// Matrix manipulations.
/*

Copyright (C) 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002,
              2003, 2004, 2005, 2006, 2007, 2009 John W. Eaton
Copyright (C) 2008 Jaroslav Hajek

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 <cfloat>

#include <iostream>
#include <vector>

#include "Array-util.h"
#include "byte-swap.h"
#include "dMatrix.h"
#include "dbleAEPBAL.h"
#include "DET.h"
#include "dbleSCHUR.h"
#include "dbleSVD.h"
#include "dbleCHOL.h"
#include "f77-fcn.h"
#include "functor.h"
#include "lo-error.h"
#include "oct-locbuf.h"
#include "lo-ieee.h"
#include "lo-mappers.h"
#include "lo-utils.h"
#include "mx-base.h"
#include "mx-m-dm.h"
#include "mx-dm-m.h"
#include "mx-inlines.cc"
#include "mx-op-defs.h"
#include "oct-cmplx.h"
#include "oct-norm.h"
#include "quit.h"

#if defined (HAVE_FFTW3)
#include "oct-fftw.h"
#endif

// Fortran functions we call.

extern "C"
{
  F77_RET_T
  F77_FUNC (xilaenv, XILAENV) (const octave_idx_type&, F77_CONST_CHAR_ARG_DECL,
			       F77_CONST_CHAR_ARG_DECL,
			       const octave_idx_type&, const octave_idx_type&,
			       const octave_idx_type&, const octave_idx_type&,
			       octave_idx_type&
			       F77_CHAR_ARG_LEN_DECL F77_CHAR_ARG_LEN_DECL);

  F77_RET_T
  F77_FUNC (dgebal, DGEBAL) (F77_CONST_CHAR_ARG_DECL,
			     const octave_idx_type&, double*, const octave_idx_type&, octave_idx_type&,
			     octave_idx_type&, double*, octave_idx_type&
			     F77_CHAR_ARG_LEN_DECL);

  F77_RET_T
  F77_FUNC (dgebak, DGEBAK) (F77_CONST_CHAR_ARG_DECL,
			     F77_CONST_CHAR_ARG_DECL,
			     const octave_idx_type&, const octave_idx_type&, const octave_idx_type&, double*,
			     const octave_idx_type&, double*, const octave_idx_type&, octave_idx_type&
			     F77_CHAR_ARG_LEN_DECL
			     F77_CHAR_ARG_LEN_DECL);


  F77_RET_T
  F77_FUNC (dgemm, DGEMM) (F77_CONST_CHAR_ARG_DECL,
			   F77_CONST_CHAR_ARG_DECL,
			   const octave_idx_type&, const octave_idx_type&, const octave_idx_type&,
			   const double&, const double*, const octave_idx_type&,
			   const double*, const octave_idx_type&, const double&,
			   double*, const octave_idx_type&
			   F77_CHAR_ARG_LEN_DECL
			   F77_CHAR_ARG_LEN_DECL);

  F77_RET_T
  F77_FUNC (dgemv, DGEMV) (F77_CONST_CHAR_ARG_DECL,
			   const octave_idx_type&, const octave_idx_type&, const double&,
			   const double*, const octave_idx_type&, const double*,
			   const octave_idx_type&, const double&, double*,
			   const octave_idx_type&
			   F77_CHAR_ARG_LEN_DECL);

  F77_RET_T
  F77_FUNC (xddot, XDDOT) (const octave_idx_type&, const double*, const octave_idx_type&,
			   const double*, const octave_idx_type&, double&);

  F77_RET_T
  F77_FUNC (dsyrk, DSYRK) (F77_CONST_CHAR_ARG_DECL,
			   F77_CONST_CHAR_ARG_DECL,
			   const octave_idx_type&, const octave_idx_type&, 
			   const double&, const double*, const octave_idx_type&,
			   const double&, double*, const octave_idx_type&
			   F77_CHAR_ARG_LEN_DECL
			   F77_CHAR_ARG_LEN_DECL);

  F77_RET_T
  F77_FUNC (dgetrf, DGETRF) (const octave_idx_type&, const octave_idx_type&, double*, const octave_idx_type&,
		      octave_idx_type*, octave_idx_type&);

  F77_RET_T
  F77_FUNC (dgetrs, DGETRS) (F77_CONST_CHAR_ARG_DECL, const octave_idx_type&, const octave_idx_type&, 
			     const double*, const octave_idx_type&,
			     const octave_idx_type*, double*, const octave_idx_type&, octave_idx_type&
			     F77_CHAR_ARG_LEN_DECL);

  F77_RET_T
  F77_FUNC (dgetri, DGETRI) (const octave_idx_type&, double*, const octave_idx_type&, const octave_idx_type*,
			     double*, const octave_idx_type&, octave_idx_type&);

  F77_RET_T
  F77_FUNC (dgecon, DGECON) (F77_CONST_CHAR_ARG_DECL, const octave_idx_type&, double*, 
			     const octave_idx_type&, const double&, double&, 
			     double*, octave_idx_type*, octave_idx_type&
			     F77_CHAR_ARG_LEN_DECL);

  F77_RET_T
  F77_FUNC (dgelsy, DGELSY) (const octave_idx_type&, const octave_idx_type&, const octave_idx_type&,
			     double*, const octave_idx_type&, double*,
			     const octave_idx_type&, octave_idx_type*, double&, octave_idx_type&,
			     double*, const octave_idx_type&, octave_idx_type&);

  F77_RET_T
  F77_FUNC (dgelsd, DGELSD) (const octave_idx_type&, const octave_idx_type&, const octave_idx_type&,
			     double*, const octave_idx_type&, double*,
			     const octave_idx_type&, double*, double&, octave_idx_type&,
			     double*, const octave_idx_type&, octave_idx_type*,
			     octave_idx_type&);

  F77_RET_T
  F77_FUNC (dpotrf, DPOTRF) (F77_CONST_CHAR_ARG_DECL, const octave_idx_type&, 
			     double *, const octave_idx_type&, 
			     octave_idx_type& F77_CHAR_ARG_LEN_DECL);

  F77_RET_T
  F77_FUNC (dpocon, DPOCON) (F77_CONST_CHAR_ARG_DECL, const octave_idx_type&, 
			     double*, const octave_idx_type&, const double&,
			     double&, double*, octave_idx_type*,
			     octave_idx_type& F77_CHAR_ARG_LEN_DECL);
  F77_RET_T
  F77_FUNC (dpotrs, DPOTRS) (F77_CONST_CHAR_ARG_DECL, const octave_idx_type&, 
			     const octave_idx_type&, const double*, 
			     const octave_idx_type&, double*, 
			     const octave_idx_type&, octave_idx_type&
			     F77_CHAR_ARG_LEN_DECL);

  F77_RET_T
  F77_FUNC (dtrtri, DTRTRI) (F77_CONST_CHAR_ARG_DECL, F77_CONST_CHAR_ARG_DECL, 
			     const octave_idx_type&, const double*, 
			     const octave_idx_type&, octave_idx_type&
			     F77_CHAR_ARG_LEN_DECL
			     F77_CHAR_ARG_LEN_DECL);
  F77_RET_T
  F77_FUNC (dtrcon, DTRCON) (F77_CONST_CHAR_ARG_DECL, F77_CONST_CHAR_ARG_DECL, 
			     F77_CONST_CHAR_ARG_DECL, const octave_idx_type&, 
			     const double*, const octave_idx_type&, double&,
			     double*, octave_idx_type*, octave_idx_type& 
			     F77_CHAR_ARG_LEN_DECL
			     F77_CHAR_ARG_LEN_DECL
			     F77_CHAR_ARG_LEN_DECL);
  F77_RET_T
  F77_FUNC (dtrtrs, DTRTRS) (F77_CONST_CHAR_ARG_DECL, F77_CONST_CHAR_ARG_DECL, 
			     F77_CONST_CHAR_ARG_DECL, const octave_idx_type&, 
			     const octave_idx_type&, const double*, 
			     const octave_idx_type&, double*, 
			     const octave_idx_type&, octave_idx_type&
			     F77_CHAR_ARG_LEN_DECL
			     F77_CHAR_ARG_LEN_DECL
			     F77_CHAR_ARG_LEN_DECL);

  // Note that the original complex fft routines were not written for
  // double complex arguments.  They have been modified by adding an
  // implicit double precision (a-h,o-z) statement at the beginning of
  // each subroutine.

  F77_RET_T
  F77_FUNC (zffti, ZFFTI) (const octave_idx_type&, Complex*);

  F77_RET_T
  F77_FUNC (zfftf, ZFFTF) (const octave_idx_type&, Complex*, Complex*);

  F77_RET_T
  F77_FUNC (zfftb, ZFFTB) (const octave_idx_type&, Complex*, Complex*);

  F77_RET_T
  F77_FUNC (dlartg, DLARTG) (const double&, const double&, double&,
			     double&, double&);

  F77_RET_T
  F77_FUNC (dtrsyl, DTRSYL) (F77_CONST_CHAR_ARG_DECL,
			     F77_CONST_CHAR_ARG_DECL,
			     const octave_idx_type&, const octave_idx_type&, const octave_idx_type&,
			     const double*, const octave_idx_type&, const double*,
			     const octave_idx_type&, const double*, const octave_idx_type&,
			     double&, octave_idx_type&
			     F77_CHAR_ARG_LEN_DECL
			     F77_CHAR_ARG_LEN_DECL);

  F77_RET_T
  F77_FUNC (xdlange, XDLANGE) (F77_CONST_CHAR_ARG_DECL, const octave_idx_type&,
			       const octave_idx_type&, const double*,
			       const octave_idx_type&, double*, double&
			       F77_CHAR_ARG_LEN_DECL); 
}

// Matrix class.

Matrix::Matrix (const RowVector& rv)
  : MArray2<double> (Array2<double> (rv, 1, rv.length ()))
{
}

Matrix::Matrix (const ColumnVector& cv)
  : MArray2<double> (Array2<double> (cv, cv.length (), 1))
{
}

Matrix::Matrix (const DiagMatrix& a)
  : MArray2<double> (a.rows (), a.cols (), 0.0)
{
  for (octave_idx_type i = 0; i < a.length (); i++)
    elem (i, i) = a.elem (i, i);
}

Matrix::Matrix (const PermMatrix& a)
  : MArray2<double> (a.rows (), a.cols (), 0.0)
{
  const Array<octave_idx_type> ia (a.pvec ());
  octave_idx_type len = a.rows ();
  if (a.is_col_perm ())
    for (octave_idx_type i = 0; i < len; i++)
      elem (ia(i), i) = 1.0;
  else
    for (octave_idx_type i = 0; i < len; i++)
      elem (i, ia(i)) = 1.0;
}

// FIXME -- could we use a templated mixed-type copy function
// here?

