undiGraph.cpp

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 *       - Pierre-Henri WUILLEMIN(_at_LIP6)                                 *
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#include <agrum/base/graphs/undiGraph.h>
 
#ifdef GUM_NO_INLINE
#  include <agrum/base/graphs/undiGraph_inl.h>
#endif   // GU%_NO_INLINE
#include <cstdio>
#include <iostream>
 
#include "graphElements.h"
 
namespace gum {
 
  UndiGraph UndiGraph::completeGraph(int n) {
    UndiGraph g;
    g.addNodes(n);
 
    for (int j = 0; j < n; ++j) {
      for (int k = j + 1; k < n; ++k) {
        g.addEdge(j, k);
      }
    }
    return g;
  }
 
  UndiGraph::UndiGraph(Size nodes_size,
                       bool nodes_resize_policy,
                       Size edges_size,
                       bool edges_resize_policy) :
      NodeGraphPart(nodes_size, nodes_resize_policy),
      EdgeGraphPart(edges_size, edges_resize_policy) {
    GUM_CONSTRUCTOR(UndiGraph);
  }
 
  UndiGraph::UndiGraph(const UndiGraph& g) : NodeGraphPart(g), EdgeGraphPart(g) {
    GUM_CONS_CPY(UndiGraph);
  }
 
  UndiGraph::~UndiGraph() {
    GUM_DESTRUCTOR(UndiGraph);
    ;
  }
 
  bool UndiGraph::hasUndirectedCycle() const {
    List< std::pair< NodeId, NodeId > > open_nodes;
    NodeProperty< bool >                examined_nodes = nodesPropertyFromVal(false);
    std::pair< NodeId, NodeId >         thePair;
    NodeId                              current, from_current;
 
    for (const auto node: nodes()) {
      // check if the node has already been examined (if this is not the case,
      // this means that we are on a new connected component)
      if (!examined_nodes[node]) {
        // indicates that we are examining a new node
        examined_nodes[node] = true;
 
        // check recursively all the nodes of node's connected component
        thePair.first  = node;
        thePair.second = node;
        open_nodes.insert(thePair);
 
        while (!open_nodes.empty()) {
          // get a node to propagate
          thePair = open_nodes.front();
          open_nodes.popFront();
 
          current      = thePair.first;
          from_current = thePair.second;
 
          // check the neighbours
          for (const auto new_node: neighbours(current))
 
            // avoid to check the node we are coming from
            if (new_node != from_current) {
              if (examined_nodes[new_node]) return true;
              else {
                examined_nodes[new_node] = true;
                thePair.first            = new_node;
                thePair.second           = current;
                open_nodes.insert(thePair);
              }
            }
        }
      }
    }
 
    return false;
  }
 
  std::string UndiGraph::toString() const {
    std::string s = NodeGraphPart::toString();
    s += " , ";
    s += EdgeGraphPart::toString();
    return s;
  }
 
  std::string UndiGraph::toDot() const {
    std::stringstream output;
    std::stringstream nodeStream;
    std::stringstream edgeStream;
    List< NodeId >    treatedNodes;
    output << "digraph \""
           << "no_name\" {" << std::endl
           << "edge [dir=none]" << std::endl;
    nodeStream << "node [shape = ellipse];" << std::endl;
    std::string tab = "  ";
 
    for (const auto node: nodes()) {
      nodeStream << tab << node << ";";
 
      if (neighbours(node).size() > 0)
        for (const auto nei: neighbours(node))
          if (!treatedNodes.exists(nei))
            edgeStream << tab << node << " -> " << nei << ";" << std::endl;
 
      treatedNodes.insert(node);
    }
 
    output << nodeStream.str() << std::endl << edgeStream.str() << std::endl << "}" << std::endl;
 
    return output.str();
  }

  UndiGraph UndiGraph::partialUndiGraph(NodeSet nodes) {
    UndiGraph partialGraph;
 
    for (const auto node: nodes) {
      partialGraph.addNodeWithId(node);
 
      for (const auto nei: neighbours(node))
        if (nodes.contains(nei) && partialGraph.existsNode(nei)) partialGraph.addEdge(node, nei);
    }
 
    return partialGraph;
  }
 
  NodeProperty< NodeId > UndiGraph::nodes2ConnectedComponent() const {
    NodeProperty< NodeId > res;
 
    NodeId numCC = 0;
    for (const auto node: nodes()) {
      if (res.exists(node)) continue;
      NodeSet nodes{node};
      while (!nodes.empty()) {
        auto actual = *(nodes.begin());
        nodes.erase(actual);
        res.insert(actual, numCC);
        for (const auto nei: neighbours(actual)) {
          if (!res.exists(nei))
            if (!nodes.exists(nei)) nodes.insert(nei);
        }
      }
      numCC += 1;
    }
 
    return res;
  }

  std::ostream& operator<<(std::ostream& stream, const UndiGraph& g) {
    stream << g.toString();
    return stream;
  }
 
} /* namespace gum */