/**
* Creation of the ClusterMixin var.
*
* This contains all the functions the Network object can use to employ clustering
*/
/**
* This is only called in the constructor of the network object
*
*/
exports.startWithClustering = function() {
// cluster if the data set is big
this.clusterToFit(this.constants.clustering.initialMaxNodes, true);
// updates the lables after clustering
this.updateLabels();
// this is called here because if clusterin is disabled, the start and stabilize are called in
// the setData function.
if (this.stabilize) {
this._stabilize();
}
this.start();
};
/**
* This function clusters until the initialMaxNodes has been reached
*
* @param {Number} maxNumberOfNodes
* @param {Boolean} reposition
*/
exports.clusterToFit = function(maxNumberOfNodes, reposition) {
var numberOfNodes = this.nodeIndices.length;
var maxLevels = 50;
var level = 0;
// we first cluster the hubs, then we pull in the outliers, repeat
while (numberOfNodes > maxNumberOfNodes && level < maxLevels) {
if (level % 3 == 0) {
this.forceAggregateHubs(true);
this.normalizeClusterLevels();
}
else {
this.increaseClusterLevel(); // this also includes a cluster normalization
}
numberOfNodes = this.nodeIndices.length;
level += 1;
}
// after the clustering we reposition the nodes to reduce the initial chaos
if (level > 0 && reposition == true) {
this.repositionNodes();
}
this._updateCalculationNodes();
};
/**
* This function can be called to open up a specific cluster. It is only called by
* It will unpack the cluster back one level.
*
* @param node | Node object: cluster to open.
*/
exports.openCluster = function(node) {
var isMovingBeforeClustering = this.moving;
if (node.clusterSize > this.constants.clustering.sectorThreshold && this._nodeInActiveArea(node) &&
!(this._sector() == "default" && this.nodeIndices.length == 1)) {
// this loads a new sector, loads the nodes and edges and nodeIndices of it.
this._addSector(node);
var level = 0;
// we decluster until we reach a decent number of nodes
while ((this.nodeIndices.length < this.constants.clustering.initialMaxNodes) && (level < 10)) {
this.decreaseClusterLevel();
level += 1;
}
}
else {
this._expandClusterNode(node,false,true);
// update the index list, dynamic edges and labels
this._updateNodeIndexList();
this._updateDynamicEdges();
this._updateCalculationNodes();
this.updateLabels();
}
// if the simulation was settled, we restart the simulation if a cluster has been formed or expanded
if (this.moving != isMovingBeforeClustering) {
this.start();
}
};
/**
* This calls the updateClustes with default arguments
*/
exports.updateClustersDefault = function() {
if (this.constants.clustering.enabled == true) {
this.updateClusters(0,false,false);
}
};
/**
* This function can be called to increase the cluster level. This means that the nodes with only one edge connection will
* be clustered with their connected node. This can be repeated as many times as needed.
* This can be called externally (by a keybind for instance) to reduce the complexity of big datasets.
*/
exports.increaseClusterLevel = function() {
this.updateClusters(-1,false,true);
};
/**
* This function can be called to decrease the cluster level. This means that the nodes with only one edge connection will
* be unpacked if they are a cluster. This can be repeated as many times as needed.
* This can be called externally (by a key-bind for instance) to look into clusters without zooming.
*/
exports.decreaseClusterLevel = function() {
this.updateClusters(1,false,true);
};
/**
* This is the main clustering function. It clusters and declusters on zoom or forced
* This function clusters on zoom, it can be called with a predefined zoom direction
* If out, check if we can form clusters, if in, check if we can open clusters.
* This function is only called from _zoom()
*
* @param {Number} zoomDirection | -1 / 0 / +1 for zoomOut / determineByZoom / zoomIn
* @param {Boolean} recursive | enabled or disable recursive calling of the opening of clusters
* @param {Boolean} force | enabled or disable forcing
* @param {Boolean} doNotStart | if true do not call start
*
*/
exports.updateClusters = function(zoomDirection,recursive,force,doNotStart) {
var isMovingBeforeClustering = this.moving;
var amountOfNodes = this.nodeIndices.length;
// on zoom out collapse the sector if the scale is at the level the sector was made
if (this.previousScale > this.scale && zoomDirection == 0) {
this._collapseSector();
}
// check if we zoom in or out
if (this.previousScale > this.scale || zoomDirection == -1) { // zoom out
// forming clusters when forced pulls outliers in. When not forced, the edge length of the
// outer nodes determines if it is being clustered
this._formClusters(force);
}
else if (this.previousScale < this.scale || zoomDirection == 1) { // zoom in
if (force == true) {
// _openClusters checks for each node if the formationScale of the cluster is smaller than
// the current scale and if so, declusters. When forced, all clusters are reduced by one step
this._openClusters(recursive,force);
}
else {
// if a cluster takes up a set percentage of the active window
this._openClustersBySize();
}
}
this._updateNodeIndexList();
// if a cluster was NOT formed and the user zoomed out, we try clustering by hubs
if (this.nodeIndices.length == amountOfNodes && (this.previousScale > this.scale || zoomDirection == -1)) {
this._aggregateHubs(force);
this._updateNodeIndexList();
}
// we now reduce chains.
