49 lines
2.0 KiB
JavaScript
49 lines
2.0 KiB
JavaScript
import {takeSampleFrom} from "./helpers";
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import {placeNearToNearestNeighbour} from "./interpCommon";
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/**
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* Perform interpolation where the "parent" node is found by brute-force.
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* A "parent" of a node to be interpolated is a node whose position in 2D space
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* is already known and have the least high-dimensional distance to the node in
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* question.
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* For each point to be interpolated:
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* - Phase 1: find the "parent" by comparing high-d distance against every
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points already plotted on the graph.
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this is essentially a nearest neighbour finding problem.
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* - Phase 2 and 3 are passed onto placeNearToNearestNeighbour
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* @param {list} sampleSet - nodes already plotted on the 2D graph
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* @param {list} remainderSet - nodes to be interpolated onto the graph
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* @param {function} distanceFn - f(nodex, nodey) that calculate high-dimensional
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* distance between 2 nodes
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* @param {number} endingIts - for phase 3, how many iterations to refine the
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* placement of each interpolated point
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*/
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export default function(sampleSet, remainderSet, distanceFn, endingIts) {
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let
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sampleSubset = takeSampleFrom(sampleSet, Math.sqrt(sampleSet.length)).sample,
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sampleSubsetDistanceCache = [];
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// For each datapoint "node" to be interpolated
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for (let i = remainderSet.length-1; i>=0; i--) {
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let
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node = remainderSet[i],
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nearestSample, minDist, sample, dist, index;
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// For each datapoint "sample" in the sample set
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for (let j = sampleSet.length-1; j>=0; j--) {
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sample = sampleSet[j];
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dist = distanceFn(node, sample);
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if (nearestSample === undefined || dist < minDist) {
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minDist = dist;
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nearestSample = sample;
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}
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index = sampleSubset.indexOf(sample);
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if (index !== -1)
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sampleSubsetDistanceCache[index] = dist;
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}
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placeNearToNearestNeighbour(node, nearestSample, minDist, sampleSubset, sampleSubsetDistanceCache, endingIts);
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}
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}
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