
(FPCore (ux uy maxCos) :precision binary32 (+ (- 1.0 ux) (* ux maxCos)))
float code(float ux, float uy, float maxCos) {
return (1.0f - ux) + (ux * maxCos);
}
real(4) function code(ux, uy, maxcos)
real(4), intent (in) :: ux
real(4), intent (in) :: uy
real(4), intent (in) :: maxcos
code = (1.0e0 - ux) + (ux * maxcos)
end function
function code(ux, uy, maxCos) return Float32(Float32(Float32(1.0) - ux) + Float32(ux * maxCos)) end
function tmp = code(ux, uy, maxCos) tmp = (single(1.0) - ux) + (ux * maxCos); end
\begin{array}{l}
\\
\left(1 - ux\right) + ux \cdot maxCos
\end{array}
Sampling outcomes in binary32 precision:
Herbie found 5 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (ux uy maxCos) :precision binary32 (+ (- 1.0 ux) (* ux maxCos)))
float code(float ux, float uy, float maxCos) {
return (1.0f - ux) + (ux * maxCos);
}
real(4) function code(ux, uy, maxcos)
real(4), intent (in) :: ux
real(4), intent (in) :: uy
real(4), intent (in) :: maxcos
code = (1.0e0 - ux) + (ux * maxcos)
end function
function code(ux, uy, maxCos) return Float32(Float32(Float32(1.0) - ux) + Float32(ux * maxCos)) end
function tmp = code(ux, uy, maxCos) tmp = (single(1.0) - ux) + (ux * maxCos); end
\begin{array}{l}
\\
\left(1 - ux\right) + ux \cdot maxCos
\end{array}
(FPCore (ux uy maxCos) :precision binary32 (+ (* maxCos (- ux (/ ux maxCos))) 1.0))
float code(float ux, float uy, float maxCos) {
return (maxCos * (ux - (ux / maxCos))) + 1.0f;
}
real(4) function code(ux, uy, maxcos)
real(4), intent (in) :: ux
real(4), intent (in) :: uy
real(4), intent (in) :: maxcos
code = (maxcos * (ux - (ux / maxcos))) + 1.0e0
end function
function code(ux, uy, maxCos) return Float32(Float32(maxCos * Float32(ux - Float32(ux / maxCos))) + Float32(1.0)) end
function tmp = code(ux, uy, maxCos) tmp = (maxCos * (ux - (ux / maxCos))) + single(1.0); end
\begin{array}{l}
\\
maxCos \cdot \left(ux - \frac{ux}{maxCos}\right) + 1
\end{array}
Initial program 99.8%
Taylor expanded in maxCos around inf 98.0%
sub-neg98.0%
+-commutative98.0%
mul-1-neg98.0%
associate-+l+98.0%
+-commutative98.0%
distribute-lft-in98.7%
mul-1-neg98.7%
unsub-neg98.7%
rgt-mult-inverse99.9%
Simplified99.9%
(FPCore (ux uy maxCos) :precision binary32 (- 1.0 (* ux (- 1.0 maxCos))))
float code(float ux, float uy, float maxCos) {
return 1.0f - (ux * (1.0f - maxCos));
}
real(4) function code(ux, uy, maxcos)
real(4), intent (in) :: ux
real(4), intent (in) :: uy
real(4), intent (in) :: maxcos
code = 1.0e0 - (ux * (1.0e0 - maxcos))
end function
function code(ux, uy, maxCos) return Float32(Float32(1.0) - Float32(ux * Float32(Float32(1.0) - maxCos))) end
function tmp = code(ux, uy, maxCos) tmp = single(1.0) - (ux * (single(1.0) - maxCos)); end
\begin{array}{l}
\\
1 - ux \cdot \left(1 - maxCos\right)
\end{array}
Initial program 99.8%
associate-+l-99.9%
*-un-lft-identity99.9%
*-commutative99.9%
distribute-rgt-out--99.9%
Applied egg-rr99.9%
(FPCore (ux uy maxCos) :precision binary32 (+ (- 1.0 ux) (* maxCos ux)))
float code(float ux, float uy, float maxCos) {
return (1.0f - ux) + (maxCos * ux);
}
real(4) function code(ux, uy, maxcos)
real(4), intent (in) :: ux
real(4), intent (in) :: uy
real(4), intent (in) :: maxcos
code = (1.0e0 - ux) + (maxcos * ux)
end function
function code(ux, uy, maxCos) return Float32(Float32(Float32(1.0) - ux) + Float32(maxCos * ux)) end
function tmp = code(ux, uy, maxCos) tmp = (single(1.0) - ux) + (maxCos * ux); end
\begin{array}{l}
\\
\left(1 - ux\right) + maxCos \cdot ux
\end{array}
Initial program 99.8%
Final simplification99.8%
(FPCore (ux uy maxCos) :precision binary32 (- 1.0 ux))
float code(float ux, float uy, float maxCos) {
return 1.0f - ux;
}
real(4) function code(ux, uy, maxcos)
real(4), intent (in) :: ux
real(4), intent (in) :: uy
real(4), intent (in) :: maxcos
code = 1.0e0 - ux
end function
function code(ux, uy, maxCos) return Float32(Float32(1.0) - ux) end
function tmp = code(ux, uy, maxCos) tmp = single(1.0) - ux; end
\begin{array}{l}
\\
1 - ux
\end{array}
Initial program 99.8%
Taylor expanded in maxCos around inf 98.0%
sub-neg98.0%
+-commutative98.0%
mul-1-neg98.0%
associate-+l+98.0%
+-commutative98.0%
distribute-lft-in98.7%
mul-1-neg98.7%
unsub-neg98.7%
rgt-mult-inverse99.9%
Simplified99.9%
Taylor expanded in maxCos around 0 98.1%
neg-mul-198.1%
sub-neg98.1%
Simplified98.1%
(FPCore (ux uy maxCos) :precision binary32 1.0)
float code(float ux, float uy, float maxCos) {
return 1.0f;
}
real(4) function code(ux, uy, maxcos)
real(4), intent (in) :: ux
real(4), intent (in) :: uy
real(4), intent (in) :: maxcos
code = 1.0e0
end function
function code(ux, uy, maxCos) return Float32(1.0) end
function tmp = code(ux, uy, maxCos) tmp = single(1.0); end
\begin{array}{l}
\\
1
\end{array}
Initial program 99.8%
Taylor expanded in maxCos around inf 98.0%
sub-neg98.0%
+-commutative98.0%
mul-1-neg98.0%
associate-+l+98.0%
+-commutative98.0%
distribute-lft-in98.7%
mul-1-neg98.7%
unsub-neg98.7%
rgt-mult-inverse99.9%
Simplified99.9%
Taylor expanded in ux around 0 74.4%
herbie shell --seed 2024146
(FPCore (ux uy maxCos)
:name "UniformSampleCone, z"
:precision binary32
:pre (and (and (and (<= 2.328306437e-10 ux) (<= ux 1.0)) (and (<= 2.328306437e-10 uy) (<= uy 1.0))) (and (<= 0.0 maxCos) (<= maxCos 1.0)))
(+ (- 1.0 ux) (* ux maxCos)))