Sperp_tau.cpp

// Copyright (c) 2022--present, The Simons Foundation
// Copyright (c) 2022--present, Max Planck Institute for Polymer Research, Mainz, Germany
// This file is part of TRIQS/ctseg 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.
 
#include "./Sperp_tau.hpp"
#include "../logs.hpp"
 
namespace triqs_ctseg::measures {
 
  Sperp_tau::Sperp_tau(params_t const &p, work_data_t const &wdata, configuration_t const &config, results_t &results)
     : wdata{wdata}, config{config}, results{results} {
 
    beta = p.beta;
 
    n_color = config.n_color();
 
    ss_tau   = gf<imtime>({beta, Boson, p.n_tau_chi2}, {1, 1});
    ss_tau() = 0;
    Z        = 0;
  }
 
  // -------------------------------------
 
  void Sperp_tau::accumulate(double s) {
 
    LOG("\n =================== MEASURE < S_x S_x > (tau) ================ \n");
 
    Z += s;
 
    for (auto const &[k, line] : itertools::enumerate(config.Jperp_list)) {
      auto dtau1 = double(line.tau_Splus - line.tau_Sminus);
      auto dtau2 = double(line.tau_Sminus - line.tau_Splus);
      ss_tau[closest_mesh_pt(dtau1)] += 0.5 / (real(wdata.Jperp(dtau1)(0, 0)));
      ss_tau[closest_mesh_pt(dtau2)] += 0.5 / (real(wdata.Jperp(dtau2)(0, 0)));
    }
  }
 
  // -------------------------------------
 
  void Sperp_tau::collect_results(mpi::communicator const &c) {
 
    Z = mpi::all_reduce(Z, c);
 
    ss_tau = mpi::all_reduce(ss_tau, c);
    ss_tau = ss_tau / (-beta * Z * ss_tau.mesh().delta());
 
    // Fix the point at zero and beta
    ss_tau[0] *= 2;
    ss_tau[ss_tau.mesh().size() - 1] *= 2;
 
    // store the result (not reused later, hence we can move it).
    results.Sperp_tau = std::move(ss_tau);
  }
 
} // namespace triqs_ctseg::measures