34 lines
883 B
JavaScript
34 lines
883 B
JavaScript
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const sum = (arr) => arr.reduce((a, b) => a + b, 0);
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function getStdev(arr) {
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if (Array.isArray(arr) && arr.length > 0) {
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const n = arr.length;
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const mean = arr.reduce((a, b) => a + b) / n;
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return Math.sqrt(
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arr.map((x) => Math.pow(x - mean, 2)).reduce((a, b) => a + b) / n
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);
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} else {
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return 0;
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}
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}
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export const avg = (arr) => sum(arr) / arr.length;
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export const geomMean = (arr) => {
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let n = arr.length;
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let logavg = sum(arr.map((x) => Math.log(x))); // works for low numbers much better, numerically
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let result = Math.exp(logavg / n);
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return result;
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};
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export const getCoefficientOfVariation = (arr) => {
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let nonPositiveNumbers = arr.filter((x) => x <= 0);
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if (nonPositiveNumbers.length == 0) {
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let gm = geomMean(arr);
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let stdev = getStdev(arr);
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return stdev / gm;
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} else {
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return getStdev(arr) / avg(arr);
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}
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};
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