block_mask.h

// ---------------------------------------------------------------------
//
// Copyright (C) 2009 - 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_fe_block_mask_h
#define dealii_fe_block_mask_h

#include <deal.II/base/config.h>
#include <deal.II/base/exceptions.h>
#include <deal.II/base/memory_consumption.h>

#include <vector>
#include <iosfwd>

DEAL_II_NAMESPACE_OPEN



class BlockMask
{
public:
  BlockMask () = default;

  BlockMask (const std::vector<bool> &block_mask);

  BlockMask (const unsigned int n_blocks,
             const bool         initializer);

  unsigned int size () const;

  bool operator[] (const unsigned int block_index) const;

  bool
  represents_n_blocks (const unsigned int n) const;

  unsigned int
  n_selected_blocks (const unsigned int overall_number_of_blocks = numbers::invalid_unsigned_int) const;

  unsigned int
  first_selected_block (const unsigned int overall_number_of_blocks = numbers::invalid_unsigned_int) const;

  bool
  represents_the_all_selected_mask () const;

  BlockMask operator | (const BlockMask &mask) const;

  BlockMask operator & (const BlockMask &mask) const;

  bool operator== (const BlockMask &mask) const;

  bool operator!= (const BlockMask &mask) const;

  std::size_t
  memory_consumption () const;

private:
  std::vector<bool> block_mask;

  // make the output operator a friend so it can access
  // the block_mask array
  friend
  std::ostream &operator << (std::ostream &out,
                             const BlockMask &mask);
};


std::ostream &operator << (std::ostream &out,
                           const BlockMask &mask);


// -------------------- inline functions ---------------------

inline
BlockMask::BlockMask(const std::vector<bool> &block_mask)
  :
  block_mask (block_mask)
{}


inline
BlockMask::BlockMask(const unsigned int n_blocks,
                     const bool         initializer)
  :
  block_mask (n_blocks, initializer)
{}


inline
unsigned int
BlockMask::size () const
{
  return block_mask.size();
}


inline
bool
BlockMask::operator [](const unsigned int block_index) const
{
  // if the mask represents the all-block mask
  // then always return true
  if (block_mask.size() == 0)
    return true;
  else
    {
      // otherwise check the validity of the index and
      // return whatever is appropriate
      Assert (block_index < block_mask.size(),
              ExcIndexRange (block_index, 0, block_mask.size()));
      return block_mask[block_index];
    }
}


inline
bool
BlockMask::represents_n_blocks(const unsigned int n) const
{
  return ((block_mask.size() == 0)
          ||
          (block_mask.size() == n));
}


inline
unsigned int
BlockMask::n_selected_blocks(const unsigned int n) const
{
  if ((n != numbers::invalid_unsigned_int) && (size() > 0))
    AssertDimension (n, size());

  const unsigned int real_n = (n != numbers::invalid_unsigned_int
                               ?
                               n
                               :
                               size());
  if (block_mask.size() == 0)
    return real_n;
  else
    {
      AssertDimension (real_n, block_mask.size());
      unsigned int c = 0;
      for (unsigned int i=0; i<block_mask.size(); ++i)
        if (block_mask[i] == true)
          ++c;
      return c;
    }
}


inline
unsigned int
BlockMask::first_selected_block(const unsigned int n) const
{
  if ((n != numbers::invalid_unsigned_int) && (size() > 0))
    AssertDimension (n, size());

  if (block_mask.size() == 0)
    return 0;
  else
    {
      for (unsigned int c=0; c<block_mask.size(); ++c)
        if (block_mask[c] == true)
          return c;

      Assert (false, ExcMessage ("No block is selected at all!"));
      return numbers::invalid_unsigned_int;
    }
}



inline
bool
BlockMask::represents_the_all_selected_mask () const
{
  return (block_mask.size() == 0);
}



inline
BlockMask
BlockMask::operator | (const BlockMask &mask) const
{
  // if one of the two masks denotes the all-block mask,
  // then return the other one
  if (block_mask.size() == 0)
    return mask;
  else if (mask.block_mask.size() == 0)
    return *this;
  else
    {
      // if both masks have individual entries set, form
      // the combination of the two
      AssertDimension(block_mask.size(), mask.block_mask.size());
      std::vector<bool> new_mask (block_mask.size());
      for (unsigned int i=0; i<block_mask.size(); ++i)
        new_mask[i] = (block_mask[i] || mask.block_mask[i]);

      return new_mask;
    }
}


inline
BlockMask
BlockMask::operator & (const BlockMask &mask) const
{
  // if one of the two masks denotes the all-block mask,
  // then return the other one
  if (block_mask.size() == 0)
    return mask;
  else if (mask.block_mask.size() == 0)
    return *this;
  else
    {
      // if both masks have individual entries set, form
      // the combination of the two
      AssertDimension(block_mask.size(), mask.block_mask.size());
      std::vector<bool> new_mask (block_mask.size());
      for (unsigned int i=0; i<block_mask.size(); ++i)
        new_mask[i] = (block_mask[i] && mask.block_mask[i]);

      return new_mask;
    }
}


inline
bool
BlockMask::operator== (const BlockMask &mask) const
{
  return block_mask == mask.block_mask;
}


inline
bool
BlockMask::operator!= (const BlockMask &mask) const
{
  return block_mask != mask.block_mask;
}


DEAL_II_NAMESPACE_CLOSE

#endif