float*
circuitModel(vtx_data * graph, int nG)
{
int i, j, e, rv, count;
float *Dij = N_NEW(nG * (nG + 1) / 2, float);
double **Gm;
double **Gm_inv;
Gm = new_array(nG, nG, 0.0);
Gm_inv = new_array(nG, nG, 0.0);
/* set non-diagonal entries */
if (graph->ewgts) {
for (i = 0; i < nG; i++) {
for (e = 1; e < graph[i].nedges; e++) {
j = graph[i].edges[e];
/* conductance is 1/resistance */
Gm[i][j] = Gm[j][i] = -1.0 / graph[i].ewgts[e]; /* negate */
}
}
} else {
for (i = 0; i < nG; i++) {
for (e = 1; e < graph[i].nedges; e++) {
j = graph[i].edges[e];
/* conductance is 1/resistance */
Gm[i][j] = Gm[j][i] = -1.0; /* ewgts are all 1 */
}
}
}
rv = solveCircuit(nG, Gm, Gm_inv);
if (rv) {
float v;
count = 0;
for (i = 0; i < nG; i++) {
for (j = i; j < nG; j++) {
if (i == j)
v = 0.0;
else
v = (float) (Gm_inv[i][i] + Gm_inv[j][j] -
2.0 * Gm_inv[i][j]);
Dij[count++] = v;
}
}
} else {
free(Dij);
Dij = NULL;
}
free_array(Gm);
free_array(Gm_inv);
return Dij;
}
int circuit_model(graph_t * g, int nG)
{
double **Gm;
double **Gm_inv;
int rv;
long i, j;
node_t *v;
edge_t *e;
Gm = new_array(nG, nG, 0.0);
Gm_inv = new_array(nG, nG, 0.0);
/* set non-diagonal entries */
for (v = agfstnode(g); v; v = agnxtnode(g, v)) {
for (e = agfstedge(g, v); e; e = agnxtedge(g, e, v)) {
i = AGID(agtail(e));
j = AGID(aghead(e));
if (i == j)
continue;
/* conductance is 1/resistance */
Gm[i][j] = Gm[j][i] = -1.0 / ED_dist(e); /* negate */
}
}
rv = solveCircuit(nG, Gm, Gm_inv);
if (rv)
for (i = 0; i < nG; i++) {
for (j = 0; j < nG; j++) {
GD_dist(g)[i][j] =
Gm_inv[i][i] + Gm_inv[j][j] - 2.0 * Gm_inv[i][j];
}
}
free_array(Gm);
free_array(Gm_inv);
return rv;
}
