block_sparsity_pattern.h

// ---------------------------------------------------------------------
//
// Copyright (C) 2000 - 2017 by the deal.II authors
//
// This file is part of the deal.II library.
//
// The deal.II library is free software; you can use it, redistribute
// it, and/or modify it under the terms of the GNU Lesser General
// Public License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
// The full text of the license can be found in the file LICENSE at
// the top level of the deal.II distribution.
//
// ---------------------------------------------------------------------

#ifndef dealii_block_sparsity_pattern_h
#define dealii_block_sparsity_pattern_h


#include <deal.II/base/config.h>
#include <deal.II/base/exceptions.h>
#include <deal.II/base/table.h>
#include <deal.II/base/subscriptor.h>
#include <deal.II/base/smartpointer.h>
#include <deal.II/lac/sparsity_pattern.h>
#include <deal.II/lac/trilinos_sparsity_pattern.h>
#include <deal.II/lac/dynamic_sparsity_pattern.h>
#include <deal.II/lac/block_indices.h>

DEAL_II_NAMESPACE_OPEN


template <typename number> class BlockSparseMatrix;
class BlockDynamicSparsityPattern;

template <typename SparsityPatternType>
class BlockSparsityPatternBase : public Subscriptor
{
public:
  typedef types::global_dof_index size_type;

  static const size_type invalid_entry = SparsityPattern::invalid_entry;

  BlockSparsityPatternBase ();

  BlockSparsityPatternBase (const size_type n_block_rows,
                            const size_type n_block_columns);

  BlockSparsityPatternBase (const BlockSparsityPatternBase &bsp);

  ~BlockSparsityPatternBase ();

  void reinit (const size_type n_block_rows,
               const size_type n_block_columns);

  BlockSparsityPatternBase &operator = (const BlockSparsityPatternBase &);

  void collect_sizes ();

  SparsityPatternType &
  block (const size_type row,
         const size_type column);


  const SparsityPatternType &
  block (const size_type row,
         const size_type column) const;

  const BlockIndices &
  get_row_indices () const;

  const BlockIndices &
  get_column_indices () const;

  void compress ();

  size_type n_block_rows () const;

  size_type n_block_cols () const;

  bool empty () const;

  size_type max_entries_per_row () const;

  void add (const size_type i, const size_type j);

  template <typename ForwardIterator>
  void add_entries (const size_type  row,
                    ForwardIterator  begin,
                    ForwardIterator  end,
                    const bool       indices_are_sorted = false);

  size_type n_rows () const;

  size_type n_cols () const;

  bool exists (const size_type i, const size_type j) const;

  unsigned int row_length (const size_type row) const;

  size_type n_nonzero_elements () const;

  void print (std::ostream &out) const;

  void print_gnuplot (std::ostream &out) const;

  DeclException4 (ExcIncompatibleRowNumbers,
                  int, int, int, int,
                  << "The blocks [" << arg1 << ',' << arg2 << "] and ["
                  << arg3 << ',' << arg4 << "] have differing row numbers.");
  DeclException4 (ExcIncompatibleColNumbers,
                  int, int, int, int,
                  << "The blocks [" << arg1 << ',' << arg2 << "] and ["
                  << arg3 << ',' << arg4 << "] have differing column numbers.");

protected:

  size_type rows;

  size_type columns;

  Table<2,SmartPointer<SparsityPatternType, BlockSparsityPatternBase<SparsityPatternType> > > sub_objects;

  BlockIndices    row_indices;

  BlockIndices    column_indices;

private:
  std::vector<size_type > counter_within_block;

  std::vector<std::vector<size_type > > block_column_indices;

  template <typename number>
  friend class BlockSparseMatrix;
};



class BlockSparsityPattern : public BlockSparsityPatternBase<SparsityPattern>
{
public:

  BlockSparsityPattern () = default;

  BlockSparsityPattern (const size_type n_rows,
                        const size_type n_columns);

  void reinit (const size_type n_block_rows,
               const size_type n_block_columns);

  void reinit (const BlockIndices &row_indices,
               const BlockIndices &col_indices,
               const std::vector<std::vector<unsigned int> > &row_lengths);


  bool is_compressed () const;

  std::size_t memory_consumption () const;

  void copy_from (const BlockDynamicSparsityPattern &dsp);
};



class BlockDynamicSparsityPattern : public BlockSparsityPatternBase<DynamicSparsityPattern>
{
public:

  BlockDynamicSparsityPattern () = default;

  BlockDynamicSparsityPattern (const size_type n_rows,
                               const size_type n_columns);

  BlockDynamicSparsityPattern (const std::vector<size_type> &row_block_sizes,
                               const std::vector<size_type> &col_block_sizes);

  BlockDynamicSparsityPattern (const std::vector<IndexSet> &partitioning);

