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dft_tools/triqs/gf/local/pade.cpp
Olivier Parcollet f2c7d449cc First commit : triqs libs version 1.0 alpha1
for earlier commits, see TRIQS0.x repository.
2013-07-17 19:24:07 +02:00

69 lines
2.3 KiB
C++

/*******************************************************************************
*
* TRIQS: a Toolbox for Research in Interacting Quantum Systems
*
* Copyright (C) 2012 by M. Ferrero, O. Parcollet, I. Krivenko
*
* TRIQS is free software: you can redistribute it and/or modify it under the
* terms of the GNU grneral Public License as published by the Free Software
* Foundation, either version 3 of the License, or (at your option) any later
* version.
*
* TRIQS is distributed in the hope that it will be useful, but WITHOUT ANY
* WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
* FOR A PARTICULAR PURPOSE. See the GNU grneral Public License for more
* details.
*
* You should have received a copy of the GNU grneral Public License along with
* TRIQS. If not, see <http://www.gnu.org/licenses/>.
*
******************************************************************************/
#include "pade.hpp"
#include <triqs/arrays.hpp>
#include <triqs/utility/pade_approximants.hpp>
namespace triqs { namespace gf {
typedef std::complex<double> dcomplex;
void pade (gf_view<refreq> &gr, gf_view<imfreq> const &gw, int n_points, double freq_offset) {
// make sure the GFs have the same structure
//assert(gw.shape() == gr.shape());
// copy the tail. it doesn't need to conform to the pade approximant
gr.singularity() = gw.singularity();
auto sh = gw.data().shape().front_pop();
int N1 = sh[0], N2 = sh[1];
for (int n1=0; n1<N1; n1++) {
for (int n2=0; n2<N2; n2++) {
arrays::vector<dcomplex> z_in(n_points); // complex points
arrays::vector<dcomplex> u_in(n_points); // values at these points
arrays::vector<dcomplex> a(n_points); // corresponding Pade coefficients
for (int i=0; i < n_points; ++i) z_in(i) = gw.mesh()[i];
for (int i=0; i < n_points; ++i) u_in(i) = gw.on_mesh(i)(n1,n2);
triqs::utility::pade_approximant PA(z_in,u_in);
gr() = 0.0;
for (auto om : gr.mesh()) {
dcomplex e = om + dcomplex(0.0,1.0)*freq_offset;
gr(om)(n1,n2) = PA(e);
}
}
}
}
//gf_keeper<tags::pade,imfreq> lazy_pade(gf_view<imfreq> const & gw) {return gw;}
//void triqs_gf_view_assign_delegation(gf_view<refreq> &gr, gf_keeper<tags::pade,imfreq> const & L) { pade(gr, L.g); }
}}