view liboctave/array/dMatrix.cc @ 30564:796f54d4ddbf stable

update Octave Project Developers copyright for the new year In files that have the "Octave Project Developers" copyright notice, update for 2021. In all .txi and .texi files except gpl.txi and gpl.texi in the doc/liboctave and doc/interpreter directories, change the copyright to "Octave Project Developers", the same as used for other source files. Update copyright notices for 2022 (not done since 2019). For gpl.txi and gpl.texi, change the copyright notice to be "Free Software Foundation, Inc." and leave the date at 2007 only because this file only contains the text of the GPL, not anything created by the Octave Project Developers. Add Paul Thomas to contributors.in.
author John W. Eaton <jwe@octave.org>
date Tue, 28 Dec 2021 18:22:40 -0500
parents 117ebe363f56
children 55f0173e4f08
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////////////////////////////////////////////////////////////////////////
//
// Copyright (C) 1994-2022 The Octave Project Developers
//
// See the file COPYRIGHT.md in the top-level directory of this
// distribution or <https://octave.org/copyright/>.
//
// 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
// <https://www.gnu.org/licenses/>.
//
////////////////////////////////////////////////////////////////////////

#if defined (HAVE_CONFIG_H)
#  include "config.h"
#endif

#include <algorithm>
#include <istream>
#include <limits>
#include <ostream>

#include "Array-util.h"
#include "CColVector.h"
#include "CMatrix.h"
#include "DET.h"
#include "PermMatrix.h"
#include "boolMatrix.h"
#include "byte-swap.h"
#include "chMatrix.h"
#include "chol.h"
#include "dColVector.h"
#include "dDiagMatrix.h"
#include "dMatrix.h"
#include "dRowVector.h"
#include "lo-blas-proto.h"
#include "lo-error.h"
#include "lo-ieee.h"
#include "lo-lapack-proto.h"
#include "lo-mappers.h"
#include "lo-utils.h"
#include "mx-dm-m.h"
#include "mx-inlines.cc"
#include "mx-m-dm.h"
#include "mx-op-defs.h"
#include "oct-cmplx.h"
#include "oct-fftw.h"
#include "oct-locbuf.h"
#include "oct-norm.h"
#include "quit.h"
#include "schur.h"
#include "svd.h"

// Matrix class.

Matrix::Matrix (const RowVector& rv)
  : NDArray (rv)
{ }

Matrix::Matrix (const ColumnVector& cv)
  : NDArray (cv)
{ }

Matrix::Matrix (const DiagMatrix& a)
  : NDArray (a.dims (), 0.0)
{
  for (octave_idx_type i = 0; i < a.length (); i++)
    elem (i, i) = a.elem (i, i);
}

Matrix::Matrix (const MDiagArray2<double>& a)
  : NDArray (a.dims (), 0.0)
{
  for (octave_idx_type i = 0; i < a.length (); i++)
    elem (i, i) = a.elem (i, i);
}

Matrix::Matrix (const DiagArray2<double>& a)
  : NDArray (a.dims (), 0.0)
{
  for (octave_idx_type i = 0; i < a.length (); i++)
    elem (i, i) = a.elem (i, i);
}

Matrix::Matrix (const PermMatrix& a)
  : NDArray (a.dims (), 0.0)
{
  const Array<octave_idx_type> ia (a.col_perm_vec ());
  octave_idx_type len = a.rows ();
  for (octave_idx_type i = 0; i < len; i++)
    elem (ia(i), i) = 1.0;
}

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

Matrix::Matrix (const boolMatrix& a)
  : NDArray (a)
{ }

Matrix::Matrix (const charMatrix& a)
  : NDArray (a.dims ())
{
  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 (numel (), data (), a.data ());
}

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

bool
Matrix::issymmetric (void) const
{
  if (issquare () && 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)
{
  Array<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.numel ();

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

  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.numel ();

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

  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");

  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");

  if (r1 > r2) { std::swap (r1, r2); }
  if (c1 > c2) { std::swap (c1, c2); }

  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");

  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");

  octave_idx_type nc_insert = nc;
  Matrix retval (nr, nc + a.numel ());
  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.numel ())
    (*current_liboctave_error_handler) ("row dimension mismatch for append");

  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");

  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");

  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.numel ())
    (*current_liboctave_error_handler) ("column dimension mismatch for stack");

  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");

  octave_idx_type nr_insert = nr;
  Matrix retval (nr + a.numel (), 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");

  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 do_mx_unary_op<double, Complex> (a, mx_inline_real);
}

Matrix
imag (const ComplexMatrix& a)
{
  return do_mx_unary_op<double, Complex> (a, mx_inline_imag);
}

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

  return index (octave::idx_vector (r1, r2+1), octave::idx_vector (c1, c2+1));
}

Matrix
Matrix::extract_n (octave_idx_type r1, octave_idx_type c1, octave_idx_type nr,
                   octave_idx_type nc) const
{
  return index (octave::idx_vector (r1, r1 + nr), octave::idx_vector (c1, c1 + nc));
}

// extract row or column i.

