/*

Copyright (C) 1996-2018 John W. Eaton
Copyright (C) 2009 VZLU Prague

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 "CColVector.h"
#include "CMatrix.h"
#include "PermMatrix.h"
#include "dColVector.h"
#include "dMatrix.h"
#include "fCColVector.h"
#include "fCMatrix.h"
#include "fColVector.h"
#include "fMatrix.h"
#include "lo-error.h"
#include "lo-lapack-proto.h"
#include "lo-qrupdate-proto.h"
#include "lu.h"
#include "oct-locbuf.h"

namespace octave
{
  namespace math
  {
    // FIXME: PermMatrix::col_perm_vec returns Array<octave_idx_type>
    // but ipvt is an Array<octave_f77_int_type>.  This could cause
    // trouble for large arrays if octave_f77_int_type is 32-bits but
    // octave_idx_type is 64.  Since this constructor is called from
    // Fluupdate, it could be given values that are out of range.  We
    // should ensure that the values are within range here.

    template <typename T>
    lu<T>::lu (const T& l, const T& u, const PermMatrix& p)
      : a_fact (u), l_fact (l), ipvt (p.transpose ().col_perm_vec ())
    {
      if (l.columns () != u.rows ())
        (*current_liboctave_error_handler) ("lu: dimension mismatch");
    }

    template <typename T>
    bool
    lu<T>::packed (void) const
    {
      return l_fact.dims () == dim_vector ();
    }

    template <typename T>
    void
    lu<T>::unpack (void)
    {
      if (packed ())
        {
          l_fact = L ();
          a_fact = U (); // FIXME: sub-optimal

          // FIXME: getp returns Array<octave_idx_type> but ipvt is
          // Array<octave_f77_int_type>.  However, getp produces its
          // result from a valid ipvt array so validation should not be
          // necessary.  OTOH, it might be better to have a version of
          // getp that doesn't cause us to convert from
          // Array<octave_f77_int_type> to Array<octave_idx_type> and
          // back again.

          ipvt = getp ();
        }
    }

    template <typename T>
    T
    lu<T>::L (void) const
    {
      if (packed ())
        {
          octave_idx_type a_nr = a_fact.rows ();
          octave_idx_type a_nc = a_fact.columns ();
          octave_idx_type mn = (a_nr < a_nc ? a_nr : a_nc);

          T l (a_nr, mn, ELT_T (0.0));

          for (octave_idx_type i = 0; i < a_nr; i++)
            {
              if (i < a_nc)
                l.xelem (i, i) = 1.0;

              for (octave_idx_type j = 0; j < (i < a_nc ? i : a_nc); j++)
                l.xelem (i, j) = a_fact.xelem (i, j);
            }

          return l;
        }
      else
        return l_fact;
    }

    template <typename T>
    T
    lu<T>::U (void) const
    {
      if (packed ())
        {
          octave_idx_type a_nr = a_fact.rows ();
          octave_idx_type a_nc = a_fact.columns ();
          octave_idx_type mn = (a_nr < a_nc ? a_nr : a_nc);

          T u (mn, a_nc, ELT_T (0.0));

          for (octave_idx_type i = 0; i < mn; i++)
            {
              for (octave_idx_type j = i; j < a_nc; j++)
                u.xelem (i, j) = a_fact.xelem (i, j);
            }

          return u;
        }
      else
        return a_fact;
    }

    template <typename T>
    T
    lu<T>::Y (void) const
    {
      if (! packed ())
        (*current_liboctave_error_handler)
          ("lu: Y () not implemented for unpacked form");

      return a_fact;
    }

    template <typename T>
    Array<octave_idx_type>
    lu<T>::getp (void) const
    {
      if (packed ())
        {
          octave_idx_type a_nr = a_fact.rows ();

