/*

Copyright (C) 1994, 1995, 1996, 1997, 2002, 2003, 2004, 2005, 2007
              John W. Eaton
Copyright (C) 2008, 2009 Jaroslav Hajek
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
<http://www.gnu.org/licenses/>.

*/

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

#include "dbleQR.h"
#include "f77-fcn.h"
#include "lo-error.h"
#include "Range.h"
#include "idx-vector.h"
#include "oct-locbuf.h"

extern "C"
{
  F77_RET_T
  F77_FUNC (dgeqrf, DGEQRF) (const octave_idx_type&, const octave_idx_type&, double*, const octave_idx_type&,
			     double*, double*, const octave_idx_type&, octave_idx_type&); 

  F77_RET_T
  F77_FUNC (dorgqr, DORGQR) (const octave_idx_type&, const octave_idx_type&, const octave_idx_type&, double*,
			     const octave_idx_type&, double*, double*, const octave_idx_type&, octave_idx_type&);

#ifdef HAVE_QRUPDATE

  F77_RET_T
  F77_FUNC (dqr1up, DQR1UP) (const octave_idx_type&, const octave_idx_type&, const octave_idx_type&, 
                             double*, const octave_idx_type&, double*, const octave_idx_type&,
                             double*, double*, double*);

  F77_RET_T
  F77_FUNC (dqrinc, DQRINC) (const octave_idx_type&, const octave_idx_type&, const octave_idx_type&, 
                             double*, const octave_idx_type&, double*, const octave_idx_type&,
                             const octave_idx_type&, const double*, double*);

  F77_RET_T
  F77_FUNC (dqrdec, DQRDEC) (const octave_idx_type&, const octave_idx_type&, const octave_idx_type&, 
                             double*, const octave_idx_type&, double*, const octave_idx_type&,
                             const octave_idx_type&, double*);

  F77_RET_T
  F77_FUNC (dqrinr, DQRINR) (const octave_idx_type&, const octave_idx_type&, 
                             double*, const octave_idx_type&, double*, const octave_idx_type&,
                             const octave_idx_type&, const double*, double*);

  F77_RET_T
  F77_FUNC (dqrder, DQRDER) (const octave_idx_type&, const octave_idx_type&, 
                             double*, const octave_idx_type&, double*, const octave_idx_type&,
                             const octave_idx_type&, double*);

  F77_RET_T
  F77_FUNC (dqrshc, DQRSHC) (const octave_idx_type&, const octave_idx_type&, const octave_idx_type&,
                             double*, const octave_idx_type&, double*, const octave_idx_type&,
                             const octave_idx_type&, const octave_idx_type&,
                             double*);

#endif
}

QR::QR (const Matrix& a, QR::type qr_type)
  : q (), r ()
{
  init (a, qr_type);
}

void
QR::init (const Matrix& a, QR::type qr_type)
{
  octave_idx_type m = a.rows ();
  octave_idx_type n = a.cols ();

  octave_idx_type min_mn = m < n ? m : n;
  OCTAVE_LOCAL_BUFFER (double, tau, min_mn);

  octave_idx_type info = 0;

  Matrix afact = a;
  if (m > n && qr_type == QR::std)
    afact.resize (m, m);

  if (m > 0)
    {
      // workspace query.
      double rlwork;
      F77_XFCN (dgeqrf, DGEQRF, (m, n, afact.fortran_vec (), m, tau, &rlwork, -1, info));

      // allocate buffer and do the job.
      octave_idx_type lwork = rlwork; lwork = std::max (lwork, 1);
      OCTAVE_LOCAL_BUFFER (double, work, lwork);
      F77_XFCN (dgeqrf, DGEQRF, (m, n, afact.fortran_vec (), m, tau, work, lwork, info));
    }

  form (n, afact, tau, qr_type);
}

void QR::form (octave_idx_type n, Matrix& afact, 
               double *tau, QR::type qr_type)
{
  octave_idx_type m = afact.rows (), min_mn = std::min (m, n);
  octave_idx_type info;

  if (qr_type == QR::raw)
    {
      for (octave_idx_type j = 0; j < min_mn; j++)
	{
	  octave_idx_type limit = j < min_mn - 1 ? j : min_mn - 1;
	  for (octave_idx_type i = limit + 1; i < m; i++)
	    afact.elem (i, j) *= tau[j];
	}

