fn() fordFulkersonAlgorithm
Computes a maximum flow in a directed graph.

Defined in <seqan/graph_algorithms.h>
Signature TValue fordFulkeronAlgorithm(g, source, sink, capacity, flow);

Parameters

flow A property map with the flow of each edge.
capacity A property map of edge capacities.
sink A sink vertex. Types: VertexDescriptor
g A directed graph. Types: Directed Graph
source A source vertex. Types: VertexDescriptor

Return Values

TValue The value of the flow. TValue is the Value tpye of the type of flow.

Detailed Description

Example

#include <iostream>
#include <seqan/graph_algorithms.h>

using namespace seqan;

int main()
{
    typedef Graph<Directed<> > TGraph;
    typedef VertexDescriptor<TGraph>::Type TVertexDescriptor;
    typedef EdgeDescriptor<TGraph>::Type TEdgeDescriptor;
    typedef Iterator<TGraph, EdgeIterator>::Type TEdgeIterator;
    typedef Size<TGraph>::Type TSize;

    // Create graph with 10 directed edges (0,1), (0,4), ...
    TSize numEdges = 10;
    TVertexDescriptor edges[] = {0,1, 0,4, 1,2, 1,4, 2,3, 2,4, 4,1, 4,5, 5,2, 5,3};
    TGraph g;
    addEdges(g,edges, numEdges);
    // Print graph.
    std::cout << g << "\n";

    // Create external property map for the edge capacities and assign to the graph.
    String<unsigned int> capMap;
    unsigned capacity[] =    {16,  13,  12,  10,  20,  9,   4,   14,  7,   4};
    assignEdgeMap(g, capMap, capacity);

    // Run the Ford-Fulkerson algorithm for maximum flow computation from source
    // vertex 0 to sink vertex 3.  valF is the value of the flow.
    String<unsigned int> flow;
    unsigned valF = fordFulkersonAlgorithm(g, 0, 3, capMap, flow);

    // Print the result to stdout.
    std::cout << "Ford-Fulkerson (Value of the flow = " << valF << ")\n";
    TEdgeIterator itEdge(g);
    for(;!atEnd(itEdge);goNext(itEdge))
        std::cout << "(" << sourceVertex(itEdge) << "," << targetVertex(itEdge) << "): "
                  << "Flow: " << getProperty(flow, getValue(itEdge)) << ", Capacity: "
                  << getProperty(capMap, getValue(itEdge)) << "\n";

    return 0;
}
Adjacency list:
0 -> 4,1,
1 -> 4,2,
2 -> 4,3,
3 -> 
4 -> 5,1,
5 -> 3,2,
Edge list:
Source: 0,Target: 4 (Id: 1)
Source: 0,Target: 1 (Id: 0)
Source: 1,Target: 4 (Id: 3)
Source: 1,Target: 2 (Id: 2)
Source: 2,Target: 4 (Id: 5)
Source: 2,Target: 3 (Id: 4)
Source: 4,Target: 5 (Id: 7)
Source: 4,Target: 1 (Id: 6)
Source: 5,Target: 3 (Id: 9)
Source: 5,Target: 2 (Id: 8)

Ford-Fulkerson (Value of the flow = 23)
(0,4): Flow: 11, Capacity: 13
(0,1): Flow: 12, Capacity: 16
(1,4): Flow: 0, Capacity: 10
(1,2): Flow: 12, Capacity: 12
(2,4): Flow: 0, Capacity: 9
(2,3): Flow: 19, Capacity: 20
(4,5): Flow: 11, Capacity: 14
(4,1): Flow: 0, Capacity: 4
(5,3): Flow: 4, Capacity: 4
(5,2): Flow: 7, Capacity: 7