if (this.previousScale > this.scale || zoomDirection == -1) { // zoom out
this.handleChains();
this._updateNodeIndexList();
}
this.previousScale = this.scale;
// rest of the update the index list, dynamic edges and labels
this._updateDynamicEdges();
this.updateLabels();
// if a cluster was formed, we increase the clusterSession
if (this.nodeIndices.length < amountOfNodes) { // this means a clustering operation has taken place
this.clusterSession += 1;
// if clusters have been made, we normalize the cluster level
this.normalizeClusterLevels();
}
if (doNotStart == false || doNotStart === undefined) {
// if the simulation was settled, we restart the simulation if a cluster has been formed or expanded
if (this.moving != isMovingBeforeClustering) {
this.start();
}
}
this._updateCalculationNodes();
};
/**
* This function handles the chains. It is called on every updateClusters().
*/
exports.handleChains = function() {
// after clustering we check how many chains there are
var chainPercentage = this._getChainFraction();
if (chainPercentage > this.constants.clustering.chainThreshold) {
this._reduceAmountOfChains(1 - this.constants.clustering.chainThreshold / chainPercentage)
}
};
/**
* this functions starts clustering by hubs
* The minimum hub threshold is set globally
*
* @private
*/
exports._aggregateHubs = function(force) {
this._getHubSize();
this._formClustersByHub(force,false);
};
/**
* This function is fired by keypress. It forces hubs to form.
*
*/
exports.forceAggregateHubs = function(doNotStart) {
var isMovingBeforeClustering = this.moving;
var amountOfNodes = this.nodeIndices.length;
this._aggregateHubs(true);
// update the index list, dynamic edges and labels
this._updateNodeIndexList();
this._updateDynamicEdges();
this.updateLabels();
// if a cluster was formed, we increase the clusterSession
if (this.nodeIndices.length != amountOfNodes) {
this.clusterSession += 1;
}
if (doNotStart == false || doNotStart === undefined) {
// if the simulation was settled, we restart the simulation if a cluster has been formed or expanded
if (this.moving != isMovingBeforeClustering) {
this.start();
}
}
};
/**
* If a cluster takes up more than a set percentage of the screen, open the cluster
*
* @private
*/
exports._openClustersBySize = function() {
for (var nodeId in this.nodes) {
if (this.nodes.hasOwnProperty(nodeId)) {
var node = this.nodes[nodeId];
if (node.inView() == true) {
if ((node.width*this.scale > this.constants.clustering.screenSizeThreshold * this.frame.canvas.clientWidth) ||
(node.height*this.scale > this.constants.clustering.screenSizeThreshold * this.frame.canvas.clientHeight)) {
this.openCluster(node);
}
}
}
}
};
/**
* This function loops over all nodes in the nodeIndices list. For each node it checks if it is a cluster and if it
* has to be opened based on the current zoom level.
*
* @private
*/
exports._openClusters = function(recursive,force) {
for (var i = 0; i < this.nodeIndices.length; i++) {
var node = this.nodes[this.nodeIndices[i]];
this._expandClusterNode(node,recursive,force);
this._updateCalculationNodes();
}
};
/**
* This function checks if a node has to be opened. This is done by checking the zoom level.
* If the node contains child nodes, this function is recursively called on the child nodes as well.
* This recursive behaviour is optional and can be set by the recursive argument.
