Chris@16: // Copyright 2005 The Trustees of Indiana University.
Chris@16: 
Chris@16: // Use, modification and distribution is subject to the Boost Software
Chris@16: // License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
Chris@16: // http://www.boost.org/LICENSE_1_0.txt)
Chris@16: 
Chris@16: //  Authors: Douglas Gregor
Chris@16: //           Andrew Lumsdaine
Chris@16: #ifndef BOOST_GRAPH_METIS_HPP
Chris@16: #define BOOST_GRAPH_METIS_HPP
Chris@16: 
Chris@16: #ifdef BOOST_GRAPH_METIS_NO_INLINE
Chris@16: #  define BOOST_GRAPH_METIS_INLINE_KEYWORD
Chris@16: #else
Chris@16: #  define BOOST_GRAPH_METIS_INLINE_KEYWORD inline
Chris@16: #endif
Chris@16: 
Chris@16: #include <string>
Chris@16: #include <iostream>
Chris@16: #include <iterator>
Chris@16: #include <utility>
Chris@16: #include <sstream>
Chris@16: #include <exception>
Chris@16: #include <vector>
Chris@16: #include <algorithm>
Chris@16: 
Chris@16: namespace boost { namespace graph {
Chris@16: 
Chris@16: class metis_exception : public std::exception {};
Chris@16: class metis_input_exception : public metis_exception {};
Chris@16: 
Chris@16: class metis_reader
Chris@16: {
Chris@16:  public:
Chris@16:   typedef std::size_t vertices_size_type;
Chris@16:   typedef std::size_t edges_size_type;
Chris@16:   typedef double vertex_weight_type;
Chris@16:   typedef double edge_weight_type;
Chris@16: 
Chris@16:   class edge_iterator
Chris@16:   {
Chris@16:   public:
Chris@16:     typedef std::input_iterator_tag iterator_category;
Chris@16:     typedef std::pair<vertices_size_type, vertices_size_type> value_type;
Chris@16:     typedef const value_type& reference;
Chris@16:     typedef const value_type* pointer;
Chris@16:     typedef std::ptrdiff_t difference_type;
Chris@16: 
Chris@16:   private:
Chris@16:     class postincrement_proxy
Chris@16:     {
Chris@16:       postincrement_proxy(const value_type& value) : value(value) { }
Chris@16: 
Chris@16:     public:
Chris@16:       reference operator*() const { return value; }
Chris@16: 
Chris@16:     private:
Chris@16:       value_type value;
Chris@16:       friend class edge_iterator;
Chris@16:     };
Chris@16:     
Chris@16:   public:
Chris@16:     edge_iterator& operator++();
Chris@16:     postincrement_proxy operator++(int);
Chris@16: 
Chris@16:     reference operator*() const { return self->edge; }
Chris@16:     pointer operator->() const { return &self->edge; }
Chris@16: 
Chris@16:     // Default copy constructor and assignment operator are okay
Chris@16: 
Chris@16:   private:
Chris@16:     edge_iterator(metis_reader* self);
Chris@16:     void advance(bool skip_initial_read);
Chris@16:     
Chris@16:     metis_reader* self;
Chris@16: 
Chris@16:     friend class metis_reader;
Chris@16:     friend bool operator==(edge_iterator, edge_iterator);
Chris@16:     friend bool operator!=(edge_iterator, edge_iterator);
Chris@16:   };
Chris@16:   friend class edge_iterator;
Chris@16: 
Chris@16:   class edge_weight_iterator
Chris@16:   {
Chris@16:   public:
Chris@16:     typedef std::input_iterator_tag iterator_category;
Chris@16:     typedef edge_weight_type value_type;
Chris@16:     typedef const value_type& reference;
Chris@16:     typedef const value_type* pointer;
Chris@16: 
Chris@16:     // Default copy constructor and assignment operator are okay
Chris@16: 
Chris@16:     reference operator*() const { return self->edge_weight; }
Chris@16:     pointer operator->() const { return &self->edge_weight; }
Chris@16: 
Chris@16:     edge_weight_iterator& operator++() { return *this; }
Chris@16:     edge_weight_iterator operator++(int) { return *this; }
Chris@16: 
Chris@16:   private:
Chris@16:     edge_weight_iterator(metis_reader* self) : self(self) { }
Chris@16: 
Chris@16:     metis_reader* self;
Chris@16:     
Chris@16:     friend class metis_reader;
Chris@16:   };
Chris@16:   
Chris@16:   metis_reader(std::istream& in) : in(in), edge_weight(1.0) { start(); }
Chris@16: 
Chris@16:   edge_iterator begin();
Chris@16:   edge_iterator end();
Chris@16:   edge_weight_iterator weight_begin();
Chris@16: 
Chris@16:   vertices_size_type num_vertices() const { return n_vertices; }
Chris@16:   edges_size_type num_edges() const { return n_edges; }
Chris@16: 
Chris@16:   std::size_t num_vertex_weights() const { return n_vertex_weights; }
Chris@16: 
Chris@16:   vertex_weight_type vertex_weight(vertices_size_type v, std::size_t n)
Chris@16:   { return vertex_weights[v*num_vertex_weights() + n]; }
Chris@16: 
Chris@16:   bool has_edge_weights() const { return edge_weights; }
