ov-bool-sparse.cc

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////////////////////////////////////////////////////////////////////////
//
// Copyright (C) 1998-2024 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 <istream>
#include <ostream>
#include <vector>
 
#include "dim-vector.h"
 
#include "mxarray.h"
#include "ov-base.h"
#include "ov-scalar.h"
#include "ov-bool.h"
#include "ov-bool-mat.h"
#include "errwarn.h"
#include "ops.h"
#include "oct-locbuf.h"
 
#include "oct-hdf5.h"
 
#include "ov-re-sparse.h"
#include "ov-cx-sparse.h"
#include "ov-bool-sparse.h"
 
#include "ov-base-sparse.h"
#include "ov-base-sparse.cc"
 
template class octave_base_sparse<SparseBoolMatrix>;
 
DEFINE_OV_TYPEID_FUNCTIONS_AND_DATA (octave_sparse_bool_matrix,
                                     "sparse bool matrix", "logical");
 
static octave_base_value *
default_numeric_conversion_function (const octave_base_value& a)
{
  const octave_sparse_bool_matrix& v
    = dynamic_cast<const octave_sparse_bool_matrix&> (a);
 
  return
    new octave_sparse_matrix (SparseMatrix (v.sparse_bool_matrix_value ()));
}
 
octave_base_value::type_conv_info
octave_sparse_bool_matrix::numeric_conversion_function () const
{
  return octave_base_value::type_conv_info (default_numeric_conversion_function,
         octave_sparse_matrix::static_type_id ());
}
 
double
octave_sparse_bool_matrix::double_value (bool) const
{
  if (isempty ())
    err_invalid_conversion ("bool sparse matrix", "real scalar");
 
  if (numel () > 1)
    warn_implicit_conversion ("Octave:array-to-scalar",
                              "bool sparse matrix", "real scalar");
 
  return matrix(0, 0);
}
 
Complex
octave_sparse_bool_matrix::complex_value (bool) const
{
  if (rows () == 0 || columns () == 0)
    err_invalid_conversion ("bool sparse matrix", "complex scalar");
 
  if (numel () > 1)
    warn_implicit_conversion ("Octave:array-to-scalar",
                              "bool sparse matrix", "complex scalar");
 
  return Complex (matrix(0, 0), 0);
}
 
octave_value
octave_sparse_bool_matrix::convert_to_str_internal (bool pad, bool force,
    char type) const
{
  octave_value tmp = octave_value (array_value ());
  return tmp.convert_to_str (pad, force, type);
}
 
// FIXME: These are inefficient ways of creating full matrices
 
Matrix
octave_sparse_bool_matrix::matrix_value (bool) const
{
  return Matrix (matrix.matrix_value ());
}
 
ComplexMatrix
octave_sparse_bool_matrix::complex_matrix_value (bool) const
{
  return ComplexMatrix (matrix.matrix_value ());
}
 
ComplexNDArray
octave_sparse_bool_matrix::complex_array_value (bool) const
{
  return ComplexNDArray (ComplexMatrix (matrix.matrix_value ()));
}
 
NDArray
octave_sparse_bool_matrix::array_value (bool) const
{
  return NDArray (Matrix (matrix.matrix_value ()));
}
 
charNDArray
octave_sparse_bool_matrix::char_array_value (bool) const
{
  charNDArray retval (dims (), 0);
  octave_idx_type nc = matrix.cols ();
  octave_idx_type nr = matrix.rows ();
 
  for (octave_idx_type j = 0; j < nc; j++)
    for (octave_idx_type i = matrix.cidx (j); i < matrix.cidx (j+1); i++)
      retval(matrix.ridx (i) + nr * j) = static_cast<char> (matrix.data (i));
 
  return retval;
}
 
boolMatrix
octave_sparse_bool_matrix::bool_matrix_value (bool) const
{
  return matrix.matrix_value ();
}
 
boolNDArray
octave_sparse_bool_matrix::bool_array_value (bool) const
{
  return boolNDArray (matrix.matrix_value ());
}
 
SparseMatrix
octave_sparse_bool_matrix::sparse_matrix_value (bool) const
{
  return SparseMatrix (this->matrix);
}
 
