[gf<retime>] Real time

This is a specialisation of gf and views for imaginary Matsubara frequencies.


gf<retime, Target, Opt>

The Target template parameter can take the following values:

Target Meaning
scalar_valued The function is scalar valued (double, complex…).
matrix_valued [default] The function is matrix valued.

Domain & mesh


The singularity is a high frequency expansion, High-Frequency moments of the Green’s function.

Evaluation method

  • Linear interpolation on the mesh.
  • Return type:
    • If Target==scalar_valued: a complex
    • If Target==matrix_valued: an object modeling ImmutableMatrix concept.
  • When the point is outside of the mesh, the evaluation of the gf returns:
    • the evaluation of the high frequency tail

Data storage

  • If Target==scalar_valued :
    • data_t: 1d array of complex<double>.
    • g.data()(i) is the value of g for the i-th point of the mesh.
  • If Target==matrix_valued :
    • data_t: 3d array (C ordered) of complex<double>.
    • g.data()(i, range(), range()) is the value of g for the i-th point of the mesh.

HDF5 storage convention

h5 tag: ReTime


#include <triqs/gfs.hpp>
#include <triqs/mesh.hpp>
using namespace triqs::gfs;
using namespace triqs::mesh;

int main() {
  double tmin = 0, tmax = 10; // the time interval
  auto n_times = 100;         // we will have 100 points

  // we want a 2x2 matrix-valued Green function
  auto g = gf<retime>{{tmin, tmax, n_times}, {2, 2}};