*
* @param {Node} parentNode | to check for cluster and expand
* @param {Boolean} recursive | enabled or disable recursive calling
* @param {Boolean} force | enabled or disable forcing
* @param {Boolean} [openAll] | This will recursively force all nodes in the parent to be released
* @private
*/
exports._expandClusterNode = function(parentNode, recursive, force, openAll) {
// first check if node is a cluster
if (parentNode.clusterSize > 1) {
// this means that on a double tap event or a zoom event, the cluster fully unpacks if it is smaller than 20
if (parentNode.clusterSize < this.constants.clustering.sectorThreshold) {
openAll = true;
}
recursive = openAll ? true : recursive;
// if the last child has been added on a smaller scale than current scale decluster
if (parentNode.formationScale < this.scale || force == true) {
// we will check if any of the contained child nodes should be removed from the cluster
for (var containedNodeId in parentNode.containedNodes) {
if (parentNode.containedNodes.hasOwnProperty(containedNodeId)) {
var childNode = parentNode.containedNodes[containedNodeId];
// force expand will expand the largest cluster size clusters. Since we cluster from outside in, we assume that
// the largest cluster is the one that comes from outside
if (force == true) {
if (childNode.clusterSession == parentNode.clusterSessions[parentNode.clusterSessions.length-1]
|| openAll) {
this._expelChildFromParent(parentNode,containedNodeId,recursive,force,openAll);
}
}
else {
if (this._nodeInActiveArea(parentNode)) {
this._expelChildFromParent(parentNode,containedNodeId,recursive,force,openAll);
}
}
}
}
}
}
};
/**
* ONLY CALLED FROM _expandClusterNode
*
* This function will expel a child_node from a parent_node. This is to de-cluster the node. This function will remove
* the child node from the parent contained_node object and put it back into the global nodes object.
* The same holds for the edge that was connected to the child node. It is moved back into the global edges object.
*
* @param {Node} parentNode | the parent node
* @param {String} containedNodeId | child_node id as it is contained in the containedNodes object of the parent node
* @param {Boolean} recursive | This will also check if the child needs to be expanded.
* With force and recursive both true, the entire cluster is unpacked
* @param {Boolean} force | This will disregard the zoom level and will expel this child from the parent
* @param {Boolean} openAll | This will recursively force all nodes in the parent to be released
* @private
*/
exports._expelChildFromParent = function(parentNode, containedNodeId, recursive, force, openAll) {
var childNode = parentNode.containedNodes[containedNodeId];
// if child node has been added on smaller scale than current, kick out
if (childNode.formationScale < this.scale || force == true) {
// unselect all selected items
this._unselectAll();
// put the child node back in the global nodes object
this.nodes[containedNodeId] = childNode;
// release the contained edges from this childNode back into the global edges
this._releaseContainedEdges(parentNode,childNode);
// reconnect rerouted edges to the childNode
this._connectEdgeBackToChild(parentNode,childNode);
// validate all edges in dynamicEdges
this._validateEdges(parentNode);
// undo the changes from the clustering operation on the parent node
parentNode.options.mass -= childNode.options.mass;
parentNode.clusterSize -= childNode.clusterSize;
parentNode.options.fontSize = Math.min(this.constants.clustering.maxFontSize, this.constants.nodes.fontSize + this.constants.clustering.fontSizeMultiplier*(parentNode.clusterSize-1));
parentNode.dynamicEdgesLength = parentNode.dynamicEdges.length;
// place the child node near the parent, not at the exact same location to avoid chaos in the system
childNode.x = parentNode.x + parentNode.growthIndicator * (0.5 - Math.random());
childNode.y = parentNode.y + parentNode.growthIndicator * (0.5 - Math.random());
// remove node from the list
delete parentNode.containedNodes[containedNodeId];
// check if there are other childs with this clusterSession in the parent.