SparseComplexMatrix
octave_sparse_bool_matrix::sparse_complex_matrix_value (bool) const
{
  return SparseComplexMatrix (this->matrix);
}
 
octave_value
octave_sparse_bool_matrix::as_double () const
{
  return SparseMatrix (this->matrix);
}
 
bool
octave_sparse_bool_matrix::save_binary (std::ostream& os, bool)
{
  dim_vector dv = this->dims ();
  if (dv.ndims () < 1)
    return false;
 
  // Ensure that additional memory is deallocated
  matrix.maybe_compress ();
 
  octave_idx_type nr = dv(0);
  octave_idx_type nc = dv(1);
  octave_idx_type nz = nnz ();
 
  // For compatiblity, indices are always saved with 4 bytes
#if OCTAVE_SIZEOF_IDX_TYPE == OCTAVE_SIZEOF_INT
  if (nr < 0 || nc < 0 || nz < 0)
    return false;
#else
  octave_idx_type max_val = std::numeric_limits<uint32_t>::max ();
  if (nr < 0 || nr > max_val || nc < 0 || nc > max_val
      || nz < 0 || nz > max_val)
    return false;
#endif
 
  int32_t itmp;
  // Use negative value for ndims to be consistent with other formats
  itmp = -2;
  os.write (reinterpret_cast<char *> (&itmp), 4);
 
  itmp = nr;
  os.write (reinterpret_cast<char *> (&itmp), 4);
 
  itmp = nc;
  os.write (reinterpret_cast<char *> (&itmp), 4);
 
  itmp = nz;
  os.write (reinterpret_cast<char *> (&itmp), 4);
 
  // add one to the printed indices to go from
  // zero-based to one-based arrays
  for (int i = 0; i < nc+1; i++)
    {
      octave_quit ();
      itmp = matrix.cidx (i);
      os.write (reinterpret_cast<char *> (&itmp), 4);
    }
 
  for (int i = 0; i < nz; i++)
    {
      octave_quit ();
      itmp = matrix.ridx (i);
      os.write (reinterpret_cast<char *> (&itmp), 4);
    }
 
  OCTAVE_LOCAL_BUFFER (char, htmp, nz);
 
  for (int i = 0; i < nz; i++)
    htmp[i] = (matrix.data (i) ? 1 : 0);
 
  os.write (htmp, nz);
 
  return true;
}
 
bool
octave_sparse_bool_matrix::load_binary (std::istream& is, bool swap,
                                        octave::mach_info::float_format /* fmt */)
{
  int32_t nz, nc, nr, tmp;
  if (! is.read (reinterpret_cast<char *> (&tmp), 4))
    return false;
 
  if (swap)
    swap_bytes<4> (&tmp);
 
  if (tmp != -2)
    error ("load: only 2-D sparse matrices are supported");
 
  if (! is.read (reinterpret_cast<char *> (&nr), 4))
    return false;
  if (! is.read (reinterpret_cast<char *> (&nc), 4))
    return false;
  if (! is.read (reinterpret_cast<char *> (&nz), 4))
    return false;
 
  if (swap)
    {
      swap_bytes<4> (&nr);
      swap_bytes<4> (&nc);
      swap_bytes<4> (&nz);
    }
 
  SparseBoolMatrix m (static_cast<octave_idx_type> (nr),
                      static_cast<octave_idx_type> (nc),
                      static_cast<octave_idx_type> (nz));
 
  for (int i = 0; i < nc+1; i++)
    {
      octave_quit ();
      if (! is.read (reinterpret_cast<char *> (&tmp), 4))
        return false;
      if (swap)
        swap_bytes<4> (&tmp);
      m.cidx (i) = tmp;
    }
 
  for (int i = 0; i < nz; i++)
    {
      octave_quit ();
      if (! is.read (reinterpret_cast<char *> (&tmp), 4))
        return false;
      if (swap)
        swap_bytes<4> (&tmp);
      m.ridx (i) = tmp;
    }
 
  if (! is)
    return false;
 
