Package org.graphstream.algorithm

Class Eccentricity

java.lang.Object
org.graphstream.algorithm.Eccentricity
All Implemented Interfaces:
Algorithm
public class Eccentricity
extends Object
implements Algorithm
Compute the eccentricity of a connected graph.

In a graph G, if d(u,v) is the shortest length between two nodes u and v (ie the number of edges of the shortest path) let e(u) be the d(u,v) such that v is the farthest of u. Eccentricity of a graph G is a subgraph induced by vertices u with minimum e(u).

Requirements

This algorithm needs that APSP algorithm has been computed before its own computation.

Example

 import java.io.StringReader;
 import java.io.IOException;
 
 import org.graphstream.algorithm.Centroid;
 import org.graphstream.graph.Graph;
 import org.graphstream.graph.implementations.DefaultGraph;
 import org.graphstream.stream.file.FileSourceDGS;
 
 //                     +--- E
 // A --- B --- C -- D -|--- F
 //                     +--- G
 
 public class EccentriciyTest {
        static String my_graph = "DGS004\n" + "my 0 0\n" + "an A \n" + "an B \n"
                        + "an C \n" + "an D \n" + "an E \n" + "an F \n" + "an G \n"
                        + "ae AB A B \n" + "ae BC B C \n" + "ae CD C D \n" + "ae DE D E \n"
                        + "ae DF D F \n" + "ae DG D G \n";
 
        public static void main(String[] args) throws IOException {
                Graph graph = new DefaultGraph("Centroid Test");
                StringReader reader = new StringReader(my_graph);
 
                FileSourceDGS source = new FileSourceDGS();
                source.addSink(graph);
                source.readAll(reader);
 
                APSP apsp = new APSP();
                apsp.init(graph);
                apsp.compute();
 
                Eccentricity eccentricity = new Eccentricity();
                eccentricity.init(graph);
                eccentricity.compute();
 
                for (Node n : graph.getEachNode()) {
                        Boolean in = n.getAttribute("eccentricity");
 
                        System.out.printf("%s is%s in the eccentricity.\n", n.getId(), in ? ""
                                        : " not");
                }
 
                // Output will be :
                //
                // A is not in the eccentricity
                // B is not in the eccentricity
                // C is in the eccentricity
                // D is not in the eccentricity
                // E is not in the eccentricity
                // F is not in the eccentricity
                // G is not in the eccentricity
        }
 }
See Also:
APSP.APSPInfo
Computational Complexity :
O(n2)
Scientific Reference :
F. Harary, Graph Theory. Westview Press, Oct. 1969. [Online]. Available: http://www.amazon.com/exec/obidos/ redirect?tag=citeulike07-20\&path=ASIN/0201410338

  • Constructor Details

    • Eccentricity

      public Eccentricity()
      Build a new eccentricity algorithm with default parameters.

    • Eccentricity

      public Eccentricity​(String eccentricityAttribute)
      Build a new eccentricity algorithm, specifying the attribute name of the computation result
      Parameters:
      eccentricityAttribute - attribute name of the computation result.

    • Eccentricity

      public Eccentricity​(String eccentricityAttribute, Object isInEccentricity, Object isNotInEccentricity)
      Build a new eccentricity as in Eccentricity(String) but specifying values of eccentricity membership.
      Parameters:
      eccentricityAttribute - attribute name of the computation result.
      isInEccentricity - the value of elements eccentricity attribute when this element is in the eccentricity.
      isNotInEccentricity - the value of elements eccentricity attribute when this element is not in the eccentricity.

    • Eccentricity

      public Eccentricity​(String eccentricityAttribute, Object isInEccentricity, Object isNotInEccentricity, String apspInfoAttribute)
      Build a new eccentricity algorithm as in Eccentricity(String, Object, Object) but specifying the name of the attribute where the APSP informations are stored.
      Parameters:
      eccentricityAttribute - attribute name of the computation result.
      isInEccentricity - the value of elements eccentricity attribute when this element is in the eccentricity.
      isNotInEccentricity - the value of elements eccentricity attribute when this element is not in the eccentricity.
      apspInfoAttribute - the name of the attribute where the APSP informations are stored

  • Method Details

    • init

      public void init​(org.graphstream.graph.Graph graph)
      Description copied from interface: Algorithm
      Initialization of the algorithm. This method has to be called before the Algorithm.compute() method to initialize or reset the algorithm according to the new given graph.
      Specified by:
      init in interface Algorithm
      Parameters:
      graph - The graph this algorithm is using.

    • compute

      public void compute()
      Description copied from interface: Algorithm
      Run the algorithm. The Algorithm.init(Graph) method has to be called before computing.
      Specified by:
      compute in interface Algorithm
      See Also:
      Algorithm.init(Graph)

    • getAPSPInfoAttribute

      public String getAPSPInfoAttribute()
      Get the APSP info attribute name.
      Returns:
      the name of the attribute where the APSP informations are stored.

    • setAPSPInfoAttribute

      public void setAPSPInfoAttribute​(String attribute)
      Set the APSP info attribute name.
      Parameters:
      attribute - the name of the attribute where the APSP informations are stored.

    • getIsInEccentricityValue

      public Object getIsInEccentricityValue()
      Get the value of the eccentricity attribute when element is in the eccentricity. Default value is Boolean.TRUE.
      Returns:
      the value of elements eccentricity attribute when this element is in the eccentricity.

    • setIsInEccentricityValue

      public void setIsInEccentricityValue​(Object value)
      Set the value of the eccentricity attribute when element is in the eccentricity. On computation, this value is used to set the eccentricity attribute.
      Parameters:
      value - the value of elements eccentricity attribute when this element is in the eccentricity.

    • getIsNotInEccentricityValue

      public Object getIsNotInEccentricityValue()
      Get the value of the eccentricity attribute when element is not in the eccentricity. Default value is Boolean.FALSE.
      Returns:
      the value of elements eccentricity attribute when this element is not in the eccentricity.

    • setIsNotInEccentricityValue

      public void setIsNotInEccentricityValue​(Object value)
      Set the value of the eccentricity attribute when element is not in the eccentricity. On computation, this value is used to set the eccentricity attribute.
      Parameters:
      value - the value of elements eccentricity attribute when this element is not in the eccentricity.

    • getEccentricityAttribute

      public String getEccentricityAttribute()
      Get the name of the attribute where computation result is stored. Value of this attribute can be getIsInEccentricityValue() if the element is in the eccentricity, getIsNotInEccentricityValue() else.
      Returns:
      the eccentricity attribute name.

    • setEccentricityAttribute

      public void setEccentricityAttribute​(String eccentricityAttribute)
      Set the name of the attribute where computation result is stored.
      Parameters:
      eccentricityAttribute - the name of the element attribute where computation result is stored.

    • defaultResult

      public String defaultResult()