29 lines
716 B
JavaScript
29 lines
716 B
JavaScript
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import defaultSource from "./defaultSource.js";
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export default (function sourceRandomNormal(source) {
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function randomNormal(mu, sigma) {
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var x, r;
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mu = mu == null ? 0 : +mu;
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sigma = sigma == null ? 1 : +sigma;
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return function() {
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var y;
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// If available, use the second previously-generated uniform random.
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if (x != null) y = x, x = null;
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// Otherwise, generate a new x and y.
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else do {
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x = source() * 2 - 1;
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y = source() * 2 - 1;
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r = x * x + y * y;
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} while (!r || r > 1);
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return mu + sigma * y * Math.sqrt(-2 * Math.log(r) / r);
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};
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}
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randomNormal.source = sourceRandomNormal;
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return randomNormal;
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})(defaultSource);
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