RowVector
Matrix::row (octave_idx_type i) const
{
  return index (octave::idx_vector (i), octave::idx_vector::colon);
}

ColumnVector
Matrix::column (octave_idx_type i) const
{
  return index (octave::idx_vector::colon, octave::idx_vector (i));
}

// Local function to calculate the 1-norm.
static
double
norm1 (const Matrix& a)
{
  double anorm = 0.0;
  RowVector colsum = a.abs ().sum ().row (0);

  for (octave_idx_type i = 0; i < colsum.numel (); i++)
    {
      double sum = colsum.xelem (i);
      if (octave::math::isinf (sum) || octave::math::isnan (sum))
        {
          anorm = sum;  // Pass Inf or NaN to output
          break;
        }
      else
        anorm = std::max (anorm, sum);
    }

  return anorm;
}

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, bool force,
                 bool 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,
                  bool force, bool calc_cond) const
{
  Matrix retval;

  F77_INT nr = octave::to_f77_int (rows ());
  F77_INT nc = octave::to_f77_int (cols ());

  if (nr != nc || nr == 0 || nc == 0)
    (*current_liboctave_error_handler) ("inverse requires square matrix");

  int typ = mattype.type ();
  char uplo = (typ == MatrixType::Lower ? 'L' : 'U');
  char udiag = 'N';
  retval = *this;
  double *tmp_data = retval.fortran_vec ();

  F77_INT tmp_info = 0;

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

  info = tmp_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)
    {
      F77_INT dtrcon_info = 0;
      char job = '1';

      OCTAVE_LOCAL_BUFFER (double, work, 3 * nr);
      OCTAVE_LOCAL_BUFFER (F77_INT, 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,
                  bool force, bool calc_cond) const
{
  Matrix retval;

  F77_INT nr = octave::to_f77_int (rows ());
  F77_INT nc = octave::to_f77_int (cols ());

  if (nr != nc || nr == 0 || nc == 0)
    (*current_liboctave_error_handler) ("inverse requires square matrix");

  Array<F77_INT> ipvt (dim_vector (nr, 1));
  F77_INT *pipvt = ipvt.fortran_vec ();

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

  Array<double> z (dim_vector (1, 1));
  F77_INT lwork = -1;

  F77_INT tmp_info = 0;

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

  lwork = static_cast<F77_INT> (z(0));
  lwork = (lwork < 4 * nc ? 4 * nc : lwork);
  z.resize (dim_vector (lwork, 1));
  double *pz = z.fortran_vec ();

  info = 0;
  tmp_info = 0;

  // Calculate the norm of the matrix for later use when determining rcon.
  double anorm;
  if (calc_cond)
    anorm = norm1 (retval);

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

  info = tmp_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)
    {
      F77_INT dgecon_info = 0;

      // Now calculate the condition number for non-singular matrix.
      char job = '1';
      Array<F77_INT> iz (dim_vector (nc, 1));
      F77_INT *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
    {
      F77_INT 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,
                 bool force, bool calc_cond) const
{
  int typ = mattype.type (false);
  Matrix ret;

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

  if (typ == MatrixType::Diagonal)  // a scalar is classified as Diagonal.
    {
      ret = 1 / (*this);
      if (calc_cond)
        {
          double scalar = this->elem (0);
          if (octave::math::isfinite (scalar) && scalar != 0)
            rcon = 1.0;
          else if (octave::math::isinf (scalar) || scalar == 0)
            rcon = 0.0;
          else
            rcon = octave::numeric_limits<double>::NaN ();
        }
    }
  else if (typ == MatrixType::Upper || typ == MatrixType::Lower)
    ret = tinverse (mattype, info, rcon, force, calc_cond);
  else
    {
      if (mattype.ishermitian ())
        {
          octave::math::chol<Matrix> chol (*this, info, true, 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.ishermitian ())
        ret = finverse (mattype, info, rcon, force, calc_cond);

      if ((calc_cond || mattype.ishermitian ()) && rcon == 0.0)
        ret = Matrix (rows (), columns (),
                      octave::numeric_limits<double>::Inf ());
    }

  return ret;
}

Matrix
Matrix::pseudo_inverse (double tol) const
{
  octave::math::svd<Matrix> result (*this,
                                    octave::math::svd<Matrix>::Type::economy);

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

  ColumnVector sigma = S.extract_diag ();

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

  if (tol <= 0.0)
    {
      tol = std::max (nr, nc) * sigma.elem (0)
            * std::numeric_limits<double>::epsilon ();

      if (tol == 0)
        tol = std::numeric_limits<double>::min ();
    }

  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_FFTW)

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

  ComplexMatrix retval (nr, nc);

  std::size_t npts, nsamples;

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

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

  octave::fftw::fft (in, out, npts, nsamples);

  return retval;
}

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

  ComplexMatrix retval (nr, nc);

  std::size_t npts, nsamples;