Matrix::Matrix (const boolMatrix& a)
  : MArray2<double> (a.rows (), a.cols ())
{
  for (octave_idx_type i = 0; i < a.rows (); i++)
    for (octave_idx_type j = 0; j < a.cols (); j++)
      elem (i, j) = a.elem (i, j);
}

Matrix::Matrix (const charMatrix& a)
  : MArray2<double> (a.rows (), a.cols ())
{
  for (octave_idx_type i = 0; i < a.rows (); i++)
    for (octave_idx_type j = 0; j < a.cols (); j++)
      elem (i, j) = static_cast<unsigned char> (a.elem (i, j));
}

bool
Matrix::operator == (const Matrix& a) const
{
  if (rows () != a.rows () || cols () != a.cols ())
    return false;

  return mx_inline_equal (data (), a.data (), length ());
}

bool
Matrix::operator != (const Matrix& a) const
{
  return !(*this == a);
}

bool
Matrix::is_symmetric (void) const
{
  if (is_square () && rows () > 0)
    {
      for (octave_idx_type i = 0; i < rows (); i++)
	for (octave_idx_type j = i+1; j < cols (); j++)
	  if (elem (i, j) != elem (j, i))
	    return false;

      return true;
    }

  return false;
}

Matrix&
Matrix::insert (const Matrix& a, octave_idx_type r, octave_idx_type c)
{
  Array2<double>::insert (a, r, c);
  return *this;
}

Matrix&
Matrix::insert (const RowVector& a, octave_idx_type r, octave_idx_type c)
{
  octave_idx_type a_len = a.length ();

  if (r < 0 || r >= rows () || c < 0 || c + a_len > cols ())
    {
      (*current_liboctave_error_handler) ("range error for insert");
      return *this;
    }

  if (a_len > 0)
    {
      make_unique ();

      for (octave_idx_type i = 0; i < a_len; i++)
	xelem (r, c+i) = a.elem (i);
    }

  return *this;
}

Matrix&
Matrix::insert (const ColumnVector& a, octave_idx_type r, octave_idx_type c)
{
  octave_idx_type a_len = a.length ();

  if (r < 0 || r + a_len > rows () || c < 0 || c >= cols ())
    {
      (*current_liboctave_error_handler) ("range error for insert");
      return *this;
    }

  if (a_len > 0)
    {
      make_unique ();

      for (octave_idx_type i = 0; i < a_len; i++)
	xelem (r+i, c) = a.elem (i);
    }

  return *this;
}

Matrix&
Matrix::insert (const DiagMatrix& a, octave_idx_type r, octave_idx_type c)
{
  octave_idx_type a_nr = a.rows ();
  octave_idx_type a_nc = a.cols ();

  if (r < 0 || r + a_nr > rows () || c < 0 || c + a_nc > cols ())
    {
      (*current_liboctave_error_handler) ("range error for insert");
      return *this;
    }

  fill (0.0, r, c, r + a_nr - 1, c + a_nc - 1);

  octave_idx_type a_len = a.length ();

  if (a_len > 0)
    {
      make_unique ();

      for (octave_idx_type i = 0; i < a_len; i++)
	xelem (r+i, c+i) = a.elem (i, i);
    }

  return *this;
}

Matrix&
Matrix::fill (double val)
{
  octave_idx_type nr = rows ();
  octave_idx_type nc = cols ();

  if (nr > 0 && nc > 0)
    {
      make_unique ();

      for (octave_idx_type j = 0; j < nc; j++)
	for (octave_idx_type i = 0; i < nr; i++)
	  xelem (i, j) = val;
    }

  return *this;
}

Matrix&
Matrix::fill (double val, octave_idx_type r1, octave_idx_type c1, octave_idx_type r2, octave_idx_type c2)
{
  octave_idx_type nr = rows ();
  octave_idx_type nc = cols ();

  if (r1 < 0 || r2 < 0 || c1 < 0 || c2 < 0
      || r1 >= nr || r2 >= nr || c1 >= nc || c2 >= nc)
    {
      (*current_liboctave_error_handler) ("range error for fill");
      return *this;
    }

  if (r1 > r2) { octave_idx_type tmp = r1; r1 = r2; r2 = tmp; }
  if (c1 > c2) { octave_idx_type tmp = c1; c1 = c2; c2 = tmp; }

  if (r2 >= r1 && c2 >= c1)
    {
      make_unique ();

      for (octave_idx_type j = c1; j <= c2; j++)
	for (octave_idx_type i = r1; i <= r2; i++)
	  xelem (i, j) = val;
    }

  return *this;
}

Matrix
Matrix::append (const Matrix& a) const
{
  octave_idx_type nr = rows ();
  octave_idx_type nc = cols ();
  if (nr != a.rows ())
    {
      (*current_liboctave_error_handler) ("row dimension mismatch for append");
      return Matrix ();
    }

  octave_idx_type nc_insert = nc;
  Matrix retval (nr, nc + a.cols ());
  retval.insert (*this, 0, 0);
  retval.insert (a, 0, nc_insert);
  return retval;
}

Matrix
Matrix::append (const RowVector& a) const
{
  octave_idx_type nr = rows ();
  octave_idx_type nc = cols ();
  if (nr != 1)
    {
      (*current_liboctave_error_handler) ("row dimension mismatch for append");
      return Matrix ();
    }

  octave_idx_type nc_insert = nc;
  Matrix retval (nr, nc + a.length ());
  retval.insert (*this, 0, 0);
  retval.insert (a, 0, nc_insert);
  return retval;
}

Matrix
Matrix::append (const ColumnVector& a) const
{
  octave_idx_type nr = rows ();
  octave_idx_type nc = cols ();
  if (nr != a.length ())
    {
      (*current_liboctave_error_handler) ("row dimension mismatch for append");
      return Matrix ();
    }

  octave_idx_type nc_insert = nc;
  Matrix retval (nr, nc + 1);
  retval.insert (*this, 0, 0);
  retval.insert (a, 0, nc_insert);
  return retval;
}

Matrix
Matrix::append (const DiagMatrix& a) const
{
  octave_idx_type nr = rows ();
  octave_idx_type nc = cols ();
  if (nr != a.rows ())
    {
      (*current_liboctave_error_handler) ("row dimension mismatch for append");
      return *this;
    }

  octave_idx_type nc_insert = nc;
  Matrix retval (nr, nc + a.cols ());
  retval.insert (*this, 0, 0);
  retval.insert (a, 0, nc_insert);
  return retval;
}

Matrix
Matrix::stack (const Matrix& a) const
{
  octave_idx_type nr = rows ();
  octave_idx_type nc = cols ();
  if (nc != a.cols ())
    {
      (*current_liboctave_error_handler)
	("column dimension mismatch for stack");
      return Matrix ();
    }

  octave_idx_type nr_insert = nr;
  Matrix retval (nr + a.rows (), nc);
  retval.insert (*this, 0, 0);
  retval.insert (a, nr_insert, 0);
  return retval;
}

Matrix
Matrix::stack (const RowVector& a) const
{
  octave_idx_type nr = rows ();
  octave_idx_type nc = cols ();
  if (nc != a.length ())
    {
      (*current_liboctave_error_handler)
	("column dimension mismatch for stack");
      return Matrix ();
    }

  octave_idx_type nr_insert = nr;
  Matrix retval (nr + 1, nc);
  retval.insert (*this, 0, 0);
  retval.insert (a, nr_insert, 0);
  return retval;
}

Matrix
Matrix::stack (const ColumnVector& a) const
{
  octave_idx_type nr = rows ();
  octave_idx_type nc = cols ();
  if (nc != 1)
    {
      (*current_liboctave_error_handler)
	("column dimension mismatch for stack");
      return Matrix ();
    }

  octave_idx_type nr_insert = nr;
  Matrix retval (nr + a.length (), nc);
  retval.insert (*this, 0, 0);
  retval.insert (a, nr_insert, 0);
  return retval;
}

Matrix
Matrix::stack (const DiagMatrix& a) const
{
  octave_idx_type nr = rows ();
  octave_idx_type nc = cols ();
  if (nc != a.cols ())
    {
      (*current_liboctave_error_handler)
	("column dimension mismatch for stack");
      return Matrix ();
    }

  octave_idx_type nr_insert = nr;
  Matrix retval (nr + a.rows (), nc);
  retval.insert (*this, 0, 0);
  retval.insert (a, nr_insert, 0);
  return retval;
}

Matrix
real (const ComplexMatrix& a)
{
  return Matrix (mx_inline_real_dup (a.data (), a.length ()),
                 a.rows (), a.cols ());
}

Matrix
imag (const ComplexMatrix& a)
{
  return Matrix (mx_inline_imag_dup (a.data (), a.length ()),
                 a.rows (), a.cols ());
}

Matrix
Matrix::extract (octave_idx_type r1, octave_idx_type c1, octave_idx_type r2, octave_idx_type c2) const
{
  if (r1 > r2) { octave_idx_type tmp = r1; r1 = r2; r2 = tmp; }
  if (c1 > c2) { octave_idx_type tmp = c1; c1 = c2; c2 = tmp; }

  octave_idx_type new_r = r2 - r1 + 1;
  octave_idx_type new_c = c2 - c1 + 1;

  Matrix result (new_r, new_c);

  for (octave_idx_type j = 0; j < new_c; j++)
    for (octave_idx_type i = 0; i < new_r; i++)
      result.xelem (i, j) = elem (r1+i, c1+j);

  return result;
}

Matrix
Matrix::extract_n (octave_idx_type r1, octave_idx_type c1, octave_idx_type nr, octave_idx_type nc) const
{
  Matrix result (nr, nc);

  for (octave_idx_type j = 0; j < nc; j++)
    for (octave_idx_type i = 0; i < nr; i++)
      result.xelem (i, j) = elem (r1+i, c1+j);

  return result;
}

// extract row or column i.

RowVector
Matrix::row (octave_idx_type i) const
{
  return MArray<double> (index (idx_vector (i), idx_vector::colon));
}

ColumnVector
Matrix::column (octave_idx_type i) const
{
  return MArray<double> (index (idx_vector::colon, idx_vector (i)));
}

Matrix
Matrix::inverse (void) const
{
  octave_idx_type info;
  double rcon;
  MatrixType mattype (*this);
  return inverse (mattype, info, rcon, 0, 0);
}

Matrix
Matrix::inverse (octave_idx_type& info) const
{
  double rcon;
  MatrixType mattype (*this);
  return inverse (mattype, info, rcon, 0, 0);
}

Matrix
Matrix::inverse (octave_idx_type& info, double& rcon, int force,
		 int calc_cond) const
{
  MatrixType mattype (*this);
  return inverse (mattype, info, rcon, force, calc_cond);
}

Matrix
Matrix::inverse (MatrixType& mattype) const
{
  octave_idx_type info;
  double rcon;
  return inverse (mattype, info, rcon, 0, 0);
}

Matrix
Matrix::inverse (MatrixType &mattype, octave_idx_type& info) const
{
  double rcon;
  return inverse (mattype, info, rcon, 0, 0);
}

Matrix
Matrix::tinverse (MatrixType &mattype, octave_idx_type& info, double& rcon, 
		  int force, int calc_cond) const
{
  Matrix retval;

  octave_idx_type nr = rows ();
  octave_idx_type nc = cols ();

  if (nr != nc || nr == 0 || nc == 0)
    (*current_liboctave_error_handler) ("inverse requires square matrix");
  else
    {
      int typ = mattype.type ();
      char uplo = (typ == MatrixType::Lower ? 'L' : 'U');
      char udiag = 'N';
      retval = *this;
      double *tmp_data = retval.fortran_vec ();

      F77_XFCN (dtrtri, DTRTRI, (F77_CONST_CHAR_ARG2 (&uplo, 1),
				 F77_CONST_CHAR_ARG2 (&udiag, 1),
				 nr, tmp_data, nr, info 
				 F77_CHAR_ARG_LEN (1)
				 F77_CHAR_ARG_LEN (1)));

      // Throw-away extra info LAPACK gives so as to not change output.
      rcon = 0.0;
      if (info != 0) 
	info = -1;
      else if (calc_cond) 
	{
	  octave_idx_type dtrcon_info = 0;
	  char job = '1';

	  OCTAVE_LOCAL_BUFFER (double, work, 3 * nr);
	  OCTAVE_LOCAL_BUFFER (octave_idx_type, iwork, nr);

	  F77_XFCN (dtrcon, DTRCON, (F77_CONST_CHAR_ARG2 (&job, 1),
				     F77_CONST_CHAR_ARG2 (&uplo, 1),
				     F77_CONST_CHAR_ARG2 (&udiag, 1),
				     nr, tmp_data, nr, rcon, 
				     work, iwork, dtrcon_info 
				     F77_CHAR_ARG_LEN (1)
				     F77_CHAR_ARG_LEN (1)
				     F77_CHAR_ARG_LEN (1)));

	  if (dtrcon_info != 0) 
	    info = -1;
	}

      if (info == -1 && ! force)
	retval = *this; // Restore matrix contents.
    }

  return retval;
}


Matrix
Matrix::finverse (MatrixType &mattype, octave_idx_type& info, double& rcon, 
		  int force, int calc_cond) const
{
  Matrix retval;

  octave_idx_type nr = rows ();
  octave_idx_type nc = cols ();

  if (nr != nc || nr == 0 || nc == 0)
    (*current_liboctave_error_handler) ("inverse requires square matrix");
  else
    {
      Array<octave_idx_type> ipvt (nr);
      octave_idx_type *pipvt = ipvt.fortran_vec ();

      retval = *this;
      double *tmp_data = retval.fortran_vec ();

      Array<double> z(1);
      octave_idx_type lwork = -1;