      r = afact;
    }
  else
    {
      // Attempt to minimize copying.
      if (m >= n)
        {
          // afact will become q.
          q = afact;
          octave_idx_type k = qr_type == QR::economy ? n : m;
          r = Matrix (k, n);
          for (octave_idx_type j = 0; j < n; j++)
            {
              octave_idx_type i = 0;
              for (; i <= j; i++)
                r.xelem (i, j) = afact.xelem (i, j);
              for (;i < k; i++)
                r.xelem (i, j) = 0;
            }
          afact = Matrix (); // optimize memory
        }
      else
        {
          // afact will become r.
          q = Matrix (m, m);
          for (octave_idx_type j = 0; j < m; j++)
            for (octave_idx_type i = j + 1; i < m; i++)
              {
                q.xelem (i, j) = afact.xelem (i, j);
                afact.xelem (i, j) = 0;
              }
          r = afact;
        }


      if (m > 0)
        {
          octave_idx_type k = q.columns ();
          // workspace query.
          double rlwork;
          F77_XFCN (dorgqr, DORGQR, (m, k, min_mn, q.fortran_vec (), m, tau,
                                     &rlwork, -1, info));

          // allocate buffer and do the job.
          octave_idx_type lwork = rlwork; lwork = std::max (lwork, 1);
          OCTAVE_LOCAL_BUFFER (double, work, lwork);
          F77_XFCN (dorgqr, DORGQR, (m, k, min_mn, q.fortran_vec (), m, tau,
                                     work, lwork, info));
        }
    }
}

QR::QR (const Matrix& q_arg, const Matrix& r_arg)
{
  octave_idx_type qr = q_arg.rows (), qc = q_arg.columns ();
  octave_idx_type rr = r_arg.rows (), rc = r_arg.columns ();
  if (qc == rr && (qr == qc || (qr > qc && rr == rc)))
    {
      q = q_arg;
      r = r_arg;
    }
  else
    (*current_liboctave_error_handler) ("QR dimensions mismatch");
}

QR::type
QR::get_type (void) const
{
  QR::type retval;
  if (!q.is_empty () && q.is_square ())
    retval = QR::std;
  else if (q.rows () > q.columns () && r.is_square ())
    retval = QR::economy;
  else
    retval = QR::raw;
  return retval;
}

#ifdef HAVE_QRUPDATE

void
QR::update (const ColumnVector& u, const ColumnVector& v)
{
  octave_idx_type m = q.rows ();
  octave_idx_type n = r.columns ();
  octave_idx_type k = q.columns ();

  if (u.length () == m && v.length () == n)
    {
      ColumnVector utmp = u, vtmp = v;
      OCTAVE_LOCAL_BUFFER (double, w, 2*k);
      F77_XFCN (dqr1up, DQR1UP, (m, n, k, q.fortran_vec (), m, r.fortran_vec (), k,
                                 utmp.fortran_vec (), vtmp.fortran_vec (), w));
    }
  else
    (*current_liboctave_error_handler) ("qrupdate: dimensions mismatch");
}

void
QR::update (const Matrix& u, const Matrix& v)
{
  octave_idx_type m = q.rows ();
  octave_idx_type n = r.columns ();
  octave_idx_type k = q.columns ();

  if (u.rows () == m && v.rows () == n && u.cols () == v.cols ())
    {
      OCTAVE_LOCAL_BUFFER (double, w, 2*k);
      for (octave_idx_type i = 0; i < u.cols (); i++)
        {
          ColumnVector utmp = u.column (i), vtmp = v.column (i);
          F77_XFCN (dqr1up, DQR1UP, (m, n, k, q.fortran_vec (), m, r.fortran_vec (), k,
                                     utmp.fortran_vec (), vtmp.fortran_vec (), w));
        }
    }
  else
    (*current_liboctave_error_handler) ("qrupdate: dimensions mismatch");
}

void
QR::insert_col (const ColumnVector& u, octave_idx_type j)
{
  octave_idx_type m = q.rows ();
  octave_idx_type n = r.columns ();
  octave_idx_type k = q.columns ();

  if (u.length () != m)
    (*current_liboctave_error_handler) ("qrinsert: dimensions mismatch");
  else if (j < 0 || j > n) 
    (*current_liboctave_error_handler) ("qrinsert: index out of range");
  else
    {
      if (k < m)
        {
          q.resize (m, k+1);
          r.resize (k+1, n+1);
        }
      else
        {
          r.resize (k, n+1);
        }

      ColumnVector utmp = u;
      OCTAVE_LOCAL_BUFFER (double, w, k);
      F77_XFCN (dqrinc, DQRINC, (m, n, k, q.fortran_vec (), q.rows (),
                                 r.fortran_vec (), r.rows (), j + 1, 
                                 utmp.data (), w));
    }
}

void
QR::insert_col (const Matrix& u, const Array<octave_idx_type>& j)
{
  octave_idx_type m = q.rows ();
  octave_idx_type n = r.columns ();
  octave_idx_type k = q.columns ();

