TRIQS/TRIQS — pull request #51 by krivenko (2012-03-27 23:02:07+00:00)
Title: New method GFBloc_ReFreq::setFromPadeOf()

I have implemented a new method of `GFBloc_ReFreq` which performs a simple analytic continuation procedure to set data of a real frequency Green's function from an imaginary frequency counterpart. It uses the Padé approximation algorithm i.e., is intended to work with numerically exact data, in contrast to more sophisticated schemes like maxent.

This code is based on a FORTRAN program written by A. Poteryaev. A detailed description of the algorithm can be found in H. J. Vidberg, J. W. Serene. J. Low Temp. Phys. 29, 3-4, 179 (1977).
Also I provide a short script to test this new method: https://gist.github.com/2221062

TODO: The code from Poteryaev has one useful feature which has not been realized yet. It allows to choose a subset of Matsubara points to construct a Padé approximant of a Green's function. I'm going to add this, but first I need to dig deeper into Boost.Python and the architecture of TRIQS.