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import * as is from '../../is';
import * as util from '../../util';
const defaults = util.defaults({
root: null,
weight: edge => 1,
directed: false,
alpha: 0
});
let elesfn = ({
degreeCentralityNormalized: function( options ){
options = defaults( options );
let cy = this.cy();
let nodes = this.nodes();
let numNodes = nodes.length;
if( !options.directed ){
let degrees = {};
let maxDegree = 0;
for( let i = 0; i < numNodes; i++ ){
let node = nodes[ i ];
// add current node to the current options object and call degreeCentrality
options.root = node;
let currDegree = this.degreeCentrality( options );
if( maxDegree < currDegree.degree ){
maxDegree = currDegree.degree;
}
degrees[ node.id() ] = currDegree.degree;
}
return {
degree: function( node ){
if( maxDegree === 0 ){ return 0; }
if( is.string( node ) ){
// from is a selector string
node = cy.filter( node );
}
return degrees[ node.id() ] / maxDegree;
}
};
} else {
let indegrees = {};
let outdegrees = {};
let maxIndegree = 0;
let maxOutdegree = 0;
for( let i = 0; i < numNodes; i++ ){
let node = nodes[ i ];
let id = node.id();
// add current node to the current options object and call degreeCentrality
options.root = node;
let currDegree = this.degreeCentrality( options );
if( maxIndegree < currDegree.indegree )
maxIndegree = currDegree.indegree;
if( maxOutdegree < currDegree.outdegree )
maxOutdegree = currDegree.outdegree;
indegrees[ id ] = currDegree.indegree;
outdegrees[ id ] = currDegree.outdegree;
}
return {
indegree: function( node ){
if ( maxIndegree == 0 ){ return 0; }
if( is.string( node ) ){
// from is a selector string
node = cy.filter( node );
}
return indegrees[ node.id() ] / maxIndegree;
},
outdegree: function( node ){
if ( maxOutdegree === 0 ){ return 0; }
if( is.string( node ) ){
// from is a selector string
node = cy.filter( node );
}
return outdegrees[ node.id() ] / maxOutdegree;
}
};
}
}, // degreeCentralityNormalized
// Implemented from the algorithm in Opsahl's paper
// "Node centrality in weighted networks: Generalizing degree and shortest paths"
// check the heading 2 "Degree"
degreeCentrality: function( options ){
options = defaults( options );
let cy = this.cy();
let callingEles = this;
let { root, weight, directed, alpha } = options;
root = cy.collection(root)[0];
if( !directed ){
let connEdges = root.connectedEdges().intersection( callingEles );
let k = connEdges.length;
let s = 0;
// Now, sum edge weights
for( let i = 0; i < connEdges.length; i++ ){
s += weight( connEdges[i] );
}
return {
degree: Math.pow( k, 1 - alpha ) * Math.pow( s, alpha )
};
} else {
let edges = root.connectedEdges();
let incoming = edges.filter( edge => edge.target().same(root) && callingEles.has(edge) );
let outgoing = edges.filter( edge => edge.source().same(root) && callingEles.has(edge) );
let k_in = incoming.length;
let k_out = outgoing.length;
let s_in = 0;
let s_out = 0;
// Now, sum incoming edge weights
for( let i = 0; i < incoming.length; i++ ){
s_in += weight( incoming[i] );
}
// Now, sum outgoing edge weights
for( let i = 0; i < outgoing.length; i++ ){
s_out += weight( outgoing[i] );
}
return {
indegree: Math.pow( k_in, 1 - alpha ) * Math.pow( s_in, alpha ),
outdegree: Math.pow( k_out, 1 - alpha ) * Math.pow( s_out, alpha )
};
}
} // degreeCentrality
}); // elesfn
// nice, short mathematical alias
elesfn.dc = elesfn.degreeCentrality;
elesfn.dcn = elesfn.degreeCentralityNormalised = elesfn.degreeCentralityNormalized;
export default elesfn;
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