  Array<octave_idx_type> jsi;
  Array<octave_idx_type> js = j.sort (jsi, ASCENDING);
  octave_idx_type nj = js.length ();
  bool dups = false;
  for (octave_idx_type i = 0; i < nj - 1; i++)
    dups = dups && js(i) == js(i+1);

  if (dups)
    (*current_liboctave_error_handler) ("qrinsert: duplicate index detected");
  else if (u.length () != m || u.columns () != nj)
    (*current_liboctave_error_handler) ("qrinsert: dimensions mismatch");
  else if (nj > 0 && (js(0) < 0 || js(nj-1) > n))
    (*current_liboctave_error_handler) ("qrinsert: index out of range");
  else if (nj > 0)
    {
      octave_idx_type kmax = std::min (k + nj, m);
      if (k < m)
        {
          q.resize (m, kmax);
          r.resize (kmax, n + nj);
        }
      else
        {
          r.resize (k, n + nj);
        }

      OCTAVE_LOCAL_BUFFER (double, w, kmax);
      for (octave_idx_type i = 0; i < js.length (); i++)
        {
          ColumnVector utmp = u.column (jsi(i));
          F77_XFCN (dqrinc, DQRINC, (m, n + i, std::min (kmax, k + i), 
                                     q.fortran_vec (), q.rows (),
                                     r.fortran_vec (), r.rows (), js(i) + 1, 
                                     utmp.data (), w));
        }
    }
}

void
QR::delete_col (octave_idx_type j)
{
  octave_idx_type m = q.rows ();
  octave_idx_type k = r.rows ();
  octave_idx_type n = r.columns ();

  if (j < 0 || j > n-1) 
    (*current_liboctave_error_handler) ("qrdelete: index out of range");
  else
    {
      OCTAVE_LOCAL_BUFFER (double, w, k);
      F77_XFCN (dqrdec, DQRDEC, (m, n, k, q.fortran_vec (), q.rows (),
				 r.fortran_vec (), r.rows (), j + 1, w));

      if (k < m)
        {
          q.resize (m, k-1);
          r.resize (k-1, n-1);
        }
      else
        {
          r.resize (k, n-1);
        }
    }
}

void
QR::delete_col (const Array<octave_idx_type>& j)
{
  octave_idx_type m = q.rows ();
  octave_idx_type n = r.columns ();
  octave_idx_type k = q.columns ();

  Array<octave_idx_type> jsi;
  Array<octave_idx_type> js = j.sort (jsi, DESCENDING);
  octave_idx_type nj = js.length ();
  bool dups = false;
  for (octave_idx_type i = 0; i < nj - 1; i++)
    dups = dups && js(i) == js(i+1);

  if (dups)
    (*current_liboctave_error_handler) ("qrinsert: duplicate index detected");
  else if (nj > 0 && (js(0) > n-1 || js(nj-1) < 0))
    (*current_liboctave_error_handler) ("qrinsert: index out of range");
  else if (nj > 0)
    {
      OCTAVE_LOCAL_BUFFER (double, w, k);
      for (octave_idx_type i = 0; i < js.length (); i++)
        {
          F77_XFCN (dqrdec, DQRDEC, (m, n - i, k == m ? k : k - i, 
                                     q.fortran_vec (), q.rows (),
                                     r.fortran_vec (), r.rows (), js(i) + 1, w));
        }
      if (k < m)
        {
          q.resize (m, k - nj);
          r.resize (k - nj, n - nj);
        }
      else
        {
          r.resize (k, n - nj);
        }

    }
}

void
QR::insert_row (const RowVector& u, octave_idx_type j)
{
  octave_idx_type m = r.rows ();
  octave_idx_type n = r.columns ();
  octave_idx_type k = std::min (m, n);

  if (! q.is_square () || u.length () != n)
    (*current_liboctave_error_handler) ("qrinsert: dimensions mismatch");
  else if (j < 0 || j > m) 
    (*current_liboctave_error_handler) ("qrinsert: index out of range");
  else
    {
      q.resize (m + 1, m + 1);
      r.resize (m + 1, n);
      RowVector utmp = u;
      OCTAVE_LOCAL_BUFFER (double, w, k);
      F77_XFCN (dqrinr, DQRINR, (m, n, q.fortran_vec (), q.rows (),
				 r.fortran_vec (), r.rows (), 
                                 j + 1, utmp.fortran_vec (), w));

