Module org.jgrapht.core
Package org.jgrapht.alg.interfaces

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 Details

    • 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

      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

      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

      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 $T$