/* Free the edge list created by find_edges. */
public static void free_edgeslist(edgeslist *edge_list /* list to be freed */
)
{
edgeslist *next_list; /* next guy in list */
while (edge_list != null)
{
next_list = edge_list->next;
Marshal.FreeHGlobal((IntPtr)(edge_list));
edge_list = next_list;
}
}
public static void add_edges(vtx_data **graph, /* graph data structure */
edgeslist *new_edges, /* list of edges connecting graph */
ilists **old_edges, /* edges data overwritten for connecting */
flists **old_ewgts, /* weights of edges overwritten */
bool useEdgeWeights /* are edge weights being used? */
)
{
ilists * save_list; /* space to save old edge list */
flists * save_ewgts; /* space to save old edge weights */
edgeslist *edges; /* loops through new edges */
float * new_ewgts; /* new edge weights */
int * new_list; /* new edge list */
int nedges; /* number of edges a vertex has */
int vtx, vtx2; /* two vertices in edge to be added */
int i, j; /* loop counter */
*old_edges = null;
*old_ewgts = null;
edges = new_edges;
while (edges != null)
{
for (j = 0; j < 2; j++)
{
if (j == 0)
{
vtx = edges->vtx1;
vtx2 = edges->vtx2;
}
else
{
vtx = edges->vtx2;
vtx2 = edges->vtx1;
}
/* Copy old edge list to new edge list. */
nedges = graph[vtx]->nedges;
new_list = (int *)Marshal.AllocHGlobal((nedges + 1) * sizeof(int));
for (i = 0; i < nedges; i++)
{
new_list[i] = graph[vtx]->edges[i];
}
new_list[nedges] = vtx2;
/* Save old edges. */
save_list = (ilists *)Marshal.AllocHGlobal(sizeof(ilists));
save_list->list = graph[vtx]->edges;
/* Add new list at FRONT of linked list to facilitate uncoarsening. */
save_list->next = *old_edges;
*old_edges = save_list;
/* Now modify graph to have new edges list. */
graph[vtx]->nedges++;
graph[vtx]->edges = new_list;
/* If using edge weights, I have to modify those too. */
if (useEdgeWeights)
{
new_ewgts = (float *)Marshal.AllocHGlobal((nedges + 1) * sizeof(float));
for (i = 1; i < nedges; i++)
{
new_ewgts[i] = graph[vtx]->ewgts[i];
}
new_ewgts[nedges] = 1;
new_ewgts[0] = graph[vtx]->ewgts[0] - new_ewgts[nedges];
/* Save old edge weights. */
save_ewgts = (flists *)Marshal.AllocHGlobal(sizeof(flists));
save_ewgts->list = graph[vtx]->ewgts;
save_ewgts->next = *old_ewgts;
*old_ewgts = save_ewgts;
/* Finally, modify graph to have new edge weights. */
graph[vtx]->ewgts = new_ewgts;
}
}
edges = edges->next;
}
}
