worker.hpp

// Copyright (c) 2017-2018 Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
// Copyright (c) 2017-2018 Centre national de la recherche scientifique (CNRS)
// Copyright (c) 2018-2020 Simons Foundation
// Copyright (c) 2017 Igor Krivenko
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program 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 General Public License for more details.
//
// You may obtain a copy of the License at
//     https://www.gnu.org/licenses/gpl-3.0.txt
//
// Authors: Maxime Charlebois, Michel Ferrero, Igor Krivenko, Nils Wentzell
 
#pragma once
 
#include "../atom_diag.hpp"
#include "../../hilbert_space/hilbert_space.hpp"
 
#include <climits>
#include <vector>
 
using namespace triqs::hilbert_space;
 
namespace triqs::atom_diag {
 
  // Division of Hilbert Space into Hilbert subspaces, using either autopartitioning or quantum numbers.
  template <bool Complex> struct atom_diag_worker {
 
    //using atom_diag = atom_diag<Complex>;
    using scalar_t       = typename atom_diag<Complex>::scalar_t;
    using matrix_t       = typename atom_diag<Complex>::matrix_t;
    using many_body_op_t = typename atom_diag<Complex>::many_body_op_t;
 
    atom_diag_worker(atom_diag<Complex> *hdiag, int n_min = 0, int n_max = INT_MAX) : hdiag(hdiag), n_min(n_min), n_max(n_max) {}
 
    //void autopartition();
    void autopartition(many_body_op_t const &hyb = many_body_op_t());
    void partition_with_qn(std::vector<many_body_op_t> const &qn_vector);
 
    private:
    atom_diag<Complex> *hdiag;
    int n_min, n_max;
 
    // Create matrix of an operator acting from one subspace to another
    matrix_t make_op_matrix(many_body_op_t const &op, int from_sp, int to_sp) const;
 
    void complete();
    bool fock_state_filter(fock_state_t s);
  };
 
} // namespace triqs::atom_diag