  OCTAVE_LOCAL_BUFFER (char, htmp, nz);
 
  if (! is.read (htmp, nz))
    return false;
 
  for (int i = 0; i < nz; i++)
    m.data(i) = (htmp[i] ? 1 : 0);
 
  if (! m.indices_ok ())
    return false;
 
  matrix = m;
 
  return true;
}
 
bool
octave_sparse_bool_matrix::save_hdf5 (octave_hdf5_id loc_id, const char *name,
                                      bool)
{
  bool retval = false;
 
#if defined (HAVE_HDF5)
 
  dim_vector dv = dims ();
  int empty = save_hdf5_empty (loc_id, name, dv);
  if (empty)
    return (empty > 0);
 
  // Ensure that additional memory is deallocated
  matrix.maybe_compress ();
#if defined (HAVE_HDF5_18)
  hid_t group_hid = H5Gcreate (loc_id, name, octave_H5P_DEFAULT,
                               octave_H5P_DEFAULT, octave_H5P_DEFAULT);
#else
  hid_t group_hid = H5Gcreate (loc_id, name, 0);
#endif
  if (group_hid < 0)
    return false;
 
  hid_t space_hid, data_hid;
  space_hid = data_hid = -1;
  SparseBoolMatrix m = sparse_bool_matrix_value ();
  octave_idx_type tmp;
  hsize_t hdims[2];
 
  space_hid = H5Screate_simple (0, hdims, nullptr);
  if (space_hid < 0)
    {
      H5Gclose (group_hid);
      return false;
    }
#if defined (HAVE_HDF5_18)
  data_hid = H5Dcreate (group_hid, "nr", H5T_NATIVE_IDX, space_hid,
                        octave_H5P_DEFAULT, octave_H5P_DEFAULT,
                        octave_H5P_DEFAULT);
#else
  data_hid = H5Dcreate (group_hid, "nr", H5T_NATIVE_IDX, space_hid,
                        octave_H5P_DEFAULT);
#endif
  if (data_hid < 0)
    {
      H5Sclose (space_hid);
      H5Gclose (group_hid);
      return false;
    }
 
  tmp = m.rows ();
  retval = H5Dwrite (data_hid, H5T_NATIVE_IDX, octave_H5S_ALL,
                     octave_H5S_ALL, octave_H5P_DEFAULT, &tmp) >= 0;
  H5Dclose (data_hid);
  if (! retval)
    {
      H5Sclose (space_hid);
      H5Gclose (group_hid);
      return false;
    }
 
#if defined (HAVE_HDF5_18)
  data_hid = H5Dcreate (group_hid, "nc", H5T_NATIVE_IDX, space_hid,
                        octave_H5P_DEFAULT, octave_H5P_DEFAULT,
                        octave_H5P_DEFAULT);
#else
  data_hid = H5Dcreate (group_hid, "nc", H5T_NATIVE_IDX, space_hid,
                        octave_H5P_DEFAULT);
#endif
  if (data_hid < 0)
    {
      H5Sclose (space_hid);
      H5Gclose (group_hid);
      return false;
    }
 
  tmp = m.cols ();
  retval = H5Dwrite (data_hid, H5T_NATIVE_IDX, octave_H5S_ALL, octave_H5S_ALL,
                     octave_H5P_DEFAULT, &tmp) >= 0;
  H5Dclose (data_hid);
  if (! retval)
    {
      H5Sclose (space_hid);
      H5Gclose (group_hid);
      return false;
    }
 
#if defined (HAVE_HDF5_18)
  data_hid = H5Dcreate (group_hid, "nz", H5T_NATIVE_IDX, space_hid,
                        octave_H5P_DEFAULT, octave_H5P_DEFAULT,
                        octave_H5P_DEFAULT);
#else
  data_hid = H5Dcreate (group_hid, "nz", H5T_NATIVE_IDX, space_hid,
                        octave_H5P_DEFAULT);
#endif
  if (data_hid < 0)
    {
      H5Sclose (space_hid);
      H5Gclose (group_hid);
      return false;
    }
 
  tmp = m.nnz ();
  retval = H5Dwrite (data_hid, H5T_NATIVE_IDX, octave_H5S_ALL, octave_H5S_ALL,
                     octave_H5P_DEFAULT, &tmp) >= 0;
  H5Dclose (data_hid);
  if (! retval)
    {
      H5Sclose (space_hid);
      H5Gclose (group_hid);
      return false;
    }
 
