Unverified Commit bb79babd authored by Peter Doak's avatar Peter Doak Committed by GitHub
Browse files

Merge pull request #146 from gbalduzz/check_double_counting 

Added comment and check about double counting.
parents cce8d0b2 1294a8ec

include/dca/phys/dca_data/dca_data.hpp

+22 −0
Original line number Diff line number Diff line
@@ -6,6 +6,7 @@ 
// See CITATION.md for citation guidelines, if DCA++ is used for scientific publications.

//

// Author: Peter Staar (taa@zurich.ibm.com)

//         Giovanni Balduzzi (gbalduzz@itp.phys.ethz.ch)

//

// This class contains all functions needed for the MOMS DCA calculation.

//
@@ -126,6 +127,13 @@ private: 


public:

  func::function<int, NuNuDmn> H_symmetry;



  // Interaction Hamiltonian. Each entry H_interactions(nu1, nu2, delta_r) represents the

  // correlation strength between the two orbitals nu1 nu2 at distance delta_r. This correlation

  // must be symmetric, or double counted, i.e.

  // H_interactions(nu1, nu2, delta_r) == H_interactions(nu2, nu1, -delta_r). Each pair of terms

  // represents a single addendum in the physical hamiltonian proportional to n_{nu1} * n_{nu2}, or

  // H = \sum_{nu1, nu2, r1, r2} H_interactions(nu1, nu2, r1 - r2) n_{nu1} n_{nu2} / 2.

  func::function<double, func::dmn_variadic<NuDmn, NuDmn, RClusterDmn>> H_interactions;



  func::function<std::complex<double>, func::dmn_variadic<NuDmn, NuDmn, KClusterDmn>> H_DCA;
@@ -212,6 +220,8 @@ public: // Optional members getters. 
    assert(!G4_err_.empty());

    return G4_err_;

  }



  // Note: this contribution to the Hamiltonian is not double counted.

  auto& get_non_density_interactions() {

    if (not non_density_interactions_)

      non_density_interactions_.reset(
@@ -487,6 +497,18 @@ void DcaData<Parameters>::initialize_H_0_and_H_i() { 


  Parameters::model_type::initialize_H_interaction(H_interactions, parameters_);



  // Check symmetry of H_interactions.

  const int r0 = RClusterDmn::parameter_type::origin_index();

  for (int r = 0; r < RClusterDmn::dmn_size(); ++r) {

    const int minus_r = RClusterDmn::parameter_type::subtract(r, r0);

    for (int nu2 = 0; nu2 < NuDmn::dmn_size(); ++nu2)

      for (int nu1 = 0; nu1 < NuDmn::dmn_size(); ++nu1) {

        if (std::abs(H_interactions(nu1, nu2, r) - H_interactions(nu2, nu1, minus_r)) > 1e-8) {

          throw(std::logic_error("Double counting is not consistent."));

        }

      }

  }



  if (models::has_non_density_interaction<Lattice>::value) {

    models::initializeNonDensityInteraction<Lattice>(get_non_density_interactions(), parameters_);

  }