
(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 9 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 61.6%
log-recN/A
neg-mul-1N/A
associate-*r*N/A
*-commutativeN/A
*-lowering-*.f32N/A
sub-negN/A
log1p-defineN/A
log1p-lowering-log1p.f32N/A
*-commutativeN/A
distribute-rgt-neg-inN/A
*-lowering-*.f32N/A
metadata-evalN/A
*-commutativeN/A
neg-mul-1N/A
neg-lowering-neg.f3299.5%
Simplified99.5%
(FPCore (s u)
:precision binary32
(*
u
(+
(* s (+ 4.0 (* u 8.0)))
(*
(/ (* s 455.1111111111111) (+ 21.333333333333332 (* u -64.0)))
(* u u)))))
float code(float s, float u) {
return u * ((s * (4.0f + (u * 8.0f))) + (((s * 455.1111111111111f) / (21.333333333333332f + (u * -64.0f))) * (u * u)));
}
real(4) function code(s, u)
real(4), intent (in) :: s
real(4), intent (in) :: u
code = u * ((s * (4.0e0 + (u * 8.0e0))) + (((s * 455.1111111111111e0) / (21.333333333333332e0 + (u * (-64.0e0)))) * (u * u)))
end function
function code(s, u) return Float32(u * Float32(Float32(s * Float32(Float32(4.0) + Float32(u * Float32(8.0)))) + Float32(Float32(Float32(s * Float32(455.1111111111111)) / Float32(Float32(21.333333333333332) + Float32(u * Float32(-64.0)))) * Float32(u * u)))) end
function tmp = code(s, u) tmp = u * ((s * (single(4.0) + (u * single(8.0)))) + (((s * single(455.1111111111111)) / (single(21.333333333333332) + (u * single(-64.0)))) * (u * u))); end
\begin{array}{l}
\\
u \cdot \left(s \cdot \left(4 + u \cdot 8\right) + \frac{s \cdot 455.1111111111111}{21.333333333333332 + u \cdot -64} \cdot \left(u \cdot u\right)\right)
\end{array}
Initial program 61.6%
Taylor expanded in u around 0
*-lowering-*.f32N/A
distribute-rgt-inN/A
associate-*r*N/A
associate-+r+N/A
+-lowering-+.f32N/A
*-commutativeN/A
*-commutativeN/A
associate-*l*N/A
*-commutativeN/A
distribute-lft-outN/A
*-lowering-*.f32N/A
+-lowering-+.f32N/A
*-commutativeN/A
*-lowering-*.f32N/A
*-commutativeN/A
associate-*l*N/A
unpow2N/A
Simplified93.5%
distribute-lft-inN/A
flip-+N/A
/-lowering-/.f32N/A
*-commutativeN/A
*-commutativeN/A
--lowering--.f32N/A
*-lowering-*.f32N/A
*-commutativeN/A
*-lowering-*.f32N/A
*-commutativeN/A
*-lowering-*.f32N/A
*-lowering-*.f32N/A
*-lowering-*.f32N/A
*-lowering-*.f32N/A
*-lowering-*.f32N/A
*-lowering-*.f32N/A
*-commutativeN/A
--lowering--.f32N/A
Applied egg-rr91.8%
distribute-lft-out--N/A
associate-/r*N/A
/-lowering-/.f32N/A
Applied egg-rr91.7%
Taylor expanded in u around 0
*-commutativeN/A
*-lowering-*.f3294.8%
Simplified94.8%
(FPCore (s u) :precision binary32 (* s (+ (* (* u u) (+ 8.0 (* u (+ 21.333333333333332 (* u 64.0))))) (* u 4.0))))
float code(float s, float u) {
return s * (((u * u) * (8.0f + (u * (21.333333333333332f + (u * 64.0f))))) + (u * 4.0f));
}
real(4) function code(s, u)
real(4), intent (in) :: s
real(4), intent (in) :: u
code = s * (((u * u) * (8.0e0 + (u * (21.333333333333332e0 + (u * 64.0e0))))) + (u * 4.0e0))
end function
function code(s, u) return Float32(s * Float32(Float32(Float32(u * u) * Float32(Float32(8.0) + Float32(u * Float32(Float32(21.333333333333332) + Float32(u * Float32(64.0)))))) + Float32(u * Float32(4.0)))) end