  H5Sclose (space_hid);
 
  hdims[0] = m.cols () + 1;
  hdims[1] = 1;
 
  space_hid = H5Screate_simple (2, hdims, nullptr);
 
  if (space_hid < 0)
    {
      H5Gclose (group_hid);
      return false;
    }
 
#if defined (HAVE_HDF5_18)
  data_hid = H5Dcreate (group_hid, "cidx", H5T_NATIVE_IDX, space_hid,
                        octave_H5P_DEFAULT, octave_H5P_DEFAULT,
                        octave_H5P_DEFAULT);
#else
  data_hid = H5Dcreate (group_hid, "cidx", H5T_NATIVE_IDX, space_hid,
                        octave_H5P_DEFAULT);
#endif
  if (data_hid < 0)
    {
      H5Sclose (space_hid);
      H5Gclose (group_hid);
      return false;
    }
 
  octave_idx_type *itmp = m.xcidx ();
  retval = H5Dwrite (data_hid, H5T_NATIVE_IDX, octave_H5S_ALL, octave_H5S_ALL,
                     octave_H5P_DEFAULT, itmp) >= 0;
  H5Dclose (data_hid);
  if (! retval)
    {
      H5Sclose (space_hid);
      H5Gclose (group_hid);
      return false;
    }
 
  H5Sclose (space_hid);
 
  hdims[0] = m.nnz ();
  hdims[1] = 1;
 
  space_hid = H5Screate_simple (2, hdims, nullptr);
 
  if (space_hid < 0)
    {
      H5Gclose (group_hid);
      return false;
    }
 
#if defined (HAVE_HDF5_18)
  data_hid = H5Dcreate (group_hid, "ridx", H5T_NATIVE_IDX, space_hid,
                        octave_H5P_DEFAULT, octave_H5P_DEFAULT,
                        octave_H5P_DEFAULT);
#else
  data_hid = H5Dcreate (group_hid, "ridx", H5T_NATIVE_IDX, space_hid,
                        octave_H5P_DEFAULT);
#endif
  if (data_hid < 0)
    {
      H5Sclose (space_hid);
      H5Gclose (group_hid);
      return false;
    }
 
  itmp = m.xridx ();
  retval = H5Dwrite (data_hid, H5T_NATIVE_IDX, octave_H5S_ALL, octave_H5S_ALL,
                     octave_H5P_DEFAULT, itmp) >= 0;
  H5Dclose (data_hid);
  if (! retval)
    {
      H5Sclose (space_hid);
      H5Gclose (group_hid);
      return false;
    }
 
#if defined (HAVE_HDF5_18)
  data_hid = H5Dcreate (group_hid, "data", H5T_NATIVE_HBOOL, space_hid,
                        octave_H5P_DEFAULT, octave_H5P_DEFAULT,
                        octave_H5P_DEFAULT);
#else
  data_hid = H5Dcreate (group_hid, "data", H5T_NATIVE_HBOOL, space_hid,
                        octave_H5P_DEFAULT);
#endif
  if (data_hid < 0)
    {
      H5Sclose (space_hid);
      H5Gclose (group_hid);
      return false;
    }
 
  OCTAVE_LOCAL_BUFFER (hbool_t, htmp, m.nnz ());
  for (int i = 0; i < m.nnz (); i++)
    htmp[i] = m.xdata(i);
 
  retval = H5Dwrite (data_hid, H5T_NATIVE_HBOOL, octave_H5S_ALL, octave_H5S_ALL,
                     octave_H5P_DEFAULT, htmp) >= 0;
  H5Dclose (data_hid);
  H5Sclose (space_hid);
  H5Gclose (group_hid);
 
#else
  octave_unused_parameter (loc_id);
  octave_unused_parameter (name);
 
  warn_save ("hdf5");
#endif
 
  return retval;
}
 
bool
octave_sparse_bool_matrix::load_hdf5 (octave_hdf5_id loc_id, const char *name)
{
  bool retval = false;
 