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

  ComplexMatrix tmp (*this);
  const Complex *in (tmp.data ());
  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 = data ();
  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
{
  (*current_liboctave_error_handler)
    ("support for FFTW was unavailable or disabled when liboctave was built");

  return ComplexMatrix ();
}

ComplexMatrix
Matrix::ifourier (void) const
{
  (*current_liboctave_error_handler)
    ("support for FFTW was unavailable or disabled when liboctave was built");

  return ComplexMatrix ();
}

ComplexMatrix
Matrix::fourier2d (void) const
{
  (*current_liboctave_error_handler)
    ("support for FFTW was unavailable or disabled when liboctave was built");

  return ComplexMatrix ();
}

ComplexMatrix
Matrix::ifourier2d (void) const
{
  (*current_liboctave_error_handler)
    ("support for FFTW was unavailable or disabled when liboctave was built");

  return ComplexMatrix ();
}

#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, bool calc_cond) const
{
  MatrixType mattype (*this);
  return determinant (mattype, info, rcon, calc_cond);
}

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

  info = 0;
  rcon = 0.0;

  F77_INT nr = octave::to_f77_int (rows ());
  F77_INT nc = octave::to_f77_int (cols ());

  if (nr != nc)
    (*current_liboctave_error_handler) ("matrix must be square");

  volatile int typ = mattype.type ();

  // Even though the matrix is marked as singular (Rectangular), we may still
  // get a useful number from the LU factorization, because it always completes.

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

  if (typ == MatrixType::Lower || typ == MatrixType::Upper)
    {
      for (F77_INT i = 0; i < nc; i++)
        retval *= elem (i, i);
    }
  else if (typ == MatrixType::Hermitian)
    {
      Matrix atmp = *this;
      double *tmp_data = atmp.fortran_vec ();

      // Calculate the norm of the matrix for later use when determining rcon.
      double anorm;
      if (calc_cond)
        anorm = norm1 (*this);

      F77_INT tmp_info = 0;

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

      info = tmp_info;

      if (info != 0)
        {
          rcon = 0.0;
          mattype.mark_as_unsymmetric ();
          typ = MatrixType::Full;
        }
      else
        {
          if (calc_cond)
            {
              Array<double> z (dim_vector (3 * nc, 1));
              double *pz = z.fortran_vec ();
              Array<F77_INT> iz (dim_vector (nc, 1));
              F77_INT *piz = iz.fortran_vec ();

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

              info = tmp_info;

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

          for (F77_INT 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<F77_INT> ipvt (dim_vector (nr, 1));
      F77_INT *pipvt = ipvt.fortran_vec ();

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

      info = 0;
      F77_INT tmp_info = 0;

      // Calculate the norm of the matrix for later use when determining rcon.
      double anorm;
      if (calc_cond)
        anorm = norm1 (*this);

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

      info = tmp_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 (dim_vector (4 * nc, 1));
              double *pz = z.fortran_vec ();
              Array<F77_INT> iz (dim_vector (nc, 1));
              F77_INT *piz = iz.fortran_vec ();

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

              info = tmp_info;
            }

          if (info != 0)
            {
              info = -1;
              retval = DET ();
            }
          else
            {
              for (F77_INT 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::numeric_limits<double>::NaN ();
  F77_INT nr = octave::to_f77_int (rows ());
  F77_INT nc = octave::to_f77_int (cols ());

  if (nr != nc)
    (*current_liboctave_error_handler) ("matrix must be square");

  if (nr == 0 || nc == 0)
    rcon = octave::numeric_limits<double>::Inf ();
  else
    {
      volatile 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 = data ();
          F77_INT info = 0;
          char norm = '1';
          char uplo = 'U';
          char dia = 'N';

          Array<double> z (dim_vector (3 * nc, 1));
          double *pz = z.fortran_vec ();
          Array<F77_INT> iz (dim_vector (nc, 1));
          F77_INT *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 = data ();
          F77_INT info = 0;
          char norm = '1';
          char uplo = 'L';
          char dia = 'N';

          Array<double> z (dim_vector (3 * nc, 1));
          double *pz = z.fortran_vec ();
          Array<F77_INT> iz (dim_vector (nc, 1));
          F77_INT *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;

          if (typ == MatrixType::Hermitian)
            {
              F77_INT info = 0;
              char job = 'L';

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

              anorm = norm1 (atmp);

              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 (dim_vector (3 * nc, 1));
                  double *pz = z.fortran_vec ();
                  Array<F77_INT> iz (dim_vector (nc, 1));
                  F77_INT *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)
            {
              F77_INT info = 0;

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

              Array<F77_INT> ipvt (dim_vector (nr, 1));
              F77_INT *pipvt = ipvt.fortran_vec ();

              if (anorm < 0.0)
                anorm = norm1 (atmp);

