COIN-OR::LEMON - Graph Library

Changeset 211:9222a9b8b323 in lemon-0.x for src/work/jacint/dijkstra.h


Ignore:
Timestamp:
03/19/04 23:16:05 (17 years ago)
Author:
jacint
Branch:
default
Phase:
public
Convert:
svn:c9d7d8f5-90d6-0310-b91f-818b3a526b0e/lemon/trunk@306
Message:

updating

File:
1 edited

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  • src/work/jacint/dijkstra.h

    r171 r211  
    11// -*- C++ -*-
    2 
    3 //ha predecessor az elejen nem invalid, akkor hagyd csak ugy
    4 //scanned mutatja hogy jo ertek van-e benne vagy szemet
    5 
    62/*
    7  *template <Graph, T, Heap=FibHeap>
     3 *template <Graph, T, Heap=FibHeap, LengthMap=Graph::EdgeMap<T> >
    84 *
    95 *Constructor:
    106 *
    11  *Dijkstra(Graph G, NodeIt s, Graph::EdgeMap<T> length)
     7 *Dijkstra(Graph G, LengthMap length)
    128 *
    139 *
    14  *Member functions:
     10 *Methods:
    1511 *
    16  *void run()
     12 *void run(Node s)
    1713 *
    18  *  The following function should be used after run() was already run.
     14 *T dist(Node v) : After run(s) was run, it returns the distance from s to v.
     15 *   Returns T() if v is not reachable from s.
    1916 *
    20  *T dist(NodeIt v) : returns the distance from s to v.
    21  *   It is 0 if v is not reachable from s.
     17 *Edge pred(Node v) : After run(s) was run, it returns the last
     18 *   edge of a shortest s-v path. It is INVALID for s and for
     19 *   the nodes not reachable from s.
    2220 *
    23  *EdgeIt pred(NodeIt v) : returns the last edge
    24  *   of a shortest s-v path. Returns an invalid iterator
    25  *   if v=s or v is not reachable from s.
    26  *
    27  *bool reach(NodeIt v) : true iff v is reachable from s
     21 *bool reached(Node v) : After run(s) was run, it is true iff v is
     22 *   reachable from s
    2823 *
    2924 */
    3025
    31 #ifndef DIJKSTRA_H
    32 #define DIJKSTRA_H
     26#ifndef HUGO_DIJKSTRA_H
     27#define HUGO_DIJKSTRA_H
    3328
    3429#include <fib_heap.h>
     30#include <invalid.h>
    3531
    3632namespace hugo {
    37 
     33 
    3834  template <typename Graph, typename T,
    39     typename Heap=FibHeap<typename Graph::NodeIt, T,
    40     typename Graph::NodeMap<int> > >
    41     class Dijkstra{
    42       typedef typename Graph::NodeIt NodeIt;
    43       typedef typename Graph::EdgeIt EdgeIt;
    44       typedef typename Graph::OutEdgeIt OutEdgeIt;
    45      
    46       Graph& G;
    47       NodeIt s;
    48       typename Graph::NodeMap<EdgeIt> predecessor;
    49       typename Graph::NodeMap<T> distance;
    50       typename Graph::EdgeMap<T>& length;
    51       typename Graph::NodeMap<bool> reached;
    52          
     35    typename Heap=FibHeap<typename Graph::Node, T,
     36    typename Graph::NodeMap<int> >,
     37    typename LengthMap=typename Graph::EdgeMap<T> >
     38  class Dijkstra{
     39    typedef typename Graph::Node Node;
     40    typedef typename Graph::NodeIt NodeIt;
     41    typedef typename Graph::Edge Edge;
     42    typedef typename Graph::OutEdgeIt OutEdgeIt;
     43   
     44    const Graph& G;
     45    const LengthMap& length;
     46    typename Graph::NodeMap<Edge> predecessor;
     47    typename Graph::NodeMap<T> distance;
     48    typename Graph::NodeMap<bool> reach;
     49   
    5350  public :
    54 
     51   
    5552    /*
    5653      The distance of the nodes is 0.
    5754    */
    58     Dijkstra(Graph& _G, NodeIt const _s,
    59              typename Graph::EdgeMap<T>& _length) :
    60       G(_G), s(_s), predecessor(G), distance(G),
    61       length(_length), reached(G, false) { }
     55    Dijkstra(Graph& _G, LengthMap& _length) : G(_G),
     56      length(_length), predecessor(_G), distance(_G), reach(_G) { }
    6257   
     58
     59    void run(Node s) {
    6360     
    64       void run() {
     61      NodeIt u;
     62      for ( G.first(u) ; G.valid(u) ; G.next(u) ) {
     63        predecessor.set(u,INVALID);
     64        distance.set(u,0);
     65        reach.set(u,false);
     66      }
     67     
     68      typename Graph::NodeMap<bool> scanned(G,false);
     69      typename Graph::NodeMap<int> heap_map(G,-1);
     70     
     71      Heap heap(heap_map);
     72
     73      heap.push(s,0);
     74      reach.set(s, true);
     75
     76      while ( !heap.empty() ) {
    6577       
    66         typename Graph::NodeMap<bool> scanned(G, false);
    67         typename Graph::NodeMap<int> heap_map(G,-1);
     78        Node v=heap.top();
     79        T oldvalue=heap.get(v);
     80        heap.pop();
     81        distance.set(v, oldvalue);
     82        scanned.set(v,true);
    6883
    69         Heap heap(heap_map);
    70 
    71         heap.push(s,0);
    72         reached.set(s, true);
    73 
    74         while ( !heap.empty() ) {
    75 
    76           NodeIt v=heap.top();
    77           T oldvalue=heap.get(v);
    78           heap.pop();
    79           distance.set(v, oldvalue);
    80           scanned.set(v,true);
    81 
    82           OutEdgeIt e;
    83           for( G.getFirst(e,v); G.valid(e); G.next(e)) {
    84             NodeIt w=G.bNode(e);
     84        OutEdgeIt e;
     85        for( G.first(e,v); G.valid(e); G.next(e)) {
     86          Node w=G.head(e);
    8587           
    86             if ( !scanned.get(w) ) {
    87               if ( !reached.get(w) ) {
    88                 reached.set(w,true);
    89                 heap.push(w,oldvalue+length.get(e));
    90                 predecessor.set(w,e);
    91               } else if ( oldvalue+length.get(e) < heap.get(w) ) {
    92                 predecessor.set(w,e);
    93                 heap.decrease(w, oldvalue+length.get(e));
    94               }
     88          if ( !scanned[w] ) {
     89            if ( !reach[w] ) {
     90              reach.set(w,true);
     91              heap.push(w,oldvalue+length[e]);
     92              predecessor.set(w,e);
     93            } else if ( oldvalue+length[e] < heap.get(w) ) {
     94              predecessor.set(w,e);
     95              heap.decrease(w, oldvalue+length[e]);
    9596            }
    9697          }
    9798        }
    98       }
    99      
     99      }
     100    }
     101   
    100102
    101       T dist(NodeIt v) {
    102         return distance.get(v);
    103       }
     103    T dist(Node v) {
     104      return distance[v];
     105    }
    104106
    105107
    106       EdgeIt pred(NodeIt v) {
    107         if ( v!=s ) return predecessor.get(v);
    108         else return EdgeIt();
    109       }
     108    Edge pred(Node v) {
     109      return predecessor[v];
     110    }
    110111     
    111112
    112       bool reach(NodeIt v) {
    113         return reached.get(v);
    114       }
    115      
    116     };
     113    bool reached(Node v) {
     114      return reach[v];
     115    }
     116   
     117  };
    117118 
    118119}
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