Chris@16: 
Chris@16:  private:
Chris@16:   void start();
Chris@16: 
Chris@16:   // Configuration information
Chris@16:   std::istream& in;
Chris@16: 
Chris@16:   // Information about the current METIS file
Chris@16:   vertices_size_type n_vertices;
Chris@16:   edges_size_type n_edges;
Chris@16:   std::size_t n_vertex_weights;
Chris@16:   bool edge_weights;
Chris@16: 
Chris@16:   // Information about the current edge/vertex
Chris@16:   std::istringstream line_in;
Chris@16:   std::pair<vertices_size_type, vertices_size_type> edge;
Chris@16:   std::vector<vertex_weight_type> vertex_weights;
Chris@16:   edge_weight_type edge_weight;    
Chris@16: 
Chris@16:   friend bool operator==(edge_iterator, edge_iterator);
Chris@16:   friend bool operator!=(edge_iterator, edge_iterator);
Chris@16: };
Chris@16: 
Chris@16: class metis_distribution
Chris@16: {
Chris@16:  public:  
Chris@16:   typedef int process_id_type;
Chris@16:   typedef std::size_t size_type;
Chris@16:   typedef std::vector<process_id_type>::iterator iterator;
Chris@16: 
Chris@16:   metis_distribution(std::istream& in, process_id_type my_id);
Chris@16:   
Chris@16:   size_type block_size(process_id_type id, size_type) const;
Chris@16:   process_id_type operator()(size_type n) const { return vertices[n]; }
Chris@16:   size_type local(size_type n) const;
Chris@16:   size_type global(size_type n) const { return global(my_id, n); }
Chris@16:   size_type global(process_id_type id, size_type n) const;
Chris@16: 
Chris@16:   iterator begin() { return vertices.begin(); }
Chris@16:   iterator end()   { return vertices.end(); }
Chris@16: 
Chris@16:  private:
Chris@16:   std::istream& in;
Chris@16:   process_id_type my_id;
Chris@16:   std::vector<process_id_type> vertices;
Chris@16: };
Chris@16: 
Chris@16: #if !defined(BOOST_GRAPH_METIS_NO_INLINE) || defined(BOOST_GRAPH_METIS_SOURCE)
Chris@16: BOOST_GRAPH_METIS_INLINE_KEYWORD
Chris@16: bool operator==(metis_reader::edge_iterator x, metis_reader::edge_iterator y)
Chris@16: {
Chris@16:   return (x.self == y.self
Chris@16:           || (x.self && x.self->edge.first == x.self->num_vertices())
Chris@16:           || (y.self && y.self->edge.first == y.self->num_vertices()));
Chris@16: }
Chris@16: 
Chris@16: BOOST_GRAPH_METIS_INLINE_KEYWORD
Chris@16: bool operator!=(metis_reader::edge_iterator x, metis_reader::edge_iterator y)
Chris@16: {
Chris@16:   return !(x == y);
Chris@16: }
Chris@16: 
Chris@16: BOOST_GRAPH_METIS_INLINE_KEYWORD
Chris@16: metis_reader::edge_iterator::edge_iterator(metis_reader* self) 
Chris@16:   : self(self) 
Chris@16: {
Chris@16:   if (self) advance(true);
Chris@16: }
Chris@16: 
Chris@16: BOOST_GRAPH_METIS_INLINE_KEYWORD
Chris@16: metis_reader::edge_iterator& metis_reader::edge_iterator::operator++()
Chris@16: {
Chris@16:   advance(false);
Chris@16:   return *this;
Chris@16: }
Chris@16: 
Chris@16: BOOST_GRAPH_METIS_INLINE_KEYWORD
Chris@16: void metis_reader::edge_iterator::advance(bool skip_initial_read)
Chris@16: {
Chris@16:   do {
Chris@16: 
Chris@16:     if (!skip_initial_read) {
Chris@16:       // Try to read the next edge
Chris@16:       if (self->line_in >> std::ws >> self->edge.second) {
Chris@16:         --self->edge.second;
Chris@16:         if (self->has_edge_weights()) {
Chris@16:           if (!(self->line_in >> self->edge_weight))
Chris@16:             boost::throw_exception(metis_input_exception());
Chris@16:         }
Chris@16:         return;
Chris@16:       }
Chris@16: 
Chris@16:       // Check if we're done
Chris@16:       ++self->edge.first;
Chris@16:       if (self->edge.first == self->num_vertices())
Chris@16:         return;
Chris@16:     }
Chris@16: 
Chris@16:     // Find the next line
Chris@16:     std::string line;
Chris@16:     while (getline(self->in, line) && !line.empty() && line[0] == '%') {
Chris@16:       /* Keep reading lines in the loop header... */
Chris@16:     }
Chris@16:     if (!self->in) boost::throw_exception(metis_input_exception());
Chris@16:     self->line_in.str(line);
Chris@16:     self->line_in.clear();
Chris@16: 
Chris@16:     // Read the next line
Chris@16:     std::size_t weights_left = self->n_vertex_weights;
Chris@16:     vertex_weight_type weight;
Chris@16:     while (weights_left > 0) {
Chris@16:       if (self->line_in >> weight) self->vertex_weights.push_back(weight);
Chris@16:       else boost::throw_exception(metis_input_exception());
Chris@16:       --weights_left;
Chris@16:     }
Chris@16: 
Chris@16:     // Successive iterations will pick up edges for this vertex.