#if defined (HAVE_HDF5)
 
  octave_idx_type nr, nc, nz;
  hid_t group_hid, data_hid, space_hid;
  hsize_t rank;
 
  dim_vector dv;
  int empty = load_hdf5_empty (loc_id, name, dv);
  if (empty > 0)
    matrix.resize (dv);
  if (empty)
    return (empty > 0);
 
#if defined (HAVE_HDF5_18)
  group_hid = H5Gopen (loc_id, name, octave_H5P_DEFAULT);
#else
  group_hid = H5Gopen (loc_id, name);
#endif
  if (group_hid < 0) return false;
 
#if defined (HAVE_HDF5_18)
  data_hid = H5Dopen (group_hid, "nr", octave_H5P_DEFAULT);
#else
  data_hid = H5Dopen (group_hid, "nr");
#endif
  space_hid = H5Dget_space (data_hid);
  rank = H5Sget_simple_extent_ndims (space_hid);
 
  if (rank != 0)
    {
      H5Dclose (data_hid);
      H5Gclose (group_hid);
      return false;
    }
 
  if (H5Dread (data_hid, H5T_NATIVE_IDX, octave_H5S_ALL, octave_H5S_ALL,
               octave_H5P_DEFAULT, &nr)
      < 0)
    {
      H5Dclose (data_hid);
      H5Gclose (group_hid);
      return false;
    }
 
  H5Dclose (data_hid);
 
#if defined (HAVE_HDF5_18)
  data_hid = H5Dopen (group_hid, "nc", octave_H5P_DEFAULT);
#else
  data_hid = H5Dopen (group_hid, "nc");
#endif
  space_hid = H5Dget_space (data_hid);
  rank = H5Sget_simple_extent_ndims (space_hid);
 
  if (rank != 0)
    {
      H5Dclose (data_hid);
      H5Gclose (group_hid);
      return false;
    }
 
  if (H5Dread (data_hid, H5T_NATIVE_IDX, octave_H5S_ALL, octave_H5S_ALL,
               octave_H5P_DEFAULT, &nc)
      < 0)
    {
      H5Dclose (data_hid);
      H5Gclose (group_hid);
      return false;
    }
 
  H5Dclose (data_hid);
 
#if defined (HAVE_HDF5_18)
  data_hid = H5Dopen (group_hid, "nz", octave_H5P_DEFAULT);
#else
  data_hid = H5Dopen (group_hid, "nz");
#endif
  space_hid = H5Dget_space (data_hid);
  rank = H5Sget_simple_extent_ndims (space_hid);
 
  if (rank != 0)
    {
      H5Dclose (data_hid);
      H5Gclose (group_hid);
      return false;
    }
 
  if (H5Dread (data_hid, H5T_NATIVE_IDX, octave_H5S_ALL, octave_H5S_ALL,
               octave_H5P_DEFAULT, &nz)
      < 0)
    {
      H5Dclose (data_hid);
      H5Gclose (group_hid);
      return false;
    }
 
  H5Dclose (data_hid);
 
  SparseBoolMatrix m (static_cast<octave_idx_type> (nr),
                      static_cast<octave_idx_type> (nc),
                      static_cast<octave_idx_type> (nz));
 
#if defined (HAVE_HDF5_18)
  data_hid = H5Dopen (group_hid, "cidx", octave_H5P_DEFAULT);
#else
  data_hid = H5Dopen (group_hid, "cidx");
#endif
  space_hid = H5Dget_space (data_hid);
  rank = H5Sget_simple_extent_ndims (space_hid);
 
  if (rank != 2)
    {
      H5Sclose (space_hid);
      H5Dclose (data_hid);
      H5Gclose (group_hid);
      return false;
    }
 
  OCTAVE_LOCAL_BUFFER (hsize_t, hdims, rank);
  OCTAVE_LOCAL_BUFFER (hsize_t, maxdims, rank);
 
  H5Sget_simple_extent_dims (space_hid, hdims, maxdims);
 
  if (static_cast<int> (hdims[0]) != nc + 1
      || static_cast<int> (hdims[1]) != 1)
    {
      H5Sclose (space_hid);
      H5Dclose (data_hid);
      H5Gclose (group_hid);
      return false;
    }
 
  octave_idx_type *itmp = m.xcidx ();
  if (H5Dread (data_hid, H5T_NATIVE_IDX, octave_H5S_ALL, octave_H5S_ALL,
               octave_H5P_DEFAULT, itmp)
      < 0)
    {
      H5Sclose (space_hid);
      H5Dclose (data_hid);
      H5Gclose (group_hid);
      return false;
    }
 