          Array<octave_idx_type> pvt (dim_vector (a_nr, 1));

          for (octave_idx_type i = 0; i < a_nr; i++)
            pvt.xelem (i) = i;

          for (octave_idx_type i = 0; i < ipvt.numel (); i++)
            {
              octave_idx_type k = ipvt.xelem (i);

              if (k != i)
                {
                  octave_idx_type tmp = pvt.xelem (k);
                  pvt.xelem (k) = pvt.xelem (i);
                  pvt.xelem (i) = tmp;
                }
            }

          return pvt;
        }
      else
        return ipvt;
    }

    template <typename T>
    PermMatrix
    lu<T>::P (void) const
    {
      return PermMatrix (getp (), false);
    }

    template <typename T>
    ColumnVector
    lu<T>::P_vec (void) const
    {
      octave_idx_type a_nr = a_fact.rows ();

      ColumnVector p (a_nr);

      Array<octave_idx_type> pvt = getp ();

      for (octave_idx_type i = 0; i < a_nr; i++)
        p.xelem (i) = static_cast<double> (pvt.xelem (i) + 1);

      return p;
    }

    template <typename T>
    bool
    lu<T>::regular (void) const
    {
      bool retval = true;

      octave_idx_type k = std::min (a_fact.rows (), a_fact.columns ());

      for (octave_idx_type i = 0; i < k; i++)
        {
          if (a_fact(i, i) == ELT_T ())
            {
              retval = false;
              break;
            }
        }

      return retval;
    }

#if ! defined (HAVE_QRUPDATE_LUU)

    template <typename T>
    void
    lu<T>::update (const VT&, const VT&)
    {
      (*current_liboctave_error_handler)
        ("luupdate: support for qrupdate with LU updates "
         "was unavailable or disabled when liboctave was built");
    }

    template <typename T>
    void
    lu<T>::update (const T&, const T&)
    {
      (*current_liboctave_error_handler)
        ("luupdate: support for qrupdate with LU updates "
         "was unavailable or disabled when liboctave was built");
    }

    template <typename T>
    void
    lu<T>::update_piv (const VT&, const VT&)
    {
      (*current_liboctave_error_handler)
        ("luupdate: support for qrupdate with LU updates "
         "was unavailable or disabled when liboctave was built");
    }

    template <typename T>
    void
    lu<T>::update_piv (const T&, const T&)
    {
      (*current_liboctave_error_handler)
        ("luupdate: support for qrupdate with LU updates "
         "was unavailable or disabled when liboctave was built");
    }

#endif

    // Specializations.

    template <>
    lu<Matrix>::lu (const Matrix& a)
    {
      F77_INT a_nr = to_f77_int (a.rows ());
      F77_INT a_nc = to_f77_int (a.columns ());
      F77_INT mn = (a_nr < a_nc ? a_nr : a_nc);

      ipvt.resize (dim_vector (mn, 1));
      F77_INT *pipvt = ipvt.fortran_vec ();

      a_fact = a;
      double *tmp_data = a_fact.fortran_vec ();

      F77_INT info = 0;

      F77_XFCN (dgetrf, DGETRF, (a_nr, a_nc, tmp_data, a_nr, pipvt, info));

      for (F77_INT i = 0; i < mn; i++)
        pipvt[i] -= 1;
    }

#if defined (HAVE_QRUPDATE_LUU)

    template <>
    void
    lu<Matrix>::update (const ColumnVector& u, const ColumnVector& v)
    {
      if (packed ())
        unpack ();

      Matrix& l = l_fact;
      Matrix& r = a_fact;

      F77_INT m = to_f77_int (l.rows ());
      F77_INT n = to_f77_int (r.columns ());
      F77_INT k = to_f77_int (l.columns ());

      F77_INT u_nel = to_f77_int (u.numel ());
      F77_INT v_nel = to_f77_int (v.numel ());

      if (u_nel != m || v_nel != n)
        (*current_liboctave_error_handler) ("luupdate: dimensions mismatch");