var othersPresent = false;
for (var childNodeId in parentNode.containedNodes) {
if (parentNode.containedNodes.hasOwnProperty(childNodeId)) {
if (parentNode.containedNodes[childNodeId].clusterSession == childNode.clusterSession) {
othersPresent = true;
break;
}
}
}
// if there are no others, remove the cluster session from the list
if (othersPresent == false) {
parentNode.clusterSessions.pop();
}
this._repositionBezierNodes(childNode);
// this._repositionBezierNodes(parentNode);
// remove the clusterSession from the child node
childNode.clusterSession = 0;
// recalculate the size of the node on the next time the node is rendered
parentNode.clearSizeCache();
// restart the simulation to reorganise all nodes
this.moving = true;
}
// check if a further expansion step is possible if recursivity is enabled
if (recursive == true) {
this._expandClusterNode(childNode,recursive,force,openAll);
}
};
/**
* position the bezier nodes at the center of the edges
*
* @param node
* @private
*/
exports._repositionBezierNodes = function(node) {
for (var i = 0; i < node.dynamicEdges.length; i++) {
node.dynamicEdges[i].positionBezierNode();
}
};
/**
* This function checks if any nodes at the end of their trees have edges below a threshold length
* This function is called only from updateClusters()
* forceLevelCollapse ignores the length of the edge and collapses one level
* This means that a node with only one edge will be clustered with its connected node
*
* @private
* @param {Boolean} force
*/
exports._formClusters = function(force) {
if (force == false) {
this._formClustersByZoom();
}
else {
this._forceClustersByZoom();
}
};
/**
* This function handles the clustering by zooming out, this is based on a minimum edge distance
*
* @private
*/
exports._formClustersByZoom = function() {
var dx,dy,length,
minLength = this.constants.clustering.clusterEdgeThreshold/this.scale;
// check if any edges are shorter than minLength and start the clustering
// the clustering favours the node with the larger mass
for (var edgeId in this.edges) {
if (this.edges.hasOwnProperty(edgeId)) {
var edge = this.edges[edgeId];
if (edge.connected) {
if (edge.toId != edge.fromId) {
dx = (edge.to.x - edge.from.x);
dy = (edge.to.y - edge.from.y);
length = Math.sqrt(dx * dx + dy * dy);
if (length < minLength) {
// first check which node is larger
var parentNode = edge.from;
var childNode = edge.to;
if (edge.to.options.mass > edge.from.options.mass) {
parentNode = edge.to;
childNode = edge.from;
}
if (childNode.dynamicEdgesLength == 1) {
this._addToCluster(parentNode,childNode,false);
}
else if (parentNode.dynamicEdgesLength == 1) {
this._addToCluster(childNode,parentNode,false);
}
}
}
}
}
}
};
/**
* This function forces the network to cluster all nodes with only one connecting edge to their
* connected node.
*
* @private
*/
exports._forceClustersByZoom = function() {
for (var nodeId in this.nodes) {
// another node could have absorbed this child.
if (this.nodes.hasOwnProperty(nodeId)) {
var childNode = this.nodes[nodeId];
// the edges can be swallowed by another decrease
if (childNode.dynamicEdgesLength == 1 && childNode.dynamicEdges.length != 0) {
var edge = childNode.dynamicEdges[0];
var parentNode = (edge.toId == childNode.id) ? this.nodes[edge.fromId] : this.nodes[edge.toId];
// group to the largest node
if (childNode.id != parentNode.id) {
if (parentNode.options.mass > childNode.options.mass) {
this._addToCluster(parentNode,childNode,true);
}
else {
this._addToCluster(childNode,parentNode,true);
}
}
}
}
}
};
/**
* To keep the nodes of roughly equal size we normalize the cluster levels.
* This function clusters a node to its smallest connected neighbour.
*
* @param node
* @private
*/
exports._clusterToSmallestNeighbour = function(node) {
var smallestNeighbour = -1;
var smallestNeighbourNode = null;
for (var i = 0; i < node.dynamicEdges.length; i++) {
if (node.dynamicEdges[i] !== undefined) {
var neighbour = null;
if (node.dynamicEdges[i].fromId != node.id) {
neighbour = node.dynamicEdges[i].from;
}
else if (node.dynamicEdges[i].toId != node.id) {
neighbour = node.dynamicEdges[i].to;
}
if (neighbour != null && smallestNeighbour > neighbour.clusterSessions.length) {
smallestNeighbour = neighbour.clusterSessions.length;
smallestNeighbourNode = neighbour;
}
}
}
if (neighbour != null && this.nodes[neighbour.id] !== undefined) {
this._addToCluster(neighbour, node, true);
}
};
/**
* This function forms clusters from hubs, it loops over all nodes
*
* @param {Boolean} force | Disregard zoom level
* @param {Boolean} onlyEqual | This only clusters a hub with a specific number of edges
* @private
*/
exports._formClustersByHub = function(force, onlyEqual) {
// we loop over all nodes in the list
for (var nodeId in this.nodes) {
// we check if it is still available since it can be used by the clustering in this loop
if (this.nodes.hasOwnProperty(nodeId)) {
this._formClusterFromHub(this.nodes[nodeId],force,onlyEqual);
}
}
};
/**
* This function forms a cluster from a specific preselected hub node
