20 lines
728 B
JavaScript
20 lines
728 B
JavaScript
/**
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* Calculates the stress. Basically, it computes the difference between
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* high dimensional distance and real distance. The lower the stress is,
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* the better layout.
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* @return {number} - stress of the layout.
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*/
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export function getStress(nodes, distance) {
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let totalDiffSq = 0, totalHighDistSq = 0;
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for (let j = 0; j < nodes.length; j++) {
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for (let i = 0; i < j; i++) {
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let source = nodes[i], target = nodes[j];
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let lowDDist = Math.hypot(target.x - source.x, target.y - source.y);
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let highDDist = distance(source, target);
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totalDiffSq += Math.pow(highDDist - lowDDist, 2);
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totalHighDistSq += highDDist * highDDist;
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}
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}
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return Math.sqrt(totalDiffSq / totalHighDistSq);
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}
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