
(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 12 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 58.3%
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.f3299.3%
Simplified99.3%
(FPCore (s u)
:precision binary32
(let* ((t_0 (+ 8.0 (* u (+ 21.333333333333332 (* u 64.0))))) (t_1 (* u t_0)))
(*
s
(/
u
(/
(+
(* (* u u) (* t_0 (+ 8.0 (* u 21.333333333333332))))
(+ 16.0 (* (* u -4.0) t_0)))
(+ 64.0 (* t_0 (* t_1 (* u t_1)))))))))
float code(float s, float u) {
float t_0 = 8.0f + (u * (21.333333333333332f + (u * 64.0f)));
float t_1 = u * t_0;
return s * (u / ((((u * u) * (t_0 * (8.0f + (u * 21.333333333333332f)))) + (16.0f + ((u * -4.0f) * t_0))) / (64.0f + (t_0 * (t_1 * (u * t_1))))));
}
real(4) function code(s, u)
real(4), intent (in) :: s
real(4), intent (in) :: u
real(4) :: t_0
real(4) :: t_1
t_0 = 8.0e0 + (u * (21.333333333333332e0 + (u * 64.0e0)))
t_1 = u * t_0
code = s * (u / ((((u * u) * (t_0 * (8.0e0 + (u * 21.333333333333332e0)))) + (16.0e0 + ((u * (-4.0e0)) * t_0))) / (64.0e0 + (t_0 * (t_1 * (u * t_1))))))
end function
function code(s, u) t_0 = Float32(Float32(8.0) + Float32(u * Float32(Float32(21.333333333333332) + Float32(u * Float32(64.0))))) t_1 = Float32(u * t_0) return Float32(s * Float32(u / Float32(Float32(Float32(Float32(u * u) * Float32(t_0 * Float32(Float32(8.0) + Float32(u * Float32(21.333333333333332))))) + Float32(Float32(16.0) + Float32(Float32(u * Float32(-4.0)) * t_0))) / Float32(Float32(64.0) + Float32(t_0 * Float32(t_1 * Float32(u * t_1))))))) end
function tmp = code(s, u) t_0 = single(8.0) + (u * (single(21.333333333333332) + (u * single(64.0)))); t_1 = u * t_0; tmp = s * (u / ((((u * u) * (t_0 * (single(8.0) + (u * single(21.333333333333332))))) + (single(16.0) + ((u * single(-4.0)) * t_0))) / (single(64.0) + (t_0 * (t_1 * (u * t_1)))))); end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := 8 + u \cdot \left(21.333333333333332 + u \cdot 64\right)\\
t_1 := u \cdot t\_0\\
s \cdot \frac{u}{\frac{\left(u \cdot u\right) \cdot \left(t\_0 \cdot \left(8 + u \cdot 21.333333333333332\right)\right) + \left(16 + \left(u \cdot -4\right) \cdot t\_0\right)}{64 + t\_0 \cdot \left(t\_1 \cdot \left(u \cdot t\_1\right)\right)}}
\end{array}
\end{array}
Initial program 58.3%
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-*.f3294.5%
Simplified94.5%
+-commutativeN/A
flip3-+N/A
metadata-evalN/A
+-commutativeN/A
metadata-evalN/A
/-lowering-/.f32N/A
Applied egg-rr94.4%
Taylor expanded in u around 0
Simplified95.4%
clear-numN/A
un-div-invN/A
/-lowering-/.f32N/A
Applied egg-rr95.6%
Final simplification95.6%
(FPCore (s u)
:precision binary32
(let* ((t_0 (+ 21.333333333333332 (* u 64.0))))
(*
s
(*
u
(+
4.0
(/
(* u (- 64.0 (* t_0 (* u (* u 21.333333333333332)))))
(- 8.0 (* u t_0))))))))
float code(float s, float u) {
float t_0 = 21.333333333333332f + (u * 64.0f);
return s * (u * (4.0f + ((u * (64.0f - (t_0 * (u * (u * 21.333333333333332f))))) / (8.0f - (u * t_0)))));
}
real(4) function code(s, u)
real(4), intent (in) :: s
real(4), intent (in) :: u
real(4) :: t_0
t_0 = 21.333333333333332e0 + (u * 64.0e0)
code = s * (u * (4.0e0 + ((u * (64.0e0 - (t_0 * (u * (u * 21.333333333333332e0))))) / (8.0e0 - (u * t_0)))))
end function