      ColumnVector utmp = u;
      ColumnVector vtmp = v;
      F77_XFCN (dlu1up, DLU1UP, (m, n, l.fortran_vec (), m, r.fortran_vec (),
                                 k, utmp.fortran_vec (), vtmp.fortran_vec ()));
    }

    template <>
    void
    lu<Matrix>::update (const Matrix& u, const Matrix& v)
    {
      if (packed ())
        unpack ();

      Matrix& l = l_fact;
      Matrix& r = a_fact;

      F77_INT m = to_f77_int (l.rows ());
      F77_INT n = to_f77_int (r.columns ());
      F77_INT k = to_f77_int (l.columns ());

      F77_INT u_nr = to_f77_int (u.rows ());
      F77_INT u_nc = to_f77_int (u.columns ());

      F77_INT v_nr = to_f77_int (v.rows ());
      F77_INT v_nc = to_f77_int (v.columns ());

      if (u_nr != m || v_nr != n || u_nc != v_nc)
        (*current_liboctave_error_handler) ("luupdate: dimensions mismatch");

      for (volatile F77_INT i = 0; i < u_nc; i++)
        {
          ColumnVector utmp = u.column (i);
          ColumnVector vtmp = v.column (i);
          F77_XFCN (dlu1up, DLU1UP, (m, n, l.fortran_vec (),
                                     m, r.fortran_vec (), k,
                                     utmp.fortran_vec (), vtmp.fortran_vec ()));
        }
    }

    template <>
    void
    lu<Matrix>::update_piv (const ColumnVector& u, const ColumnVector& v)
    {
      if (packed ())
        unpack ();

      Matrix& l = l_fact;
      Matrix& r = a_fact;

      F77_INT m = to_f77_int (l.rows ());
      F77_INT n = to_f77_int (r.columns ());
      F77_INT k = to_f77_int (l.columns ());

      F77_INT u_nel = to_f77_int (u.numel ());
      F77_INT v_nel = to_f77_int (v.numel ());

      if (u_nel != m || v_nel != n)
        (*current_liboctave_error_handler) ("luupdate: dimensions mismatch");

      ColumnVector utmp = u;
      ColumnVector vtmp = v;
      OCTAVE_LOCAL_BUFFER (double, w, m);
      for (F77_INT i = 0; i < m; i++) ipvt(i) += 1; // increment
      F77_XFCN (dlup1up, DLUP1UP, (m, n, l.fortran_vec (),
                                   m, r.fortran_vec (), k,
                                   ipvt.fortran_vec (),
                                   utmp.data (), vtmp.data (), w));
      for (F77_INT i = 0; i < m; i++) ipvt(i) -= 1; // decrement
    }

    template <>
    void
    lu<Matrix>::update_piv (const Matrix& u, const Matrix& v)
    {
      if (packed ())
        unpack ();

      Matrix& l = l_fact;
      Matrix& r = a_fact;

      F77_INT m = to_f77_int (l.rows ());
      F77_INT n = to_f77_int (r.columns ());
      F77_INT k = to_f77_int (l.columns ());

      F77_INT u_nr = to_f77_int (u.rows ());
      F77_INT u_nc = to_f77_int (u.columns ());

      F77_INT v_nr = to_f77_int (v.rows ());
      F77_INT v_nc = to_f77_int (v.columns ());

      if (u_nr != m || v_nr != n || u_nc != v_nc)
        (*current_liboctave_error_handler) ("luupdate: dimensions mismatch");

      OCTAVE_LOCAL_BUFFER (double, w, m);
      for (F77_INT i = 0; i < m; i++) ipvt(i) += 1; // increment
      for (volatile F77_INT i = 0; i < u_nc; i++)
        {
          ColumnVector utmp = u.column (i);
          ColumnVector vtmp = v.column (i);
          F77_XFCN (dlup1up, DLUP1UP, (m, n, l.fortran_vec (),
                                       m, r.fortran_vec (), k,
                                       ipvt.fortran_vec (),
                                       utmp.data (), vtmp.data (), w));
        }
      for (F77_INT i = 0; i < m; i++) ipvt(i) -= 1; // decrement
    }