  BlockDynamicSparsityPattern (const BlockIndices &row_indices,
                               const BlockIndices &col_indices);


  void reinit (const std::vector<size_type> &row_block_sizes,
               const std::vector<size_type> &col_block_sizes);

  void reinit(const std::vector<IndexSet> &partitioning);

  void reinit (const BlockIndices &row_indices, const BlockIndices &col_indices);

  size_type column_number (const size_type row,
                           const unsigned int index) const;

  using BlockSparsityPatternBase<DynamicSparsityPattern>::reinit;
};

#ifdef DEAL_II_WITH_TRILINOS


namespace TrilinosWrappers
{

  class BlockSparsityPattern :
    public ::BlockSparsityPatternBase<SparsityPattern>
  {
  public:

    BlockSparsityPattern () = default;

    BlockSparsityPattern (const size_type n_rows,
                          const size_type n_columns);

    BlockSparsityPattern (const std::vector<size_type> &row_block_sizes,
                          const std::vector<size_type> &col_block_sizes);

    DEAL_II_DEPRECATED
    BlockSparsityPattern (const std::vector<Epetra_Map> &parallel_partitioning);

    BlockSparsityPattern (const std::vector<IndexSet> &parallel_partitioning,
                          const MPI_Comm &communicator = MPI_COMM_WORLD);

    BlockSparsityPattern (const std::vector<IndexSet> &row_parallel_partitioning,
                          const std::vector<IndexSet> &column_parallel_partitioning,
                          const std::vector<IndexSet> &writeable_rows,
                          const MPI_Comm              &communicator = MPI_COMM_WORLD);

    void reinit (const std::vector<size_type> &row_block_sizes,
                 const std::vector<size_type> &col_block_sizes);

    DEAL_II_DEPRECATED
    void reinit (const std::vector<Epetra_Map> &parallel_partitioning);

    void reinit (const std::vector<IndexSet> &parallel_partitioning,
                 const MPI_Comm              &communicator = MPI_COMM_WORLD);

    void reinit (const std::vector<IndexSet> &row_parallel_partitioning,
                 const std::vector<IndexSet> &column_parallel_partitioning,
                 const MPI_Comm              &communicator = MPI_COMM_WORLD);

    void reinit (const std::vector<IndexSet> &row_parallel_partitioning,
                 const std::vector<IndexSet> &column_parallel_partitioning,
                 const std::vector<IndexSet> &writeable_rows,
                 const MPI_Comm              &communicator = MPI_COMM_WORLD);

    using BlockSparsityPatternBase<SparsityPattern>::reinit;
  };

} /* namespace TrilinosWrappers */

#endif

/*---------------------- Template functions -----------------------------------*/



template <typename SparsityPatternType>
inline
SparsityPatternType &
BlockSparsityPatternBase<SparsityPatternType>::block (const size_type row,
                                                      const size_type column)
{
  Assert (row<rows, ExcIndexRange(row,0,rows));
  Assert (column<columns, ExcIndexRange(column,0,columns));
  return *sub_objects[row][column];
}



template <typename SparsityPatternType>
inline
const SparsityPatternType &
BlockSparsityPatternBase<SparsityPatternType>::block (const size_type row,
                                                      const size_type column) const
{
  Assert (row<rows, ExcIndexRange(row,0,rows));
  Assert (column<columns, ExcIndexRange(column,0,columns));
  return *sub_objects[row][column];
}



template <typename SparsityPatternType>
inline
const BlockIndices &
BlockSparsityPatternBase<SparsityPatternType>::get_row_indices () const
{
  return row_indices;
}



template <typename SparsityPatternType>
inline
const BlockIndices &
BlockSparsityPatternBase<SparsityPatternType>::get_column_indices () const
{
  return column_indices;
}



template <typename SparsityPatternType>
inline
void
BlockSparsityPatternBase<SparsityPatternType>::add (const size_type i,
                                                    const size_type j)
{
  // if you get an error here, are
  // you sure you called
  // <tt>collect_sizes()</tt> before?
  const std::pair<size_type,size_type>
  row_index = row_indices.global_to_local (i),
  col_index = column_indices.global_to_local (j);
  sub_objects[row_index.first][col_index.first]->add (row_index.second,
                                                      col_index.second);
}



template <typename SparsityPatternType>
template <typename ForwardIterator>
void
BlockSparsityPatternBase<SparsityPatternType>::add_entries (const size_type row,
                                                            ForwardIterator begin,
                                                            ForwardIterator end,
                                                            const bool      indices_are_sorted)
{
  // Resize scratch arrays
  if (block_column_indices.size() < this->n_block_cols())
    {
      block_column_indices.resize (this->n_block_cols());
      counter_within_block.resize (this->n_block_cols());
    }

  const size_type n_cols = static_cast<size_type>(end - begin);

