/*** Calculate the forces the nodes apply on eachother based on a repulsion field.* This field is linearly approximated.** @private*/_calculateNodeForces: function () {var dx, dy, angle, distance, fx, fy, combinedClusterSize,repulsingForce, node1, node2, i, j;var nodes = this.calculationNodes;var nodeIndices = this.calculationNodeIndices;// approximation constantsvar a_base = -2 / 3;var b = 4 / 3;// repulsing forces between nodesvar nodeDistance = this.constants.physics.repulsion.nodeDistance;var minimumDistance = nodeDistance;// we loop from i over all but the last entree in the array// j loops from i+1 to the last. This way we do not double count any of the indices, nor i == jfor (i = 0; i < nodeIndices.length - 1; i++) {node1 = nodes[nodeIndices[i]];for (j = i + 1; j < nodeIndices.length; j++) {node2 = nodes[nodeIndices[j]];combinedClusterSize = node1.clusterSize + node2.clusterSize - 2;dx = node2.x - node1.x;dy = node2.y - node1.y;distance = Math.sqrt(dx * dx + dy * dy);minimumDistance = (combinedClusterSize == 0) ? nodeDistance : (nodeDistance * (1 + combinedClusterSize * this.constants.clustering.distanceAmplification));var a = a_base / minimumDistance;if (distance < 2 * minimumDistance) {if (distance < 0.5 * minimumDistance) {repulsingForce = 1.0;}else {repulsingForce = a * distance + b; // linear approx of  1 / (1 + Math.exp((distance / minimumDistance - 1) * steepness))
          }// amplify the repulsion for clusters.repulsingForce *= (combinedClusterSize == 0) ? 1 : 1 + combinedClusterSize * this.constants.clustering.forceAmplification;repulsingForce = repulsingForce / distance;fx = dx * repulsingForce;fy = dy * repulsingForce;node1.fx -= fx;node1.fy -= fy;node2.fx += fx;node2.fy += fy;}}}}
};

/*** Calculate the forces the nodes apply on eachother based on a repulsion field.* This field is linearly approximated.** @private*/_calculateNodeForces: function () {var dx, dy, angle, distance, fx, fy, combinedClusterSize,repulsingForce, node1, node2, i, j;var nodes = this.calculationNodes;var nodeIndices = this.calculationNodeIndices;// approximation constantsvar a_base = -2 / 3;var b = 4 / 3;// repulsing forces between nodesvar nodeDistance = this.constants.physics.repulsion.nodeDistance;var minimumDistance = nodeDistance;// we loop from i over all but the last entree in the array// j loops from i+1 to the last. This way we do not double count any of the indices, nor i == jfor (i = 0; i < nodeIndices.length - 1; i++) {node1 = nodes[nodeIndices[i]];for (j = i + 1; j < nodeIndices.length; j++) {node2 = nodes[nodeIndices[j]];combinedClusterSize = node1.clusterSize + node2.clusterSize - 2;dx = node2.x - node1.x;dy = node2.y - node1.y;distance = Math.sqrt(dx * dx + dy * dy);if(distance == 0){distance = 0.001;}minimumDistance = (combinedClusterSize == 0) ? nodeDistance : (nodeDistance * (1 + combinedClusterSize * this.constants.clustering.distanceAmplification));var a = a_base / minimumDistance;if (distance < 2 * minimumDistance) {if (distance < 0.5 * minimumDistance) {repulsingForce = 1.0;}else {repulsingForce = a * distance + b; // linear approx of  1 / (1 + Math.exp((distance / minimumDistance - 1) * steepness))
          }// amplify the repulsion for clusters.repulsingForce *= (combinedClusterSize == 0) ? 1 : 1 + combinedClusterSize * this.constants.clustering.forceAmplification;repulsingForce = repulsingForce / distance;fx = dx * repulsingForce;fy = dy * repulsingForce;node1.fx -= fx;node1.fy -= fy;node2.fx += fx;node2.fy += fy;}}}}
};