org.graphstream.algorithm.Eccentricity Maven / Gradle / Ivy
/*
* Copyright 2006 - 2013
* Stefan Balev
* Julien Baudry
* Antoine Dutot
* Yoann Pigné
* Guilhelm Savin
*
* This file is part of GraphStream .
*
* GraphStream is a library whose purpose is to handle static or dynamic
* graph, create them from scratch, file or any source and display them.
*
* This program is free software distributed under the terms of two licenses, the
* CeCILL-C license that fits European law, and the GNU Lesser General Public
* License. You can use, modify and/ or redistribute the software under the terms
* of the CeCILL-C license as circulated by CEA, CNRS and INRIA at the following
* URL or under the terms of the GNU LGPL as published by
* the Free Software Foundation, either version 3 of the License, or (at your
* option) any later version.
*
* This program is distributed in the hope that it will be useful, but WITHOUT ANY
* WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
* PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program. If not, see
* 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
* }
* }
*
*
* @complexity O(n2)
* @see org.graphstream.algorithm.APSP.APSPInfo
* @reference F. Harary, Graph Theory. Westview Press, Oct. 1969. [Online].
* Available: http://www.amazon.com/exec/obidos/
* redirect?tag=citeulike07-20\&path=ASIN/0201410338
*/
public class Eccentricity implements Algorithm {
/**
* The graph on which centroid is computed.
*/
protected Graph graph;
/**
* Attribute in which APSPInfo are stored.
*/
protected String apspInfoAttribute = APSP.APSPInfo.ATTRIBUTE_NAME;
/**
* Attribute to store eccentricity information.
*/
protected String eccentricityAttribute = "eccentricity";
/**
* Value of the attribute if node is in the eccentricity.
*/
protected Object isInEccentricity = Boolean.TRUE;
/**
* Value of the attribute if node is not in the eccentricity.
*/
protected Object isNotInEccentricity = Boolean.FALSE;
/**
* Build a new eccentricity algorithm with default parameters.
*/
public Eccentricity() {
this("eccentricity");
}
/**
* Build a new eccentricity algorithm, specifying the attribute name of the
* computation result
*
* @param eccentricityAttribute
* attribute name of the computation result.
*/
public Eccentricity(String eccentricityAttribute) {
this(eccentricityAttribute, Boolean.TRUE, Boolean.FALSE);
}
/**
* Build a new eccentricity as in {@link #Eccentricity(String)} but
* specifying values of eccentricity membership.
*
* @param eccentricityAttribute
* attribute name of the computation result.
* @param isInEccentricity
* the value of elements eccentricity attribute when this element
* is in the eccentricity.
* @param isNotInEccentricity
* the value of elements eccentricity attribute when this element
* is not in the eccentricity.
*/
public Eccentricity(String eccentricityAttribute, Object isInEccentricity,
Object isNotInEccentricity) {
this(eccentricityAttribute, Boolean.TRUE, Boolean.FALSE,
APSP.APSPInfo.ATTRIBUTE_NAME);
}
/**
* Build a new eccentricity algorithm as in
* {@link #Eccentricity(String, Object, Object)} but specifying the name of
* the attribute where the APSP informations are stored.
*
* @param eccentricityAttribute
* attribute name of the computation result.
* @param isInEccentricity
* the value of elements eccentricity attribute when this element
* is in the eccentricity.
* @param isNotInEccentricity
* the value of elements eccentricity attribute when this element
* is not in the eccentricity.
* @param apspInfoAttribute
* the name of the attribute where the APSP informations are
* stored
*/
public Eccentricity(String eccentricityAttribute, Object isInEccentricity,
Object isNotInEccentricity, String apspInfoAttribute) {
this.eccentricityAttribute = eccentricityAttribute;
this.isInEccentricity = isInEccentricity;
this.isNotInEccentricity = isNotInEccentricity;
this.apspInfoAttribute = apspInfoAttribute;
}
/*
* (non-Javadoc)
*
* @see
* org.graphstream.algorithm.Algorithm#init(org.graphstream.graph.Graph)
*/
public void init(Graph graph) {
this.graph = graph;
}
/*
* (non-Javadoc)
*
* @see org.graphstream.algorithm.Algorithm#compute()
*/
public void compute() {
double min = Double.MAX_VALUE;
HashSet eccentricity = new HashSet();
for (Node node : graph.getEachNode()) {
double m = Double.MIN_VALUE;
APSP.APSPInfo info = node.getAttribute(apspInfoAttribute);
if (info == null)
System.err
.printf("APSPInfo missing. Did you compute APSP before ?\n");
for (Node other : graph.getEachNode()) {
if (node != other) {
double d = info.getLengthTo(other.getId());
if (d < 0)
System.err
.printf("Found a negative length value in eccentricity algorithm. "
+ "Is graph connected ?\n");
else if (d > m)
m = d;
}
}
if (m < min) {
eccentricity.clear();
eccentricity.add(node);
min = m;
} else if (m == min) {
eccentricity.add(node);
}
}
for (Node node : graph.getEachNode())
node.setAttribute(eccentricityAttribute, eccentricity
.contains(node) ? isInEccentricity : isNotInEccentricity);
eccentricity.clear();
}
/**
* Get the APSP info attribute name.
*
* @return the name of the attribute where the APSP informations are stored.
*/
public String getAPSPInfoAttribute() {
return apspInfoAttribute;
}
/**
* Set the APSP info attribute name.
*
* @param attribute
* the name of the attribute where the APSP informations are
* stored.
*/
public void setAPSPInfoAttribute(String attribute) {
apspInfoAttribute = attribute;
}
/**
* Get the value of the eccentricity attribute when element is in the
* eccentricity. Default value is Boolean.TRUE.
*
* @return the value of elements eccentricity attribute when this element is
* in the eccentricity.
*/
public Object getIsInEccentricityValue() {
return isInEccentricity;
}
/**
* Set the value of the eccentricity attribute when element is in the
* eccentricity. On computation, this value is used to set the eccentricity
* attribute.
*
* @param value
* the value of elements eccentricity attribute when this element
* is in the eccentricity.
*/
public void setIsInEccentricityValue(Object value) {
isInEccentricity = value;
}
/**
* Get the value of the eccentricity attribute when element is not in the
* eccentricity. Default value is Boolean.FALSE.
*
* @return the value of elements eccentricity attribute when this element is
* not in the eccentricity.
*/
public Object getIsNotInEccentricityValue() {
return isNotInEccentricity;
}
/**
* 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.
*
* @param value
* the value of elements eccentricity attribute when this element
* is not in the eccentricity.
*/
public void setIsNotInEccentricityValue(Object value) {
isNotInEccentricity = value;
}
/**
* Get the name of the attribute where computation result is stored. Value
* of this attribute can be {@link #getIsInEccentricityValue()} if the
* element is in the eccentricity, {@link #getIsNotInEccentricityValue()}
* else.
*
* @return the eccentricity attribute name.
*/
public String getEccentricityAttribute() {
return eccentricityAttribute;
}
/**
* Set the name of the attribute where computation result is stored.
*
* @param eccentricityAttribute
* the name of the element attribute where computation result is
* stored.
*/
public void setEccentricityAttribute(String eccentricityAttribute) {
this.eccentricityAttribute = eccentricityAttribute;
}
}
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