#endif

    template <>
    lu<FloatMatrix>::lu (const FloatMatrix& a)
    {
      F77_INT a_nr = to_f77_int (a.rows ());
      F77_INT a_nc = to_f77_int (a.columns ());
      F77_INT mn = (a_nr < a_nc ? a_nr : a_nc);

      ipvt.resize (dim_vector (mn, 1));
      F77_INT *pipvt = ipvt.fortran_vec ();

      a_fact = a;
      float *tmp_data = a_fact.fortran_vec ();

      F77_INT info = 0;

      F77_XFCN (sgetrf, SGETRF, (a_nr, a_nc, tmp_data, a_nr, pipvt, info));

      for (F77_INT i = 0; i < mn; i++)
        pipvt[i] -= 1;
    }

#if defined (HAVE_QRUPDATE_LUU)

    template <>
    void
    lu<FloatMatrix>::update (const FloatColumnVector& u,
                             const FloatColumnVector& v)
    {
      if (packed ())
        unpack ();

      FloatMatrix& l = l_fact;
      FloatMatrix& r = a_fact;

      F77_INT m = to_f77_int (l.rows ());
      F77_INT n = to_f77_int (r.columns ());
      F77_INT k = to_f77_int (l.columns ());

      F77_INT u_nel = to_f77_int (u.numel ());
      F77_INT v_nel = to_f77_int (v.numel ());

      if (u_nel != m || v_nel != n)
        (*current_liboctave_error_handler) ("luupdate: dimensions mismatch");

      FloatColumnVector utmp = u;
      FloatColumnVector vtmp = v;
      F77_XFCN (slu1up, SLU1UP, (m, n, l.fortran_vec (),
                                 m, r.fortran_vec (), k,
                                 utmp.fortran_vec (), vtmp.fortran_vec ()));
    }

    template <>
    void
    lu<FloatMatrix>::update (const FloatMatrix& u, const FloatMatrix& v)
    {
      if (packed ())
        unpack ();

      FloatMatrix& l = l_fact;
      FloatMatrix& r = a_fact;

      F77_INT m = to_f77_int (l.rows ());
      F77_INT n = to_f77_int (r.columns ());
      F77_INT k = to_f77_int (l.columns ());

      F77_INT u_nr = to_f77_int (u.rows ());
      F77_INT u_nc = to_f77_int (u.columns ());

      F77_INT v_nr = to_f77_int (v.rows ());
      F77_INT v_nc = to_f77_int (v.columns ());

      if (u_nr != m || v_nr != n || u_nc != v_nc)
        (*current_liboctave_error_handler) ("luupdate: dimensions mismatch");

      for (volatile F77_INT i = 0; i < u_nc; i++)
        {
          FloatColumnVector utmp = u.column (i);
          FloatColumnVector vtmp = v.column (i);
          F77_XFCN (slu1up, SLU1UP, (m, n, l.fortran_vec (),
                                     m, r.fortran_vec (), k,
                                     utmp.fortran_vec (), vtmp.fortran_vec ()));
        }
    }

    template <>
    void
    lu<FloatMatrix>::update_piv (const FloatColumnVector& u,
                                 const FloatColumnVector& v)
    {
      if (packed ())
        unpack ();

      FloatMatrix& l = l_fact;
      FloatMatrix& r = a_fact;

      F77_INT m = to_f77_int (l.rows ());
      F77_INT n = to_f77_int (r.columns ());
      F77_INT k = to_f77_int (l.columns ());

      F77_INT u_nel = to_f77_int (u.numel ());
      F77_INT v_nel = to_f77_int (v.numel ());

      if (u_nel != m || v_nel != n)
        (*current_liboctave_error_handler) ("luupdate: dimensions mismatch");

