18 lines
714 B
JavaScript
18 lines
714 B
JavaScript
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function Lanczos_Gamma(num)
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{
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var p = [
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0.99999999999980993, 676.5203681218851, -1259.1392167224028,
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771.32342877765313, -176.61502916214059, 12.507343278686905, -0.13857109526572012, 9.9843695780195716e-6, 1.5056327351493116e-7
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];
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var i;
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var g = 7;
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if (num < 0.5) return Math.PI / (Math.sin(Math.PI * num) * calculus.LanczosGamma(1 - num));
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num -= 1;
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var a = p[0];
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var t = num + g + 0.5;
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for (i = 1; i < p.length; i++) {
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a += p[i] / (num + i);
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}
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return Math.sqrt(2 * Math.PI) * Math.pow(t, num + 0.5) * Math.exp(-t) * a;
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}
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console.log(Lanczos_Gamma(5));
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