      // Query the optimum work array size.
      F77_XFCN (dgetri, DGETRI, (nc, tmp_data, nr, pipvt, 
				 z.fortran_vec (), lwork, info));

      lwork = static_cast<octave_idx_type> (z(0));
      lwork = (lwork < 2 *nc ? 2*nc : lwork);
      z.resize (lwork);
      double *pz = z.fortran_vec ();

      info = 0;

      // Calculate the norm of the matrix, for later use.
      double anorm = 0;
      if (calc_cond) 
	anorm = retval.abs().sum().row(static_cast<octave_idx_type>(0)).max();

      F77_XFCN (dgetrf, DGETRF, (nc, nc, tmp_data, nr, pipvt, info));

      // Throw-away extra info LAPACK gives so as to not change output.
      rcon = 0.0;
      if (info != 0) 
	info = -1;
      else if (calc_cond) 
	{
	  octave_idx_type dgecon_info = 0;

	  // Now calculate the condition number for non-singular matrix.
	  char job = '1';
	  Array<octave_idx_type> iz (nc);
	  octave_idx_type *piz = iz.fortran_vec ();
	  F77_XFCN (dgecon, DGECON, (F77_CONST_CHAR_ARG2 (&job, 1),
				     nc, tmp_data, nr, anorm, 
				     rcon, pz, piz, dgecon_info
				     F77_CHAR_ARG_LEN (1)));

	  if (dgecon_info != 0) 
	    info = -1;
	}

      if (info == -1 && ! force)
	retval = *this; // Restore matrix contents.
      else
	{
	  octave_idx_type dgetri_info = 0;

	  F77_XFCN (dgetri, DGETRI, (nc, tmp_data, nr, pipvt,
				     pz, lwork, dgetri_info));

	  if (dgetri_info != 0) 
	    info = -1;
	}

      if (info != 0)
	mattype.mark_as_rectangular();
    }

  return retval;
}

Matrix
Matrix::inverse (MatrixType &mattype, octave_idx_type& info, double& rcon, 
		 int force, int calc_cond) const
{
  int typ = mattype.type (false);
  Matrix ret;

  if (typ == MatrixType::Unknown)
    typ = mattype.type (*this);

  if (typ == MatrixType::Upper || typ == MatrixType::Lower)
    ret = tinverse (mattype, info, rcon, force, calc_cond);
  else
    {
      if (mattype.is_hermitian ())
	{
	  CHOL chol (*this, info, calc_cond);
	  if (info == 0)
	    {
	      if (calc_cond)
		rcon = chol.rcond ();
	      else
		rcon = 1.0;
	      ret = chol.inverse ();
	    }
	  else
	    mattype.mark_as_unsymmetric ();
	}

      if (!mattype.is_hermitian ())
	ret = finverse(mattype, info, rcon, force, calc_cond);

      if ((mattype.is_hermitian () || calc_cond) && rcon == 0.)
	ret = Matrix (rows (), columns (), octave_Inf);
    }

  return ret;
}

Matrix
Matrix::pseudo_inverse (double tol) const
{
  SVD result (*this, SVD::economy);

  DiagMatrix S = result.singular_values ();
  Matrix U = result.left_singular_matrix ();
  Matrix V = result.right_singular_matrix ();

  ColumnVector sigma = S.diag ();

  octave_idx_type r = sigma.length () - 1;
  octave_idx_type nr = rows ();
  octave_idx_type nc = cols ();

  if (tol <= 0.0)
    {
      if (nr > nc)
	tol = nr * sigma.elem (0) * DBL_EPSILON;
      else
	tol = nc * sigma.elem (0) * DBL_EPSILON;
    }

  while (r >= 0 && sigma.elem (r) < tol)
    r--;

  if (r < 0)
    return Matrix (nc, nr, 0.0);
  else
    {
      Matrix Ur = U.extract (0, 0, nr-1, r);
      DiagMatrix D = DiagMatrix (sigma.extract (0, r)) . inverse ();
      Matrix Vr = V.extract (0, 0, nc-1, r);
      return Vr * D * Ur.transpose ();
    }
}

#if defined (HAVE_FFTW3)

ComplexMatrix
Matrix::fourier (void) const
{
  size_t nr = rows ();
  size_t nc = cols ();

  ComplexMatrix retval (nr, nc);

  size_t npts, nsamples;

  if (nr == 1 || nc == 1)
    {
      npts = nr > nc ? nr : nc;
      nsamples = 1;
    }
  else
    {
      npts = nr;
      nsamples = nc;
    }

  const double *in (fortran_vec ());
  Complex *out (retval.fortran_vec ());

  octave_fftw::fft (in, out, npts, nsamples); 

  return retval;
}

ComplexMatrix
Matrix::ifourier (void) const
{
  size_t nr = rows ();
  size_t nc = cols ();

  ComplexMatrix retval (nr, nc);

  size_t npts, nsamples;

  if (nr == 1 || nc == 1)
    {
      npts = nr > nc ? nr : nc;
      nsamples = 1;
    }
  else
    {
      npts = nr;
      nsamples = nc;
    }

  ComplexMatrix tmp (*this);
  Complex *in (tmp.fortran_vec ());
  Complex *out (retval.fortran_vec ());

  octave_fftw::ifft (in, out, npts, nsamples); 

  return retval;
}

ComplexMatrix
Matrix::fourier2d (void) const
{
  dim_vector dv(rows (), cols ());

  const double *in = fortran_vec ();
  ComplexMatrix retval (rows (), cols ());
  octave_fftw::fftNd (in, retval.fortran_vec (), 2, dv);

  return retval;
}

ComplexMatrix
Matrix::ifourier2d (void) const
{
  dim_vector dv(rows (), cols ());

  ComplexMatrix retval (*this);
  Complex *out (retval.fortran_vec ());

  octave_fftw::ifftNd (out, out, 2, dv);

  return retval;
}

#else

ComplexMatrix
Matrix::fourier (void) const
{
  ComplexMatrix retval;

  octave_idx_type nr = rows ();
  octave_idx_type nc = cols ();

  octave_idx_type npts, nsamples;

  if (nr == 1 || nc == 1)
    {
      npts = nr > nc ? nr : nc;
      nsamples = 1;
    }
  else
    {
      npts = nr;
      nsamples = nc;
    }

  octave_idx_type nn = 4*npts+15;

  Array<Complex> wsave (nn);
  Complex *pwsave = wsave.fortran_vec ();

  retval = ComplexMatrix (*this);
  Complex *tmp_data = retval.fortran_vec ();

  F77_FUNC (zffti, ZFFTI) (npts, pwsave);

  for (octave_idx_type j = 0; j < nsamples; j++)
    {
      OCTAVE_QUIT;

      F77_FUNC (zfftf, ZFFTF) (npts, &tmp_data[npts*j], pwsave);
    }

  return retval;
}

ComplexMatrix
Matrix::ifourier (void) const
{
  ComplexMatrix retval;

  octave_idx_type nr = rows ();
  octave_idx_type nc = cols ();

  octave_idx_type npts, nsamples;

  if (nr == 1 || nc == 1)
    {
      npts = nr > nc ? nr : nc;
      nsamples = 1;
    }
  else
    {
      npts = nr;
      nsamples = nc;
    }

  octave_idx_type nn = 4*npts+15;

  Array<Complex> wsave (nn);
  Complex *pwsave = wsave.fortran_vec ();

  retval = ComplexMatrix (*this);
  Complex *tmp_data = retval.fortran_vec ();

  F77_FUNC (zffti, ZFFTI) (npts, pwsave);

  for (octave_idx_type j = 0; j < nsamples; j++)
    {
      OCTAVE_QUIT;

      F77_FUNC (zfftb, ZFFTB) (npts, &tmp_data[npts*j], pwsave);
    }

  for (octave_idx_type j = 0; j < npts*nsamples; j++)
    tmp_data[j] = tmp_data[j] / static_cast<double> (npts);

  return retval;
}

ComplexMatrix
Matrix::fourier2d (void) const
{
  ComplexMatrix retval;

  octave_idx_type nr = rows ();
  octave_idx_type nc = cols ();

  octave_idx_type npts, nsamples;

  if (nr == 1 || nc == 1)
    {
      npts = nr > nc ? nr : nc;
      nsamples = 1;
    }
  else
    {
      npts = nr;
      nsamples = nc;
    }

  octave_idx_type nn = 4*npts+15;

  Array<Complex> wsave (nn);
  Complex *pwsave = wsave.fortran_vec ();

  retval = ComplexMatrix (*this);
  Complex *tmp_data = retval.fortran_vec ();

  F77_FUNC (zffti, ZFFTI) (npts, pwsave);

  for (octave_idx_type j = 0; j < nsamples; j++)
    {
      OCTAVE_QUIT;

      F77_FUNC (zfftf, ZFFTF) (npts, &tmp_data[npts*j], pwsave);
    }

  npts = nc;
  nsamples = nr;
  nn = 4*npts+15;

  wsave.resize (nn);
  pwsave = wsave.fortran_vec ();

  Array<Complex> tmp (npts);
  Complex *prow = tmp.fortran_vec ();

  F77_FUNC (zffti, ZFFTI) (npts, pwsave);

  for (octave_idx_type j = 0; j < nsamples; j++)
    {
      OCTAVE_QUIT;

      for (octave_idx_type i = 0; i < npts; i++)
	prow[i] = tmp_data[i*nr + j];

      F77_FUNC (zfftf, ZFFTF) (npts, prow, pwsave);

      for (octave_idx_type i = 0; i < npts; i++)
	tmp_data[i*nr + j] = prow[i];
    }

  return retval;
}

ComplexMatrix
Matrix::ifourier2d (void) const
{
  ComplexMatrix retval;

  octave_idx_type nr = rows ();
  octave_idx_type nc = cols ();

  octave_idx_type npts, nsamples;

  if (nr == 1 || nc == 1)
    {
      npts = nr > nc ? nr : nc;
      nsamples = 1;
    }
  else
    {
      npts = nr;
      nsamples = nc;
    }

  octave_idx_type nn = 4*npts+15;

  Array<Complex> wsave (nn);
  Complex *pwsave = wsave.fortran_vec ();

  retval = ComplexMatrix (*this);
  Complex *tmp_data = retval.fortran_vec ();

  F77_FUNC (zffti, ZFFTI) (npts, pwsave);

  for (octave_idx_type j = 0; j < nsamples; j++)
    {
      OCTAVE_QUIT;

      F77_FUNC (zfftb, ZFFTB) (npts, &tmp_data[npts*j], pwsave);
    }

  for (octave_idx_type j = 0; j < npts*nsamples; j++)
    tmp_data[j] = tmp_data[j] / static_cast<double> (npts);

  npts = nc;
  nsamples = nr;
  nn = 4*npts+15;

  wsave.resize (nn);
  pwsave = wsave.fortran_vec ();

  Array<Complex> tmp (npts);
  Complex *prow = tmp.fortran_vec ();

  F77_FUNC (zffti, ZFFTI) (npts, pwsave);

  for (octave_idx_type j = 0; j < nsamples; j++)
    {
      OCTAVE_QUIT;

      for (octave_idx_type i = 0; i < npts; i++)
	prow[i] = tmp_data[i*nr + j];

      F77_FUNC (zfftb, ZFFTB) (npts, prow, pwsave);

      for (octave_idx_type i = 0; i < npts; i++)
	tmp_data[i*nr + j] = prow[i] / static_cast<double> (npts);
    }

  return retval;
}

#endif

DET
Matrix::determinant (void) const
{
  octave_idx_type info;
  double rcon;
  return determinant (info, rcon, 0);
}

DET
Matrix::determinant (octave_idx_type& info) const
{
  double rcon;
  return determinant (info, rcon, 0);
}

DET
Matrix::determinant (octave_idx_type& info, double& rcon, int calc_cond) const
{
  MatrixType mattype (*this);
  return determinant (mattype, info, rcon, calc_cond);
}

