[gf<refreq>] Real frequencies

This is a specialisation of gf for real frequencies.

Synopsis

gf<refreq, 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

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: ReFreq

Examples

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

int main() {
  double wmin = 0, wmax = 10; // Frequencies interval
  auto n_freq = 100;          // Number of points

  // We want a 2x2 matrix valued function on this mesh...
  auto g = gf<refreq>{{wmin, wmax, n_freq}, {2, 2}};
};