Interface MinimumSTCutAlgorithm<V,​E>

  • Type Parameters:
    V - the graph vertex type
    E - the graph edge type
    All Known Implementing Classes:
    BoykovKolmogorovMFImpl, DinicMFImpl, EdmondsKarpMFImpl, GusfieldGomoryHuCutTree, MaximumFlowAlgorithmBase, PushRelabelMFImpl

    public interface MinimumSTCutAlgorithm<V,​E>
    Given a weighted graph $G(V,E)$ (directed or undirected). This class computes a minimum $s-t$ cut. A cut is a partitioning of the vertices into two disjoint sets $S, T $such that $s \in S, t \in T$, and that $S \cup T = V%. The capacity of a cut is defined as the sum of the weights of the edges from $S$ to $T$. In case of a directed graph, only the edges with their tail in $S$ and their head in $T$ are counted. In cased of a undirected graph, all edges with one endpoint in $S$ and one endpoint in $T$ are counted. For a given $s$ and $t$, this class computes two partitions $S$ and $T$ such that the capacity of the cut is minimized. When each edge has equal weight, by definition this class minimizes the number of edges from $S$ to $T$. Note: it is not recommended to use this class to calculate the overall minimum cut in a graph by iteratively invoking this class for all source-sink pairs. This is computationally expensive. Instead, use the StoerWagnerMinimumCut implementation.
    Author:
    Joris Kinable
    • Method Detail

      • calculateMinCut

        double calculateMinCut​(V source,
                               V sink)
        Computes a minimum capacity $s-t$ cut.
        Parameters:
        source - s
        sink - t
        Returns:
        capacity of the cut
      • getCutCapacity

        double getCutCapacity()
        Returns the capacity of the cut obtained after the last invocation of calculateMinCut(Object, Object)
        Returns:
        capacity of the cut
      • getSourcePartition

        java.util.Set<V> getSourcePartition()
        Returns the source partition $S$, $s \in S$, of the cut obtained after the last invocation of calculateMinCut(Object, Object)
        Returns:
        source partition S
      • getSinkPartition

        java.util.Set<V> getSinkPartition()
        Returns the sink partition $T$, $t \in T$, of the cut obtained after the last invocation of calculateMinCut(Object, Object)
        Returns:
        source partition T
      • getCutEdges

        java.util.Set<E> getCutEdges()
        Returns the set of edges which run from $S$ to $T$, in the $s-t$ cut obtained after the last invocation of calculateMinCut(Object, Object) In case of a directed graph, only the edges with their tail in $S$ and their head in $T$ are returned. In cased of a undirected graph, all edges with one endpoint in $S$ and one endpoint in $T$ are returned.
        Returns:
        set of edges which run from $S$ to $T$