
(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 14 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 63.1%
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
(let* ((t_0 (+ 21.333333333333332 (* u 64.0))))
(*
s
(*
u
(+
4.0
(/
(* (* u u) (- 64.0 (* t_0 (* u (* u 21.333333333333332)))))
(* u (- 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 * u) * (64.0f - (t_0 * (u * (u * 21.333333333333332f))))) / (u * (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 * u) * (64.0e0 - (t_0 * (u * (u * 21.333333333333332e0))))) / (u * (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(Float32(u * u) * Float32(Float32(64.0) - Float32(t_0 * Float32(u * Float32(u * Float32(21.333333333333332)))))) / Float32(u * 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 * u) * (single(64.0) - (t_0 * (u * (u * single(21.333333333333332)))))) / (u * (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{\left(u \cdot u\right) \cdot \left(64 - t\_0 \cdot \left(u \cdot \left(u \cdot 21.333333333333332\right)\right)\right)}{u \cdot \left(8 - u \cdot t\_0\right)}\right)\right)
\end{array}
\end{array}
Initial program 63.1%
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-*.f3291.5%
Simplified91.5%
distribute-lft-inN/A
flip-+N/A
fmm-defN/A
*-commutativeN/A
div-subN/A
--lowering--.f32N/A
Applied egg-rr91.5%
Taylor expanded in u around 0
*-commutativeN/A
*-lowering-*.f32N/A
unpow2N/A
*-lowering-*.f3292.8%
Simplified92.8%
sub-divN/A
associate-*l*N/A
fmm-defN/A
*-commutativeN/A
/-lowering-/.f32N/A
Applied egg-rr92.8%
(FPCore (s u)
:precision binary32
(*
s
(*
u
(+
4.0
(*
u
(+
8.0
(*
u
(+ 21.333333333333332 (* u (+ 64.0 (* u 170.66666666666666)))))))))))
float code(float s, float u) {
return s * (u * (4.0f + (u * (8.0f + (u * (21.333333333333332f + (u * (64.0f + (u * 170.66666666666666f)))))))));
}
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 + (u * 170.66666666666666e0)))))))))
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(Float32(64.0) + Float32(u * Float32(170.66666666666666))))))))))) end
function tmp = code(s, u) tmp = s * (u * (single(4.0) + (u * (single(8.0) + (u * (single(21.333333333333332) + (u * (single(64.0) + (u * single(170.66666666666666)))))))))); end
\begin{array}{l}
\\
s \cdot \left(u \cdot \left(4 + u \cdot \left(8 + u \cdot \left(21.333333333333332 + u \cdot \left(64 + u \cdot 170.66666666666666\right)\right)\right)\right)\right)
\end{array}
Initial program 63.1%
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-*.f3291.5%
Simplified91.5%
distribute-lft-inN/A
flip-+N/A
fmm-defN/A
*-commutativeN/A
div-subN/A
--lowering--.f32N/A
Applied egg-rr91.5%
Taylor expanded in u around 0
*-commutativeN/A
*-lowering-*.f32N/A
unpow2N/A
*-lowering-*.f3292.8%
Simplified92.8%
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-*.f3292.4%
Simplified92.4%
(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(u * Float32(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(u \cdot \left(u \cdot \left(8 + u \cdot \left(21.333333333333332 + u \cdot 64\right)\right)\right) + u \cdot 4\right)
\end{array}
Initial program 63.1%
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-*.f3291.5%
Simplified91.5%
+-commutativeN/A
distribute-rgt-inN/A
+-lowering-+.f32N/A