              Array<double> z (dim_vector (4 * nc, 1));
              double *pz = z.fortran_vec ();
              Array<F77_INT> iz (dim_vector (nc, 1));
              F77_INT *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, blas_trans_type transt) const
{
  Matrix retval;

  F77_INT nr = octave::to_f77_int (rows ());
  F77_INT nc = octave::to_f77_int (cols ());

  F77_INT b_nr = octave::to_f77_int (b.rows ());
  F77_INT b_nc = octave::to_f77_int (b.cols ());

  if (nr != b_nr)
    (*current_liboctave_error_handler)
      ("matrix dimension mismatch solution of linear equations");

  if (nr == 0 || nc == 0 || b_nc == 0)
    retval = Matrix (nc, b_nc, 0.0);
  else
    {
      volatile int typ = mattype.type ();

      if (typ != MatrixType::Permuted_Upper && typ != MatrixType::Upper)
        (*current_liboctave_error_handler) ("incorrect matrix type");

      rcon = 1.0;
      info = 0;

      if (typ == MatrixType::Permuted_Upper)
        (*current_liboctave_error_handler)
          ("permuted triangular matrix not implemented");

      const double *tmp_data = data ();

      retval = b;
      double *result = retval.fortran_vec ();

      char uplo = 'U';
      char trans = get_blas_char (transt);
      char dia = 'N';

      F77_INT tmp_info = 0;

      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, tmp_info
                                 F77_CHAR_ARG_LEN (1)
                                 F77_CHAR_ARG_LEN (1)
                                 F77_CHAR_ARG_LEN (1)));

      info = tmp_info;

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

          Array<double> z (dim_vector (3 * nc, 1));
          double *pz = z.fortran_vec ();
          Array<F77_INT> iz (dim_vector (nc, 1));
          F77_INT *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, tmp_info
                                     F77_CHAR_ARG_LEN (1)
                                     F77_CHAR_ARG_LEN (1)
                                     F77_CHAR_ARG_LEN (1)));

          info = tmp_info;

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

          // FIXME: Why calculate this, rather than just compare to 0.0?
          volatile double rcond_plus_one = rcon + 1.0;

          if (rcond_plus_one == 1.0 || octave::math::isnan (rcon))
            {
              info = -2;

              if (sing_handler)
                sing_handler (rcon);
              else
                octave::warn_singular_matrix (rcon);
            }
        }
    }

  return retval;
}

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

  F77_INT nr = octave::to_f77_int (rows ());
  F77_INT nc = octave::to_f77_int (cols ());

  F77_INT b_nr = octave::to_f77_int (b.rows ());
  F77_INT b_nc = octave::to_f77_int (b.cols ());

  if (nr != b_nr)
    (*current_liboctave_error_handler)
      ("matrix dimension mismatch solution of linear equations");

  if (nr == 0 || nc == 0 || b_nc == 0)
    retval = Matrix (nc, b_nc, 0.0);
  else
    {
      volatile int typ = mattype.type ();

      if (typ != MatrixType::Permuted_Lower && typ != MatrixType::Lower)
        (*current_liboctave_error_handler) ("incorrect matrix type");

      rcon = 1.0;
      info = 0;

      if (typ == MatrixType::Permuted_Lower)
        (*current_liboctave_error_handler)
          ("permuted triangular matrix not implemented");

      const double *tmp_data = data ();

      retval = b;
      double *result = retval.fortran_vec ();

      char uplo = 'L';
      char trans = get_blas_char (transt);
      char dia = 'N';

      F77_INT tmp_info = 0;

      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, tmp_info
                                 F77_CHAR_ARG_LEN (1)
                                 F77_CHAR_ARG_LEN (1)
                                 F77_CHAR_ARG_LEN (1)));

      info = tmp_info;

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

          Array<double> z (dim_vector (3 * nc, 1));
          double *pz = z.fortran_vec ();
          Array<F77_INT> iz (dim_vector (nc, 1));
          F77_INT *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, tmp_info
                                     F77_CHAR_ARG_LEN (1)
                                     F77_CHAR_ARG_LEN (1)
                                     F77_CHAR_ARG_LEN (1)));

          info = tmp_info;

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

          volatile double rcond_plus_one = rcon + 1.0;

          if (rcond_plus_one == 1.0 || octave::math::isnan (rcon))
            {
              info = -2;

              if (sing_handler)
                sing_handler (rcon);
              else
                octave::warn_singular_matrix (rcon);
            }
        }
    }

  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;

  F77_INT nr = octave::to_f77_int (rows ());
  F77_INT nc = octave::to_f77_int (cols ());

  if (nr != nc || nr != b.rows ())
    (*current_liboctave_error_handler)
      ("matrix dimension mismatch solution of linear equations");

  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 when determining rcon.
      double anorm = -1.0;

      if (typ == MatrixType::Hermitian)
        {
          info = 0;
          char job = 'L';

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

          // The norm of the matrix for later use when determining rcon.
          if (calc_cond)
            anorm = norm1 (atmp);

