RhodeCode

      _level->initFinish();

      for (OutArcIt e(_graph, _source); e != INVALID; ++e) {

        if (_tolerance.positive((*_capacity)[e])) {

          Node u = _graph.target(e);

          if ((*_level)[u] == _level->maxLevel()) continue;

          _flow->set(e, (*_capacity)[e]);

          _excess->set(u, (*_excess)[u] + (*_capacity)[e]);

          if (u != _target && !_level->active(u)) {

            _level->activate(u);

          }

        }

      }

    }

    /// \brief Initializes the internal data structures.

    ///

    /// Initializes the internal data structures and sets the initial

    /// flow to the given \c flowMap. The \c flowMap should contain a

    /// flow or at least a preflow, ie. in each node excluding the

    /// target the incoming flow should greater or equal to the

    /// outgoing flow.

    /// \return %False when the given \c flowMap is not a preflow.

    template <typename FlowMap>

      createStructures();

      for (ArcIt e(_graph); e != INVALID; ++e) {

        _flow->set(e, flowMap[e]);

      }

      for (NodeIt n(_graph); n != INVALID; ++n) {

        Value excess = 0;

        for (InArcIt e(_graph, n); e != INVALID; ++e) {

          excess += (*_flow)[e];

        }

        for (OutArcIt e(_graph, n); e != INVALID; ++e) {

          excess -= (*_flow)[e];

        }

        if (excess < 0 && n != _source) return false;

        _excess->set(n, excess);

      }

      typename Digraph::template NodeMap<bool> reached(_graph, false);

      _level->initStart();

      _level->initAddItem(_target);

      std::vector<Node> queue;

  typedef concepts::Digraph Digraph;

  typedef Digraph::Node Node;

  typedef Digraph::Arc Arc;

  typedef concepts::ReadMap<Arc,VType> CapMap;

  typedef concepts::ReadWriteMap<Arc,VType> FlowMap;

  typedef concepts::WriteMap<Node,bool> CutMap;

  Digraph g;

  Node n;

  Arc e;

  CapMap cap;

  FlowMap flow;

  CutMap cut;

  Preflow<Digraph, CapMap>::SetFlowMap<FlowMap>::Create preflow_test(g,cap,n,n);

  preflow_test.capacityMap(cap);

  flow = preflow_test.flowMap();

  preflow_test.flowMap(flow);

  preflow_test.source(n);

  preflow_test.target(n);

  preflow_test.init();

  preflow_test.startFirstPhase();

  preflow_test.startSecondPhase();

  preflow_test.run();

  preflow_test.runMinCut();

  preflow_test.flowValue();

  preflow_test.minCut(n);

  preflow_test.minCutMap(cut);

  preflow_test.flow(e);

}

int cutValue (const SmartDigraph& g,

              const SmartDigraph::NodeMap<bool>& cut,

              const SmartDigraph::ArcMap<int>& cap) {

  int c=0;

  for(SmartDigraph::ArcIt e(g); e!=INVALID; ++e) {

    if (cut[g.source(e)] && !cut[g.target(e)]) c+=cap[e];

  }

  return c;

}

bool checkFlow(const SmartDigraph& g,

    arcMap("capacity", cap).

    node("source",s).

    node("target",t).

    run();

  PType preflow_test(g, cap, s, t);

  preflow_test.run();

  check(checkFlow(g, preflow_test.flowMap(), cap, s, t),

        "The flow is not feasible.");

  CutMap min_cut(g);

  preflow_test.minCutMap(min_cut);

  int min_cut_value=cutValue(g,min_cut,cap);

  check(preflow_test.flowValue() == min_cut_value,

        "The max flow value is not equal to the three min cut values.");

  FlowMap flow(g);

  for(ArcIt e(g); e!=INVALID; ++e) flow[e] = preflow_test.flowMap()[e];

  int flow_value=preflow_test.flowValue();

  for(ArcIt e(g); e!=INVALID; ++e) cap[e]=2*cap[e];

  preflow_test.startFirstPhase();

  CutMap min_cut1(g);

  preflow_test.minCutMap(min_cut1);

  min_cut_value=cutValue(g,min_cut1,cap);

  check(preflow_test.flowValue() == min_cut_value &&

        min_cut_value == 2*flow_value,

        "The max flow value or the min cut value is wrong.");

  preflow_test.startSecondPhase();

  check(checkFlow(g, preflow_test.flowMap(), cap, s, t),

        "The flow is not feasible.");

  CutMap min_cut2(g);

  preflow_test.minCutMap(min_cut2);

  min_cut_value=cutValue(g,min_cut2,cap);

  check(preflow_test.flowValue() == min_cut_value &&

        min_cut_value == 2*flow_value,

        "The max flow value or the three min cut values were not doubled");