*-commutativeN/A
*-lowering-*.f32N/A
*-lowering-*.f32N/A
+-lowering-+.f32N/A
*-lowering-*.f32N/A
+-lowering-+.f32N/A
*-lowering-*.f32N/A
*-lowering-*.f3291.8%
Applied egg-rr91.8%
Final simplification91.8%
(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 63.1%
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-*.f3291.5%
Simplified91.5%
(FPCore (s u) :precision binary32 (* u (+ (* s 4.0) (* s (* u (+ (* u 21.333333333333332) 8.0))))))
float code(float s, float u) {
return u * ((s * 4.0f) + (s * (u * ((u * 21.333333333333332f) + 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 * ((u * 21.333333333333332e0) + 8.0e0))))
end function
function code(s, u) return Float32(u * Float32(Float32(s * Float32(4.0)) + Float32(s * Float32(u * Float32(Float32(u * Float32(21.333333333333332)) + Float32(8.0)))))) end
function tmp = code(s, u) tmp = u * ((s * single(4.0)) + (s * (u * ((u * single(21.333333333333332)) + single(8.0))))); end
\begin{array}{l}
\\
u \cdot \left(s \cdot 4 + s \cdot \left(u \cdot \left(u \cdot 21.333333333333332 + 8\right)\right)\right)
\end{array}
Initial program 63.1%
Applied egg-rr99.3%
Taylor expanded in u around 0
*-lowering-*.f32N/A
+-lowering-+.f32N/A
*-commutativeN/A
*-lowering-*.f32N/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-*.f3289.6%
Simplified89.6%
*-commutativeN/A
*-lowering-*.f32N/A
+-lowering-+.f32N/A
*-lowering-*.f32N/A
*-commutativeN/A
associate-*l*N/A
*-lowering-*.f32N/A
*-lowering-*.f32N/A
+-lowering-+.f32N/A
*-lowering-*.f3289.6%
Applied egg-rr89.6%
Final simplification89.6%
(FPCore (s u) :precision binary32 (* u (+ (* s 4.0) (* (+ (* u 21.333333333333332) 8.0) (* u s)))))
float code(float s, float u) {
return u * ((s * 4.0f) + (((u * 21.333333333333332f) + 8.0f) * (u * s)));
}
real(4) function code(s, u)
real(4), intent (in) :: s
real(4), intent (in) :: u
code = u * ((s * 4.0e0) + (((u * 21.333333333333332e0) + 8.0e0) * (u * s)))
end function
function code(s, u) return Float32(u * Float32(Float32(s * Float32(4.0)) + Float32(Float32(Float32(u * Float32(21.333333333333332)) + Float32(8.0)) * Float32(u * s)))) end
function tmp = code(s, u) tmp = u * ((s * single(4.0)) + (((u * single(21.333333333333332)) + single(8.0)) * (u * s))); end
\begin{array}{l}
\\
u \cdot \left(s \cdot 4 + \left(u \cdot 21.333333333333332 + 8\right) \cdot \left(u \cdot s\right)\right)
\end{array}
Initial program 63.1%
Taylor expanded in u around 0
*-lowering-*.f32N/A
+-lowering-+.f32N/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
*-commutativeN/A
*-lowering-*.f32N/A
+-lowering-+.f32N/A
*-commutativeN/A
*-lowering-*.f3289.6%
Simplified89.6%
Final simplification89.6%
(FPCore (s u) :precision binary32 (* u (* s (+ 4.0 (* u (+ (* u 21.333333333333332) 8.0))))))
float code(float s, float u) {
return u * (s * (4.0f + (u * ((u * 21.333333333333332f) + 8.0f))));
}
real(4) function code(s, u)
real(4), intent (in) :: s
real(4), intent (in) :: u
code = u * (s * (4.0e0 + (u * ((u * 21.333333333333332e0) + 8.0e0))))
end function
function code(s, u) return Float32(u * Float32(s * Float32(Float32(4.0) + Float32(u * Float32(Float32(u * Float32(21.333333333333332)) + Float32(8.0)))))) end
function tmp = code(s, u) tmp = u * (s * (single(4.0) + (u * ((u * single(21.333333333333332)) + single(8.0))))); end