      FloatColumnVector utmp = u;
      FloatColumnVector vtmp = v;
      OCTAVE_LOCAL_BUFFER (float, w, m);
      for (F77_INT i = 0; i < m; i++) ipvt(i) += 1; // increment
      F77_XFCN (slup1up, SLUP1UP, (m, n, l.fortran_vec (),
                                   m, r.fortran_vec (), k,
                                   ipvt.fortran_vec (),
                                   utmp.data (), vtmp.data (), w));
      for (F77_INT i = 0; i < m; i++) ipvt(i) -= 1; // decrement
    }

    template <>
    void
    lu<FloatMatrix>::update_piv (const FloatMatrix& u, const FloatMatrix& v)
    {
      if (packed ())
        unpack ();

      FloatMatrix& l = l_fact;
      FloatMatrix& r = a_fact;

      F77_INT m = to_f77_int (l.rows ());
      F77_INT n = to_f77_int (r.columns ());
      F77_INT k = to_f77_int (l.columns ());

      F77_INT u_nr = to_f77_int (u.rows ());
      F77_INT u_nc = to_f77_int (u.columns ());

      F77_INT v_nr = to_f77_int (v.rows ());
      F77_INT v_nc = to_f77_int (v.columns ());

      if (u_nr != m || v_nr != n || u_nc != v_nc)
        (*current_liboctave_error_handler) ("luupdate: dimensions mismatch");

      OCTAVE_LOCAL_BUFFER (float, w, m);
      for (F77_INT i = 0; i < m; i++) ipvt(i) += 1; // increment
      for (volatile F77_INT i = 0; i < u_nc; i++)
        {
          FloatColumnVector utmp = u.column (i);
          FloatColumnVector vtmp = v.column (i);
          F77_XFCN (slup1up, SLUP1UP, (m, n, l.fortran_vec (),
                                       m, r.fortran_vec (), k,
                                       ipvt.fortran_vec (),
                                       utmp.data (), vtmp.data (), w));
        }
      for (F77_INT i = 0; i < m; i++) ipvt(i) -= 1; // decrement
    }

#endif

    template <>
    lu<ComplexMatrix>::lu (const ComplexMatrix& a)
    {
      F77_INT a_nr = to_f77_int (a.rows ());
      F77_INT a_nc = to_f77_int (a.columns ());
      F77_INT mn = (a_nr < a_nc ? a_nr : a_nc);

      ipvt.resize (dim_vector (mn, 1));
      F77_INT *pipvt = ipvt.fortran_vec ();

      a_fact = a;
      Complex *tmp_data = a_fact.fortran_vec ();

      F77_INT info = 0;

      F77_XFCN (zgetrf, ZGETRF, (a_nr, a_nc, F77_DBLE_CMPLX_ARG (tmp_data),
                                 a_nr, pipvt, info));

      for (F77_INT i = 0; i < mn; i++)
        pipvt[i] -= 1;
    }

#if defined (HAVE_QRUPDATE_LUU)

    template <>
    void
    lu<ComplexMatrix>::update (const ComplexColumnVector& u,
                               const ComplexColumnVector& v)
    {
      if (packed ())
        unpack ();

      ComplexMatrix& l = l_fact;
      ComplexMatrix& r = a_fact;

      F77_INT m = to_f77_int (l.rows ());
      F77_INT n = to_f77_int (r.columns ());
      F77_INT k = to_f77_int (l.columns ());

      F77_INT u_nel = to_f77_int (u.numel ());
      F77_INT v_nel = to_f77_int (v.numel ());

      if (u_nel != m || v_nel != n)
        (*current_liboctave_error_handler) ("luupdate: dimensions mismatch");

      ComplexColumnVector utmp = u;
      ComplexColumnVector vtmp = v;
      F77_XFCN (zlu1up, ZLU1UP, (m, n, F77_DBLE_CMPLX_ARG (l.fortran_vec ()), m,
                                 F77_DBLE_CMPLX_ARG (r.fortran_vec ()), k,
                                 F77_DBLE_CMPLX_ARG (utmp.fortran_vec ()),
                                 F77_DBLE_CMPLX_ARG (vtmp.fortran_vec ())));
    }

    template <>
    void
    lu<ComplexMatrix>::update (const ComplexMatrix& u, const ComplexMatrix& v)
    {
      if (packed ())
        unpack ();

