#include "fracture.h"

double net_conductivity(const net_t *net, const double *voltages) {
  if (net->voltage_bound) {
    // the voltage drop across the network is fixed to one with voltage
    // boundary conditions, so the conductivity is the total current flowing
    double tot_cur = 0;
    for (uint_t i = 0; i < net->graph->num_spanning_edges; i++) {
      uint_t e = net->graph->spanning_edges[i];

      if (!net->fuses[e]) {
        uint_t v1, v2, s1, s2;
        double v1y, v2y;

        v1 = net->graph->ev[2 * e];
        v2 = net->graph->ev[2 * e + 1];

        v1y = net->graph->vx[2 * v1 + 1];
        v2y = net->graph->vx[2 * v2 + 1];

        s1 = v1y < v2y ? v1 : v2;
        s2 = v1y < v2y ? v2 : v1;

        tot_cur += voltages[s1] - voltages[s2];
      }
    }

    return fabs(tot_cur);
  } else {
    // the current across the network is fixed to one with current boundary
    // conditions, so the conductivity is the inverse of the total voltage drop
    return 1 / fabs(voltages[net->graph->nv] - voltages[net->graph->nv + 1]);
  }
}