DET
Matrix::determinant (MatrixType& mattype,
                     octave_idx_type& info, double& rcon, int calc_cond) const
{
  DET retval (1.0);

  octave_idx_type nr = rows ();
  octave_idx_type nc = cols ();

  if (nr != nc)
    (*current_liboctave_error_handler) ("matrix must be square");
  else
    {
      volatile int typ = mattype.type ();

      if (typ == MatrixType::Unknown)
        typ = mattype.type (*this);

      if (typ == MatrixType::Lower || typ == MatrixType::Upper)
        {
          for (octave_idx_type i = 0; i < nc; i++) 
            retval *= elem (i,i);
        }
      else if (typ == MatrixType::Hermitian)
        {
          Matrix atmp = *this;
          double *tmp_data = atmp.fortran_vec ();

          info = 0;
          double anorm = 0;
          if (calc_cond) anorm = xnorm (*this, 1);


          char job = 'L';
          F77_XFCN (dpotrf, DPOTRF, (F77_CONST_CHAR_ARG2 (&job, 1), nr, 
                                     tmp_data, nr, info
                                     F77_CHAR_ARG_LEN (1)));

          if (info != 0) 
            {
              rcon = 0.0;
              mattype.mark_as_unsymmetric ();
              typ = MatrixType::Full;
            }
          else 
            {
              Array<double> z (3 * nc);
              double *pz = z.fortran_vec ();
              Array<octave_idx_type> iz (nc);
              octave_idx_type *piz = iz.fortran_vec ();

              F77_XFCN (dpocon, DPOCON, (F77_CONST_CHAR_ARG2 (&job, 1),
                                         nr, tmp_data, nr, anorm,
                                         rcon, pz, piz, info
                                         F77_CHAR_ARG_LEN (1)));

              if (info != 0) 
                rcon = 0.0;

              for (octave_idx_type i = 0; i < nc; i++) 
                retval *= atmp (i,i);

              retval = retval.square ();
            }
        }
      else if (typ != MatrixType::Full)
        (*current_liboctave_error_handler) ("det: invalid dense matrix type");

      if (typ == MatrixType::Full)
        {
          Array<octave_idx_type> ipvt (nr);
          octave_idx_type *pipvt = ipvt.fortran_vec ();

          Matrix atmp = *this;
          double *tmp_data = atmp.fortran_vec ();

          info = 0;

          // Calculate the norm of the matrix, for later use.
          double anorm = 0;
          if (calc_cond) anorm = xnorm (*this, 1);

          F77_XFCN (dgetrf, DGETRF, (nr, nr, tmp_data, nr, pipvt, info));

          // Throw-away extra info LAPACK gives so as to not change output.
          rcon = 0.0;
          if (info != 0) 
            {
              info = -1;
              retval = DET ();
            } 
          else 
            {
              if (calc_cond) 
                {
                  // Now calc the condition number for non-singular matrix.
                  char job = '1';
                  Array<double> z (4 * nc);
                  double *pz = z.fortran_vec ();
                  Array<octave_idx_type> iz (nc);
                  octave_idx_type *piz = iz.fortran_vec ();

                  F77_XFCN (dgecon, DGECON, (F77_CONST_CHAR_ARG2 (&job, 1),
                                             nc, tmp_data, nr, anorm, 
                                             rcon, pz, piz, info
                                             F77_CHAR_ARG_LEN (1)));
                }

              if (info != 0) 
                {
                  info = -1;
                  retval = DET ();
                } 
              else 
                {
                  for (octave_idx_type i = 0; i < nc; i++) 
                    {
                      double c = atmp(i,i);
                      retval *= (ipvt(i) != (i+1)) ? -c : c;
                    }
                }
            }
        }
    }

  return retval;
}

double
Matrix::rcond (void) const
{
  MatrixType mattype (*this);
  return rcond (mattype);
}

double
Matrix::rcond (MatrixType &mattype) const
{
  double rcon;
  octave_idx_type nr = rows ();
  octave_idx_type nc = cols ();

  if (nr != nc)
    (*current_liboctave_error_handler) ("matrix must be square");
  else if (nr == 0 || nc == 0)
    rcon = octave_Inf;
  else
    {
      int typ = mattype.type ();

      if (typ == MatrixType::Unknown)
	typ = mattype.type (*this);

      // Only calculate the condition number for LU/Cholesky
      if (typ == MatrixType::Upper)
	{
	  const double *tmp_data = fortran_vec ();
	  octave_idx_type info = 0;
	  char norm = '1';
	  char uplo = 'U';
	  char dia = 'N';

	  Array<double> z (3 * nc);
	  double *pz = z.fortran_vec ();
	  Array<octave_idx_type> iz (nc);
	  octave_idx_type *piz = iz.fortran_vec ();

	  F77_XFCN (dtrcon, DTRCON, (F77_CONST_CHAR_ARG2 (&norm, 1), 
				     F77_CONST_CHAR_ARG2 (&uplo, 1), 
				     F77_CONST_CHAR_ARG2 (&dia, 1), 
				     nr, tmp_data, nr, rcon,
				     pz, piz, info
				     F77_CHAR_ARG_LEN (1)
				     F77_CHAR_ARG_LEN (1)
				     F77_CHAR_ARG_LEN (1)));

	  if (info != 0) 
	    rcon = 0.0;
	}
      else if  (typ == MatrixType::Permuted_Upper)
	(*current_liboctave_error_handler)
	  ("permuted triangular matrix not implemented");
      else if (typ == MatrixType::Lower)
	{
	  const double *tmp_data = fortran_vec ();
	  octave_idx_type info = 0;
	  char norm = '1';
	  char uplo = 'L';
	  char dia = 'N';

	  Array<double> z (3 * nc);
	  double *pz = z.fortran_vec ();
	  Array<octave_idx_type> iz (nc);
	  octave_idx_type *piz = iz.fortran_vec ();

	  F77_XFCN (dtrcon, DTRCON, (F77_CONST_CHAR_ARG2 (&norm, 1), 
				     F77_CONST_CHAR_ARG2 (&uplo, 1), 
				     F77_CONST_CHAR_ARG2 (&dia, 1), 
				     nr, tmp_data, nr, rcon,
				     pz, piz, info
				     F77_CHAR_ARG_LEN (1)
				     F77_CHAR_ARG_LEN (1)
				     F77_CHAR_ARG_LEN (1)));

	  if (info != 0) 
	    rcon = 0.0;
	}
      else if (typ == MatrixType::Permuted_Lower)
	(*current_liboctave_error_handler)
	  ("permuted triangular matrix not implemented");
      else if (typ == MatrixType::Full || typ == MatrixType::Hermitian)
	{
	  double anorm = -1.0;
	  Matrix atmp = *this;
	  double *tmp_data = atmp.fortran_vec ();

	  if (typ == MatrixType::Hermitian)
	    {
	      octave_idx_type info = 0;
	      char job = 'L';
	      anorm = atmp.abs().sum().
		row(static_cast<octave_idx_type>(0)).max();

	      F77_XFCN (dpotrf, DPOTRF, (F77_CONST_CHAR_ARG2 (&job, 1), nr, 
					 tmp_data, nr, info
					 F77_CHAR_ARG_LEN (1)));

	      if (info != 0) 
		{
		  rcon = 0.0;
		  mattype.mark_as_unsymmetric ();
		  typ = MatrixType::Full;
		}
	      else 
		{
		  Array<double> z (3 * nc);
		  double *pz = z.fortran_vec ();
		  Array<octave_idx_type> iz (nc);
		  octave_idx_type *piz = iz.fortran_vec ();

		  F77_XFCN (dpocon, DPOCON, (F77_CONST_CHAR_ARG2 (&job, 1),
					     nr, tmp_data, nr, anorm,
					     rcon, pz, piz, info
					     F77_CHAR_ARG_LEN (1)));

		  if (info != 0) 
		    rcon = 0.0;
		}
	    }

	  if (typ == MatrixType::Full)
	    {
	      octave_idx_type info = 0;

	      Array<octave_idx_type> ipvt (nr);
	      octave_idx_type *pipvt = ipvt.fortran_vec ();

	      if(anorm < 0.)
		anorm = atmp.abs().sum().
		  row(static_cast<octave_idx_type>(0)).max();

	      Array<double> z (4 * nc);
	      double *pz = z.fortran_vec ();
	      Array<octave_idx_type> iz (nc);
	      octave_idx_type *piz = iz.fortran_vec ();

	      F77_XFCN (dgetrf, DGETRF, (nr, nr, tmp_data, nr, pipvt, info));

	      if (info != 0) 
		{
		  rcon = 0.0;
		  mattype.mark_as_rectangular ();
		}
	      else 
		{
		  char job = '1';
		  F77_XFCN (dgecon, DGECON, (F77_CONST_CHAR_ARG2 (&job, 1),
					     nc, tmp_data, nr, anorm, 
					     rcon, pz, piz, info
					     F77_CHAR_ARG_LEN (1)));

		  if (info != 0) 
		    rcon = 0.0;
		}
	    }
	}
      else
	rcon = 0.0;
    }

  return rcon;
}

Matrix
Matrix::utsolve (MatrixType &mattype, const Matrix& b, octave_idx_type& info,
		double& rcon, solve_singularity_handler sing_handler,
		bool calc_cond) const
{
  Matrix retval;

  octave_idx_type nr = rows ();
  octave_idx_type nc = cols ();

  if (nr != b.rows ())
    (*current_liboctave_error_handler)
      ("matrix dimension mismatch solution of linear equations");
  else if (nr == 0 || nc == 0 || b.cols () == 0)
    retval = Matrix (nc, b.cols (), 0.0);
  else
    {
      volatile int typ = mattype.type ();

      if (typ == MatrixType::Permuted_Upper ||
	  typ == MatrixType::Upper)
	{
	  octave_idx_type b_nc = b.cols ();
	  rcon = 1.;
	  info = 0;

	  if (typ == MatrixType::Permuted_Upper)
	    {
	      (*current_liboctave_error_handler)
		("permuted triangular matrix not implemented");
	    }
	  else
	    {
	      const double *tmp_data = fortran_vec ();

	      if (calc_cond)
		{
		  char norm = '1';
		  char uplo = 'U';
		  char dia = 'N';

		  Array<double> z (3 * nc);
		  double *pz = z.fortran_vec ();
		  Array<octave_idx_type> iz (nc);
		  octave_idx_type *piz = iz.fortran_vec ();

		  F77_XFCN (dtrcon, DTRCON, (F77_CONST_CHAR_ARG2 (&norm, 1), 
					     F77_CONST_CHAR_ARG2 (&uplo, 1), 
					     F77_CONST_CHAR_ARG2 (&dia, 1), 
					     nr, tmp_data, nr, rcon,
					     pz, piz, info
					     F77_CHAR_ARG_LEN (1)
					     F77_CHAR_ARG_LEN (1)
					     F77_CHAR_ARG_LEN (1)));

		  if (info != 0) 
		    info = -2;

		  volatile double rcond_plus_one = rcon + 1.0;

		  if (rcond_plus_one == 1.0 || xisnan (rcon))
		    {
		      info = -2;

		      if (sing_handler)
			sing_handler (rcon);
		      else
			(*current_liboctave_error_handler)
			  ("matrix singular to machine precision, rcond = %g",
			   rcon);
		    }
		}

	      if (info == 0)
		{
		  retval = b;
		  double *result = retval.fortran_vec ();

		  char uplo = 'U';
		  char trans = 'N';
		  char dia = 'N';

		  F77_XFCN (dtrtrs, DTRTRS, (F77_CONST_CHAR_ARG2 (&uplo, 1), 
					     F77_CONST_CHAR_ARG2 (&trans, 1), 
					     F77_CONST_CHAR_ARG2 (&dia, 1), 
					     nr, b_nc, tmp_data, nr,
					     result, nr, info
					     F77_CHAR_ARG_LEN (1)
					     F77_CHAR_ARG_LEN (1)
					     F77_CHAR_ARG_LEN (1)));
		}
	    }
	}
      else
	(*current_liboctave_error_handler) ("incorrect matrix type");
    }

  return retval;
}

Matrix
Matrix::ltsolve (MatrixType &mattype, const Matrix& b, octave_idx_type& info,
		double& rcon, solve_singularity_handler sing_handler,
		bool calc_cond) const
{
  Matrix retval;

  octave_idx_type nr = rows ();
  octave_idx_type nc = cols ();

  if (nr != b.rows ())
    (*current_liboctave_error_handler)
      ("matrix dimension mismatch solution of linear equations");
  else if (nr == 0 || nc == 0 || b.cols () == 0)
    retval = Matrix (nc, b.cols (), 0.0);
  else
    {
      volatile int typ = mattype.type ();

      if (typ == MatrixType::Permuted_Lower ||
	  typ == MatrixType::Lower)
	{
	  octave_idx_type b_nc = b.cols ();
	  rcon = 1.;
	  info = 0;

	  if (typ == MatrixType::Permuted_Lower)
	    {
	      (*current_liboctave_error_handler)
		("permuted triangular matrix not implemented");
	    }
	  else
	    {
	      const double *tmp_data = fortran_vec ();

	      if (calc_cond)
		{
		  char norm = '1';
		  char uplo = 'L';
		  char dia = 'N';

