/*

Copyright (C) 2005, 2006, 2007, 2008 David Bateman
Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005 Andy Adler

This file is part of Octave.

Octave 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 3 of the License, or (at your
option) any later version.

Octave 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 Octave; see the file COPYING.  If not, see
<http://www.gnu.org/licenses/>.

*/

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include "defun-dld.h"
#include "error.h"
#include "gripes.h"
#include "oct-obj.h"
#include "utils.h"

#include "oct-sparse.h"
#include "ov-re-sparse.h"
#include "ov-cx-sparse.h"
#include "SparseQR.h"
#include "SparseCmplxQR.h"

#ifdef IDX_TYPE_LONG
#define CXSPARSE_NAME(name) cs_dl ## name
#else
#define CXSPARSE_NAME(name) cs_di ## name
#endif

static RowVector
put_int (octave_idx_type *p, octave_idx_type n)
{
  RowVector ret (n);
  for (octave_idx_type i = 0; i < n; i++)
    ret.xelem(i) = p[i] + 1;
  return ret;
}

#if HAVE_CXSPARSE
static octave_value_list
dmperm_internal (bool rank, const octave_value arg, int nargout)
{
  octave_value_list retval;
  octave_idx_type nr = arg.rows ();
  octave_idx_type nc = arg.columns ();
  SparseMatrix m;
  SparseComplexMatrix cm;
  CXSPARSE_NAME () csm;
  csm.m = nr;
  csm.n = nc;
  csm.x = 0;
  csm.nz = -1;

  if (arg.is_real_type ())
    {
      m = arg.sparse_matrix_value ();
      csm.nzmax = m.nnz();
      csm.p = m.xcidx ();
      csm.i = m.xridx ();
    }
  else
    {
      cm = arg.sparse_complex_matrix_value ();
      csm.nzmax = cm.nnz();
      csm.p = cm.xcidx ();
      csm.i = cm.xridx ();
    }

  if (!error_state)
    {
      if (nargout <= 1 || rank)
	{
#if defined(CS_VER) && (CS_VER >= 2)
	  octave_idx_type *jmatch = CXSPARSE_NAME (_maxtrans) (&csm, 0);
#else
	  octave_idx_type *jmatch = CXSPARSE_NAME (_maxtrans) (&csm);
#endif
	  if (rank)
	    {
	      octave_idx_type r = 0;
	      for (octave_idx_type i = 0; i < nc; i++)
		if (jmatch[nr+i] >= 0)
		  r++;
	      retval(0) = static_cast<double>(r);
	    }
	  else
	    retval(0) = put_int (jmatch + nr, nc);
	  CXSPARSE_NAME (_free) (jmatch);
	}
      else
	{
#if defined(CS_VER) && (CS_VER >= 2)
	  CXSPARSE_NAME (d) *dm = CXSPARSE_NAME(_dmperm) (&csm, 0);
#else
	  CXSPARSE_NAME (d) *dm = CXSPARSE_NAME(_dmperm) (&csm);
#endif

	  //retval(5) = put_int (dm->rr, 5);
	  //retval(4) = put_int (dm->cc, 5);
#if defined(CS_VER) && (CS_VER >= 2)
	  retval(3) = put_int (dm->s, dm->nb+1);
	  retval(2) = put_int (dm->r, dm->nb+1);
	  retval(1) = put_int (dm->q, nc);
	  retval(0) = put_int (dm->p, nr);
#else
	  retval(3) = put_int (dm->S, dm->nb+1);
	  retval(2) = put_int (dm->R, dm->nb+1);
	  retval(1) = put_int (dm->Q, nc);
	  retval(0) = put_int (dm->P, nr);
#endif
	  CXSPARSE_NAME (_dfree) (dm);
	}
    }
  return retval;
}
#endif

DEFUN_DLD (dmperm, args, nargout,
  "-*- texinfo -*-\n\
@deftypefn {Loadable Function} {@var{p} =} dmperm (@var{s})\n\
@deftypefnx {Loadable Function} {[@var{p}, @var{q}, @var{r}, @var{s}] =} dmperm (@var{s})\n\
\n\
@cindex Dulmage-Mendelsohn decomposition\n\
Perform a Dulmage-Mendelsohn permutation on the sparse matrix @var{s}.\n\
With a single output argument @dfn{dmperm} performs the row permutations\n\
@var{p} such that @code{@var{s} (@var{p},:)} has no zero elements on the\n\
diagonal.\n\
\n\
Called with two or more output arguments, returns the row and column\n\
permutations, such that @code{@var{s} (@var{p}, @var{q})} is in block\n\
triangular form. The values of @var{r} and @var{s} define the boundaries\n\
of the blocks. If @var{s} is square then @code{@var{r} == @var{s}}.\n\
\n\
The method used is described in: A. Pothen & C.-J. Fan. Computing the block\n\
triangular form of a sparse matrix. ACM Trans. Math. Software,\n\
16(4):303-324, 1990.\n\
@seealso{colamd, ccolamd}\n\
@end deftypefn")
{
  int nargin = args.length();
  octave_value_list retval;
  
  if (nargin != 1)
    {
      print_usage ();
      return retval;
    }

#if HAVE_CXSPARSE
  retval = dmperm_internal (false, args(0), nargout);
#else
  error ("dmperm: not available in this version of Octave");
#endif

  return retval;
}

/* 

%!testif HAVE_CXSPARSE
%! n=20;
%! a=speye(n,n);a=a(randperm(n),:);
%! assert(a(dmperm(a),:),speye(n))

%!testif HAVE_CXSPARSE
%! n=20;
%! d=0.2;
%! a=tril(sprandn(n,n,d),-1)+speye(n,n);
%! a=a(randperm(n),randperm(n));
%! [p,q,r,s]=dmperm(a);
%! assert(tril(a(p,q),-1),sparse(n,n))

*/

DEFUN_DLD (sprank, args, nargout,
  "-*- texinfo -*-\n\
@deftypefn {Loadable Function} {@var{p} =} sprank (@var{s})\n\
\n\
@cindex Structural Rank\n\
Calculates the structural rank of a sparse matrix @var{s}. Note that\n\
only the structure of the matrix is used in this calculation based on\n\
a Dulmage-Mendelsohn permutation to block triangular form. As such the numerical\n\
rank of the matrix @var{s} is bounded by @code{sprank (@var{s}) >=\n\
rank (@var{s})}. Ignoring floating point errors @code{sprank (@var{s}) ==\n\
rank (@var{s})}.\n\
@seealso{dmperm}\n\
@end deftypefn")
{
  int nargin = args.length();
  octave_value_list retval;
  
  if (nargin != 1)
    {
      print_usage ();
      return retval;
    }

#if HAVE_CXSPARSE
  retval = dmperm_internal (true, args(0), nargout);
#else
  error ("sprank: not available in this version of Octave");
#endif

  return retval;
}

/* 

%!error(sprank(1,2));
%!testif HAVE_CXSPARSE
%! assert(sprank(speye(20)), 20)
%!testif HAVE_CXSPARSE
%! assert(sprank([1,0,2,0;2,0,4,0]),2)

*/
/*
;;; Local Variables: ***
;;; mode: C++ ***
;;; End: ***
*/