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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 <stack>
#include <queue>
#include <tulip/tuliphash.h>
#include <tulip/TulipPluginHeaders.h>
using namespace std;
using namespace tlp;
static const char * paramHelp[] = {
HTML_HELP_OPEN() \
HTML_HELP_DEF( "type", "bool" ) \
HTML_HELP_DEF( "default", "false" ) \
HTML_HELP_BODY() \
"indicate if the graph should be considered as directed or not" \
HTML_HELP_CLOSE(),
HTML_HELP_OPEN() \
HTML_HELP_DEF( "type", "bool" ) \
HTML_HELP_DEF( "default", "false" ) \
HTML_HELP_BODY() \
"If true the node measure will be normalized<br/>" \
" - if not directed : m(n) = 2*c(n) / (#V - 1)(#V - 2)<br/>" \
" - if directed : m(n) = c(n) / (#V - 1)(#V - 2)<br/>" \
"If true the edge measure will be normalized<br/>" \
" - if not directed : m(e) = 2*c(e) / (#V / 2)(#V / 2)<br/>" \
" - if directed : m(e) = c(e) / (#V / 2)(#V / 2)" \
HTML_HELP_CLOSE()
};
/** \addtogroup metric */
/** This plugin is an implementation of betweeness centrality parameter.
* (see http://en.wikipedia.org/wiki/Centrality#Betweenness_centrality for more details)
*
* Algorithm published by:
*
* U. Brandes, \n
* "A Faster Algorithm for Betweenness Centrality", \n
* "Journal of Mathematical Sociology" \n
* "2001", \n
* volume 25, \n
* pages 163-177
*
* The edge betweeness centrality is also computed, it is described in :
*
* Newman, M. E. J. and Girvan, M. \n
* "Finding and evaluating community structure in networks", \n
* "Physics Reviews E", \n
* "2004", \n
* volume 69
*
*
* \note The complexity of the algorithm is O(|V| * |E|) in time
* <b>HISTORY</b>
*
* - 16/02/11 Version 1.2: Edge betweeness computation added
* - 08/02/11 Version 1.1: Normalisation option added
* - 03/01/05 Version 1.0: Initial release
*
*/
class BetweennessCentrality:public DoubleAlgorithm {
public:
PLUGININFORMATION("Betweenness Centrality","David Auber","03/01/2005","Computes the betweeness centrality.","1.2","Graph")
BetweennessCentrality(const PluginContext* context):DoubleAlgorithm(context) {
addInParameter<bool>("directed", paramHelp[0], "false");
addInParameter<bool>("norm", paramHelp[1], "false", false);
}
bool run() {
result->setAllNodeValue(0.0);
result->setAllEdgeValue(0.0);
bool directed = false;
bool norm = false;
if ( dataSet!=NULL ) {
dataSet->get("directed",directed);
dataSet->get("norm", norm);
}
//Metric is 0 in this case
if(graph->numberOfNodes()<=2) return true;
Iterator<node> *it = graph->getNodes();
unsigned int count = 0;
while(it->hasNext()) {
if (pluginProgress->progress(count++,graph->numberOfNodes())!=TLP_CONTINUE) break;
node s = it->next();
stack<node> S;
TLP_HASH_MAP<node, list<node> > P;
MutableContainer<int> sigma;
sigma.setAll(0);
sigma.set(s.id,1);
MutableContainer<int> d;
d.setAll(-1);
d.set(s.id, 0);
queue<node> Q;
Q.push(s);
while(!Q.empty()) {
node v = Q.front();
Q.pop();
S.push(v);
Iterator<node> *it2;
if (directed)
it2 = graph->getOutNodes(v);
else
it2 = graph->getInOutNodes(v);
while (it2->hasNext()) {
node w = it2->next();
if (d.get(w.id)<0) {
Q.push(w);
d.set(w.id, d.get(v.id)+1);
}
if (d.get(w.id) == d.get(v.id)+1) {
sigma.add(w.id, sigma.get(v.id));
P[w].push_back(v);
}
}
delete it2;
}
MutableContainer<double> delta;
delta.setAll(0.0);
while(!S.empty()) {
node w = S.top();
S.pop();
list<node>::const_iterator itn = P[w].begin();
for (; itn!=P[w].end(); ++itn) {
node v = *itn;
delta.add(v.id, (double(sigma.get(v.id)) / double(sigma.get(w.id)) * (1.0 + delta.get(w.id))));
edge e = graph->existEdge(v,w,directed);
if(e.isValid())
result->setEdgeValue(e, result->getEdgeValue(e) + double(sigma.get(v.id)) / double(sigma.get(w.id)) * (1.0 + delta.get(w.id)));
}
if (w != s) result->setNodeValue(w, result->getNodeValue(w) + delta.get(w.id));
}
}
delete it;
//Normalization
if(norm || !directed) {
double n = graph->numberOfNodes();
it = graph->getNodes();
while(it->hasNext()) {
node s = it->next();
//In the undirected case, the metric must be divided by two, then
if(norm)
result->setNodeValue(s,result->getNodeValue(s)/((n-1.0)*(n-2.0)));
if(!directed)
result->setNodeValue(s,result->getNodeValue(s)/2.0);
}
delete it;
Iterator<edge> *itE = graph->getEdges();
while(itE->hasNext()) {
edge e = itE->next();
if(norm)
result->setEdgeValue(e,4.0*result->getEdgeValue(e)/(n*n));
if(!directed)
result->setEdgeValue(e,result->getEdgeValue(e)/(2.0));
}
delete itE;
}
return pluginProgress->state()!=TLP_CANCEL;
}
};
PLUGIN(BetweennessCentrality)
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