/* -*- mode: C -*-  */
/* 
   IGraph library.
   Copyright (C) 2011-2012  Gabor Csardi <csardi.gabor@gmail.com>
   334 Harvard st, 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 main() {

  const int nodes=10;
  igraph_t g;
  igraph_matrix_t V, V3;
  igraph_matrix_complex_t V2;
  igraph_sparsemat_t stochastic, stochasticT;
  igraph_vector_t groups;
  igraph_eigen_which_t which;
  igraph_vector_t p, selcol;

  igraph_tree(&g, nodes, /* children= */ 3, IGRAPH_TREE_UNDIRECTED);

  igraph_sparsemat_init(&stochastic, nodes, nodes, igraph_ecount(&g)*2);
  igraph_matrix_complex_init(&V2, 0, 0);
  igraph_matrix_init(&V, 0, 0);
  igraph_matrix_init(&V3, 0, 0);
  igraph_vector_init(&groups, 0);
  igraph_vector_init(&p, 0);
  igraph_vector_init(&selcol, 1);  
  
  igraph_rng_seed(igraph_rng_default(), 42);

  igraph_get_stochastic_sparsemat(&g, &stochastic, /*column-wise=*/ 0);
  igraph_sparsemat_transpose(&stochastic, &stochasticT, /*values=*/ 1);

  which.pos=IGRAPH_EIGEN_LR;
  which.howmany=1;

  igraph_eigen_matrix(/*matrix=*/ 0, &stochasticT, /*fun=*/ 0, nodes,
		      /*extra=*/ 0, /*1algorithm=*/ IGRAPH_EIGEN_LAPACK,
		      &which, /*options=*/ 0, /*storage=*/ 0, 
		      /*values=*/ 0, &V2);
  igraph_matrix_complex_real(&V2, &V);

  /* `p' is always the eigenvector corresponding to the 1-eigenvalue */
  igraph_matrix_get_col(&V, &p, 0);
  igraph_vector_print(&p);

  which.howmany=3;
  igraph_eigen_matrix(/*matrix=*/ 0, &stochastic, /*fun=*/ 0, nodes,
		      /*extra=*/ 0, /*algorithm=*/ IGRAPH_EIGEN_LAPACK,
		      &which, /*options=*/ 0, /*storage=*/ 0, 
		      /*values=*/ 0, &V2);
  igraph_matrix_complex_real(&V2, &V3);
  VECTOR(selcol)[0]=2;
  igraph_matrix_select_cols(&V3, &V, &selcol);

  /* ------------ */
  
  igraph_scg_grouping(&V, &groups, /*intervals=*/ 3, 
		      /*intervals_vector=*/ 0, IGRAPH_SCG_STOCHASTIC,
		      IGRAPH_SCG_OPTIMUM, &p, /*maxiter=*/ 10000);
  igraph_vector_print(&groups);

  /* ------------ */

  igraph_scg_grouping(&V, &groups, /*intervals=*/ 3, 
		      /*intervals_vector=*/ 0, IGRAPH_SCG_STOCHASTIC,
		      IGRAPH_SCG_INTERV_KM, &p, /*maxiter=*/ 10000);
  igraph_vector_print(&groups);

  /* ------------ */

  igraph_scg_grouping(&V, &groups, /*intervals=*/ 3, 
		      /*intervals_vector=*/ 0, IGRAPH_SCG_STOCHASTIC,
		      IGRAPH_SCG_INTERV, &p, /*maxiter=*/ 10000);
  igraph_vector_print(&groups);

  /* ------------ */

  igraph_scg_grouping(&V, &groups, /*(ignored) intervals=*/ 0, 
		      /*intervals_vector=*/ 0, IGRAPH_SCG_STOCHASTIC,
		      IGRAPH_SCG_EXACT, &p, /*maxiter=*/ 10000);
  igraph_vector_print(&groups);

  /* ------------ */  

  igraph_vector_destroy(&p);
  igraph_vector_destroy(&selcol);
  igraph_vector_destroy(&groups);
  igraph_matrix_destroy(&V);
  igraph_matrix_destroy(&V3);
  igraph_matrix_complex_destroy(&V2);
  igraph_sparsemat_destroy(&stochasticT);
  igraph_sparsemat_destroy(&stochastic);
  igraph_destroy(&g);
  
#ifdef __APPLE__
  return 0;
#else
  return 77;
#endif
}