bidirectional.h

Go to the documentation of this file.

/*
 * Copyright (c) 2022:  G-CSC, Goethe University Frankfurt
 * Author: Felix Salfelder, 2022
 * 
 * This file is part of UG4.
 * 
 * UG4 is free software: you can redistribute it and/or modify it under the
 * terms of the GNU Lesser General Public License version 3 (as published by the
 * Free Software Foundation) with the following additional attribution
 * requirements (according to LGPL/GPL v3 §7):
 * 
 * (1) The following notice must be displayed in the Appropriate Legal Notices
 * of covered and combined works: "Based on UG4 (www.ug4.org/license)".
 * 
 * (2) The following notice must be displayed at a prominent place in the
 * terminal output of covered works: "Based on UG4 (www.ug4.org/license)".
 * 
 * (3) The following bibliography is recommended for citation and must be
 * preserved in all covered files:
 * "Reiter, S., Vogel, A., Heppner, I., Rupp, M., and Wittum, G. A massively
 *   parallel geometric multigrid solver on hierarchically distributed grids.
 *   Computing and visualization in science 16, 4 (2013), 151-164"
 * "Vogel, A., Reiter, S., Rupp, M., Nägel, A., and Wittum, G. UG4 -- a novel
 *   flexible software system for simulating pde based models on high performance
 *   computers. Computing and visualization in science 16, 4 (2013), 165-179"
 * 
 * This program 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 Lesser General Public License for more details.
 */
 
#ifndef UG_GRAPH_INTERFACE_BIDIR_H
#define UG_GRAPH_INTERFACE_BIDIR_H
 
#include "sparsematrix_boost.h"
 
#ifndef NDEBUG
#include "common/stopwatch.h"
#endif
 
namespace ug{
 
// give access to edges both ways.
// keep a transpose matrix to cache iterators.
template<class T>
class BidirectionalMatrix{
public: // types
  typedef typename T::const_row_iterator const_row_iterator;
public:
  explicit BidirectionalMatrix(T const* m=nullptr)
      : _matrix(m) {
    if(m){
      refresh();
    }else{
    }
  }
  explicit BidirectionalMatrix(BidirectionalMatrix const& o)
      : _matrix(o._matrix) {
    _matrix_transpose = o._matrix_transpose; // BUG: missing copy constructor.
  }
  BidirectionalMatrix& operator=(BidirectionalMatrix const& o) {
    _matrix = o._matrix;
    _matrix_transpose = o._matrix_transpose;
    return *this;
  }
 
public: // interface
  void refresh(){
#ifndef NDEBUG
    double t = -get_clock_s();
#endif
    assert(_matrix);
    _matrix_transpose.set_as_transpose_of2(*_matrix);
    assert(_matrix->num_rows() == _matrix_transpose.num_cols());
    assert(_matrix->num_cols() == _matrix_transpose.num_rows());
#ifndef NDEBUG
    t += get_clock_s();
    UG_LOG("Transpose in bidirectional refresh " << t << "\n");
#endif
  }
 
  int num_rows() const {
    return std::max(_matrix->num_rows(), _matrix->num_cols());
  }
  int num_cols() const { untested();
    return num_rows();
  }
  int num_connections(int v) const {
    if(v<_matrix->num_rows()){
      return _matrix->num_connections(v);
    }else{
      assert(v<_matrix_transpose.num_rows());
      return _matrix_transpose.num_connections(v);
    }
  }
  int out_degree(int v) const {
    assert(_matrix);
    if(size_t(v)<_matrix->num_rows()){
      assert(size_t(v)<_matrix->num_rows());
      return boost::out_degree(v, *_matrix);
    }else{
      return 0;
    }
  }
  int in_degree(int v) const {
    // could use difference, requires zero-pruning in _matrix_transpose.
    if(size_t(v)<_matrix_transpose.num_rows()){
      return boost::out_degree(v, _matrix_transpose);
    }else{
      return 0;
    }
  }
  int degree(int v) const { untested();
    return 2*out_degree(v);
  }
 
  const_row_iterator begin_row(int row) const {
    assert(_matrix);
    if(size_t(row)<_matrix->num_rows()){
    }else{
      row = 0;
    }
    return _matrix->begin_row(row);
  }
  const_row_iterator end_row(int row) const {
    assert(_matrix);
    if(size_t(row)<_matrix->num_rows()){
      return _matrix->end_row(row);
    }else{
      return _matrix->begin_row(0);
    }
  }
 
  const_row_iterator begin_col(int col) const {
    if(size_t(col)<_matrix_transpose.num_rows()){
    }else{
      col = 0;
    }
    return _matrix_transpose.begin_row(col);
  }
  const_row_iterator end_col(int col) const {
    if(size_t(col)<_matrix_transpose.num_rows()){
      return _matrix_transpose.end_row(col);
    }else{
      return _matrix_transpose.begin_row(0);
    }
  }
 
private:
  T const* _matrix;
  T _matrix_transpose;
};
 
} // ug
 
#endif // guard