          F77_INT tmp_info = 0;

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

          info = tmp_info;

          // 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 (dim_vector (3 * nc, 1));
                  double *pz = z.fortran_vec ();
                  Array<F77_INT> iz (dim_vector (nc, 1));
                  F77_INT *piz = iz.fortran_vec ();

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

                  info = tmp_info;

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

                  volatile double rcond_plus_one = rcon + 1.0;

                  if (rcond_plus_one == 1.0 || octave::math::isnan (rcon))
                    {
                      info = -2;

                      if (sing_handler)
                        sing_handler (rcon);
                      else
                        octave::warn_singular_matrix (rcon);
                    }
                }

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

                  F77_INT b_nr = octave::to_f77_int (b.rows ());
                  F77_INT b_nc = octave::to_f77_int (b.cols ());

                  F77_XFCN (dpotrs, DPOTRS, (F77_CONST_CHAR_ARG2 (&job, 1),
                                             nr, b_nc, tmp_data, nr,
                                             result, b_nr, tmp_info
                                             F77_CHAR_ARG_LEN (1)));

                  info = tmp_info;
                }
              else
                {
                  mattype.mark_as_unsymmetric ();
                  typ = MatrixType::Full;
                }
            }
        }

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

          Array<F77_INT> ipvt (dim_vector (nr, 1));
          F77_INT *pipvt = ipvt.fortran_vec ();

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

          if (calc_cond && anorm < 0.0)
            anorm = norm1 (atmp);

          Array<double> z (dim_vector (4 * nc, 1));
          double *pz = z.fortran_vec ();
          Array<F77_INT> iz (dim_vector (nc, 1));
          F77_INT *piz = iz.fortran_vec ();

          F77_INT tmp_info = 0;

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

          info = tmp_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
                octave::warn_singular_matrix ();

              mattype.mark_as_rectangular ();
            }
          else
            {
              if (calc_cond)
                {
                  // 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, tmp_info
                                             F77_CHAR_ARG_LEN (1)));

                  info = tmp_info;

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

                  volatile double rcond_plus_one = rcon + 1.0;

                  if (rcond_plus_one == 1.0 || octave::math::isnan (rcon))
                    {
                      if (sing_handler)
                        sing_handler (rcon);
                      else
                        octave::warn_singular_matrix (rcon);
                    }
                }

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

                  F77_INT b_nr = octave::to_f77_int (b.rows ());
                  F77_INT b_nc = octave::to_f77_int (b.cols ());

                  char job = 'N';
                  F77_XFCN (dgetrs, DGETRS, (F77_CONST_CHAR_ARG2 (&job, 1),
                                             nr, b_nc, tmp_data, nr,
                                             pipvt, result, b_nr, tmp_info
                                             F77_CHAR_ARG_LEN (1)));

                  info = tmp_info;
                }
              else
                mattype.mark_as_rectangular ();
            }
        }
      else if (typ != MatrixType::Hermitian)
        (*current_liboctave_error_handler) ("incorrect matrix type");
    }

  return retval;
}

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

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

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

Matrix
Matrix::solve (MatrixType& mattype, const Matrix& b, octave_idx_type& info,
               double& rcon, solve_singularity_handler sing_handler,
               bool singular_fallback, blas_trans_type transt) 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, true, transt);
  else if (typ == MatrixType::Lower || typ == MatrixType::Permuted_Lower)
    retval = ltsolve (mattype, b, info, rcon, sing_handler, true, transt);
  else if (transt == blas_trans || transt == blas_conj_trans)
    return transpose ().solve (mattype, b, info, rcon, sing_handler,
                               singular_fallback);
  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");

  // 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& mattype, const ComplexMatrix& b) const
{
  octave_idx_type info;
  double rcon;
  return solve (mattype, b, info, rcon, nullptr);
}

ComplexMatrix
Matrix::solve (MatrixType& mattype, const ComplexMatrix& b,
               octave_idx_type& info) const
{
  double rcon;
  return solve (mattype, b, info, rcon, nullptr);
}

ComplexMatrix
Matrix::solve (MatrixType& mattype, const ComplexMatrix& b,
               octave_idx_type& info, double& rcon) const
{
  return solve (mattype, b, info, rcon, nullptr);
}

static Matrix
stack_complex_matrix (const ComplexMatrix& cm)
{
  octave_idx_type m = cm.rows ();
  octave_idx_type n = cm.cols ();
  octave_idx_type nel = m*n;
  Matrix retval (m, 2*n);
  const Complex *cmd = cm.data ();
  double *rd = retval.fortran_vec ();
  for (octave_idx_type i = 0; i < nel; i++)
    {
      rd[i] = std::real (cmd[i]);
      rd[nel+i] = std::imag (cmd[i]);
    }
  return retval;
}

static ComplexMatrix
unstack_complex_matrix (const Matrix& sm)
{
  octave_idx_type m = sm.rows ();
  octave_idx_type n = sm.cols () / 2;
  octave_idx_type nel = m*n;
  ComplexMatrix retval (m, n);
  const double *smd = sm.data ();
  Complex *rd = retval.fortran_vec ();
  for (octave_idx_type i = 0; i < nel; i++)
    rd[i] = Complex (smd[i], smd[nel+i]);
  return retval;
}