*
* @param {Node} hubNode | the node we will cluster as a hub
* @param {Boolean} force | Disregard zoom level
* @param {Boolean} onlyEqual | This only clusters a hub with a specific number of edges
* @param {Number} [absorptionSizeOffset] |
* @private
*/
exports._formClusterFromHub = function(hubNode, force, onlyEqual, absorptionSizeOffset) {
if (absorptionSizeOffset === undefined) {
absorptionSizeOffset = 0;
}
// we decide if the node is a hub
if ((hubNode.dynamicEdgesLength >= this.hubThreshold && onlyEqual == false) ||
(hubNode.dynamicEdgesLength == this.hubThreshold && onlyEqual == true)) {
// initialize variables
var dx,dy,length;
var minLength = this.constants.clustering.clusterEdgeThreshold/this.scale;
var allowCluster = false;
// we create a list of edges because the dynamicEdges change over the course of this loop
var edgesIdarray = [];
var amountOfInitialEdges = hubNode.dynamicEdges.length;
for (var j = 0; j < amountOfInitialEdges; j++) {
edgesIdarray.push(hubNode.dynamicEdges[j].id);
}
// if the hub clustering is not forces, we check if one of the edges connected
// to a cluster is small enough based on the constants.clustering.clusterEdgeThreshold
if (force == false) {
allowCluster = false;
for (j = 0; j < amountOfInitialEdges; j++) {
var edge = this.edges[edgesIdarray[j]];
if (edge !== undefined) {
if (edge.connected) {
if (edge.toId != edge.fromId) {
dx = (edge.to.x - edge.from.x);
dy = (edge.to.y - edge.from.y);
length = Math.sqrt(dx * dx + dy * dy);
if (length < minLength) {
allowCluster = true;
break;
}
}
}
}
}
}
// start the clustering if allowed
if ((!force && allowCluster) || force) {
// we loop over all edges INITIALLY connected to this hub
for (j = 0; j < amountOfInitialEdges; j++) {
edge = this.edges[edgesIdarray[j]];
// the edge can be clustered by this function in a previous loop
if (edge !== undefined) {
var childNode = this.nodes[(edge.fromId == hubNode.id) ? edge.toId : edge.fromId];
// we do not want hubs to merge with other hubs nor do we want to cluster itself.
if ((childNode.dynamicEdges.length <= (this.hubThreshold + absorptionSizeOffset)) &&
(childNode.id != hubNode.id)) {
this._addToCluster(hubNode,childNode,force);
}
}
}
}
}
};
/**
* This function adds the child node to the parent node, creating a cluster if it is not already.
*
* @param {Node} parentNode | this is the node that will house the child node
* @param {Node} childNode | this node will be deleted from the global this.nodes and stored in the parent node
* @param {Boolean} force | true will only update the remainingEdges at the very end of the clustering, ensuring single level collapse
* @private
*/
exports._addToCluster = function(parentNode, childNode, force) {
// join child node in the parent node
parentNode.containedNodes[childNode.id] = childNode;
// manage all the edges connected to the child and parent nodes
for (var i = 0; i < childNode.dynamicEdges.length; i++) {
var edge = childNode.dynamicEdges[i];
if (edge.toId == parentNode.id || edge.fromId == parentNode.id) { // edge connected to parentNode
this._addToContainedEdges(parentNode,childNode,edge);
}
else {
this._connectEdgeToCluster(parentNode,childNode,edge);
}
}
// a contained node has no dynamic edges.
childNode.dynamicEdges = [];
// remove circular edges from clusters
this._containCircularEdgesFromNode(parentNode,childNode);
// remove the childNode from the global nodes object
delete this.nodes[childNode.id];
// update the properties of the child and parent
var massBefore = parentNode.options.mass;
childNode.clusterSession = this.clusterSession;
parentNode.options.mass += childNode.options.mass;
parentNode.clusterSize += childNode.clusterSize;
parentNode.options.fontSize = Math.min(this.constants.clustering.maxFontSize, this.constants.nodes.fontSize + this.constants.clustering.fontSizeMultiplier*parentNode.clusterSize);
// keep track of the clustersessions so we can open the cluster up as it has been formed.
if (parentNode.clusterSessions[parentNode.clusterSessions.length - 1] != this.clusterSession) {
parentNode.clusterSessions.push(this.clusterSession);
}
// forced clusters only open from screen size and double tap
if (force == true) {
// parentNode.formationScale = Math.pow(1 - (1.0/11.0),this.clusterSession+3);
parentNode.formationScale = 0;
}
else {
parentNode.formationScale = this.scale; // The latest child has been added on this scale
}
// recalculate the size of the node on the next time the node is rendered
parentNode.clearSizeCache();
// set the pop-out scale for the childnode
parentNode.containedNodes[childNode.id].formationScale = parentNode.formationScale;
// nullify the movement velocity of the child, this is to avoid hectic behaviour
childNode.clearVelocity();
// the mass has altered, preservation of energy dictates the velocity to be updated
parentNode.updateVelocity(massBefore);
// restart the simulation to reorganise all nodes
this.moving = true;
};
/**
* This function will apply the changes made to the remainingEdges during the formation of the clusters.