function tmp = code(s, u) tmp = s * (((u * u) * (single(8.0) + (u * (single(21.333333333333332) + (u * single(64.0)))))) + (u * single(4.0))); end
\begin{array}{l}
\\
s \cdot \left(\left(u \cdot u\right) \cdot \left(8 + u \cdot \left(21.333333333333332 + u \cdot 64\right)\right) + u \cdot 4\right)
\end{array}
Initial program 61.6%
Taylor expanded in u around 0
*-lowering-*.f32N/A
+-lowering-+.f32N/A
*-lowering-*.f32N/A
+-lowering-+.f32N/A
*-lowering-*.f32N/A
+-lowering-+.f32N/A
*-commutativeN/A
*-lowering-*.f3293.7%
Simplified93.7%
+-commutativeN/A
distribute-lft-inN/A
*-commutativeN/A
+-lowering-+.f32N/A
associate-*r*N/A
*-lowering-*.f32N/A
*-lowering-*.f32N/A
+-lowering-+.f32N/A
*-lowering-*.f32N/A
+-lowering-+.f32N/A
*-lowering-*.f32N/A
*-lowering-*.f3293.9%
Applied egg-rr93.9%
Final simplification93.9%
(FPCore (s u) :precision binary32 (* s (* u (+ 4.0 (* u (+ 8.0 (* u (+ 21.333333333333332 (* u 64.0)))))))))
float code(float s, float u) {
return s * (u * (4.0f + (u * (8.0f + (u * (21.333333333333332f + (u * 64.0f)))))));
}
real(4) function code(s, u)
real(4), intent (in) :: s
real(4), intent (in) :: u
code = s * (u * (4.0e0 + (u * (8.0e0 + (u * (21.333333333333332e0 + (u * 64.0e0)))))))
end function
function code(s, u) return Float32(s * Float32(u * Float32(Float32(4.0) + Float32(u * Float32(Float32(8.0) + Float32(u * Float32(Float32(21.333333333333332) + Float32(u * Float32(64.0))))))))) end
function tmp = code(s, u) tmp = s * (u * (single(4.0) + (u * (single(8.0) + (u * (single(21.333333333333332) + (u * single(64.0)))))))); end
\begin{array}{l}
\\
s \cdot \left(u \cdot \left(4 + u \cdot \left(8 + u \cdot \left(21.333333333333332 + u \cdot 64\right)\right)\right)\right)
\end{array}
Initial program 61.6%
Taylor expanded in u around 0
*-lowering-*.f32N/A
+-lowering-+.f32N/A
*-lowering-*.f32N/A
+-lowering-+.f32N/A
*-lowering-*.f32N/A
+-lowering-+.f32N/A
*-commutativeN/A
*-lowering-*.f3293.7%
Simplified93.7%
(FPCore (s u) :precision binary32 (* u (+ (* s 4.0) (* (* u s) (+ 8.0 (* u 21.333333333333332))))))
float code(float s, float u) {
return u * ((s * 4.0f) + ((u * s) * (8.0f + (u * 21.333333333333332f))));
}
real(4) function code(s, u)
real(4), intent (in) :: s
real(4), intent (in) :: u
code = u * ((s * 4.0e0) + ((u * s) * (8.0e0 + (u * 21.333333333333332e0))))
end function
function code(s, u) return Float32(u * Float32(Float32(s * Float32(4.0)) + Float32(Float32(u * s) * Float32(Float32(8.0) + Float32(u * Float32(21.333333333333332)))))) end
function tmp = code(s, u) tmp = u * ((s * single(4.0)) + ((u * s) * (single(8.0) + (u * single(21.333333333333332))))); end
\begin{array}{l}
\\
u \cdot \left(s \cdot 4 + \left(u \cdot s\right) \cdot \left(8 + u \cdot 21.333333333333332\right)\right)
\end{array}
Initial program 61.6%
Taylor expanded in u around 0
*-lowering-*.f32N/A
+-lowering-+.f32N/A
*-commutativeN/A
*-lowering-*.f32N/A
distribute-rgt-inN/A
associate-*r*N/A
*-commutativeN/A
*-commutativeN/A
associate-*l*N/A
distribute-lft-outN/A
*-lowering-*.f32N/A
*-lowering-*.f32N/A