  H5Sclose (space_hid);
  H5Dclose (data_hid);
 
#if defined (HAVE_HDF5_18)
  data_hid = H5Dopen (group_hid, "ridx", octave_H5P_DEFAULT);
#else
  data_hid = H5Dopen (group_hid, "ridx");
#endif
  space_hid = H5Dget_space (data_hid);
  rank = H5Sget_simple_extent_ndims (space_hid);
 
  if (rank != 2)
    {
      H5Sclose (space_hid);
      H5Dclose (data_hid);
      H5Gclose (group_hid);
      return false;
    }
 
  H5Sget_simple_extent_dims (space_hid, hdims, maxdims);
 
  if (static_cast<int> (hdims[0]) != nz
      || static_cast<int> (hdims[1]) != 1)
    {
      H5Sclose (space_hid);
      H5Dclose (data_hid);
      H5Gclose (group_hid);
      return false;
    }
 
  itmp = m.xridx ();
  if (H5Dread (data_hid, H5T_NATIVE_IDX, octave_H5S_ALL, octave_H5S_ALL,
               octave_H5P_DEFAULT, itmp) < 0)
    {
      H5Sclose (space_hid);
      H5Dclose (data_hid);
      H5Gclose (group_hid);
      return false;
    }
 
  H5Sclose (space_hid);
  H5Dclose (data_hid);
 
#if defined (HAVE_HDF5_18)
  data_hid = H5Dopen (group_hid, "data", octave_H5P_DEFAULT);
#else
  data_hid = H5Dopen (group_hid, "data");
#endif
  space_hid = H5Dget_space (data_hid);
  rank = H5Sget_simple_extent_ndims (space_hid);
 
  if (rank != 2)
    {
      H5Sclose (space_hid);
      H5Dclose (data_hid);
      H5Gclose (group_hid);
      return false;
    }
 
  H5Sget_simple_extent_dims (space_hid, hdims, maxdims);
 
  if (static_cast<int> (hdims[0]) != nz
      || static_cast<int> (hdims[1]) != 1)
    {
      H5Sclose (space_hid);
      H5Dclose (data_hid);
      H5Gclose (group_hid);
      return false;
    }
 
  OCTAVE_LOCAL_BUFFER (hbool_t, htmp, nz);
 
  if (H5Dread (data_hid, H5T_NATIVE_HBOOL, octave_H5S_ALL, octave_H5S_ALL,
               octave_H5P_DEFAULT, htmp) >= 0
      && m.indices_ok ())
    {
      retval = true;
 
      for (int i = 0; i < nz; i++)
        m.xdata(i) = htmp[i];
 
      matrix = m;
    }
 
  H5Sclose (space_hid);
  H5Dclose (data_hid);
  H5Gclose (group_hid);
 
#else
  octave_unused_parameter (loc_id);
  octave_unused_parameter (name);
 
  warn_load ("hdf5");
#endif
 
  return retval;
}
 
mxArray *
octave_sparse_bool_matrix::as_mxArray (bool interleaved) const
{
  mwSize nz = nzmax ();
  mwSize nr = rows ();
  mwSize nc = columns ();
 
  mxArray *retval = new mxArray (interleaved, mxLOGICAL_CLASS, nr, nc, nz,
                                 mxREAL);
 
  mxLogical *pd = static_cast<mxLogical *> (retval->get_data ());
  mwIndex *ir = retval->get_ir ();
 
  const bool *pdata = matrix.data ();
  const octave_idx_type *pridx = matrix.ridx ();
 
  for (mwIndex i = 0; i < nz; i++)
    {
      pd[i] = pdata[i];
 
      ir[i] = pridx[i];
    }
 
  mwIndex *jc = retval->get_jc ();
 
  const octave_idx_type *pcidx = matrix.cidx ();
 
  for (mwIndex i = 0; i < nc + 1; i++)
    jc[i] = pcidx[i];
 
  return retval;
}