* This is a seperate function to allow for level-wise collapsing of the node barnesHutTree.
* It has to be called if a level is collapsed. It is called by _formClusters().
* @private
*/
exports._updateDynamicEdges = function() {
for (var i = 0; i < this.nodeIndices.length; i++) {
var node = this.nodes[this.nodeIndices[i]];
node.dynamicEdgesLength = node.dynamicEdges.length;
// this corrects for multiple edges pointing at the same other node
var correction = 0;
if (node.dynamicEdgesLength > 1) {
for (var j = 0; j < node.dynamicEdgesLength - 1; j++) {
var edgeToId = node.dynamicEdges[j].toId;
var edgeFromId = node.dynamicEdges[j].fromId;
for (var k = j+1; k < node.dynamicEdgesLength; k++) {
if ((node.dynamicEdges[k].toId == edgeToId && node.dynamicEdges[k].fromId == edgeFromId) ||
(node.dynamicEdges[k].fromId == edgeToId && node.dynamicEdges[k].toId == edgeFromId)) {
correction += 1;
}
}
}
}
node.dynamicEdgesLength -= correction;
}
};
/**
* This adds an edge from the childNode to the contained edges of the parent node
*
* @param parentNode | Node object
* @param childNode | Node object
* @param edge | Edge object
* @private
*/
exports._addToContainedEdges = function(parentNode, childNode, edge) {
// create an array object if it does not yet exist for this childNode
if (!(parentNode.containedEdges.hasOwnProperty(childNode.id))) {
parentNode.containedEdges[childNode.id] = []
}
// add this edge to the list
parentNode.containedEdges[childNode.id].push(edge);
// remove the edge from the global edges object
delete this.edges[edge.id];
// remove the edge from the parent object
for (var i = 0; i < parentNode.dynamicEdges.length; i++) {
if (parentNode.dynamicEdges[i].id == edge.id) {
parentNode.dynamicEdges.splice(i,1);
break;
}
}
};
/**
* This function connects an edge that was connected to a child node to the parent node.
* It keeps track of which nodes it has been connected to with the originalId array.
*
* @param {Node} parentNode | Node object
* @param {Node} childNode | Node object
* @param {Edge} edge | Edge object
* @private
*/
exports._connectEdgeToCluster = function(parentNode, childNode, edge) {
// handle circular edges
if (edge.toId == edge.fromId) {
this._addToContainedEdges(parentNode, childNode, edge);
}
else {
if (edge.toId == childNode.id) { // edge connected to other node on the "to" side
edge.originalToId.push(childNode.id);
edge.to = parentNode;
edge.toId = parentNode.id;
}
else { // edge connected to other node with the "from" side
edge.originalFromId.push(childNode.id);
edge.from = parentNode;
edge.fromId = parentNode.id;
}
this._addToReroutedEdges(parentNode,childNode,edge);
}
};
/**
* If a node is connected to itself, a circular edge is drawn. When clustering we want to contain
* these edges inside of the cluster.
*
* @param parentNode
* @param childNode
* @private
*/
exports._containCircularEdgesFromNode = function(parentNode, childNode) {
// manage all the edges connected to the child and parent nodes
for (var i = 0; i < parentNode.dynamicEdges.length; i++) {
var edge = parentNode.dynamicEdges[i];
// handle circular edges
if (edge.toId == edge.fromId) {
this._addToContainedEdges(parentNode, childNode, edge);
}
}
};
/**
* This adds an edge from the childNode to the rerouted edges of the parent node
*
* @param parentNode | Node object
* @param childNode | Node object
* @param edge | Edge object
* @private
*/
exports._addToReroutedEdges = function(parentNode, childNode, edge) {
// create an array object if it does not yet exist for this childNode
// we store the edge in the rerouted edges so we can restore it when the cluster pops open
if (!(parentNode.reroutedEdges.hasOwnProperty(childNode.id))) {
parentNode.reroutedEdges[childNode.id] = [];
}
parentNode.reroutedEdges[childNode.id].push(edge);
// this edge becomes part of the dynamicEdges of the cluster node
parentNode.dynamicEdges.push(edge);
};
/**
* This function connects an edge that was connected to a cluster node back to the child node.
