Changeset 653:c7d160f73d52 in lemon for lemon/network_simplex.h
 Timestamp:
 03/25/09 21:37:50 (10 years ago)
 Branch:
 default
 Phase:
 public
 File:

 1 edited
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lemon/network_simplex.h
r652 r653 42 42 /// \ref NetworkSimplex implements the primal Network Simplex algorithm 43 43 /// for finding a \ref min_cost_flow "minimum cost flow". 44 /// This algorithm is a specialized version of the linear programming 45 /// simplex method directly for the minimum cost flow problem. 46 /// It is one of the most efficient solution methods. 47 /// 48 /// In general this class is the fastest implementation available 49 /// in LEMON for the minimum cost flow problem. 44 50 /// 45 51 /// \tparam GR The digraph type the algorithm runs on. … … 47 53 /// By default it is \c int. 48 54 /// 49 /// \warning \c Vmust be a signed integer type.55 /// \warning The value type must be a signed integer type. 50 56 /// 51 57 /// \note %NetworkSimplex provides five different pivot rule … … 790 796 /// This function runs the algorithm. 791 797 /// The paramters can be specified using \ref lowerMap(), 792 /// \ref upperMap(), \ref capacityMap(), \ref boundMaps(), 798 /// \ref upperMap(), \ref capacityMap(), \ref boundMaps(), 793 799 /// \ref costMap(), \ref supplyMap() and \ref stSupply() 794 800 /// functions. For example, … … 799 805 /// \endcode 800 806 /// 807 /// This function can be called more than once. All the parameters 808 /// that have been given are kept for the next call, unless 809 /// \ref reset() is called, thus only the modified parameters 810 /// have to be set again. See \ref reset() for examples. 811 /// 801 812 /// \param pivot_rule The pivot rule that will be used during the 802 813 /// algorithm. For more information see \ref PivotRule. … … 805 816 bool run(PivotRule pivot_rule = BLOCK_SEARCH) { 806 817 return init() && start(pivot_rule); 818 } 819 820 /// \brief Reset all the parameters that have been given before. 821 /// 822 /// This function resets all the paramaters that have been given 823 /// using \ref lowerMap(), \ref upperMap(), \ref capacityMap(), 824 /// \ref boundMaps(), \ref costMap(), \ref supplyMap() and 825 /// \ref stSupply() functions before. 826 /// 827 /// It is useful for multiple run() calls. If this function is not 828 /// used, all the parameters given before are kept for the next 829 /// \ref run() call. 830 /// 831 /// For example, 832 /// \code 833 /// NetworkSimplex<ListDigraph> ns(graph); 834 /// 835 /// // First run 836 /// ns.lowerMap(lower).capacityMap(cap).costMap(cost) 837 /// .supplyMap(sup).run(); 838 /// 839 /// // Run again with modified cost map (reset() is not called, 840 /// // so only the cost map have to be set again) 841 /// cost[e] += 100; 842 /// ns.costMap(cost).run(); 843 /// 844 /// // Run again from scratch using reset() 845 /// // (the lower bounds will be set to zero on all arcs) 846 /// ns.reset(); 847 /// ns.capacityMap(cap).costMap(cost) 848 /// .supplyMap(sup).run(); 849 /// \endcode 850 /// 851 /// \return <tt>(*this)</tt> 852 NetworkSimplex& reset() { 853 delete _plower; 854 delete _pupper; 855 delete _pcost; 856 delete _psupply; 857 _plower = NULL; 858 _pupper = NULL; 859 _pcost = NULL; 860 _psupply = NULL; 861 _pstsup = false; 862 return *this; 807 863 } 808 864 … … 921 977 _cost.resize(all_arc_num); 922 978 _supply.resize(all_node_num); 923 _flow.resize(all_arc_num , 0);924 _pi.resize(all_node_num , 0);979 _flow.resize(all_arc_num); 980 _pi.resize(all_node_num); 925 981 926 982 _parent.resize(all_node_num); … … 931 987 _succ_num.resize(all_node_num); 932 988 _last_succ.resize(all_node_num); 933 _state.resize(all_arc_num , STATE_LOWER);989 _state.resize(all_arc_num); 934 990 935 991 // Initialize node related data … … 987 1043 _cap[i] = (*_pupper)[e]; 988 1044 _cost[i] = (*_pcost)[e]; 1045 _flow[i] = 0; 1046 _state[i] = STATE_LOWER; 989 1047 } 990 1048 } else { … … 993 1051 _source[i] = _node_id[_graph.source(e)]; 994 1052 _target[i] = _node_id[_graph.target(e)]; 1053 _flow[i] = 0; 1054 _state[i] = STATE_LOWER; 995 1055 } 996 1056 if (_pupper) { … … 1033 1093 _parent[u] = _root; 1034 1094 _pred[u] = e; 1095 _cost[e] = max_cost; 1096 _cap[e] = max_cap; 1097 _state[e] = STATE_TREE; 1035 1098 if (_supply[u] >= 0) { 1036 1099 _flow[e] = _supply[u]; … … 1042 1105 _pi[u] = max_cost; 1043 1106 } 1044 _cost[e] = max_cost;1045 _cap[e] = max_cap;1046 _state[e] = STATE_TREE;1047 1107 } 1048 1108
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