fastlens

fastlens is an FFT based evaluation of finite source effect on microlensing. See and cite Sugiyama. This method reduces the two-dimensional integration to one-dimensional fft on logarithmic space, which can be efficiently evaluated. The target quantity to be evaluated is

\[A_{\rm ext}(u; \rho) = \int{\rm d}\vec{x} A_{\rm p}(\vec{x})s(\vec{x}+\vec{u};\rho).\]

where \(s(u;\rho)\) is the source flux profile as a function of distance from source center, \(u\).

fastlens is installable from both pip and conda:

pip install fastlens

conda install -c ssunao fastlens