		  Array<double> z (3 * nc);
		  double *pz = z.fortran_vec ();
		  Array<octave_idx_type> iz (nc);
		  octave_idx_type *piz = iz.fortran_vec ();

		  F77_XFCN (dtrcon, DTRCON, (F77_CONST_CHAR_ARG2 (&norm, 1), 
					     F77_CONST_CHAR_ARG2 (&uplo, 1), 
					     F77_CONST_CHAR_ARG2 (&dia, 1), 
					     nr, tmp_data, nr, rcon,
					     pz, piz, info
					     F77_CHAR_ARG_LEN (1)
					     F77_CHAR_ARG_LEN (1)
					     F77_CHAR_ARG_LEN (1)));

		  if (info != 0) 
		    info = -2;

		  volatile double rcond_plus_one = rcon + 1.0;

		  if (rcond_plus_one == 1.0 || xisnan (rcon))
		    {
		      info = -2;

		      if (sing_handler)
			sing_handler (rcon);
		      else
			(*current_liboctave_error_handler)
			  ("matrix singular to machine precision, rcond = %g",
			   rcon);
		    }
		}

	      if (info == 0)
		{
		  retval = b;
		  double *result = retval.fortran_vec ();

		  char uplo = 'L';
		  char trans = 'N';
		  char dia = 'N';

		  F77_XFCN (dtrtrs, DTRTRS, (F77_CONST_CHAR_ARG2 (&uplo, 1), 
					     F77_CONST_CHAR_ARG2 (&trans, 1), 
					     F77_CONST_CHAR_ARG2 (&dia, 1), 
					     nr, b_nc, tmp_data, nr,
					     result, nr, info
					     F77_CHAR_ARG_LEN (1)
					     F77_CHAR_ARG_LEN (1)
					     F77_CHAR_ARG_LEN (1)));
		}
	    }
	}
      else
	(*current_liboctave_error_handler) ("incorrect matrix type");
    }

  return retval;
}

Matrix
Matrix::fsolve (MatrixType &mattype, const Matrix& b, octave_idx_type& info,
		double& rcon, solve_singularity_handler sing_handler,
		bool calc_cond) const
{
  Matrix retval;

  octave_idx_type nr = rows ();
  octave_idx_type nc = cols ();

  if (nr != nc || nr != b.rows ())
    (*current_liboctave_error_handler)
      ("matrix dimension mismatch solution of linear equations");
  else if (nr == 0 || b.cols () == 0)
    retval = Matrix (nc, b.cols (), 0.0);
  else
    {
      volatile int typ = mattype.type ();
 
     // Calculate the norm of the matrix, for later use.
      double anorm = -1.;

      if (typ == MatrixType::Hermitian)
	{
	  info = 0;
	  char job = 'L';
	  Matrix atmp = *this;
	  double *tmp_data = atmp.fortran_vec ();
	  anorm = atmp.abs().sum().row(static_cast<octave_idx_type>(0)).max();

	  F77_XFCN (dpotrf, DPOTRF, (F77_CONST_CHAR_ARG2 (&job, 1), nr, 
				     tmp_data, nr, info
				     F77_CHAR_ARG_LEN (1)));

	  // Throw-away extra info LAPACK gives so as to not change output.
	  rcon = 0.0;
	  if (info != 0) 
	    {
	      info = -2;

	      mattype.mark_as_unsymmetric ();
	      typ = MatrixType::Full;
	    }
	  else 
	    {
	      if (calc_cond)
		{
		  Array<double> z (3 * nc);
		  double *pz = z.fortran_vec ();
		  Array<octave_idx_type> iz (nc);
		  octave_idx_type *piz = iz.fortran_vec ();

		  F77_XFCN (dpocon, DPOCON, (F77_CONST_CHAR_ARG2 (&job, 1),
					     nr, tmp_data, nr, anorm,
					     rcon, pz, piz, info
					     F77_CHAR_ARG_LEN (1)));

		  if (info != 0) 
		    info = -2;

		  volatile double rcond_plus_one = rcon + 1.0;

		  if (rcond_plus_one == 1.0 || xisnan (rcon))
		    {
		      info = -2;

		      if (sing_handler)
			sing_handler (rcon);
		      else
			(*current_liboctave_error_handler)
			  ("matrix singular to machine precision, rcond = %g",
			   rcon);
		    }
		}

	      if (info == 0)
		{
		  retval = b;
		  double *result = retval.fortran_vec ();

		  octave_idx_type b_nc = b.cols ();

		  F77_XFCN (dpotrs, DPOTRS, (F77_CONST_CHAR_ARG2 (&job, 1),
					     nr, b_nc, tmp_data, nr,
					     result, b.rows(), info
					     F77_CHAR_ARG_LEN (1)));
		}
	      else
		{
		  mattype.mark_as_unsymmetric ();
		  typ = MatrixType::Full;
		}		    
	    }
	}

      if (typ == MatrixType::Full)
	{
	  info = 0;

	  Array<octave_idx_type> ipvt (nr);
	  octave_idx_type *pipvt = ipvt.fortran_vec ();

	  Matrix atmp = *this;
	  double *tmp_data = atmp.fortran_vec ();
	  if(anorm < 0.)
	    anorm = atmp.abs().sum().row(static_cast<octave_idx_type>(0)).max();

	  Array<double> z (4 * nc);
	  double *pz = z.fortran_vec ();
	  Array<octave_idx_type> iz (nc);
	  octave_idx_type *piz = iz.fortran_vec ();

	  F77_XFCN (dgetrf, DGETRF, (nr, nr, tmp_data, nr, pipvt, info));

	  // Throw-away extra info LAPACK gives so as to not change output.
	  rcon = 0.0;
	  if (info != 0) 
	    {
	      info = -2;

	      if (sing_handler)
		sing_handler (rcon);
	      else
		(*current_liboctave_error_handler)
		  ("matrix singular to machine precision");

	      mattype.mark_as_rectangular ();
	    }
	  else 
	    {
	      if (calc_cond)
		{
		  // Now calculate the condition number for 
		  // non-singular matrix.
		  char job = '1';
		  F77_XFCN (dgecon, DGECON, (F77_CONST_CHAR_ARG2 (&job, 1),
					     nc, tmp_data, nr, anorm, 
					     rcon, pz, piz, info
					     F77_CHAR_ARG_LEN (1)));

		  if (info != 0) 
		    info = -2;

		  volatile double rcond_plus_one = rcon + 1.0;

		  if (rcond_plus_one == 1.0 || xisnan (rcon))
		    {
		      info = -2;

		      if (sing_handler)
			sing_handler (rcon);
		      else
			(*current_liboctave_error_handler)
			  ("matrix singular to machine precision, rcond = %g",
			   rcon);
		    }
		}

	      if (info == 0)
		{
		  retval = b;
		  double *result = retval.fortran_vec ();

		  octave_idx_type b_nc = b.cols ();

		  char job = 'N';
		  F77_XFCN (dgetrs, DGETRS, (F77_CONST_CHAR_ARG2 (&job, 1),
					     nr, b_nc, tmp_data, nr,
					     pipvt, result, b.rows(), info
					     F77_CHAR_ARG_LEN (1)));
		}
	      else
		mattype.mark_as_rectangular ();
	    }
	}
      else if (typ != MatrixType::Hermitian)
	(*current_liboctave_error_handler) ("incorrect matrix type");
    }

  return retval;
}

Matrix
Matrix::solve (MatrixType &typ, const Matrix& b) const
{
  octave_idx_type info;
  double rcon;
  return solve (typ, b, info, rcon, 0);
}

Matrix
Matrix::solve (MatrixType &typ, const Matrix& b, octave_idx_type& info, 
	       double& rcon) const
{
  return solve (typ, b, info, rcon, 0);
}

Matrix
Matrix::solve (MatrixType &mattype, const Matrix& b, octave_idx_type& info,
	       double& rcon, solve_singularity_handler sing_handler,
	       bool singular_fallback) const
{
  Matrix retval;
  int typ = mattype.type ();

  if (typ == MatrixType::Unknown)
    typ = mattype.type (*this);

  // Only calculate the condition number for LU/Cholesky
  if (typ == MatrixType::Upper || typ == MatrixType::Permuted_Upper)
    retval = utsolve (mattype, b, info, rcon, sing_handler, false);
  else if (typ == MatrixType::Lower || typ == MatrixType::Permuted_Lower)
    retval = ltsolve (mattype, b, info, rcon, sing_handler, false);
  else if (typ == MatrixType::Full || typ == MatrixType::Hermitian)
    retval = fsolve (mattype, b, info, rcon, sing_handler, true);
  else if (typ != MatrixType::Rectangular)
    {
      (*current_liboctave_error_handler) ("unknown matrix type");
      return Matrix ();
    }

  // Rectangular or one of the above solvers flags a singular matrix
  if (singular_fallback && mattype.type () == MatrixType::Rectangular)
    {
      octave_idx_type rank;
      retval = lssolve (b, info, rank, rcon);
    }

  return retval;
}

ComplexMatrix
Matrix::solve (MatrixType &typ, const ComplexMatrix& b) const
{
  ComplexMatrix tmp (*this);
  return tmp.solve (typ, b);
}

ComplexMatrix
Matrix::solve (MatrixType &typ, const ComplexMatrix& b, 
  octave_idx_type& info) const
{
  ComplexMatrix tmp (*this);
  return tmp.solve (typ, b, info);
}

ComplexMatrix
Matrix::solve (MatrixType &typ, const ComplexMatrix& b, octave_idx_type& info,
	       double& rcon) const
{
  ComplexMatrix tmp (*this);
  return tmp.solve (typ, b, info, rcon);
}

ComplexMatrix
Matrix::solve (MatrixType &typ, const ComplexMatrix& b, octave_idx_type& info,
	       double& rcon, solve_singularity_handler sing_handler,
	       bool singular_fallback) const
{
  ComplexMatrix tmp (*this);
  return tmp.solve (typ, b, info, rcon, sing_handler, singular_fallback);
}

ColumnVector
Matrix::solve (MatrixType &typ, const ColumnVector& b) const
{
  octave_idx_type info; double rcon;
  return solve (typ, b, info, rcon);
}

ColumnVector
Matrix::solve (MatrixType &typ, const ColumnVector& b, 
	       octave_idx_type& info) const
{
  double rcon;
  return solve (typ, b, info, rcon);
}

ColumnVector
Matrix::solve (MatrixType &typ, const ColumnVector& b, octave_idx_type& info,
	       double& rcon) const
{
  return solve (typ, b, info, rcon, 0);
}

ColumnVector
Matrix::solve (MatrixType &typ, const ColumnVector& b, octave_idx_type& info,
	       double& rcon, solve_singularity_handler sing_handler) const
{
  Matrix tmp (b);
  return solve (typ, tmp, info, rcon, sing_handler).column(static_cast<octave_idx_type> (0));
}

ComplexColumnVector
Matrix::solve (MatrixType &typ, const ComplexColumnVector& b) const
{
  ComplexMatrix tmp (*this);
  return tmp.solve (typ, b);
}

ComplexColumnVector
Matrix::solve (MatrixType &typ, const ComplexColumnVector& b, 
	       octave_idx_type& info) const
{
  ComplexMatrix tmp (*this);
  return tmp.solve (typ, b, info);
}

ComplexColumnVector
Matrix::solve (MatrixType &typ, const ComplexColumnVector& b, 
	       octave_idx_type& info, double& rcon) const
{
  ComplexMatrix tmp (*this);
  return tmp.solve (typ, b, info, rcon);
}

ComplexColumnVector
Matrix::solve (MatrixType &typ, const ComplexColumnVector& b, 
	       octave_idx_type& info, double& rcon,
	       solve_singularity_handler sing_handler) const
{
  ComplexMatrix tmp (*this);
  return tmp.solve(typ, b, info, rcon, sing_handler);
}

Matrix
Matrix::solve (const Matrix& b) const
{
  octave_idx_type info;
  double rcon;
  return solve (b, info, rcon, 0);
}