Chris@16:     skip_initial_read = false;
Chris@16:   } while (true);
Chris@16: }
Chris@16: 
Chris@16: BOOST_GRAPH_METIS_INLINE_KEYWORD
Chris@16: metis_reader::edge_iterator::postincrement_proxy 
Chris@16: metis_reader::edge_iterator::operator++(int)
Chris@16: {
Chris@16:   postincrement_proxy result(**this);
Chris@16:   ++(*this);
Chris@16:   return result;
Chris@16: }
Chris@16: 
Chris@16: BOOST_GRAPH_METIS_INLINE_KEYWORD
Chris@16: metis_reader::edge_iterator metis_reader::begin()
Chris@16: {
Chris@16:   if (edge.first != 0) start();
Chris@16:   return edge_iterator(this);
Chris@16: }
Chris@16: 
Chris@16: BOOST_GRAPH_METIS_INLINE_KEYWORD
Chris@16: metis_reader::edge_iterator metis_reader::end()
Chris@16: {
Chris@16:   return edge_iterator(0);
Chris@16: }
Chris@16: 
Chris@16: BOOST_GRAPH_METIS_INLINE_KEYWORD
Chris@16: metis_reader::edge_weight_iterator metis_reader::weight_begin()
Chris@16: {
Chris@16:   return edge_weight_iterator(this);
Chris@16: }
Chris@16: 
Chris@16: BOOST_GRAPH_METIS_INLINE_KEYWORD
Chris@16: void metis_reader::start()
Chris@16: {
Chris@16:   in.seekg(0, std::ios::beg);
Chris@16:   std::string line;
Chris@16:   while (getline(in, line) && !line.empty() && line[0] == '%') {
Chris@16:     /* Keep getting lines in loop header. */
Chris@16:   }
Chris@16: 
Chris@16:   if (!in || line.empty()) boost::throw_exception(metis_input_exception());
Chris@16: 
Chris@16:   // Determine number of vertices and edges in the graph
Chris@16:   line_in.str(line);
Chris@16:   if (!(line_in >> n_vertices >> n_edges)) boost::throw_exception(metis_input_exception());
Chris@16: 
Chris@16:   // Determine whether vertex or edge weights are included in the graph
Chris@16:   int fmt = 0;
Chris@16:   line_in >> fmt;
Chris@16:   n_vertex_weights = fmt / 10;
Chris@16:   edge_weights = (fmt % 10 == 1);
Chris@16:   
Chris@16:   // Determine how many (if any!) vertex weights are included
Chris@16:   if (n_vertex_weights) line_in >> n_vertex_weights;
Chris@16: 
Chris@16:   // Setup the iteration data structures
Chris@16:   edge_weight = 1.0;
Chris@16:   edge.first = 0;
Chris@16:   edge.second = 0;
Chris@16:   vertex_weights.reserve(n_vertex_weights * num_vertices());
Chris@16: }
Chris@16: 
Chris@16: metis_distribution::metis_distribution(std::istream& in, process_id_type my_id)
Chris@16:   : in(in), my_id(my_id), 
Chris@16:     vertices(std::istream_iterator<process_id_type>(in),
Chris@16:              std::istream_iterator<process_id_type>())
Chris@16: {
Chris@16: }
Chris@16: 
Chris@16: 
Chris@16: metis_distribution::size_type 
Chris@16: metis_distribution::block_size(process_id_type id, size_type) const
Chris@16: {
Chris@16:   return std::count(vertices.begin(), vertices.end(), id);
Chris@16: }
Chris@16: 
Chris@16: metis_distribution::size_type metis_distribution::local(size_type n) const
Chris@16: {
Chris@16:   return std::count(vertices.begin(), vertices.begin() + n, vertices[n]);
Chris@16: }
Chris@16: 
Chris@16: metis_distribution::size_type 
Chris@16: metis_distribution::global(process_id_type id, size_type n) const
Chris@16: {
Chris@16:   std::vector<process_id_type>::const_iterator i = vertices.begin();
Chris@16:   while (*i != id) ++i;
Chris@16: 
Chris@16:   while (n > 0) {
Chris@16:     do { ++i; } while (*i != id); 
Chris@16:     --n;
Chris@16:   }
Chris@16: 
Chris@16:   return i - vertices.begin();
Chris@16: }
Chris@16: 
Chris@16: #endif
Chris@16: 
Chris@16: } } // end namespace boost::graph
Chris@16: 
Chris@16: #endif // BOOST_GRAPH_METIS_HPP