lib/src/graph.cpp


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#include "graph.hpp"

graph::graph(unsigned int Nx, unsigned int Ny) {
  L = {(double)Nx, (double)Ny};

  unsigned int ne = Nx * Ny;
  unsigned int nv = ne / 2;

  vertices.resize(nv);
  edges.reserve(ne);

  dual_vertices.resize(nv);
  dual_edges.reserve(ne);

  for (unsigned int i = 0; i < nv; i++) {
    vertices[i].r.x = (double)((1 + i / (Nx / 2)) % 2 + 2 * (i % (Nx / 2)));
    vertices[i].r.y = (double)(i / (Nx / 2));

    dual_vertices[i].r.x = (double)((i / (Nx / 2)) % 2 + 2 * (i % (Nx / 2)));
    dual_vertices[i].r.y = (double)(i / (Nx / 2));
  }

  for (unsigned int x = 0; x < Ny; x++) {
    for (unsigned int y = 0; y < Nx; y++) {
      unsigned int v1 = (Nx * x) / 2 + ((y + x % 2) / 2) % (Nx / 2);
      unsigned int v2 = ((Nx * (x + 1)) / 2 + ((y + (x + 1) % 2) / 2) % (Nx / 2)) % nv;

      edges.push_back({v1, v2});

      unsigned int dv1 = (Nx * x) / 2 + ((y + (x + 1) % 2) / 2) % (Nx / 2);
      unsigned int dv2 = ((Nx * (x + 1)) / 2 + ((y + x % 2) / 2) % (Nx / 2)) % nv;

      dual_edges.push_back({dv1, dv2});
    }
  }
}