Matrix
Matrix::solve (const Matrix& b, octave_idx_type& info) const
{
  double rcon;
  return solve (b, info, rcon, 0);
}

Matrix
Matrix::solve (const Matrix& b, octave_idx_type& info, double& rcon) const
{
  return solve (b, info, rcon, 0);
}

Matrix
Matrix::solve (const Matrix& b, octave_idx_type& info,
	       double& rcon, solve_singularity_handler sing_handler) const
{
  MatrixType mattype (*this);
  return solve (mattype, b, info, rcon, sing_handler);
}

ComplexMatrix
Matrix::solve (const ComplexMatrix& b) const
{
  ComplexMatrix tmp (*this);
  return tmp.solve (b);
}

ComplexMatrix
Matrix::solve (const ComplexMatrix& b, octave_idx_type& info) const
{
  ComplexMatrix tmp (*this);
  return tmp.solve (b, info);
}

ComplexMatrix
Matrix::solve (const ComplexMatrix& b, octave_idx_type& info, double& rcon) const
{
  ComplexMatrix tmp (*this);
  return tmp.solve (b, info, rcon);
}

ComplexMatrix
Matrix::solve (const ComplexMatrix& b, octave_idx_type& info, double& rcon,
	       solve_singularity_handler sing_handler) const
{
  ComplexMatrix tmp (*this);
  return tmp.solve (b, info, rcon, sing_handler);
}

ColumnVector
Matrix::solve (const ColumnVector& b) const
{
  octave_idx_type info; double rcon;
  return solve (b, info, rcon);
}

ColumnVector
Matrix::solve (const ColumnVector& b, octave_idx_type& info) const
{
  double rcon;
  return solve (b, info, rcon);
}

ColumnVector
Matrix::solve (const ColumnVector& b, octave_idx_type& info, double& rcon) const
{
  return solve (b, info, rcon, 0);
}

ColumnVector
Matrix::solve (const ColumnVector& b, octave_idx_type& info, double& rcon,
	       solve_singularity_handler sing_handler) const
{
  MatrixType mattype (*this);
  return solve (mattype, b, info, rcon, sing_handler);
}

ComplexColumnVector
Matrix::solve (const ComplexColumnVector& b) const
{
  ComplexMatrix tmp (*this);
  return tmp.solve (b);
}

ComplexColumnVector
Matrix::solve (const ComplexColumnVector& b, octave_idx_type& info) const
{
  ComplexMatrix tmp (*this);
  return tmp.solve (b, info);
}

ComplexColumnVector
Matrix::solve (const ComplexColumnVector& b, octave_idx_type& info, double& rcon) const
{
  ComplexMatrix tmp (*this);
  return tmp.solve (b, info, rcon);
}

ComplexColumnVector
Matrix::solve (const ComplexColumnVector& b, octave_idx_type& info, double& rcon,
	       solve_singularity_handler sing_handler) const
{
  ComplexMatrix tmp (*this);
  return tmp.solve (b, info, rcon, sing_handler);
}

Matrix
Matrix::lssolve (const Matrix& b) const
{
  octave_idx_type info;
  octave_idx_type rank;
  double rcon;
  return lssolve (b, info, rank, rcon);
}

Matrix
Matrix::lssolve (const Matrix& b, octave_idx_type& info) const
{
  octave_idx_type rank;
  double rcon;
  return lssolve (b, info, rank, rcon);
}

Matrix
Matrix::lssolve (const Matrix& b, octave_idx_type& info,
		 octave_idx_type& rank) const
{
  double rcon;
  return lssolve (b, info, rank, rcon);
}

Matrix
Matrix::lssolve (const Matrix& b, octave_idx_type& info,
		 octave_idx_type& rank, double &rcon) const
{
  Matrix retval;

  octave_idx_type nrhs = b.cols ();

  octave_idx_type m = rows ();
  octave_idx_type n = cols ();

  if (m != b.rows ())
    (*current_liboctave_error_handler)
      ("matrix dimension mismatch solution of linear equations");
  else if (m == 0 || n == 0 || b.cols () == 0)
    retval = Matrix (n, b.cols (), 0.0);
  else
    {
      volatile octave_idx_type minmn = (m < n ? m : n);
      octave_idx_type maxmn = m > n ? m : n;
      rcon = -1.0;
      if (m != n)
	{
	  retval = Matrix (maxmn, nrhs, 0.0);

	  for (octave_idx_type j = 0; j < nrhs; j++)
	    for (octave_idx_type i = 0; i < m; i++)
	      retval.elem (i, j) = b.elem (i, j);
	}
      else
	retval = b;

      Matrix atmp = *this;
      double *tmp_data = atmp.fortran_vec ();

      double *pretval = retval.fortran_vec ();
      Array<double> s (minmn);
      double *ps = s.fortran_vec ();

      // Ask DGELSD what the dimension of WORK should be.
      octave_idx_type lwork = -1;

      Array<double> work (1);

      octave_idx_type smlsiz;
      F77_FUNC (xilaenv, XILAENV) (9, F77_CONST_CHAR_ARG2 ("DGELSD", 6),
				   F77_CONST_CHAR_ARG2 (" ", 1),
				   0, 0, 0, 0, smlsiz
				   F77_CHAR_ARG_LEN (6)
				   F77_CHAR_ARG_LEN (1));

      octave_idx_type mnthr;
      F77_FUNC (xilaenv, XILAENV) (6, F77_CONST_CHAR_ARG2 ("DGELSD", 6),
				   F77_CONST_CHAR_ARG2 (" ", 1),
				   m, n, nrhs, -1, mnthr
				   F77_CHAR_ARG_LEN (6)
				   F77_CHAR_ARG_LEN (1));

      // We compute the size of iwork because DGELSD in older versions
      // of LAPACK does not return it on a query call.
      double dminmn = static_cast<double> (minmn);
      double dsmlsizp1 = static_cast<double> (smlsiz+1);
#if defined (HAVE_LOG2)
      double tmp = log2 (dminmn / dsmlsizp1);
#else
      double tmp = log (dminmn / dsmlsizp1) / log (2.0);
#endif
      octave_idx_type nlvl = static_cast<octave_idx_type> (tmp) + 1;
      if (nlvl < 0)
	nlvl = 0;

      octave_idx_type liwork = 3 * minmn * nlvl + 11 * minmn;
      if (liwork < 1)
	liwork = 1;
      Array<octave_idx_type> iwork (liwork);
      octave_idx_type* piwork = iwork.fortran_vec ();

      F77_XFCN (dgelsd, DGELSD, (m, n, nrhs, tmp_data, m, pretval, maxmn,
				 ps, rcon, rank, work.fortran_vec (),
				 lwork, piwork, info));

      // The workspace query is broken in at least LAPACK 3.0.0
      // through 3.1.1 when n >= mnthr.  The obtuse formula below
      // should provide sufficient workspace for DGELSD to operate
      // efficiently.
      if (n >= mnthr)
	{
	  const octave_idx_type wlalsd
	    = 9*m + 2*m*smlsiz + 8*m*nlvl + m*nrhs + (smlsiz+1)*(smlsiz+1);

	  octave_idx_type addend = m;

	  if (2*m-4 > addend)
	    addend = 2*m-4;

	  if (nrhs > addend)
	    addend = nrhs;

	  if (n-3*m > addend)
	    addend = n-3*m;

	  if (wlalsd > addend)
	    addend = wlalsd;

	  const octave_idx_type lworkaround = 4*m + m*m + addend;

	  if (work(0) < lworkaround)
	    work(0) = lworkaround;
	}
      else if (m >= n)
	{
	  octave_idx_type lworkaround
	    = 12*n + 2*n*smlsiz + 8*n*nlvl + n*nrhs + (smlsiz+1)*(smlsiz+1);

	  if (work(0) < lworkaround)
	    work(0) = lworkaround;
	}

      lwork = static_cast<octave_idx_type> (work(0));
      work.resize (lwork);

      F77_XFCN (dgelsd, DGELSD, (m, n, nrhs, tmp_data, m, pretval,
				 maxmn, ps, rcon, rank,
				 work.fortran_vec (), lwork, 
				 piwork, info));

      if (rank < minmn)
	(*current_liboctave_warning_handler) 
	  ("dgelsd: rank deficient %dx%d matrix, rank = %d", m, n, rank);
      if (s.elem (0) == 0.0)
	rcon = 0.0;
      else
	rcon = s.elem (minmn - 1) / s.elem (0);

      retval.resize (n, nrhs);
    }

  return retval;
}

ComplexMatrix
Matrix::lssolve (const ComplexMatrix& b) const
{
  ComplexMatrix tmp (*this);
  octave_idx_type info;
  octave_idx_type rank;
  double rcon;
  return tmp.lssolve (b, info, rank, rcon);
}

ComplexMatrix
Matrix::lssolve (const ComplexMatrix& b, octave_idx_type& info) const
{
  ComplexMatrix tmp (*this);
  octave_idx_type rank;
  double rcon;
  return tmp.lssolve (b, info, rank, rcon);
}

ComplexMatrix
Matrix::lssolve (const ComplexMatrix& b, octave_idx_type& info, 
		 octave_idx_type& rank) const
{
  ComplexMatrix tmp (*this);
  double rcon;
  return tmp.lssolve (b, info, rank, rcon);
}

ComplexMatrix
Matrix::lssolve (const ComplexMatrix& b, octave_idx_type& info, 
		 octave_idx_type& rank, double& rcon) const
{
  ComplexMatrix tmp (*this);
  return tmp.lssolve (b, info, rank, rcon);
}

ColumnVector
Matrix::lssolve (const ColumnVector& b) const
{
  octave_idx_type info;
  octave_idx_type rank;
  double rcon;
  return lssolve (b, info, rank, rcon);
}

ColumnVector
Matrix::lssolve (const ColumnVector& b, octave_idx_type& info) const
{
  octave_idx_type rank;
  double rcon;
  return lssolve (b, info, rank, rcon);
}

ColumnVector
Matrix::lssolve (const ColumnVector& b, octave_idx_type& info,
		 octave_idx_type& rank) const
{
  double rcon;
  return lssolve (b, info, rank, rcon);
}

ColumnVector
Matrix::lssolve (const ColumnVector& b, octave_idx_type& info,
		 octave_idx_type& rank, double &rcon) const
{
  ColumnVector retval;

  octave_idx_type nrhs = 1;

  octave_idx_type m = rows ();
  octave_idx_type n = cols ();

  if (m != b.length ())
    (*current_liboctave_error_handler)
      ("matrix dimension mismatch solution of linear equations");
  else if (m == 0 || n == 0)
    retval = ColumnVector (n, 0.0);
  else
    {
      volatile octave_idx_type minmn = (m < n ? m : n);
      octave_idx_type maxmn = m > n ? m : n;
      rcon = -1.0;
 
      if (m != n)
	{
	  retval = ColumnVector (maxmn, 0.0);

	  for (octave_idx_type i = 0; i < m; i++)
	    retval.elem (i) = b.elem (i);
	}
      else
	retval = b;

      Matrix atmp = *this;
      double *tmp_data = atmp.fortran_vec ();

      double *pretval = retval.fortran_vec ();
      Array<double> s (minmn);
      double *ps = s.fortran_vec ();

      // Ask DGELSD what the dimension of WORK should be.
      octave_idx_type lwork = -1;

      Array<double> work (1);

      octave_idx_type smlsiz;
      F77_FUNC (xilaenv, XILAENV) (9, F77_CONST_CHAR_ARG2 ("DGELSD", 6),
				   F77_CONST_CHAR_ARG2 (" ", 1),
				   0, 0, 0, 0, smlsiz
				   F77_CHAR_ARG_LEN (6)
				   F77_CHAR_ARG_LEN (1));

      // We compute the size of iwork because DGELSD in older versions
      // of LAPACK does not return it on a query call.
      double dminmn = static_cast<double> (minmn);
      double dsmlsizp1 = static_cast<double> (smlsiz+1);
#if defined (HAVE_LOG2)
      double tmp = log2 (dminmn / dsmlsizp1);
#else
      double tmp = log (dminmn / dsmlsizp1) / log (2.0);
#endif
      octave_idx_type nlvl = static_cast<octave_idx_type> (tmp) + 1;
      if (nlvl < 0)
	nlvl = 0;

      octave_idx_type liwork = 3 * minmn * nlvl + 11 * minmn;
      if (liwork < 1)
	liwork = 1;
      Array<octave_idx_type> iwork (liwork);
      octave_idx_type* piwork = iwork.fortran_vec ();

