eg_edgraph.ex.c

This is a more detailed example on how to use this module

/* EGlib "Efficient General Library" provides some basic structures and
 * algorithms commons in many optimization algorithms.
 *
 * Copyright (C) 2005 Daniel Espinoza and Marcos Goycoolea.
 * 
 * This library is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as published by the
 * Free Software Foundation; either version 2.1 of the License, or (at your
 * option) any later version.
 *
 * This library is distributed in the hope that it will be useful, but 
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 
 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public 
 * License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this library; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA 
 * */
/** @file
 * @ingroup EGeDgraph
 * */
/** @addtogroup EGeDgraph */
/** @{ */
#include "eg_elist.h"
#include "eg_edgraph.h"
/* ========================================================================= */
/** @brief example of a graph structure using the embeded substructures. */
typedef struct my_dgraph_t
{
  unsigned id;
  EGeDgraph_t G;
}
my_dgraph_t;

/* ========================================================================= */
/** @brief example of a node structure using the embeded substructures. */
typedef struct my_dnode_t
{
  unsigned id;
  EGeDgraphNode_t v;
}
my_dnode_t;

/* ========================================================================= */
/** @brief example of an edge structure using the embeded substructures. */
typedef struct my_dedge_t
{
  unsigned id;
  EGeDgraphEdge_t e;
}
my_dedge_t;

/* ========================================================================= */
/** @brief Display the contents of our graph structure */
static inline void display_DG (my_dgraph_t * myG)
{
  EGeDgraph_t *G = &(myG->G);
  my_dnode_t *cn;
  my_dedge_t *ce;
  EGeList_t *node_it,
   *edge_it;
  fprintf (stderr, "Graph %d (%d nodes, %d edges):\n", myG->id, G->n_nodes,
           G->n_edges);
  /* we display the nodes and it's contents only if it is not empty */
  if (!EGeListIsEmpty (&(G->nodes)))
  {
    fprintf (stderr, "Nodes:\n");
    for (node_it = G->nodes.next; node_it != &(G->nodes);
         node_it = node_it->next)
    {
      cn = EGcontainerOf (node_it, my_dnode_t, v.node_cn);
      fprintf (stderr, "\t%d: ", cn->id);
      if (!EGeListIsEmpty (&(cn->v.in_edge)))
      {
        fprintf (stderr, "(in edges) ");
        for (edge_it = cn->v.in_edge.next; edge_it != &(cn->v.in_edge);
             edge_it = edge_it->next)
        {
          ce = EGcontainerOf (edge_it, my_dedge_t, e.head_cn);
          fprintf (stderr, "%d ", ce->id);
        }
      }
      if (!EGeListIsEmpty (&(cn->v.out_edge)))
      {
        fprintf (stderr, "(out edges) ");
        for (edge_it = cn->v.out_edge.next; edge_it != &(cn->v.out_edge);
             edge_it = edge_it->next)
        {
          ce = EGcontainerOf (edge_it, my_dedge_t, e.tail_cn);
          fprintf (stderr, "%d ", ce->id);
        }
      }
      fprintf (stderr, "\n");
    }
  }

}

/* ========================================================================= */
/** @brief A simple example of a directed graph using (EGdEgraph) structures.
 * @return zero on success, non-zero- otherwise.
 * @par Description:
 * Show how to use a directed graph, modify it and display it's contents */
int main (void)
{
  int rval = 0;
  my_dgraph_t myG;
  my_dnode_t nodes[5];
  my_dedge_t edges[5];
  int i;

  /* initialize all structures */
  EGeDgraphInit (&(myG.G));
  myG.id = 0;
  display_DG (&myG);
  /* note that this is a backward loop that should be more eficient than the
   * regular forward loop (you save the last update condition ) */
  for (i = 5; i--;)
  {
    EGeDgraphNodeInit (&(nodes[i].v));
    EGeDgraphEdgeInit (&(edges[i].e));
    nodes[i].id = i;
    edges[i].id = i;
  }
  /* now we can use all edges and nodes and add them to the graph, we will
   * create a circular graph on 5 edges */
  for (i = 5; i--;)
    EGeDgraphAddNode (&(myG.G), &(nodes[i].v));
  display_DG (&myG);
  for (i = 5; i--;)
    EGeDgraphAddEdge (&(myG.G), &(nodes[i].v), &(nodes[(i + 1) % 5].v),
                      &(edges[i].e));
  display_DG (&myG);
  /* now we will push all incomming edges to a previous node, and all outgoing
   * edges to the next edge */
  for (i = 5; i--;)
  {
    EGeDgraphChangeHead (&(myG.G), &(edges[i].e), &(nodes[(i + 4) % 5].v));
    EGeDgraphChangeTail (&(myG.G), &(edges[i].e), &(nodes[(i + 2) % 5].v));
  }
  display_DG (&myG);
  /* now we delete one edge at a time */
  for (i = 5; i--;)
  {
    EGeDgraphDelEdge (&(myG.G), &(edges[i].e));
    display_DG (&myG);
  }
  /* and delete nodes one by one */
  for (i = 5; i--;)
  {
    EGeDgraphDelNode (&(myG.G), &(nodes[i].v));
    display_DG (&myG);
  }
  /* ending */
  EGeDgraphClear (&myG);
  for (i = 5; i--;)
  {
    EGeDgraphNodeClear (&(nodes[i].v));
    EGeDgraphEdgeClear (&(edges[i].e));
  }
  return rval;
}

/* ========================================================================= */
/** @} */

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