function code(s, u) t_0 = Float32(Float32(21.333333333333332) + Float32(u * Float32(64.0))) return Float32(s * Float32(u * Float32(Float32(4.0) + Float32(Float32(u * Float32(Float32(64.0) - Float32(t_0 * Float32(u * Float32(u * Float32(21.333333333333332)))))) / Float32(Float32(8.0) - Float32(u * t_0)))))) end
function tmp = code(s, u) t_0 = single(21.333333333333332) + (u * single(64.0)); tmp = s * (u * (single(4.0) + ((u * (single(64.0) - (t_0 * (u * (u * single(21.333333333333332)))))) / (single(8.0) - (u * t_0))))); end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := 21.333333333333332 + u \cdot 64\\
s \cdot \left(u \cdot \left(4 + \frac{u \cdot \left(64 - t\_0 \cdot \left(u \cdot \left(u \cdot 21.333333333333332\right)\right)\right)}{8 - u \cdot t\_0}\right)\right)
\end{array}
\end{array}
Initial program 58.3%
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-*.f3294.5%
Simplified94.5%
*-commutativeN/A
flip-+N/A
associate-*l/N/A
/-lowering-/.f32N/A
Applied egg-rr94.5%
Taylor expanded in u around 0
Simplified95.5%
Final simplification95.5%
(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 58.3%
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-*.f3294.5%
Simplified94.5%
+-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-*.f3294.7%
Applied egg-rr94.7%
Final simplification94.7%
(FPCore (s u) :precision binary32 (* s (* u (+ 4.0 (+ (* u (* u (+ 21.333333333333332 (* u 64.0)))) (* u 8.0))))))
float code(float s, float u) {
return s * (u * (4.0f + ((u * (u * (21.333333333333332f + (u * 64.0f)))) + (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 * (u * (21.333333333333332e0 + (u * 64.0e0)))) + (u * 8.0e0))))
end function
function code(s, u) return Float32(s * Float32(u * Float32(Float32(4.0) + Float32(Float32(u * Float32(u * Float32(Float32(21.333333333333332) + Float32(u * Float32(64.0))))) + Float32(u * Float32(8.0)))))) end
function tmp = code(s, u) tmp = s * (u * (single(4.0) + ((u * (u * (single(21.333333333333332) + (u * single(64.0))))) + (u * single(8.0))))); end
\begin{array}{l}
\\
s \cdot \left(u \cdot \left(4 + \left(u \cdot \left(u \cdot \left(21.333333333333332 + u \cdot 64\right)\right) + u \cdot 8\right)\right)\right)
\end{array}
Initial program 58.3%
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-*.f3294.5%
Simplified94.5%
+-commutativeN/A
distribute-lft-inN/A
+-lowering-+.f32N/A
*-lowering-*.f32N/A
*-lowering-*.f32N/A
+-lowering-+.f32N/A
*-lowering-*.f32N/A
*-lowering-*.f3294.5%
Applied egg-rr94.5%
(FPCore (s u) :precision binary32 (* s (* u (+ (* u (+ 8.0 (* u (+ 21.333333333333332 (* u 64.0))))) 4.0))))
float code(float s, float u) {
return s * (u * ((u * (8.0f + (u * (21.333333333333332f + (u * 64.0f))))) + 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))))) + 4.0e0))
end function
function code(s, u) return Float32(s * Float32(u * Float32(Float32(u * Float32(Float32(8.0) + Float32(u * Float32(Float32(21.333333333333332) + Float32(u * Float32(64.0)))))) + Float32(4.0)))) end
function tmp = code(s, u) tmp = s * (u * ((u * (single(8.0) + (u * (single(21.333333333333332) + (u * single(64.0)))))) + single(4.0))); end
\begin{array}{l}
\\
s \cdot \left(u \cdot \left(u \cdot \left(8 + u \cdot \left(21.333333333333332 + u \cdot 64\right)\right) + 4\right)\right)