      F77_XFCN (dgelsd, DGELSD, (m, n, nrhs, tmp_data, m, pretval, maxmn,
				 ps, rcon, rank, work.fortran_vec (),
				 lwork, piwork, info));

      lwork = static_cast<octave_idx_type> (work(0));
      work.resize (lwork);

      F77_XFCN (dgelsd, DGELSD, (m, n, nrhs, tmp_data, m, pretval,
				 maxmn, ps, rcon, rank,
				 work.fortran_vec (), lwork, 
				 piwork, info));

      if (rank < minmn)
	{
	  if (rank < minmn)
	    (*current_liboctave_warning_handler) 
	      ("dgelsd: rank deficient %dx%d matrix, rank = %d", m, n, rank);
	  if (s.elem (0) == 0.0)
	    rcon = 0.0;
	  else
	    rcon = s.elem (minmn - 1) / s.elem (0);
	}

      retval.resize (n, nrhs);
    }

  return retval;
}

ComplexColumnVector
Matrix::lssolve (const ComplexColumnVector& b) const
{
  ComplexMatrix tmp (*this);
  octave_idx_type info;
  octave_idx_type rank;
  double rcon;
  return tmp.lssolve (b, info, rank, rcon);
}

ComplexColumnVector
Matrix::lssolve (const ComplexColumnVector& b, octave_idx_type& info) const
{
  ComplexMatrix tmp (*this);
  octave_idx_type rank;
  double rcon;
  return tmp.lssolve (b, info, rank, rcon);
}

ComplexColumnVector
Matrix::lssolve (const ComplexColumnVector& b, octave_idx_type& info, 
		 octave_idx_type& rank) const
{
  ComplexMatrix tmp (*this);
  double rcon;
  return tmp.lssolve (b, info, rank, rcon);
}

ComplexColumnVector
Matrix::lssolve (const ComplexColumnVector& b, octave_idx_type& info, 
		 octave_idx_type& rank, double &rcon) const
{
  ComplexMatrix tmp (*this);
  return tmp.lssolve (b, info, rank, rcon);
}

Matrix&
Matrix::operator += (const DiagMatrix& a)
{
  octave_idx_type nr = rows ();
  octave_idx_type nc = cols ();

  octave_idx_type a_nr = a.rows ();
  octave_idx_type a_nc = a.cols ();

  if (nr != a_nr || nc != a_nc)
    {
      gripe_nonconformant ("operator +=", nr, nc, a_nr, a_nc);
      return *this;
    }

  for (octave_idx_type i = 0; i < a.length (); i++)
    elem (i, i) += a.elem (i, i);

  return *this;
}

Matrix&
Matrix::operator -= (const DiagMatrix& a)
{
  octave_idx_type nr = rows ();
  octave_idx_type nc = cols ();

  octave_idx_type a_nr = a.rows ();
  octave_idx_type a_nc = a.cols ();

  if (nr != a_nr || nc != a_nc)
    {
      gripe_nonconformant ("operator -=", nr, nc, a_nr, a_nc);
      return *this;
    }

  for (octave_idx_type i = 0; i < a.length (); i++)
    elem (i, i) -= a.elem (i, i);

  return *this;
}

// unary operations

boolMatrix
Matrix::operator ! (void) const
{
  octave_idx_type nr = rows ();
  octave_idx_type nc = cols ();

  boolMatrix b (nr, nc);

  for (octave_idx_type j = 0; j < nc; j++)
    for (octave_idx_type i = 0; i < nr; i++)
      b.elem (i, j) = ! elem (i, j);

  return b;
}

// column vector by row vector -> matrix operations

Matrix
operator * (const ColumnVector& v, const RowVector& a)
{
  Matrix retval;

  octave_idx_type len = v.length ();

  if (len != 0)
    {
      octave_idx_type a_len = a.length ();

      retval = Matrix (len, a_len);
      double *c = retval.fortran_vec ();
	  
      F77_XFCN (dgemm, DGEMM, (F77_CONST_CHAR_ARG2 ("N", 1),
			       F77_CONST_CHAR_ARG2 ("N", 1),
			       len, a_len, 1, 1.0, v.data (), len,
			       a.data (), 1, 0.0, c, len
			       F77_CHAR_ARG_LEN (1)
			       F77_CHAR_ARG_LEN (1)));
    }

  return retval;
}

// other operations.

Matrix
Matrix::map (dmapper fcn) const
{
  return MArray2<double>::map<double> (func_ptr (fcn));
}

ComplexMatrix
Matrix::map (cmapper fcn) const
{
  return MArray2<double>::map<Complex> (func_ptr (fcn));
}

boolMatrix
Matrix::map (bmapper fcn) const
{
  return MArray2<double>::map<bool> (func_ptr (fcn));
}

bool
Matrix::any_element_is_negative (bool neg_zero) const
{
  octave_idx_type nel = nelem ();

  if (neg_zero)
    {
      for (octave_idx_type i = 0; i < nel; i++)
	if (lo_ieee_signbit (elem (i)))
	  return true;
    }
  else
    {
      for (octave_idx_type i = 0; i < nel; i++)
	if (elem (i) < 0)
	  return true;
    }

  return false;
}

bool
Matrix::any_element_is_nan (void) const
{
  octave_idx_type nel = nelem ();

  for (octave_idx_type i = 0; i < nel; i++)
    {
      double val = elem (i);
      if (xisnan (val))
	return true;
    }

  return false;
}

bool
Matrix::any_element_is_inf_or_nan (void) const
{
  octave_idx_type nel = nelem ();

  for (octave_idx_type i = 0; i < nel; i++)
    {
      double val = elem (i);
      if (xisinf (val) || xisnan (val))
	return true;
    }

  return false;
}

bool
Matrix::any_element_not_one_or_zero (void) const
{
  octave_idx_type nel = nelem ();

  for (octave_idx_type i = 0; i < nel; i++)
    {
      double val = elem (i);
      if (val != 0 && val != 1)
	return true;
    }

  return false;
}

bool
Matrix::all_elements_are_int_or_inf_or_nan (void) const
{
  octave_idx_type nel = nelem ();

  for (octave_idx_type i = 0; i < nel; i++)
    {
      double val = elem (i);
      if (xisnan (val) || D_NINT (val) == val)
	continue;
      else
	return false;
    }

  return true;
}

// Return nonzero if any element of M is not an integer.  Also extract
// the largest and smallest values and return them in MAX_VAL and MIN_VAL.

bool
Matrix::all_integers (double& max_val, double& min_val) const
{
  octave_idx_type nel = nelem ();

  if (nel > 0)
    {
      max_val = elem (0);
      min_val = elem (0);
    }
  else
    return false;

  for (octave_idx_type i = 0; i < nel; i++)
    {
      double val = elem (i);

      if (val > max_val)
	max_val = val;

      if (val < min_val)
	min_val = val;

      if (D_NINT (val) != val)
	return false;
    }

  return true;
}

bool
Matrix::too_large_for_float (void) const
{
  octave_idx_type nel = nelem ();

  for (octave_idx_type i = 0; i < nel; i++)
    {
      double val = elem (i);

      if (! (xisnan (val) || xisinf (val))
	  && fabs (val) > FLT_MAX)
	return true;
    }

  return false;
}

// FIXME Do these really belong here?  Maybe they should be
// in a base class?

boolMatrix
Matrix::all (int dim) const
{
  return do_mx_red_op<boolMatrix, double> (*this, dim, mx_inline_all);
}

boolMatrix
Matrix::any (int dim) const
{
  return do_mx_red_op<boolMatrix, double> (*this, dim, mx_inline_any);
}

Matrix
Matrix::cumprod (int dim) const
{
  return do_mx_cum_op<Matrix, double> (*this, dim, mx_inline_cumprod);
}

Matrix
Matrix::cumsum (int dim) const
{
  return do_mx_cum_op<Matrix, double> (*this, dim, mx_inline_cumsum);
}

Matrix
Matrix::prod (int dim) const
{
  return do_mx_red_op<Matrix, double> (*this, dim, mx_inline_prod);
}

Matrix
Matrix::sum (int dim) const
{
  return do_mx_red_op<Matrix, double> (*this, dim, mx_inline_sum);
}

Matrix
Matrix::sumsq (int dim) const
{
  return do_mx_red_op<Matrix, double> (*this, dim, mx_inline_sumsq);
}

Matrix
Matrix::abs (void) const
{
  return Matrix (mx_inline_fabs_dup (data (), length ()),
                 rows (), cols ());
}

Matrix
Matrix::diag (octave_idx_type k) const
{
  return MArray2<double>::diag (k);
}

ColumnVector
Matrix::row_min (void) const
{
  Array<octave_idx_type> dummy_idx;
  return row_min (dummy_idx);
}

ColumnVector
Matrix::row_min (Array<octave_idx_type>& idx_arg) const
{
  ColumnVector result;

  octave_idx_type nr = rows ();
  octave_idx_type nc = cols ();

  if (nr > 0 && nc > 0)
    {
      result.resize (nr);
      idx_arg.resize (nr);

      for (octave_idx_type i = 0; i < nr; i++)
        {
	  octave_idx_type idx_j;

	  double tmp_min = octave_NaN;

	  for (idx_j = 0; idx_j < nc; idx_j++)
	    {
	      tmp_min = elem (i, idx_j);

	      if (! xisnan (tmp_min))
		break;
	    }

	  for (octave_idx_type j = idx_j+1; j < nc; j++)
	    {
	      double tmp = elem (i, j);

	      if (xisnan (tmp))
		continue;
	      else if (tmp < tmp_min)
		{
		  idx_j = j;
		  tmp_min = tmp;
		}
	    }

	  result.elem (i) = tmp_min;
	  idx_arg.elem (i) = xisnan (tmp_min) ? 0 : idx_j;
        }
    }

  return result;
}

ColumnVector
Matrix::row_max (void) const
{
  Array<octave_idx_type> dummy_idx;
  return row_max (dummy_idx);
}

ColumnVector
Matrix::row_max (Array<octave_idx_type>& idx_arg) const
{
  ColumnVector result;

  octave_idx_type nr = rows ();
  octave_idx_type nc = cols ();

  if (nr > 0 && nc > 0)
    {
      result.resize (nr);
      idx_arg.resize (nr);

      for (octave_idx_type i = 0; i < nr; i++)
        {
	  octave_idx_type idx_j;

	  double tmp_max = octave_NaN;

	  for (idx_j = 0; idx_j < nc; idx_j++)
	    {
	      tmp_max = elem (i, idx_j);

	      if (! xisnan (tmp_max))
		break;
	    }

	  for (octave_idx_type j = idx_j+1; j < nc; j++)
	    {
	      double tmp = elem (i, j);

	      if (xisnan (tmp))
		continue;
	      else if (tmp > tmp_max)
		{
		  idx_j = j;
		  tmp_max = tmp;
		}
	    }

	  result.elem (i) = tmp_max;
	  idx_arg.elem (i) = xisnan (tmp_max) ? 0 : idx_j;
        }
    }

  return result;
}

RowVector
Matrix::column_min (void) const
{
  Array<octave_idx_type> dummy_idx;
  return column_min (dummy_idx);
}

RowVector
Matrix::column_min (Array<octave_idx_type>& idx_arg) const
{
  RowVector result;

  octave_idx_type nr = rows ();
  octave_idx_type nc = cols ();

  if (nr > 0 && nc > 0)
    {
      result.resize (nc);
      idx_arg.resize (nc);

      for (octave_idx_type j = 0; j < nc; j++)
        {
	  octave_idx_type idx_i;

	  double tmp_min = octave_NaN;

	  for (idx_i = 0; idx_i < nr; idx_i++)
	    {
	      tmp_min = elem (idx_i, j);

	      if (! xisnan (tmp_min))
		break;
	    }

	  for (octave_idx_type i = idx_i+1; i < nr; i++)
	    {
	      double tmp = elem (i, j);

	      if (xisnan (tmp))
		continue;
	      else if (tmp < tmp_min)
		{
		  idx_i = i;
		  tmp_min = tmp;
		}
	    }

	  result.elem (j) = tmp_min;
	  idx_arg.elem (j) = xisnan (tmp_min) ? 0 : idx_i;
        }
    }

  return result;
}

RowVector
Matrix::column_max (void) const
{
  Array<octave_idx_type> dummy_idx;
  return column_max (dummy_idx);
}

