/* -*- mode: C -*-  */
/* 
   IGraph library.
   Copyright (C) 2008-2012  Gabor Csardi <csardi.gabor@gmail.com>
   334 Harvard street, Cambridge, MA 02139 USA
   
   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.
   
   This program 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 General Public License for more details.
   
   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 
   02110-1301 USA

*/

#include <igraph.h>

int print_matrix(const igraph_matrix_t *m) {
  long int nrow=igraph_matrix_nrow(m);
  long int ncol=igraph_matrix_ncol(m);
  long int i, j;
  for (i=0; i<nrow; i++) {
    printf("%li:", i);
    for (j=0; j<ncol; j++) {
      printf(" %3.0F", MATRIX(*m, i, j));
    }
    printf("\n");
  }
  return 0;
}

int main() {
  
  igraph_t g;
  igraph_vector_t weights;
  igraph_real_t weights_data_0[] = { 0,2,1, 0,5,2, 1,1,0, 2,2,8, 1,1,3, 1,1,4, 2,1 };
  igraph_real_t weights_data_1[] = { 6,7,8,-4,-2,-3,9,2,7 };
  igraph_real_t weights_data_2[] = { 6,7,2,-4,-2,-3,9,2,7 };
  igraph_matrix_t res;
  
  /* Graph with only positive weights */
  igraph_small(&g, 10, IGRAPH_DIRECTED, 
	       0,1, 0,2, 0,3,    1,2, 1,4, 1,5,
	       2,3, 2,6,         3,2, 3,6,
	       4,5, 4,7,         5,6, 5,8, 5,9,
	       7,5, 7,8,         8,9,
	       5,2,
	       2,1,
	       -1);
  
  igraph_vector_view(&weights, weights_data_0, 
		     sizeof(weights_data_0)/sizeof(igraph_real_t));
  
  igraph_matrix_init(&res, 0, 0);
  igraph_shortest_paths_bellman_ford(&g, &res, igraph_vss_all(), igraph_vss_all(),
				     &weights, IGRAPH_OUT);
  print_matrix(&res);
  
  igraph_matrix_destroy(&res);
  igraph_destroy(&g);

  printf("\n");

  /***************************************/

  /* Graph with negative weights */
  igraph_small(&g, 5, IGRAPH_DIRECTED, 
	       0,1, 0,3, 1,3, 1,4, 2,1, 3,2, 3,4, 4,0, 4,2, -1);
  
  igraph_vector_view(&weights, weights_data_1, 
		     sizeof(weights_data_1)/sizeof(igraph_real_t));
  
  igraph_matrix_init(&res, 0, 0);
  igraph_shortest_paths_bellman_ford(&g, &res, igraph_vss_all(), 
				     igraph_vss_all(), &weights, IGRAPH_OUT);
  print_matrix(&res);
  
  /***************************************/

  /* Same graph with negative loop */
  igraph_set_error_handler(igraph_error_handler_ignore);
  igraph_vector_view(&weights, weights_data_2, 
		     sizeof(weights_data_2)/sizeof(igraph_real_t));
  if (igraph_shortest_paths_bellman_ford(&g, &res, igraph_vss_all(),
					 igraph_vss_all(),
                                         &weights, IGRAPH_OUT) != IGRAPH_ENEGLOOP)
    return 1;
  
  igraph_matrix_destroy(&res);
  igraph_destroy(&g);

  if (!IGRAPH_FINALLY_STACK_EMPTY) return 1;

  return 0;
}