      ComplexMatrix& l = l_fact;
      ComplexMatrix& r = a_fact;

      F77_INT m = to_f77_int (l.rows ());
      F77_INT n = to_f77_int (r.columns ());
      F77_INT k = to_f77_int (l.columns ());

      F77_INT u_nr = to_f77_int (u.rows ());
      F77_INT u_nc = to_f77_int (u.columns ());

      F77_INT v_nr = to_f77_int (v.rows ());
      F77_INT v_nc = to_f77_int (v.columns ());

      if (u_nr != m || v_nr != n || u_nc != v_nc)
        (*current_liboctave_error_handler) ("luupdate: dimensions mismatch");

      for (volatile F77_INT i = 0; i < u_nc; i++)
        {
          ComplexColumnVector utmp = u.column (i);
          ComplexColumnVector vtmp = v.column (i);
          F77_XFCN (zlu1up, ZLU1UP, (m, n,
                                     F77_DBLE_CMPLX_ARG (l.fortran_vec ()),
                                     m, F77_DBLE_CMPLX_ARG (r.fortran_vec ()),
                                     k,
                                     F77_DBLE_CMPLX_ARG (utmp.fortran_vec ()),
                                     F77_DBLE_CMPLX_ARG (vtmp.fortran_vec ())));
        }
    }

    template <>
    void
    lu<ComplexMatrix>::update_piv (const ComplexColumnVector& u,
                                   const ComplexColumnVector& v)
    {
      if (packed ())
        unpack ();

      ComplexMatrix& l = l_fact;
      ComplexMatrix& r = a_fact;

      F77_INT m = to_f77_int (l.rows ());
      F77_INT n = to_f77_int (r.columns ());
      F77_INT k = to_f77_int (l.columns ());

      F77_INT u_nel = to_f77_int (u.numel ());
      F77_INT v_nel = to_f77_int (v.numel ());

      if (u_nel != m || v_nel != n)
        (*current_liboctave_error_handler) ("luupdate: dimensions mismatch");

      ComplexColumnVector utmp = u;
      ComplexColumnVector vtmp = v;
      OCTAVE_LOCAL_BUFFER (Complex, w, m);
      for (F77_INT i = 0; i < m; i++) ipvt(i) += 1; // increment
      F77_XFCN (zlup1up, ZLUP1UP, (m, n, F77_DBLE_CMPLX_ARG (l.fortran_vec ()),
                                   m, F77_DBLE_CMPLX_ARG (r.fortran_vec ()), k,
                                   ipvt.fortran_vec (),
                                   F77_CONST_DBLE_CMPLX_ARG (utmp.data ()),
                                   F77_CONST_DBLE_CMPLX_ARG (vtmp.data ()),
                                   F77_DBLE_CMPLX_ARG (w)));
      for (F77_INT i = 0; i < m; i++) ipvt(i) -= 1; // decrement
    }

    template <>
    void
    lu<ComplexMatrix>::update_piv (const ComplexMatrix& u,
                                   const ComplexMatrix& v)
    {
      if (packed ())
        unpack ();

      ComplexMatrix& l = l_fact;
      ComplexMatrix& r = a_fact;

      F77_INT m = to_f77_int (l.rows ());
      F77_INT n = to_f77_int (r.columns ());
      F77_INT k = to_f77_int (l.columns ());

      F77_INT u_nr = to_f77_int (u.rows ());
      F77_INT u_nc = to_f77_int (u.columns ());

      F77_INT v_nr = to_f77_int (v.rows ());
      F77_INT v_nc = to_f77_int (v.columns ());

      if (u_nr != m || v_nr != n || u_nc != v_nc)
        (*current_liboctave_error_handler) ("luupdate: dimensions mismatch");