RowVector
Matrix::column_max (Array<octave_idx_type>& idx_arg) const
{
  RowVector result;

  octave_idx_type nr = rows ();
  octave_idx_type nc = cols ();

  if (nr > 0 && nc > 0)
    {
      result.resize (nc);
      idx_arg.resize (nc);

      for (octave_idx_type j = 0; j < nc; j++)
        {
	  octave_idx_type idx_i;

	  double tmp_max = octave_NaN;

	  for (idx_i = 0; idx_i < nr; idx_i++)
	    {
	      tmp_max = elem (idx_i, j);

	      if (! xisnan (tmp_max))
		break;
	    }

	  for (octave_idx_type i = idx_i+1; i < nr; i++)
	    {
	      double tmp = elem (i, j);

	      if (xisnan (tmp))
		continue;
	      else if (tmp > tmp_max)
		{
		  idx_i = i;
		  tmp_max = tmp;
		}
	    }

	  result.elem (j) = tmp_max;
	  idx_arg.elem (j) = xisnan (tmp_max) ? 0 : idx_i;
        }
    }

  return result;
}

std::ostream&
operator << (std::ostream& os, const Matrix& a)
{
  for (octave_idx_type i = 0; i < a.rows (); i++)
    {
      for (octave_idx_type j = 0; j < a.cols (); j++)
	{
	  os << " ";
	  octave_write_double (os, a.elem (i, j));
	}
      os << "\n";
    }
  return os;
}

std::istream&
operator >> (std::istream& is, Matrix& a)
{
  octave_idx_type nr = a.rows ();
  octave_idx_type nc = a.cols ();

  if (nr > 0 && nc > 0)
    {
      double tmp;
      for (octave_idx_type i = 0; i < nr; i++)
	for (octave_idx_type j = 0; j < nc; j++)
	  {
	    tmp = octave_read_double (is);
	    if (is)
	      a.elem (i, j) = tmp;
	    else
	      goto done;
	  }
    }

 done:

  return is;
}

Matrix
Givens (double x, double y)
{
  double cc, s, temp_r;

  F77_FUNC (dlartg, DLARTG) (x, y, cc, s, temp_r);

  Matrix g (2, 2);

  g.elem (0, 0) = cc;
  g.elem (1, 1) = cc;
  g.elem (0, 1) = s;
  g.elem (1, 0) = -s;

  return g;
}

Matrix
Sylvester (const Matrix& a, const Matrix& b, const Matrix& c)
{
  Matrix retval;

  // FIXME -- need to check that a, b, and c are all the same
  // size.

  // Compute Schur decompositions.

  SCHUR as (a, "U");
  SCHUR bs (b, "U");
  
  // Transform c to new coordinates.

  Matrix ua = as.unitary_matrix ();
  Matrix sch_a = as.schur_matrix ();

  Matrix ub = bs.unitary_matrix ();
  Matrix sch_b = bs.schur_matrix ();
  
  Matrix cx = ua.transpose () * c * ub;
  
  // Solve the sylvester equation, back-transform, and return the
  // solution.

  octave_idx_type a_nr = a.rows ();
  octave_idx_type b_nr = b.rows ();

  double scale;
  octave_idx_type info;

  double *pa = sch_a.fortran_vec ();
  double *pb = sch_b.fortran_vec ();
  double *px = cx.fortran_vec ();

  F77_XFCN (dtrsyl, DTRSYL, (F77_CONST_CHAR_ARG2 ("N", 1),
			     F77_CONST_CHAR_ARG2 ("N", 1),
			     1, a_nr, b_nr, pa, a_nr, pb,
			     b_nr, px, a_nr, scale, info
			     F77_CHAR_ARG_LEN (1)
			     F77_CHAR_ARG_LEN (1)));


  // FIXME -- check info?
  
  retval = -ua*cx*ub.transpose ();

  return retval;
}

// matrix by matrix -> matrix operations

/* Simple Dot Product, Matrix-Vector and Matrix-Matrix Unit tests
%!assert([1 2 3] * [ 4 ; 5 ; 6], 32, 1e-14)
%!assert([1 2 ; 3 4 ] * [5 ; 6], [17 ; 39 ], 1e-14)
%!assert([1 2 ; 3 4 ] * [5 6 ; 7 8], [19 22; 43 50], 1e-14)
*/

/* Test some simple identities
%!shared M, cv, rv
%! M = randn(10,10);
%! cv = randn(10,1);
%! rv = randn(1,10);
%!assert([M*cv,M*cv],M*[cv,cv],1e-14)
%!assert([rv*M;rv*M],[rv;rv]*M,1e-14)
%!assert(2*rv*cv,[rv,rv]*[cv;cv],1e-14)
*/

static const char *
get_blas_trans_arg (bool trans)
{
  static char blas_notrans = 'N', blas_trans = 'T';
  return (trans) ? &blas_trans : &blas_notrans;
}

// the general GEMM operation

Matrix 
xgemm (bool transa, const Matrix& a, bool transb, const Matrix& b)
{
  Matrix retval;

  octave_idx_type a_nr = transa ? a.cols () : a.rows ();
  octave_idx_type a_nc = transa ? a.rows () : a.cols ();

  octave_idx_type b_nr = transb ? b.cols () : b.rows ();
  octave_idx_type b_nc = transb ? b.rows () : b.cols ();

  if (a_nc != b_nr)
    gripe_nonconformant ("operator *", a_nr, a_nc, b_nr, b_nc);
  else
    {
      if (a_nr == 0 || a_nc == 0 || b_nc == 0)
	retval = Matrix (a_nr, b_nc, 0.0);
      else if (a.data () == b.data () && a_nr == b_nc && transa != transb)
        {
	  octave_idx_type lda = a.rows ();

          retval = Matrix (a_nr, b_nc);
	  double *c = retval.fortran_vec ();

          const char *ctransa = get_blas_trans_arg (transa);
          F77_XFCN (dsyrk, DSYRK, (F77_CONST_CHAR_ARG2 ("U", 1),
                                   F77_CONST_CHAR_ARG2 (ctransa, 1),
                                   a_nr, a_nc, 1.0,
                                   a.data (), lda, 0.0, c, a_nr
                                   F77_CHAR_ARG_LEN (1)
                                   F77_CHAR_ARG_LEN (1)));
          for (int j = 0; j < a_nr; j++)
            for (int i = 0; i < j; i++)
              retval.xelem (j,i) = retval.xelem (i,j);

        }
      else
	{
	  octave_idx_type lda = a.rows (), tda = a.cols ();
	  octave_idx_type ldb = b.rows (), tdb = b.cols ();

	  retval = Matrix (a_nr, b_nc);
	  double *c = retval.fortran_vec ();

	  if (b_nc == 1)
	    {
	      if (a_nr == 1)
		F77_FUNC (xddot, XDDOT) (a_nc, a.data (), 1, b.data (), 1, *c);
	      else
		{
                  const char *ctransa = get_blas_trans_arg (transa);
		  F77_XFCN (dgemv, DGEMV, (F77_CONST_CHAR_ARG2 (ctransa, 1),
					   lda, tda, 1.0,  a.data (), lda,
					   b.data (), 1, 0.0, c, 1
					   F77_CHAR_ARG_LEN (1)));
		}
            }
          else if (a_nr == 1)
            {
              const char *crevtransb = get_blas_trans_arg (! transb);
              F77_XFCN (dgemv, DGEMV, (F77_CONST_CHAR_ARG2 (crevtransb, 1),
                                       ldb, tdb, 1.0,  b.data (), ldb,
                                       a.data (), 1, 0.0, c, 1
                                       F77_CHAR_ARG_LEN (1)));
            }
	  else
	    {
              const char *ctransa = get_blas_trans_arg (transa);
              const char *ctransb = get_blas_trans_arg (transb);
	      F77_XFCN (dgemm, DGEMM, (F77_CONST_CHAR_ARG2 (ctransa, 1),
				       F77_CONST_CHAR_ARG2 (ctransb, 1),
				       a_nr, b_nc, a_nc, 1.0, a.data (),
				       lda, b.data (), ldb, 0.0, c, a_nr
				       F77_CHAR_ARG_LEN (1)
				       F77_CHAR_ARG_LEN (1)));
	    }
	}
    }

  return retval;
}

Matrix
operator * (const Matrix& a, const Matrix& b)
{
  return xgemm (false, a, false, b);
}

// FIXME -- it would be nice to share code among the min/max
// functions below.

#define EMPTY_RETURN_CHECK(T) \
  if (nr == 0 || nc == 0) \
    return T (nr, nc);

Matrix
min (double d, const Matrix& m)
{
  octave_idx_type nr = m.rows ();
  octave_idx_type nc = m.columns ();

  EMPTY_RETURN_CHECK (Matrix);

  Matrix result (nr, nc);

  for (octave_idx_type j = 0; j < nc; j++)
    for (octave_idx_type i = 0; i < nr; i++)
      {
	OCTAVE_QUIT;
	result (i, j) = xmin (d, m (i, j));
      }

  return result;
}

Matrix
min (const Matrix& m, double d)
{
  octave_idx_type nr = m.rows ();
  octave_idx_type nc = m.columns ();

  EMPTY_RETURN_CHECK (Matrix);

  Matrix result (nr, nc);

  for (octave_idx_type j = 0; j < nc; j++)
    for (octave_idx_type i = 0; i < nr; i++)
      {
	OCTAVE_QUIT;
	result (i, j) = xmin (m (i, j), d);
      }

  return result;
}

Matrix
min (const Matrix& a, const Matrix& b)
{
  octave_idx_type nr = a.rows ();
  octave_idx_type nc = a.columns ();

  if (nr != b.rows () || nc != b.columns ())
    {
      (*current_liboctave_error_handler)
	("two-arg min expecting args of same size");
      return Matrix ();
    }

  EMPTY_RETURN_CHECK (Matrix);

  Matrix result (nr, nc);

  for (octave_idx_type j = 0; j < nc; j++)
    for (octave_idx_type i = 0; i < nr; i++)
      {
	OCTAVE_QUIT;
	result (i, j) = xmin (a (i, j), b (i, j));
      }

  return result;
}

Matrix
max (double d, const Matrix& m)
{
  octave_idx_type nr = m.rows ();
  octave_idx_type nc = m.columns ();

  EMPTY_RETURN_CHECK (Matrix);

  Matrix result (nr, nc);

  for (octave_idx_type j = 0; j < nc; j++)
    for (octave_idx_type i = 0; i < nr; i++)
      {
	OCTAVE_QUIT;
	result (i, j) = xmax (d, m (i, j));
      }

  return result;
}

Matrix
max (const Matrix& m, double d)
{
  octave_idx_type nr = m.rows ();
  octave_idx_type nc = m.columns ();

  EMPTY_RETURN_CHECK (Matrix);

  Matrix result (nr, nc);

  for (octave_idx_type j = 0; j < nc; j++)
    for (octave_idx_type i = 0; i < nr; i++)
      {
	OCTAVE_QUIT;
	result (i, j) = xmax (m (i, j), d);
      }

  return result;
}

Matrix
max (const Matrix& a, const Matrix& b)
{
  octave_idx_type nr = a.rows ();
  octave_idx_type nc = a.columns ();

  if (nr != b.rows () || nc != b.columns ())
    {
      (*current_liboctave_error_handler)
	("two-arg max expecting args of same size");
      return Matrix ();
    }

  EMPTY_RETURN_CHECK (Matrix);

  Matrix result (nr, nc);

  for (octave_idx_type j = 0; j < nc; j++)
    for (octave_idx_type i = 0; i < nr; i++)
      {
	OCTAVE_QUIT;
	result (i, j) = xmax (a (i, j), b (i, j));
      }

  return result;
}

MS_CMP_OPS(Matrix, , double, )
MS_BOOL_OPS(Matrix, double, 0.0)

SM_CMP_OPS(double, , Matrix, )
SM_BOOL_OPS(double, Matrix, 0.0)

MM_CMP_OPS(Matrix, , Matrix, )
MM_BOOL_OPS(Matrix, Matrix, 0.0)

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