\begin{array}{l}
\\
u \cdot \left(s \cdot \left(4 + u \cdot \left(u \cdot 21.333333333333332 + 8\right)\right)\right)
\end{array}
Initial program 63.1%
Applied egg-rr99.3%
Taylor expanded in u around 0
*-lowering-*.f32N/A
+-lowering-+.f32N/A
*-commutativeN/A
*-lowering-*.f32N/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-*.f3289.6%
Simplified89.6%
Taylor expanded in s around 0
*-lowering-*.f32N/A
+-lowering-+.f32N/A
*-lowering-*.f32N/A
+-lowering-+.f32N/A
*-commutativeN/A
*-lowering-*.f3289.4%
Simplified89.4%
Final simplification89.4%
(FPCore (s u) :precision binary32 (* s (* u (+ 4.0 (* u (+ (* u 21.333333333333332) 8.0))))))
float code(float s, float u) {
return s * (u * (4.0f + (u * ((u * 21.333333333333332f) + 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) + 8.0e0))))
end function
function code(s, u) return Float32(s * Float32(u * Float32(Float32(4.0) + Float32(u * Float32(Float32(u * Float32(21.333333333333332)) + Float32(8.0)))))) end
function tmp = code(s, u) tmp = s * (u * (single(4.0) + (u * ((u * single(21.333333333333332)) + single(8.0))))); end
\begin{array}{l}
\\
s \cdot \left(u \cdot \left(4 + u \cdot \left(u \cdot 21.333333333333332 + 8\right)\right)\right)
\end{array}
Initial program 63.1%
Taylor expanded in u around 0
*-lowering-*.f32N/A
+-lowering-+.f32N/A
*-lowering-*.f32N/A
+-lowering-+.f32N/A
*-commutativeN/A
*-lowering-*.f3289.4%
Simplified89.4%
Final simplification89.4%
(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(u * Float32(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 + u \cdot \left(u \cdot 8\right)\right)
\end{array}
Initial program 63.1%
Taylor expanded in u around 0
*-lowering-*.f32N/A
*-commutativeN/A
associate-*r*N/A
distribute-rgt-outN/A
*-lowering-*.f32N/A
+-lowering-+.f32N/A
*-commutativeN/A
*-lowering-*.f3285.1%
Simplified85.1%
*-commutativeN/A
associate-*r*N/A
*-lowering-*.f32N/A
*-lowering-*.f32N/A
+-lowering-+.f32N/A
*-lowering-*.f3285.1%
Applied egg-rr85.1%
+-commutativeN/A
distribute-lft-inN/A
*-commutativeN/A
+-lowering-+.f32N/A
*-lowering-*.f32N/A
*-lowering-*.f32N/A
*-commutativeN/A
*-lowering-*.f3285.2%
Applied egg-rr85.2%
Final simplification85.2%
(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 63.1%
Taylor expanded in u around 0
*-lowering-*.f32N/A
*-commutativeN/A
associate-*r*N/A
distribute-rgt-outN/A
*-lowering-*.f32N/A
+-lowering-+.f32N/A
*-commutativeN/A
*-lowering-*.f3285.1%
Simplified85.1%
+-commutativeN/A
distribute-lft-inN/A
+-lowering-+.f32N/A
*-lowering-*.f32N/A
*-lowering-*.f32N/A
*-lowering-*.f3285.2%
Applied egg-rr85.2%
Final simplification85.2%
(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 63.1%
Taylor expanded in u around 0
*-lowering-*.f32N/A
+-lowering-+.f32N/A
*-commutativeN/A
*-lowering-*.f3285.1%
Simplified85.1%
(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 63.1%
Taylor expanded in u around 0
*-lowering-*.f3272.3%
Simplified72.3%
Final simplification72.3%
(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 63.1%
Taylor expanded in u around 0
*-lowering-*.f32N/A
*-commutativeN/A
*-lowering-*.f3272.1%
Simplified72.1%
herbie shell --seed 2024288
(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))))))