8.0f), (u * u), (u * 4.0f));
}
function code(s, u) return Float32(s * fma(fma(u, fma(u, Float32(64.0), Float32(21.333333333333332)), Float32(8.0)), Float32(u * u), Float32(u * Float32(4.0)))) end
\begin{array}{l}
\\
s \cdot \mathsf{fma}\left(\mathsf{fma}\left(u, \mathsf{fma}\left(u, 64, 21.333333333333332\right), 8\right), u \cdot u, u \cdot 4\right)
\end{array}
Initial program 59.9%
Taylor expanded in u around 0
*-lowering-*.f32N/A
+-commutativeN/A
accelerator-lowering-fma.f32N/A
+-commutativeN/A
accelerator-lowering-fma.f32N/A
+-commutativeN/A
*-commutativeN/A
accelerator-lowering-fma.f3294.2
Simplified94.2%
distribute-rgt-inN/A
*-commutativeN/A
associate-*l*N/A
accelerator-lowering-fma.f32N/A
accelerator-lowering-fma.f32N/A
accelerator-lowering-fma.f32N/A
*-lowering-*.f32N/A
*-commutativeN/A
*-lowering-*.f3294.6
Applied egg-rr94.6%
(FPCore (s u) :precision binary32 (* u (* s (fma u (fma u (fma u 64.0 21.333333333333332) 8.0) 4.0))))
float code(float s, float u) {
return u * (s * fmaf(u, fmaf(u, fmaf(u, 64.0f, 21.333333333333332f), 8.0f), 4.0f));
}
function code(s, u) return Float32(u * Float32(s * fma(u, fma(u, fma(u, Float32(64.0), Float32(21.333333333333332)), Float32(8.0)), Float32(4.0)))) end
\begin{array}{l}
\\
u \cdot \left(s \cdot \mathsf{fma}\left(u, \mathsf{fma}\left(u, \mathsf{fma}\left(u, 64, 21.333333333333332\right), 8\right), 4\right)\right)
\end{array}
Initial program 59.9%
Taylor expanded in u around 0
*-lowering-*.f32N/A
+-commutativeN/A
accelerator-lowering-fma.f32N/A
+-commutativeN/A
accelerator-lowering-fma.f32N/A
+-commutativeN/A
*-commutativeN/A
accelerator-lowering-fma.f3294.2
Simplified94.2%
*-commutativeN/A
associate-*r*N/A
*-lowering-*.f32N/A
*-lowering-*.f32N/A
accelerator-lowering-fma.f32N/A
accelerator-lowering-fma.f32N/A
accelerator-lowering-fma.f3294.3
Applied egg-rr94.3%
Final simplification94.3%
(FPCore (s u) :precision binary32 (* s (* u (fma u (fma u (fma u 64.0 21.333333333333332) 8.0) 4.0))))
float code(float s, float u) {
return s * (u * fmaf(u, fmaf(u, fmaf(u, 64.0f, 21.333333333333332f), 8.0f), 4.0f));
}
function code(s, u) return Float32(s * Float32(u * fma(u, fma(u, fma(u, Float32(64.0), Float32(21.333333333333332)), Float32(8.0)), Float32(4.0)))) end
\begin{array}{l}
\\
s \cdot \left(u \cdot \mathsf{fma}\left(u, \mathsf{fma}\left(u, \mathsf{fma}\left(u, 64, 21.333333333333332\right), 8\right), 4\right)\right)
\end{array}
Initial program 59.9%
Taylor expanded in u around 0
*-lowering-*.f32N/A
+-commutativeN/A
accelerator-lowering-fma.f32N/A
+-commutativeN/A
accelerator-lowering-fma.f32N/A
+-commutativeN/A
*-commutativeN/A
accelerator-lowering-fma.f3294.2
Simplified94.2%
(FPCore (s u) :precision binary32 (* u (fma s 4.0 (* s (* u (fma u 21.333333333333332 8.0))))))
float code(float s, float u) {
return u * fmaf(s, 4.0f, (s * (u * fmaf(u, 21.333333333333332f, 8.0f))));
}
function code(s, u) return Float32(u * fma(s, Float32(4.0), Float32(s * Float32(u * fma(u, Float32(21.333333333333332), Float32(8.0)))))) end
\begin{array}{l}
\\
u \cdot \mathsf{fma}\left(s, 4, s \cdot \left(u \cdot \mathsf{fma}\left(u, 21.333333333333332, 8\right)\right)\right)
\end{array}
Initial program 59.9%