  // Resize sub-arrays to n_cols. This
  // is a bit wasteful, but we resize
  // only a few times (then the maximum
  // row length won't increase that
  // much any more). At least we know
  // that all arrays are going to be of
  // the same size, so we can check
  // whether the size of one is large
  // enough before actually going
  // through all of them.
  if (block_column_indices[0].size() < n_cols)
    for (size_type i=0; i<this->n_block_cols(); ++i)
      block_column_indices[i].resize(n_cols);

  // Reset the number of added elements
  // in each block to zero.
  for (size_type i=0; i<this->n_block_cols(); ++i)
    counter_within_block[i] = 0;

  // Go through the column indices to
  // find out which portions of the
  // values should be set in which
  // block of the matrix. We need to
  // touch all the data, since we can't
  // be sure that the data of one block
  // is stored contiguously (in fact,
  // indices will be intermixed when it
  // comes from an element matrix).
  for (ForwardIterator it = begin; it != end; ++it)
    {
      const size_type col = *it;

      const std::pair<size_type, size_type>
      col_index = this->column_indices.global_to_local(col);

      const size_type local_index = counter_within_block[col_index.first]++;

      block_column_indices[col_index.first][local_index] = col_index.second;
    }

#ifdef DEBUG
  // If in debug mode, do a check whether
  // the right length has been obtained.
  size_type length = 0;
  for (size_type i=0; i<this->n_block_cols(); ++i)
    length += counter_within_block[i];
  Assert (length == n_cols, ExcInternalError());
#endif

  // Now we found out about where the
  // individual columns should start and
  // where we should start reading out
  // data. Now let's write the data into
  // the individual blocks!
  const std::pair<size_type, size_type>
  row_index = this->row_indices.global_to_local (row);
  for (size_type block_col=0; block_col<n_block_cols(); ++block_col)
    {
      if (counter_within_block[block_col] == 0)
        continue;
      sub_objects[row_index.first][block_col]->
      add_entries (row_index.second,
                   block_column_indices[block_col].begin(),
                   block_column_indices[block_col].begin()+counter_within_block[block_col],
                   indices_are_sorted);
    }
}



template <typename SparsityPatternType>
inline
bool
BlockSparsityPatternBase<SparsityPatternType>::exists (const size_type i,
                                                       const size_type j) const
{
  // if you get an error here, are
  // you sure you called
  // <tt>collect_sizes()</tt> before?
  const std::pair<size_type, size_type>
  row_index = row_indices.global_to_local (i),
  col_index = column_indices.global_to_local (j);
  return sub_objects[row_index.first][col_index.first]->exists (row_index.second,
         col_index.second);
}



template <typename SparsityPatternType>
inline
unsigned int
BlockSparsityPatternBase<SparsityPatternType>::
row_length (const size_type row) const
{
  const std::pair<size_type, size_type>
  row_index = row_indices.global_to_local (row);

  unsigned int c = 0;

  for (size_type b=0; b<rows; ++b)
    c += sub_objects[row_index.first][b]->row_length (row_index.second);

  return c;
}



template <typename SparsityPatternType>
inline
typename BlockSparsityPatternBase<SparsityPatternType>::size_type
BlockSparsityPatternBase<SparsityPatternType>::n_block_cols () const
{
  return columns;
}



template <typename SparsityPatternType>
inline
typename BlockSparsityPatternBase<SparsityPatternType>::size_type
BlockSparsityPatternBase<SparsityPatternType>::n_block_rows () const
{
  return rows;
}


inline
BlockDynamicSparsityPattern::size_type
BlockDynamicSparsityPattern::column_number (const size_type row,
                                            const unsigned int index) const
{
  // .first= ith block, .second = jth row in that block
  const std::pair<size_type,size_type >
  row_index = row_indices.global_to_local (row);

  Assert(index<row_length(row), ExcIndexRange(index, 0, row_length(row)));

  size_type c = 0;
  size_type block_columns = 0; //sum of n_cols for all blocks to the left
  for (unsigned int b=0; b<columns; ++b)
    {
      unsigned int rowlen = sub_objects[row_index.first][b]->row_length (row_index.second);
      if (index<c+rowlen)
        return block_columns+sub_objects[row_index.first][b]->column_number(row_index.second, index-c);
      c += rowlen;
      block_columns += sub_objects[row_index.first][b]->n_cols();
    }

  Assert(false, ExcInternalError());
  return 0;
}


inline
void
BlockSparsityPattern::reinit (
  const size_type n_block_rows,
  const size_type n_block_columns)
{
  BlockSparsityPatternBase<SparsityPattern>::reinit (
    n_block_rows, n_block_columns);
}


DEAL_II_NAMESPACE_CLOSE

#endif