/* -*- 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>

#define DUMP() do {				\
    igraph_vector_complex_print(&values);	\
    igraph_vector_complex_print(&values2);	\
  } while(0)

int main() {
  
  const int nodes=10;
  igraph_matrix_t mat2;
  igraph_vector_complex_t values, values2;
  igraph_matrix_complex_t vectors, vectors2;
  igraph_eigen_which_t which;
  int i;

  igraph_rng_seed(igraph_rng_default(), 42);
  igraph_matrix_init(&mat2, nodes, nodes);
  for (i=0; i<nodes; i++) {
    int j;
    for (j=0; j<nodes; j++) {
      MATRIX(mat2, i, j) = igraph_rng_get_integer(igraph_rng_default(), 1, 10);
    }
  }

  /* Test LR, a single eigenvalue first */
  
  igraph_vector_complex_init(&values, 0);
  igraph_matrix_complex_init(&vectors, 0, 0);
  which.pos=IGRAPH_EIGEN_LR;
  which.howmany=1;
  
  igraph_eigen_matrix(&mat2, /*sparsemat=*/ 0, /*fun=*/ 0, nodes, 
		      /*extra=*/ 0, IGRAPH_EIGEN_LAPACK, &which,
		      /*options=*/ 0, /*storage=*/ 0, &values, &vectors);
  
  igraph_vector_complex_print(&values);
  igraph_matrix_complex_print(&vectors);  
  
  igraph_vector_complex_destroy(&values);
  igraph_matrix_complex_destroy(&vectors);
  
  /* LR, and SR, all eigenvalues */
  
  igraph_vector_complex_init(&values, 0);
  igraph_matrix_complex_init(&vectors, 0, 0);
  which.pos=IGRAPH_EIGEN_LR;
  which.howmany=nodes;
  igraph_eigen_matrix(&mat2, /*sparsemat=*/ 0, /*fun=*/ 0, nodes, 
		      /*extra=*/ 0, IGRAPH_EIGEN_LAPACK, &which, 
		      /*options=*/ 0, /*storage=*/ 0, &values, &vectors);
  
  igraph_vector_complex_init(&values2, 0);
  igraph_matrix_complex_init(&vectors2, 0, 0);
  which.pos=IGRAPH_EIGEN_SR;
  which.howmany=nodes;
  igraph_eigen_matrix(&mat2, /*sparsemat=*/ 0, /*fun=*/ 0, nodes, 
		      /*extra=*/ 0, IGRAPH_EIGEN_LAPACK, &which, 
		      /*options=*/ 0, /*storage=*/ 0, &values2, &vectors2);

  for (i=0; i<nodes; i++) { 
    int j;
    igraph_real_t d=
      igraph_complex_abs(igraph_complex_sub(VECTOR(values)[i],
					    VECTOR(values2)[nodes-i-1]));
    if (d > 1e-15) { DUMP(); return 2; }
    for (j=0; j<nodes; j++) { 
      igraph_real_t d=
	igraph_complex_abs(igraph_complex_sub(MATRIX(vectors, j, i), 
					      MATRIX(vectors2, j,
						     nodes-i-1)));
      if (d > 1e-15) { DUMP(); return 3; }
    }
  }

  igraph_vector_complex_destroy(&values);
  igraph_matrix_complex_destroy(&vectors);  
  igraph_vector_complex_destroy(&values2);
  igraph_matrix_complex_destroy(&vectors2);

  igraph_matrix_destroy(&mat2);

  return 0;
}