Taylor expanded in s around 0
*-commutativeN/A
log-recN/A
distribute-lft-neg-outN/A
distribute-rgt-neg-inN/A
*-lowering-*.f32N/A
cancel-sign-sub-invN/A
metadata-evalN/A
accelerator-lowering-log1p.f32N/A
*-commutativeN/A
*-lowering-*.f32N/A
neg-lowering-neg.f3299.4
Simplified99.4%
Taylor expanded in u around 0
*-lowering-*.f32N/A
+-commutativeN/A
accelerator-lowering-fma.f32N/A
*-commutativeN/A
*-commutativeN/A
associate-*l*N/A
*-commutativeN/A
distribute-lft-outN/A
*-lowering-*.f32N/A
+-commutativeN/A
*-commutativeN/A
accelerator-lowering-fma.f32N/A
*-lowering-*.f3292.5
Simplified92.5%
+-commutativeN/A
*-commutativeN/A
accelerator-lowering-fma.f32N/A
associate-*r*N/A
*-commutativeN/A
associate-*l*N/A
*-lowering-*.f32N/A
*-lowering-*.f32N/A
accelerator-lowering-fma.f3292.5
Applied egg-rr92.5%
(FPCore (s u) :precision binary32 (* u (* s (fma u (fma u 21.333333333333332 8.0) 4.0))))
float code(float s, float u) {
return u * (s * fmaf(u, fmaf(u, 21.333333333333332f, 8.0f), 4.0f));
}
function code(s, u) return Float32(u * Float32(s * fma(u, fma(u, Float32(21.333333333333332), Float32(8.0)), Float32(4.0)))) end
\begin{array}{l}
\\
u \cdot \left(s \cdot \mathsf{fma}\left(u, \mathsf{fma}\left(u, 21.333333333333332, 8\right), 4\right)\right)
\end{array}
Initial program 59.9%
Taylor expanded in s around 0
*-commutativeN/A
log-recN/A
distribute-lft-neg-outN/A
distribute-rgt-neg-inN/A
*-lowering-*.f32N/A
cancel-sign-sub-invN/A
metadata-evalN/A
accelerator-lowering-log1p.f32N/A
*-commutativeN/A
*-lowering-*.f32N/A
neg-lowering-neg.f3299.4
Simplified99.4%
Taylor expanded in u around 0
*-lowering-*.f32N/A
+-commutativeN/A
accelerator-lowering-fma.f32N/A
*-commutativeN/A
*-commutativeN/A
associate-*l*N/A
*-commutativeN/A
distribute-lft-outN/A
*-lowering-*.f32N/A
+-commutativeN/A
*-commutativeN/A
accelerator-lowering-fma.f32N/A
*-lowering-*.f3292.5
Simplified92.5%
Taylor expanded in u around 0
distribute-rgt-inN/A
associate-*r*N/A
associate-+r+N/A
associate-*r*N/A
associate-*r*N/A
unpow2N/A
*-commutativeN/A
associate-+r+N/A
*-commutativeN/A
*-commutativeN/A
unpow2N/A
associate-*r*N/A
associate-*r*N/A
*-commutativeN/A
associate-*l*N/A
distribute-lft-outN/A
associate-*r*N/A
*-commutativeN/A
distribute-rgt-inN/A
Simplified92.3%
(FPCore (s u) :precision binary32 (* s (* u (fma u (fma u 21.333333333333332 8.0) 4.0))))
float code(float s, float u) {
return s * (u * fmaf(u, fmaf(u, 21.333333333333332f, 8.0f), 4.0f));
}
function code(s, u) return Float32(s * Float32(u * fma(u, fma(u, Float32(21.333333333333332), Float32(8.0)), Float32(4.0)))) end
\begin{array}{l}
\\
s \cdot \left(u \cdot \mathsf{fma}\left(u, \mathsf{fma}\left(u, 21.333333333333332, 8\right), 4\right)\right)
\end{array}
Initial program 59.9%
Taylor expanded in u around 0
*-lowering-*.f32N/A
+-commutativeN/A
accelerator-lowering-fma.f32N/A
+-commutativeN/A
*-commutativeN/A
accelerator-lowering-fma.f3292.2
Simplified92.2%
(FPCore (s u) :precision binary32 (* u (fma u (* s 8.0) (* s 4.0))))
float code(float s, float u) {
return u * fmaf(u, (s * 8.0f), (s * 4.0f));
}
function code(s, u) return Float32(u * fma(u, Float32(s * Float32(8.0)), Float32(s * Float32(4.0)))) end
\begin{array}{l}
\\
