M4_iw.hpp

// Copyright (c) 2017--present, The Simons Foundation
// This file is part of TRIQS/ctint and is licensed under the terms of GPLv3 or later.
// SPDX-License-Identifier: GPL-3.0-or-later
// See LICENSE in the root of this distribution for details.
 
#pragma once
#include "../qmc_config.hpp"
#include "../nfft_buf.hpp"
#include "../container_set.hpp"
 
namespace triqs_ctint::measures {

  struct M4_iw {
 
    M4_iw(params_t const &params_, qmc_config_t const &qmc_config_, container_set *results);
 
    // M4_iw needs to be uncopyable due to nfft_buf_t
    M4_iw(M4_iw const &)            = delete;
    M4_iw(M4_iw &&)                 = default;
    ~M4_iw()                        = default;
    M4_iw &operator=(M4_iw const &) = delete;
    M4_iw &operator=(M4_iw &&)      = delete;

    void accumulate(mc_weight_t sign);

    void collect_results(mpi::communicator const &comm);
 
    private:
    // Capture the parameters
    params_t const &params;
 
    // The Monte-Carlo configuration
    qmc_config_t const &qmc_config;
 
    // Container for the accumulation
    block2_gf_view<prod<imfreq, imfreq, imfreq>, tensor_valued<4>> M4_iw_;
 
    // The average sign
    mc_weight_t Z = 0.0;
 
    // Container of nfft_buffers: buf_arrarr(block)(u_j,u_i)
    array<array<nfft_buf_t<2>, 2>, 1> buf_arrarr;
 
    // Intermediate scattering matrix in the measurement of M4
    block_gf<prod<imfreq, imfreq>, matrix_valued> M;
  };
 
} // namespace triqs_ctint::measures