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/**
*
* This file is part of Tulip (www.tulip-software.org)
*
* Authors: David Auber and the Tulip development Team
* from LaBRI, University of Bordeaux
*
* Tulip is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License
* as published by the Free Software Foundation, either version 3
* of the License, or (at your option) any later version.
*
* Tulip 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 General Public License for more details.
*
*/
#include <tulip/TulipPluginHeaders.h>
#include <tulip/StringCollection.h>
#include <climits>
using namespace std;
using namespace tlp;
/** \addtogroup metric */
/*@{*/
/**
* \file
* \brief A metric based on the K-core decomposition of a graph.
*
* K-cores were first introduced in:
*
* S. B. Seidman, "Network structure and minimum degree",
* Social Networks 5:269-287, 1983
*
* This is a method for simplifying a graph topology which helps in analysis
* and visualization of social networks
*
* (see http://en.wikipedia.org/wiki/K-core for more details)
*
* The K-Cores metric can also be computed according to weighted degrees. See :
*
* C. Giatsidis, D. Thilikos, M. Vazirgiannis, \n
* "Evaluating cooperation in communities with the k-core structure",\n
* "Proceedings of the 2011 International Conference on Advances in Social Networks Analysis and Mining (ASONAM)",\n
* "2011"
*
* \note Use the default parameters to compute simple K-Cores (undirected and unweighted)
*
* <b>HISTORY</b>
*
* - 2006 Version 1.0 by David Auber, LaBRI,
* University Bordeaux I, France
* - 2011 Version 2.0: Add In/Out and Weighted computation features
* by François Queyroi, LaBRI, University Bordeaux I, France
* - 2015 Performance optimization by Patrick Mary
*
*
*/
class KCores:public tlp::DoubleAlgorithm {
public:
PLUGININFORMATION("K-Cores", "David Auber","28/05/2006",
"Node partitioning measure based on the K-core decomposition of a graph.<br/>"
"K-cores were first introduced in:<br/><b>Network structure and minimum degree</b>, S. B. Seidman, Social Networks 5:269-287 (1983).<br/>"
"This is a method for simplifying a graph topology which helps in analysis and visualization of social networks.<br>"
"<b>Note</b>: use the default parameters to compute simple K-Cores (undirected and unweighted).",
"2.0", "Graph")
KCores(const tlp::PluginContext *context);
~KCores();
bool run();
};
//========================================================================================
namespace {
const char * paramHelp[] = {
//direction
HTML_HELP_OPEN() \
HTML_HELP_DEF( "type", "String Collection" ) \
HTML_HELP_DEF( "default", "InOut" ) \
HTML_HELP_BODY() \
"This parameter indicates the direction used to compute K-Cores values." \
HTML_HELP_CLOSE(),
// metric
HTML_HELP_OPEN() \
HTML_HELP_DEF( "type", "NumericProperty" ) \
HTML_HELP_DEF( "value", "An existing edge metric" ) \
HTML_HELP_BODY() \
"An existing edge metric property"\
HTML_HELP_CLOSE()
};
}
#define DEGREE_TYPE "type"
#define DEGREE_TYPES "InOut;In;Out;"
#define INOUT 0
#define IN 1
#define OUT 2
//========================================================================================
KCores::KCores(const PluginContext *context):DoubleAlgorithm(context) {
addInParameter<StringCollection>(DEGREE_TYPE, paramHelp[0], DEGREE_TYPES);
addInParameter<NumericProperty*>("metric",paramHelp[1],"",false);
addDependency("Degree","1.0");
}
//========================================================================================
KCores::~KCores() {}
//========================================================================================
bool KCores::run() {
NumericProperty* metric = NULL;
StringCollection degreeTypes(DEGREE_TYPES);
degreeTypes.setCurrent(0);
if (dataSet!=NULL) {
dataSet->get(DEGREE_TYPE, degreeTypes);
dataSet->get("metric", metric);
}
unsigned int degree_type = degreeTypes.getCurrent();
string errMsg="";
graph->applyPropertyAlgorithm("Degree", result, errMsg,
pluginProgress, dataSet);
// keep track of deleted nodes
MutableContainer<bool> deleted;
// the number of non deleted nodes
unsigned int nbNodes = graph->numberOfNodes();
// the famous k
double k = result->getNodeMin();
// loop on remaining nodes
while (nbNodes > 0) {
bool modify = true;
double next_k = DBL_MAX;
while (modify) {
modify = false;
node n;
forEach(n, graph->getNodes()) {
// nothing to do if the node
// has been already deleted
if (deleted.get(n.id))
continue;
double val = result->getNodeValue(n);
if (val <= k) {
result->setNodeValue(n, k);
Iterator<edge>* ite;
switch(degree_type) {
case INOUT:
ite = graph->getInOutEdges(n);
break;
case IN:
ite = graph->getOutEdges(n);
break;
case OUT:
default:
ite = graph->getInEdges(n);
}
// decrease neighbours weighted degree
while(ite->hasNext()) {
edge ee = ite->next();
node m = graph->opposite(ee, n);
if (deleted.get(m.id))
continue;
result->setNodeValue(m, result->getNodeValue(m) -
(metric ? metric->getEdgeDoubleValue(ee) : 1));
}
// mark node as deleted
deleted.set(n.id, true);
--nbNodes;
modify = true;
}
else if (val < next_k)
// update next k value
next_k = val;
}
}
k = next_k;
}
return true;
}
//========================================================================================
PLUGIN(KCores)
//========================================================================================
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