ComplexMatrix
Matrix::solve (MatrixType& mattype, const ComplexMatrix& b,
               octave_idx_type& info, double& rcon,
               solve_singularity_handler sing_handler,
               bool singular_fallback, blas_trans_type transt) const
{
  Matrix tmp = stack_complex_matrix (b);
  tmp = solve (mattype, tmp, info, rcon, sing_handler, singular_fallback,
               transt);
  return unstack_complex_matrix (tmp);
}

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

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

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

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

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

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

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

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

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

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

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

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

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,
               blas_trans_type transt) const
{
  ComplexMatrix tmp (*this);
  return tmp.solve (b, info, rcon, sing_handler, transt);
}

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, nullptr);
}

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

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,
               blas_trans_type transt) const
{
  ComplexMatrix tmp (*this);
  return tmp.solve (b, info, rcon, sing_handler, transt);
}

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;

  F77_INT m = octave::to_f77_int (rows ());
  F77_INT n = octave::to_f77_int (cols ());

  F77_INT b_nr = octave::to_f77_int (b.rows ());
  F77_INT b_nc = octave::to_f77_int (b.cols ());
  F77_INT nrhs = b_nc;  // alias for code readability

  if (m != b_nr)
    (*current_liboctave_error_handler)
      ("matrix dimension mismatch solution of linear equations");

  if (m == 0 || n == 0 || b_nc == 0)
    retval = Matrix (n, b_nc, 0.0);
  else
    {
      volatile F77_INT minmn = (m < n ? m : n);
      F77_INT maxmn = (m > n ? m : n);
      rcon = -1.0;
      if (m != n)
        {
          retval = Matrix (maxmn, nrhs, 0.0);

          for (F77_INT j = 0; j < nrhs; j++)
            for (F77_INT 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 (dim_vector (minmn, 1));
      double *ps = s.fortran_vec ();

      // Ask DGELSD what the dimension of WORK should be.
      F77_INT lwork = -1;

      Array<double> work (dim_vector (1, 1));

      F77_INT 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));

      F77_INT 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);
      double tmp = octave::math::log2 (dminmn / dsmlsizp1);

      F77_INT nlvl = static_cast<F77_INT> (tmp) + 1;
      if (nlvl < 0)
        nlvl = 0;

      F77_INT liwork = 3 * minmn * nlvl + 11 * minmn;
      if (liwork < 1)
        liwork = 1;
      Array<F77_INT> iwork (dim_vector (liwork, 1));
      F77_INT *piwork = iwork.fortran_vec ();

      F77_INT tmp_info = 0;
      F77_INT tmp_rank = 0;

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

      info = tmp_info;
      rank = tmp_rank;

      // 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 > m && n >= mnthr)
        {
          const F77_INT wlalsd
            = 9*m + 2*m*smlsiz + 8*m*nlvl + m*nrhs + (smlsiz+1)*(smlsiz+1);

          F77_INT 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 F77_INT lworkaround = 4*m + m*m + addend;

          if (work(0) < lworkaround)
            work(0) = lworkaround;
        }
      else if (m >= n)
        {
          F77_INT 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<F77_INT> (work(0));
      work.resize (dim_vector (lwork, 1));

      double anorm = norm1 (*this);

      if (octave::math::isinf (anorm))
        {
          rcon = 0.0;
          retval = Matrix (n, b_nc, 0.0);
        }
      else if (octave::math::isnan (anorm))
        {
          rcon = octave::numeric_limits<double>::NaN ();
          retval = Matrix (n, b_nc, octave::numeric_limits<double>::NaN ());
        }
      else
        {
          F77_XFCN (dgelsd, DGELSD, (m, n, nrhs, tmp_data, m, pretval,
                                     maxmn, ps, rcon, tmp_rank,
                                     work.fortran_vec (), lwork,
                                     piwork, tmp_info));

          info = tmp_info;
          rank = tmp_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;

  F77_INT nrhs = 1;

  F77_INT m = octave::to_f77_int (rows ());
  F77_INT n = octave::to_f77_int (cols ());

  F77_INT b_nel = octave::to_f77_int (b.numel ());

  if (m != b_nel)
    (*current_liboctave_error_handler)
      ("matrix dimension mismatch solution of linear equations");

  if (m == 0 || n == 0)
    retval = ColumnVector (n, 0.0);
  else
    {
      volatile F77_INT minmn = (m < n ? m : n);
      F77_INT maxmn = (m > n ? m : n);
      rcon = -1.0;

      if (m != n)
        {
          retval = ColumnVector (maxmn, 0.0);

          for (F77_INT 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 (dim_vector (minmn, 1));
      double *ps = s.fortran_vec ();