*
* @param parentNode | Node object
* @param childNode | Node object
* @private
*/
exports._connectEdgeBackToChild = function(parentNode, childNode) {
if (parentNode.reroutedEdges.hasOwnProperty(childNode.id)) {
for (var i = 0; i < parentNode.reroutedEdges[childNode.id].length; i++) {
var edge = parentNode.reroutedEdges[childNode.id][i];
if (edge.originalFromId[edge.originalFromId.length-1] == childNode.id) {
edge.originalFromId.pop();
edge.fromId = childNode.id;
edge.from = childNode;
}
else {
edge.originalToId.pop();
edge.toId = childNode.id;
edge.to = childNode;
}
// append this edge to the list of edges connecting to the childnode
childNode.dynamicEdges.push(edge);
// remove the edge from the parent object
for (var j = 0; j < parentNode.dynamicEdges.length; j++) {
if (parentNode.dynamicEdges[j].id == edge.id) {
parentNode.dynamicEdges.splice(j,1);
break;
}
}
}
// remove the entry from the rerouted edges
delete parentNode.reroutedEdges[childNode.id];
}
};
/**
* When loops are clustered, an edge can be both in the rerouted array and the contained array.
* This function is called last to verify that all edges in dynamicEdges are in fact connected to the
* parentNode
*
* @param parentNode | Node object
* @private
*/
exports._validateEdges = function(parentNode) {
for (var i = 0; i < parentNode.dynamicEdges.length; i++) {
var edge = parentNode.dynamicEdges[i];
if (parentNode.id != edge.toId && parentNode.id != edge.fromId) {
parentNode.dynamicEdges.splice(i,1);
}
}
};
/**
* This function released the contained edges back into the global domain and puts them back into the
* dynamic edges of both parent and child.
*
* @param {Node} parentNode |
* @param {Node} childNode |
* @private
*/
exports._releaseContainedEdges = function(parentNode, childNode) {
for (var i = 0; i < parentNode.containedEdges[childNode.id].length; i++) {
var edge = parentNode.containedEdges[childNode.id][i];
// put the edge back in the global edges object
this.edges[edge.id] = edge;
// put the edge back in the dynamic edges of the child and parent
childNode.dynamicEdges.push(edge);
parentNode.dynamicEdges.push(edge);
}
// remove the entry from the contained edges
delete parentNode.containedEdges[childNode.id];
};
// ------------------- UTILITY FUNCTIONS ---------------------------- //
/**
* This updates the node labels for all nodes (for debugging purposes)
*/
exports.updateLabels = function() {
var nodeId;
// update node labels
for (nodeId in this.nodes) {
if (this.nodes.hasOwnProperty(nodeId)) {
var node = this.nodes[nodeId];
if (node.clusterSize > 1) {
node.label = "[".concat(String(node.clusterSize),"]");
}
}
}
// update node labels
for (nodeId in this.nodes) {
if (this.nodes.hasOwnProperty(nodeId)) {
node = this.nodes[nodeId];
if (node.clusterSize == 1) {
if (node.originalLabel !== undefined) {
node.label = node.originalLabel;
}
else {
node.label = String(node.id);
}
}
}
}
// /* Debug Override */
// for (nodeId in this.nodes) {
// if (this.nodes.hasOwnProperty(nodeId)) {
// node = this.nodes[nodeId];
// node.label = String(node.level);
// }
// }
};
/**
* We want to keep the cluster level distribution rather small. This means we do not want unclustered nodes
* if the rest of the nodes are already a few cluster levels in.
* To fix this we use this function. It determines the min and max cluster level and sends nodes that have not
* clustered enough to the clusterToSmallestNeighbours function.