      OCTAVE_LOCAL_BUFFER (Complex, w, m);
      for (F77_INT i = 0; i < m; i++) ipvt(i) += 1; // increment
      for (volatile F77_INT i = 0; i < u_nc; i++)
        {
          ComplexColumnVector utmp = u.column (i);
          ComplexColumnVector vtmp = v.column (i);
          F77_XFCN (zlup1up, ZLUP1UP, (m, n,
                                       F77_DBLE_CMPLX_ARG (l.fortran_vec ()),
                                       m,
                                       F77_DBLE_CMPLX_ARG (r.fortran_vec ()),
                                       k, ipvt.fortran_vec (),
                                       F77_CONST_DBLE_CMPLX_ARG (utmp.data ()),
                                       F77_CONST_DBLE_CMPLX_ARG (vtmp.data ()),
                                       F77_DBLE_CMPLX_ARG (w)));
        }
      for (F77_INT i = 0; i < m; i++) ipvt(i) -= 1; // decrement
    }

#endif

    template <>
    lu<FloatComplexMatrix>::lu (const FloatComplexMatrix& a)
    {
      F77_INT a_nr = to_f77_int (a.rows ());
      F77_INT a_nc = to_f77_int (a.columns ());
      F77_INT mn = (a_nr < a_nc ? a_nr : a_nc);

      ipvt.resize (dim_vector (mn, 1));
      F77_INT *pipvt = ipvt.fortran_vec ();

      a_fact = a;
      FloatComplex *tmp_data = a_fact.fortran_vec ();

      F77_INT info = 0;

      F77_XFCN (cgetrf, CGETRF, (a_nr, a_nc, F77_CMPLX_ARG (tmp_data), a_nr,
                                 pipvt, info));

      for (F77_INT i = 0; i < mn; i++)
        pipvt[i] -= 1;
    }

#if defined (HAVE_QRUPDATE_LUU)

    template <>
    void
    lu<FloatComplexMatrix>::update (const FloatComplexColumnVector& u,
                                    const FloatComplexColumnVector& v)
    {
      if (packed ())
        unpack ();

      FloatComplexMatrix& l = l_fact;
      FloatComplexMatrix& r = a_fact;

      F77_INT m = to_f77_int (l.rows ());
      F77_INT n = to_f77_int (r.columns ());
      F77_INT k = to_f77_int (l.columns ());

      F77_INT u_nel = to_f77_int (u.numel ());
      F77_INT v_nel = to_f77_int (v.numel ());

      if (u_nel != m || v_nel != n)
        (*current_liboctave_error_handler) ("luupdate: dimensions mismatch");

      FloatComplexColumnVector utmp = u;
      FloatComplexColumnVector vtmp = v;
      F77_XFCN (clu1up, CLU1UP, (m, n, F77_CMPLX_ARG (l.fortran_vec ()), m,
                                 F77_CMPLX_ARG (r.fortran_vec ()), k,
                                 F77_CMPLX_ARG (utmp.fortran_vec ()),
                                 F77_CMPLX_ARG (vtmp.fortran_vec ())));
    }

    template <>
    void
    lu<FloatComplexMatrix>::update (const FloatComplexMatrix& u,
                                    const FloatComplexMatrix& v)
    {
      if (packed ())
        unpack ();

      FloatComplexMatrix& l = l_fact;
      FloatComplexMatrix& r = a_fact;

      F77_INT m = to_f77_int (l.rows ());
      F77_INT n = to_f77_int (r.columns ());
      F77_INT k = to_f77_int (l.columns ());

      F77_INT u_nr = to_f77_int (u.rows ());
      F77_INT u_nc = to_f77_int (u.columns ());