      // Ask DGELSD what the dimension of WORK should be.
      F77_INT lwork = -1;

      Array<double> work (dim_vector (1, 1));

      F77_INT 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);
      double tmp = octave::math::log2 (dminmn / dsmlsizp1);

      F77_INT nlvl = static_cast<F77_INT> (tmp) + 1;
      if (nlvl < 0)
        nlvl = 0;

      F77_INT liwork = 3 * minmn * nlvl + 11 * minmn;
      if (liwork < 1)
        liwork = 1;
      Array<F77_INT> iwork (dim_vector (liwork, 1));
      F77_INT *piwork = iwork.fortran_vec ();

      F77_INT tmp_info = 0;
      F77_INT tmp_rank = 0;

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

      info = tmp_info;
      rank = tmp_rank;

      lwork = static_cast<F77_INT> (work(0));
      work.resize (dim_vector (lwork, 1));

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

      info = tmp_info;
      rank = tmp_rank;

      if (rank < minmn)
        {
          if (s.elem (0) == 0.0)
            rcon = 0.0;
          else
            rcon = s.elem (minmn - 1) / s.elem (0);
        }

      retval.resize (n);
    }

  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)
    octave::err_nonconformant ("operator +=", nr, nc, a_nr, a_nc);

  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)
    octave::err_nonconformant ("operator -=", nr, nc, a_nr, a_nc);

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

  return *this;
}

// unary operations

// column vector by row vector -> matrix operations

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

  F77_INT len = octave::to_f77_int (v.numel ());

  if (len != 0)
    {
      F77_INT a_len = octave::to_f77_int (a.numel ());

      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.

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

boolMatrix
Matrix::all (int dim) const
{
  return NDArray::all (dim);
}

boolMatrix
Matrix::any (int dim) const
{
  return NDArray::any (dim);
}

Matrix
Matrix::cumprod (int dim) const
{
  return NDArray::cumprod (dim);
}

Matrix
Matrix::cumsum (int dim) const
{
  return NDArray::cumsum (dim);
}

Matrix
Matrix::prod (int dim) const
{
  return NDArray::prod (dim);
}

Matrix
Matrix::sum (int dim) const
{
  return NDArray::sum (dim);
}

Matrix
Matrix::sumsq (int dim) const
{
  return NDArray::sumsq (dim);
}

Matrix
Matrix::abs (void) const
{
  return NDArray::abs ();
}

Matrix
Matrix::diag (octave_idx_type k) const
{
  return NDArray::diag (k);
}

DiagMatrix
Matrix::diag (octave_idx_type m, octave_idx_type n) const
{
  DiagMatrix retval;

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

  if (nr == 1 || nc == 1)
    retval = DiagMatrix (*this, m, n);
  else
    (*current_liboctave_error_handler) ("diag: expecting vector argument");

  return retval;
}

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 (dim_vector (nr, 1));

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

          double tmp_min = octave::numeric_limits<double>::NaN ();

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

              if (! octave::math::isnan (tmp_min))
                break;
            }

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

              if (octave::math::isnan (tmp))
                continue;
              else if (tmp < tmp_min)
                {
                  idx_j = j;
                  tmp_min = tmp;
                }
            }

          result.elem (i) = tmp_min;
          idx_arg.elem (i) = (octave::math::isnan (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 (dim_vector (nr, 1));

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

          double tmp_max = octave::numeric_limits<double>::NaN ();

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

              if (! octave::math::isnan (tmp_max))
                break;
            }

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

              if (octave::math::isnan (tmp))
                continue;
              else if (tmp > tmp_max)
                {
                  idx_j = j;
                  tmp_max = tmp;
                }
            }

          result.elem (i) = tmp_max;
          idx_arg.elem (i) = (octave::math::isnan (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 (dim_vector (1, nc));

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

          double tmp_min = octave::numeric_limits<double>::NaN ();

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

              if (! octave::math::isnan (tmp_min))
                break;
            }

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

              if (octave::math::isnan (tmp))
                continue;
              else if (tmp < tmp_min)
                {
                  idx_i = i;
                  tmp_min = tmp;
                }
            }

          result.elem (j) = tmp_min;
          idx_arg.elem (j) = (octave::math::isnan (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 (dim_vector (1, nc));

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

          double tmp_max = octave::numeric_limits<double>::NaN ();

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

              if (! octave::math::isnan (tmp_max))
                break;
            }

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

              if (octave::math::isnan (tmp))
                continue;
              else if (tmp > tmp_max)
                {
                  idx_i = i;
                  tmp_max = tmp;
                }
            }

          result.elem (j) = tmp_max;
          idx_arg.elem (j) = (octave::math::isnan (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_value<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_value<double> (is);
            if (is)
              a.elem (i, j) = tmp;
            else
              return is;
          }
    }

  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.

  octave::math::schur<Matrix> as (a, "U");
  octave::math::schur<Matrix> bs (b, "U");

  // Transform c to new coordinates.