u \cdot \mathsf{fma}\left(u, s \cdot 8, s \cdot 4\right)
\end{array}
Initial program 59.9%
Taylor expanded in s around 0
*-commutativeN/A
log-recN/A
distribute-lft-neg-outN/A
distribute-rgt-neg-inN/A
*-lowering-*.f32N/A
cancel-sign-sub-invN/A
metadata-evalN/A
accelerator-lowering-log1p.f32N/A
*-commutativeN/A
*-lowering-*.f32N/A
neg-lowering-neg.f3299.4
Simplified99.4%
Taylor expanded in u around 0
*-lowering-*.f32N/A
+-commutativeN/A
accelerator-lowering-fma.f32N/A
*-commutativeN/A
*-commutativeN/A
associate-*l*N/A
*-commutativeN/A
distribute-lft-outN/A
*-lowering-*.f32N/A
+-commutativeN/A
*-commutativeN/A
accelerator-lowering-fma.f32N/A
*-lowering-*.f3292.5
Simplified92.5%
Taylor expanded in u around 0
*-commutativeN/A
*-lowering-*.f3288.2
Simplified88.2%
Final simplification88.2%
(FPCore (s u) :precision binary32 (* u (* s (fma u 8.0 4.0))))
float code(float s, float u) {
return u * (s * fmaf(u, 8.0f, 4.0f));
}
function code(s, u) return Float32(u * Float32(s * fma(u, Float32(8.0), Float32(4.0)))) end
\begin{array}{l}
\\
u \cdot \left(s \cdot \mathsf{fma}\left(u, 8, 4\right)\right)
\end{array}
Initial program 59.9%
Taylor expanded in u around 0
distribute-rgt-inN/A
associate-*r*N/A
*-commutativeN/A
*-commutativeN/A
associate-*l*N/A
distribute-lft-outN/A
*-commutativeN/A
*-lowering-*.f32N/A
+-commutativeN/A
*-commutativeN/A
accelerator-lowering-fma.f32N/A
*-commutativeN/A
*-lowering-*.f3287.6
Simplified87.6%
*-commutativeN/A
associate-*r*N/A
*-lowering-*.f32N/A
*-lowering-*.f32N/A
accelerator-lowering-fma.f3288.0
Applied egg-rr88.0%
Final simplification88.0%
(FPCore (s u) :precision binary32 (* s (* u (fma u 8.0 4.0))))
float code(float s, float u) {
return s * (u * fmaf(u, 8.0f, 4.0f));
}
function code(s, u) return Float32(s * Float32(u * fma(u, Float32(8.0), Float32(4.0)))) end
\begin{array}{l}
\\
s \cdot \left(u \cdot \mathsf{fma}\left(u, 8, 4\right)\right)
\end{array}
Initial program 59.9%
Taylor expanded in u around 0
*-lowering-*.f32N/A
+-commutativeN/A
*-commutativeN/A
accelerator-lowering-fma.f3287.9
Simplified87.9%
(FPCore (s u) :precision binary32 (* s (* u 4.0)))
float code(float s, float u) {
return s * (u * 4.0f);
}
real(4) function code(s, u)
real(4), intent (in) :: s
real(4), intent (in) :: u
code = s * (u * 4.0e0)
end function
function code(s, u) return Float32(s * Float32(u * Float32(4.0))) end
function tmp = code(s, u) tmp = s * (u * single(4.0)); end
\begin{array}{l}
\\
s \cdot \left(u \cdot 4\right)
\end{array}
Initial program 59.9%
Taylor expanded in u around 0
*-lowering-*.f3275.4
Simplified75.4%
Final simplification75.4%
(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(Float32(u * s) * Float32(4.0)) end
function tmp = code(s, u) tmp = (u * s) * single(4.0); end
\begin{array}{l}
\\
\left(u \cdot s\right) \cdot 4
\end{array}
Initial program 59.9%
Taylor expanded in u around 0
*-lowering-*.f32N/A
*-commutativeN/A
*-lowering-*.f3275.2
Simplified75.2%
Final simplification75.2%
herbie shell --seed 2024199
(FPCore (s u)
:name "Disney BSSRDF, sample scattering profile, lower"
:precision binary32
:pre (and (and (<= 0.0 s) (<= s 256.0)) (and (<= 2.328306437e-10 u) (<= u 0.25)))
(* s (log (/ 1.0 (- 1.0 (* 4.0 u))))))