+-lowering-+.f32N/A
*-commutativeN/A
*-lowering-*.f3292.2%
Simplified92.2%
Final simplification92.2%
(FPCore (s u) :precision binary32 (* s (* u (+ 4.0 (* u (+ 8.0 (* u 21.333333333333332)))))))
float code(float s, float u) {
return s * (u * (4.0f + (u * (8.0f + (u * 21.333333333333332f)))));
}
real(4) function code(s, u)
real(4), intent (in) :: s
real(4), intent (in) :: u
code = s * (u * (4.0e0 + (u * (8.0e0 + (u * 21.333333333333332e0)))))
end function
function code(s, u) return Float32(s * Float32(u * Float32(Float32(4.0) + Float32(u * Float32(Float32(8.0) + Float32(u * Float32(21.333333333333332))))))) end
function tmp = code(s, u) tmp = s * (u * (single(4.0) + (u * (single(8.0) + (u * single(21.333333333333332)))))); end
\begin{array}{l}
\\
s \cdot \left(u \cdot \left(4 + u \cdot \left(8 + u \cdot 21.333333333333332\right)\right)\right)
\end{array}
Initial program 61.6%
Taylor expanded in u around 0
*-lowering-*.f32N/A
+-lowering-+.f32N/A
*-lowering-*.f32N/A
+-lowering-+.f32N/A
*-commutativeN/A
*-lowering-*.f3292.0%
Simplified92.0%
(FPCore (s u) :precision binary32 (* u (+ (* s 4.0) (* s (* u 8.0)))))
float code(float s, float u) {
return u * ((s * 4.0f) + (s * (u * 8.0f)));
}
real(4) function code(s, u)
real(4), intent (in) :: s
real(4), intent (in) :: u
code = u * ((s * 4.0e0) + (s * (u * 8.0e0)))
end function
function code(s, u) return Float32(u * Float32(Float32(s * Float32(4.0)) + Float32(s * Float32(u * Float32(8.0))))) end
function tmp = code(s, u) tmp = u * ((s * single(4.0)) + (s * (u * single(8.0)))); end
\begin{array}{l}
\\
u \cdot \left(s \cdot 4 + s \cdot \left(u \cdot 8\right)\right)
\end{array}
Initial program 61.6%
Taylor expanded in u around 0
*-lowering-*.f32N/A
*-commutativeN/A
*-commutativeN/A
associate-*l*N/A
*-commutativeN/A
distribute-lft-outN/A
*-lowering-*.f32N/A
+-lowering-+.f32N/A
*-commutativeN/A
*-lowering-*.f3288.1%
Simplified88.1%
+-commutativeN/A
distribute-lft-inN/A
+-lowering-+.f32N/A
*-lowering-*.f32N/A
*-lowering-*.f32N/A
*-lowering-*.f3288.3%
Applied egg-rr88.3%
Final simplification88.3%
(FPCore (s u) :precision binary32 (* s (* u (+ 4.0 (* u 8.0)))))
float code(float s, float u) {
return s * (u * (4.0f + (u * 8.0f)));
}
real(4) function code(s, u)
real(4), intent (in) :: s
real(4), intent (in) :: u
code = s * (u * (4.0e0 + (u * 8.0e0)))
end function
function code(s, u) return Float32(s * Float32(u * Float32(Float32(4.0) + Float32(u * Float32(8.0))))) end
function tmp = code(s, u) tmp = s * (u * (single(4.0) + (u * single(8.0)))); end
\begin{array}{l}
\\
s \cdot \left(u \cdot \left(4 + u \cdot 8\right)\right)
\end{array}
Initial program 61.6%
Taylor expanded in u around 0
*-lowering-*.f32N/A
+-lowering-+.f32N/A
*-commutativeN/A
*-lowering-*.f3288.1%
Simplified88.1%
(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 61.6%
Taylor expanded in u around 0
*-commutativeN/A
associate-*l*N/A
*-commutativeN/A
*-lowering-*.f32N/A
*-lowering-*.f3275.7%
Simplified75.7%
Final simplification75.7%
herbie shell --seed 2024155
(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))))))