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

  Matrix ub = bs.unitary_schur_matrix ();
  Matrix sch_b = bs.schur_matrix ();

  Matrix cx = ua.transpose () * c * ub;

  // Solve the sylvester equation, back-transform, and return the solution.

  F77_INT a_nr = octave::to_f77_int (a.rows ());
  F77_INT b_nr = octave::to_f77_int (b.rows ());

  double scale;
  F77_INT 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, Mt, rvt
%! M = randn (10,10) + 100*eye (10,10);
%! Mt = M';
%! cv = randn (10,1);
%! rv = randn (1,10);
%! rvt = rv';
%!assert ([M*cv,M*cv], M*[cv,cv], 2e-13)
%!assert ([M'*cv,M'*cv], M'*[cv,cv], 2e-13)
%!assert ([rv*M;rv*M], [rv;rv]*M, 2e-13)
%!assert ([rv*M';rv*M'], [rv;rv]*M', 2e-13)
%!assert (2*rv*cv, [rv,rv]*[cv;cv], 2e-13)
%!assert (M'\cv, Mt\cv, 1e-14)
%!assert (M'\rv', Mt\rvt, 1e-14)

*/

static inline char
get_blas_trans_arg (bool trans)
{
  return trans ? 'T' : 'N';
}

// the general GEMM operation

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

  bool tra = transa != blas_no_trans;
  bool trb = transb != blas_no_trans;

  F77_INT a_nr = octave::to_f77_int (tra ? a.cols () : a.rows ());
  F77_INT a_nc = octave::to_f77_int (tra ? a.rows () : a.cols ());

  F77_INT b_nr = octave::to_f77_int (trb ? b.cols () : b.rows ());
  F77_INT b_nc = octave::to_f77_int (trb ? b.rows () : b.cols ());

  if (a_nc != b_nr)
    octave::err_nonconformant ("operator *", a_nr, a_nc, b_nr, b_nc);

  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 && tra != trb)
    {
      F77_INT lda = octave::to_f77_int (a.rows ());

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

      const char ctra = get_blas_trans_arg (tra);
      F77_XFCN (dsyrk, DSYRK, (F77_CONST_CHAR_ARG2 ("U", 1),
                               F77_CONST_CHAR_ARG2 (&ctra, 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
    {
      F77_INT lda = octave::to_f77_int (a.rows ());
      F77_INT tda = octave::to_f77_int (a.cols ());
      F77_INT ldb = octave::to_f77_int (b.rows ());
      F77_INT tdb = octave::to_f77_int (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 ctra = get_blas_trans_arg (tra);
              F77_XFCN (dgemv, DGEMV, (F77_CONST_CHAR_ARG2 (&ctra, 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 crevtrb = get_blas_trans_arg (! trb);
          F77_XFCN (dgemv, DGEMV, (F77_CONST_CHAR_ARG2 (&crevtrb, 1),
                                   ldb, tdb, 1.0,  b.data (), ldb,
                                   a.data (), 1, 0.0, c, 1
                                   F77_CHAR_ARG_LEN (1)));
        }
      else
        {
          const char ctra = get_blas_trans_arg (tra);
          const char ctrb = get_blas_trans_arg (trb);
          F77_XFCN (dgemm, DGEMM, (F77_CONST_CHAR_ARG2 (&ctra, 1),
                                   F77_CONST_CHAR_ARG2 (&ctrb, 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 (a, 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) = octave::math::min (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) = octave::math::min (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 requires same size arguments");

  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) = octave::math::min (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) = octave::math::max (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) = octave::math::max (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 requires same size arguments");

  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) = octave::math::max (a(i, j), b(i, j));
      }

  return result;
}

Matrix linspace (const ColumnVector& x1,
                 const ColumnVector& x2,
                 octave_idx_type n)

{
  octave_idx_type m = x1.numel ();

  if (x2.numel () != m)
    (*current_liboctave_error_handler)
      ("linspace: vectors must be of equal length");

  Matrix retval;

  if (n < 1)
    {
      retval.clear (m, 0);
      return retval;
    }

  retval.clear (m, n);
  for (octave_idx_type i = 0; i < m; i++)
    retval.xelem (i, 0) = x1(i);

  // The last column is unused so temporarily store delta there
  double *delta = &retval.xelem (0, n-1);
  for (octave_idx_type i = 0; i < m; i++)
    delta[i] = (x1(i) == x2(i)) ? 0 : (x2(i) - x1(i)) / (n - 1);

  for (octave_idx_type j = 1; j < n-1; j++)
    for (octave_idx_type i = 0; i < m; i++)
      retval.xelem (i, j) = x1(i) + j*delta[i];

  for (octave_idx_type i = 0; i < m; i++)
    retval.xelem (i, n-1) = x2(i);

  return retval;
}

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

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

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