    }
}

void
QR::delete_row (octave_idx_type j)
{
  octave_idx_type m = r.rows ();
  octave_idx_type n = r.columns ();

  if (! q.is_square ())
    (*current_liboctave_error_handler) ("qrdelete: dimensions mismatch");
  else if (j < 0 || j > m-1) 
    (*current_liboctave_error_handler) ("qrdelete: index out of range");
  else
    {
      OCTAVE_LOCAL_BUFFER (double, w, 2*m);
      F77_XFCN (dqrder, DQRDER, (m, n, q.fortran_vec (), q.rows (),
				 r.fortran_vec (), r.rows (), j + 1,
                                 w));

      q.resize (m - 1, m - 1);
      r.resize (m - 1, n);
    }
}

void
QR::shift_cols (octave_idx_type i, octave_idx_type j)
{
  octave_idx_type m = q.rows ();
  octave_idx_type k = r.rows ();
  octave_idx_type n = r.columns ();

  if (i < 0 || i > n-1 || j < 0 || j > n-1) 
    (*current_liboctave_error_handler) ("qrshift: index out of range");
  else
    {
      OCTAVE_LOCAL_BUFFER (double, w, 2*k);
      F77_XFCN (dqrshc, DQRSHC, (m, n, k, 
                                 q.fortran_vec (), q.rows (),
                                 r.fortran_vec (), r.rows (),
                                 i + 1, j + 1, w));
    }
}

#else

// Replacement update methods.

void
QR::update (const ColumnVector& u, const ColumnVector& v)
{
  warn_qrupdate_once ();

  octave_idx_type m = q.rows ();
  octave_idx_type n = r.columns ();

  if (u.length () == m && v.length () == n)
    {
      init(q*r + Matrix (u) * Matrix (v).transpose (), get_type ());
    }
  else
    (*current_liboctave_error_handler) ("qrupdate: dimensions mismatch");
}

void
QR::update (const Matrix& u, const Matrix& v)
{
  warn_qrupdate_once ();

  octave_idx_type m = q.rows ();
  octave_idx_type n = r.columns ();

  if (u.rows () == m && v.rows () == n && u.cols () == v.cols ())
    {
      init(q*r + u * v.transpose (), get_type ());
    }
  else
    (*current_liboctave_error_handler) ("qrupdate: dimensions mismatch");
}

static
Matrix insert_col (const Matrix& a, octave_idx_type i,
                        const ColumnVector& x)
{
  Matrix retval (a.rows (), a.columns () + 1);
  retval.assign (idx_vector::colon, idx_vector (0, i),
                 a.index (idx_vector::colon, idx_vector (0, i)));
  retval.assign (idx_vector::colon, idx_vector (i), x);
  retval.assign (idx_vector::colon, idx_vector (i+1, retval.columns ()),
                 a.index (idx_vector::colon, idx_vector (i, a.columns ())));
  return retval;
}

static
Matrix insert_row (const Matrix& a, octave_idx_type i,
                        const RowVector& x)
{
  Matrix retval (a.rows () + 1, a.columns ());
  retval.assign (idx_vector (0, i), idx_vector::colon,
                 a.index (idx_vector (0, i), idx_vector::colon));
  retval.assign (idx_vector (i), idx_vector::colon, x);
  retval.assign (idx_vector (i+1, retval.rows ()), idx_vector::colon,
                 a.index (idx_vector (i, a.rows ()), idx_vector::colon));
  return retval;
}

static
Matrix delete_col (const Matrix& a, octave_idx_type i)
{
  Matrix retval = a;
  retval.delete_elements (1, idx_vector (i));
  return retval;
}

static
Matrix delete_row (const Matrix& a, octave_idx_type i)
{
  Matrix retval = a;
  retval.delete_elements (0, idx_vector (i));
  return retval;
}

static
Matrix shift_cols (const Matrix& a, 
                        octave_idx_type i, octave_idx_type j)
{
  octave_idx_type n = a.columns ();
  Array<octave_idx_type> p (n);
  for (octave_idx_type k = 0; k < n; k++) p(k) = k;
  if (i < j)
    {
      for (octave_idx_type k = i; k < j; k++) p(k) = k+1;
      p(j) = i;
    }
  else if (j < i)
    {
      p(j) = i;
      for (octave_idx_type k = j+1; k < i+1; k++) p(k) = k-1;
    }

  return a.index (idx_vector::colon, idx_vector (p));
}

void
QR::insert_col (const ColumnVector& u, octave_idx_type j)
{
  warn_qrupdate_once ();

  octave_idx_type m = q.rows ();
  octave_idx_type n = r.columns ();

  if (u.length () != m)
    (*current_liboctave_error_handler) ("qrinsert: dimensions mismatch");
  else if (j < 0 || j > n) 
    (*current_liboctave_error_handler) ("qrinsert: index out of range");
  else
    {
      init (::insert_col (q*r, j, u), get_type ());
    }
}

void
QR::insert_col (const Matrix& u, const Array<octave_idx_type>& j)
{
  warn_qrupdate_once ();

  octave_idx_type m = q.rows ();
  octave_idx_type n = r.columns ();

