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https://github.com/triqs/dft_tools
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60 lines
2.5 KiB
C++
60 lines
2.5 KiB
C++
/*******************************************************************************
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*
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* TRIQS: a Toolbox for Research in Interacting Quantum Systems
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*
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* Copyright (C) 2012 by H. Hafermann, O. Parcollet
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*
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* TRIQS is free software: you can redistribute it and/or modify it under the
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* terms of the GNU General Public License as published by the Free Software
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* Foundation, either version 3 of the License, or (at your option) any later
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* version.
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*
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* TRIQS is distributed in the hope that it will be useful, but WITHOUT ANY
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* WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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* FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
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* details.
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*
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* You should have received a copy of the GNU General Public License along with
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* TRIQS. If not, see <http://www.gnu.org/licenses/>.
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*
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******************************************************************************/
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#pragma once
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#include <triqs/gfs/imfreq.hpp>
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#include <triqs/gfs/block.hpp>
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#include <triqs/gfs/local/tail.hpp>
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#include <triqs/arrays/blas_lapack/gelss.hpp>
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#include <triqs/python_tools/cython_proxy.hpp>
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namespace triqs { namespace gfs { namespace local {
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using triqs::gfs::imfreq;
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using triqs::gfs::block_index;
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using triqs::gfs::block_index;
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namespace tgl = triqs::gfs::local;
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// routine for fitting the tail (singularity) of a Matsubara Green's function
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// this is a *linear* least squares problem (with non-linear basis functions)
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// which is solved by singular value decomposition of the design matrix
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// the routine fits the real part (even moments) and the imaginary part
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//(odd moments) separately, since this is more stable
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// input:
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// the input gf<imfreq> Green's function: gf
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// the known moments in the form of a tail(_view): known_moments
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// the TOTAL number of desired moments (including the known ones): n_moments
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// the index of the first and last frequency to fit (the last one is included): n_min, n_max
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// output: returns the tail obtained by fitting
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tail fit_tail_impl(gf_view<imfreq> gf, const tail_view known_moments, int n_moments, int n_min, int n_max) ;
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void set_tail_from_fit(gf_view<imfreq> gf, tail_view known_moments, int n_moments, int n_min, int n_max,
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bool replace_by_fit = false) ;
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void set_tail_from_fit(gf_view<block_index, gf<imfreq>> block_gf, tail_view known_moments, int n_moments, int n_min,
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int n_max, bool replace_by_fit = false) ;
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void set_tail_from_fit(gf_view<imfreq, scalar_valued> gf, tail_view known_moments, int n_moments, int n_min, int n_max, bool replace_by_fit = false) ;
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}}} // namespace
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