*/
exports.normalizeClusterLevels = function() {
var maxLevel = 0;
var minLevel = 1e9;
var clusterLevel = 0;
var nodeId;
// we loop over all nodes in the list
for (nodeId in this.nodes) {
if (this.nodes.hasOwnProperty(nodeId)) {
clusterLevel = this.nodes[nodeId].clusterSessions.length;
if (maxLevel < clusterLevel) {maxLevel = clusterLevel;}
if (minLevel > clusterLevel) {minLevel = clusterLevel;}
}
}
if (maxLevel - minLevel > this.constants.clustering.clusterLevelDifference) {
var amountOfNodes = this.nodeIndices.length;
var targetLevel = maxLevel - this.constants.clustering.clusterLevelDifference;
// we loop over all nodes in the list
for (nodeId in this.nodes) {
if (this.nodes.hasOwnProperty(nodeId)) {
if (this.nodes[nodeId].clusterSessions.length < targetLevel) {
this._clusterToSmallestNeighbour(this.nodes[nodeId]);
}
}
}
this._updateNodeIndexList();
this._updateDynamicEdges();
// if a cluster was formed, we increase the clusterSession
if (this.nodeIndices.length != amountOfNodes) {
this.clusterSession += 1;
}
}
};
/**
* This function determines if the cluster we want to decluster is in the active area
* this means around the zoom center
*
* @param {Node} node
* @returns {boolean}
* @private
*/
exports._nodeInActiveArea = function(node) {
return (
Math.abs(node.x - this.areaCenter.x) <= this.constants.clustering.activeAreaBoxSize/this.scale
&&
Math.abs(node.y - this.areaCenter.y) <= this.constants.clustering.activeAreaBoxSize/this.scale
)
};
/**
* This is an adaptation of the original repositioning function. This is called if the system is clustered initially
* It puts large clusters away from the center and randomizes the order.
*
*/
exports.repositionNodes = function() {
for (var i = 0; i < this.nodeIndices.length; i++) {
var node = this.nodes[this.nodeIndices[i]];
if ((node.xFixed == false || node.yFixed == false)) {
var radius = 10 * 0.1*this.nodeIndices.length * Math.min(100,node.options.mass);
var angle = 2 * Math.PI * Math.random();
if (node.xFixed == false) {node.x = radius * Math.cos(angle);}
if (node.yFixed == false) {node.y = radius * Math.sin(angle);}
this._repositionBezierNodes(node);
}
}
};
/**
* We determine how many connections denote an important hub.
* We take the mean + 2*std as the important hub size. (Assuming a normal distribution of data, ~2.2%)
*
* @private
*/
exports._getHubSize = function() {
var average = 0;
var averageSquared = 0;
var hubCounter = 0;
var largestHub = 0;
for (var i = 0; i < this.nodeIndices.length; i++) {
var node = this.nodes[this.nodeIndices[i]];
if (node.dynamicEdgesLength > largestHub) {
largestHub = node.dynamicEdgesLength;
}
average += node.dynamicEdgesLength;
averageSquared += Math.pow(node.dynamicEdgesLength,2);
hubCounter += 1;
}
average = average / hubCounter;
averageSquared = averageSquared / hubCounter;
var variance = averageSquared - Math.pow(average,2);
var standardDeviation = Math.sqrt(variance);
this.hubThreshold = Math.floor(average + 2*standardDeviation);
// always have at least one to cluster
if (this.hubThreshold > largestHub) {
this.hubThreshold = largestHub;
}
// console.log("average",average,"averageSQ",averageSquared,"var",variance,"std",standardDeviation);
// console.log("hubThreshold:",this.hubThreshold);
};
/**
* We reduce the amount of "extension nodes" or chains. These are not quickly clustered with the outliers and hubs methods
* with this amount we can cluster specifically on these chains.
*
* @param {Number} fraction | between 0 and 1, the percentage of chains to reduce
* @private
*/
exports._reduceAmountOfChains = function(fraction) {
this.hubThreshold = 2;
var reduceAmount = Math.floor(this.nodeIndices.length * fraction);
for (var nodeId in this.nodes) {
if (this.nodes.hasOwnProperty(nodeId)) {
if (this.nodes[nodeId].dynamicEdgesLength == 2 && this.nodes[nodeId].dynamicEdges.length >= 2) {
if (reduceAmount > 0) {
this._formClusterFromHub(this.nodes[nodeId],true,true,1);
reduceAmount -= 1;
}
}
}
}
};
/**
* We get the amount of "extension nodes" or chains. These are not quickly clustered with the outliers and hubs methods
* with this amount we can cluster specifically on these chains.
*
* @private
*/
exports._getChainFraction = function() {
var chains = 0;
var total = 0;
for (var nodeId in this.nodes) {
if (this.nodes.hasOwnProperty(nodeId)) {
if (this.nodes[nodeId].dynamicEdgesLength == 2 && this.nodes[nodeId].dynamicEdges.length >= 2) {
chains += 1;
}
total += 1;
}
}
return chains/total;
};