      F77_INT v_nr = to_f77_int (v.rows ());
      F77_INT v_nc = to_f77_int (v.columns ());

      if (u_nr != m || v_nr != n || u_nc != v_nc)
        (*current_liboctave_error_handler) ("luupdate: dimensions mismatch");

      for (volatile F77_INT i = 0; i < u_nc; i++)
        {
          FloatComplexColumnVector utmp = u.column (i);
          FloatComplexColumnVector vtmp = v.column (i);
          F77_XFCN (clu1up, CLU1UP, (m, n, F77_CMPLX_ARG (l.fortran_vec ()),
                                     m, F77_CMPLX_ARG (r.fortran_vec ()), k,
                                     F77_CMPLX_ARG (utmp.fortran_vec ()),
                                     F77_CMPLX_ARG (vtmp.fortran_vec ())));
        }
    }

    template <>
    void
    lu<FloatComplexMatrix>::update_piv (const FloatComplexColumnVector& u,
                                        const FloatComplexColumnVector& v)
    {
      if (packed ())
        unpack ();

      FloatComplexMatrix& l = l_fact;
      FloatComplexMatrix& r = a_fact;

      F77_INT m = to_f77_int (l.rows ());
      F77_INT n = to_f77_int (r.columns ());
      F77_INT k = to_f77_int (l.columns ());

      F77_INT u_nel = to_f77_int (u.numel ());
      F77_INT v_nel = to_f77_int (v.numel ());

      if (u_nel != m || v_nel != n)
        (*current_liboctave_error_handler) ("luupdate: dimensions mismatch");

      FloatComplexColumnVector utmp = u;
      FloatComplexColumnVector vtmp = v;
      OCTAVE_LOCAL_BUFFER (FloatComplex, w, m);
      for (F77_INT i = 0; i < m; i++) ipvt(i) += 1; // increment
      F77_XFCN (clup1up, CLUP1UP, (m, n, F77_CMPLX_ARG (l.fortran_vec ()),
                                   m, F77_CMPLX_ARG (r.fortran_vec ()), k,
                                   ipvt.fortran_vec (),
                                   F77_CONST_CMPLX_ARG (utmp.data ()),
                                   F77_CONST_CMPLX_ARG (vtmp.data ()),
                                   F77_CMPLX_ARG (w)));
      for (F77_INT i = 0; i < m; i++) ipvt(i) -= 1; // decrement
    }

    template <>
    void
    lu<FloatComplexMatrix>::update_piv (const FloatComplexMatrix& u,
                                        const FloatComplexMatrix& v)
    {
      if (packed ())
        unpack ();

      FloatComplexMatrix& l = l_fact;
      FloatComplexMatrix& r = a_fact;

      F77_INT m = to_f77_int (l.rows ());
      F77_INT n = to_f77_int (r.columns ());
      F77_INT k = to_f77_int (l.columns ());

      F77_INT u_nr = to_f77_int (u.rows ());
      F77_INT u_nc = to_f77_int (u.columns ());

      F77_INT v_nr = to_f77_int (v.rows ());
      F77_INT v_nc = to_f77_int (v.columns ());

      if (u_nr != m || v_nr != n || u_nc != v_nc)
        (*current_liboctave_error_handler) ("luupdate: dimensions mismatch");

      OCTAVE_LOCAL_BUFFER (FloatComplex, w, m);
      for (F77_INT i = 0; i < m; i++) ipvt(i) += 1; // increment
      for (volatile F77_INT i = 0; i < u_nc; i++)
        {
          FloatComplexColumnVector utmp = u.column (i);
          FloatComplexColumnVector vtmp = v.column (i);
          F77_XFCN (clup1up, CLUP1UP, (m, n, F77_CMPLX_ARG (l.fortran_vec ()),
                                       m, F77_CMPLX_ARG (r.fortran_vec ()), k,
                                       ipvt.fortran_vec (),
                                       F77_CONST_CMPLX_ARG (utmp.data ()),
                                       F77_CONST_CMPLX_ARG (vtmp.data ()),
                                       F77_CMPLX_ARG (w)));
        }
      for (F77_INT i = 0; i < m; i++) ipvt(i) -= 1; // decrement
    }

#endif

    // Instantiations we need.

    template class lu<Matrix>;

    template class lu<FloatMatrix>;

    template class lu<ComplexMatrix>;

    template class lu<FloatComplexMatrix>;
  }
}