  Array<octave_idx_type> jsi;
  Array<octave_idx_type> js = j.sort (jsi, ASCENDING);
  octave_idx_type nj = js.length ();
  bool dups = false;
  for (octave_idx_type i = 0; i < nj - 1; i++)
    dups = dups && js(i) == js(i+1);

  if (dups)
    (*current_liboctave_error_handler) ("qrinsert: duplicate index detected");
  else if (u.length () != m || u.columns () != nj)
    (*current_liboctave_error_handler) ("qrinsert: dimensions mismatch");
  else if (nj > 0 && (js(0) < 0 || js(nj-1) > n))
    (*current_liboctave_error_handler) ("qrinsert: index out of range");
  else if (nj > 0)
    {
      Matrix a = q*r;
      for (octave_idx_type i = 0; i < js.length (); i++)
        a = ::insert_col (a, js(i), u.column (i));
      init (a, get_type ());
    }
}

void
QR::delete_col (octave_idx_type j)
{
  warn_qrupdate_once ();

  octave_idx_type m = q.rows ();
  octave_idx_type n = r.columns ();

  if (j < 0 || j > n-1) 
    (*current_liboctave_error_handler) ("qrdelete: index out of range");
  else
    {
      init (::delete_col (q*r, j), get_type ());
    }
}

void
QR::delete_col (const Array<octave_idx_type>& j)
{
  warn_qrupdate_once ();

  octave_idx_type m = q.rows ();
  octave_idx_type n = r.columns ();

  Array<octave_idx_type> jsi;
  Array<octave_idx_type> js = j.sort (jsi, DESCENDING);
  octave_idx_type nj = js.length ();
  bool dups = false;
  for (octave_idx_type i = 0; i < nj - 1; i++)
    dups = dups && js(i) == js(i+1);

  if (dups)
    (*current_liboctave_error_handler) ("qrinsert: duplicate index detected");
  else if (nj > 0 && (js(0) > n-1 || js(nj-1) < 0))
    (*current_liboctave_error_handler) ("qrinsert: index out of range");
  else if (nj > 0)
    {
      Matrix a = q*r;
      for (octave_idx_type i = 0; i < js.length (); i++)
        a = ::delete_col (a, js(i));
      init (a, get_type ());
    }
}

void
QR::insert_row (const RowVector& u, octave_idx_type j)
{
  warn_qrupdate_once ();

  octave_idx_type m = r.rows ();
  octave_idx_type n = r.columns ();

  if (! q.is_square () || u.length () != n)
    (*current_liboctave_error_handler) ("qrinsert: dimensions mismatch");
  else if (j < 0 || j > m) 
    (*current_liboctave_error_handler) ("qrinsert: index out of range");
  else
    {
      init (::insert_row (q*r, j, u), get_type ());
    }
}

void
QR::delete_row (octave_idx_type j)
{
  octave_idx_type m = r.rows ();
  octave_idx_type n = r.columns ();

  if (! q.is_square ())
    (*current_liboctave_error_handler) ("qrdelete: dimensions mismatch");
  else if (j < 0 || j > m-1) 
    (*current_liboctave_error_handler) ("qrdelete: index out of range");
  else
    {
      init (::delete_row (q*r, j), get_type ());
    }
}

void
QR::shift_cols (octave_idx_type i, octave_idx_type j)
{
  warn_qrupdate_once ();

  octave_idx_type m = q.rows ();
  octave_idx_type n = r.columns ();

  if (i < 0 || i > n-1 || j < 0 || j > n-1) 
    (*current_liboctave_error_handler) ("qrshift: index out of range");
  else
    {
      init (::shift_cols (q*r, i, j), get_type ());
    }
}

void warn_qrupdate_once (void)
{
  static bool warned = false;
  if (! warned)
    {
      (*current_liboctave_warning_handler)
        ("In this version of Octave, QR & Cholesky updating routines\n"
         "simply update the matrix and recalculate factorizations.\n"
         "To use fast algorithms, link Octave with the qrupdate library.\n"
         "See <http://sourceforge.net/projects/qrupdate>.\n");
      warned = true;
    }
}

#endif

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