\end{array}
Initial program 58.3%
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-*.f3294.5%
Simplified94.5%
Final simplification94.5%
(FPCore (s u) :precision binary32 (* s (+ (* u 4.0) (* (* u u) (+ 8.0 (* u 21.333333333333332))))))
float code(float s, float u) {
return s * ((u * 4.0f) + ((u * 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 * u) * (8.0e0 + (u * 21.333333333333332e0))))
end function
function code(s, u) return Float32(s * Float32(Float32(u * Float32(4.0)) + Float32(Float32(u * u) * Float32(Float32(8.0) + Float32(u * Float32(21.333333333333332)))))) end
function tmp = code(s, u) tmp = s * ((u * single(4.0)) + ((u * u) * (single(8.0) + (u * single(21.333333333333332))))); end
\begin{array}{l}
\\
s \cdot \left(u \cdot 4 + \left(u \cdot u\right) \cdot \left(8 + u \cdot 21.333333333333332\right)\right)
\end{array}
Initial program 58.3%
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-*.f3294.5%
Simplified94.5%
+-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-*.f3294.7%
Applied egg-rr94.7%
Taylor expanded in u around 0
Simplified92.9%
Final simplification92.9%
(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 58.3%
Taylor expanded in u around 0
*-lowering-*.f32N/A
+-lowering-+.f32N/A
*-lowering-*.f32N/A
+-lowering-+.f32N/A
*-commutativeN/A
*-lowering-*.f3292.8%
Simplified92.8%
(FPCore (s u) :precision binary32 (* s (+ (* u 4.0) (* (* u u) 8.0))))
float code(float s, float u) {
return s * ((u * 4.0f) + ((u * 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 * u) * 8.0e0))
end function
function code(s, u) return Float32(s * Float32(Float32(u * Float32(4.0)) + Float32(Float32(u * u) * Float32(8.0)))) end
function tmp = code(s, u) tmp = s * ((u * single(4.0)) + ((u * u) * single(8.0))); end
\begin{array}{l}
\\
s \cdot \left(u \cdot 4 + \left(u \cdot u\right) \cdot 8\right)
\end{array}
Initial program 58.3%
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-*.f3294.5%
Simplified94.5%
+-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-*.f3294.7%
Applied egg-rr94.7%
Taylor expanded in u around 0
*-commutativeN/A
*-lowering-*.f32N/A
unpow2N/A
*-lowering-*.f3289.0%
Simplified89.0%
Final simplification89.0%
(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 58.3%
Taylor expanded in u around 0
*-lowering-*.f32N/A
+-lowering-+.f32N/A
*-commutativeN/A
*-lowering-*.f3288.8%
Simplified88.8%
(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 58.3%
Taylor expanded in u around 0
*-lowering-*.f3276.5%
Simplified76.5%
Final simplification76.5%
(FPCore (s u) :precision binary32 (* 4.0 (* u s)))
float code(float s, float u) {
return 4.0f * (u * s);
}
real(4) function code(s, u)
real(4), intent (in) :: s
real(4), intent (in) :: u
code = 4.0e0 * (u * s)
end function
function code(s, u) return Float32(Float32(4.0) * Float32(u * s)) end
function tmp = code(s, u) tmp = single(4.0) * (u * s); end
\begin{array}{l}
\\
4 \cdot \left(u \cdot s\right)
\end{array}
Initial program 58.3%
Taylor expanded in u around 0
*-lowering-*.f32N/A
*-commutativeN/A
*-lowering-*.f3276.3%
Simplified76.3%
herbie shell --seed 2024161
(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))))))