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tai2/bessel.js

Created April 18, 2025 08:47
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  1. tai2 created this gist Apr 18, 2025.
    35 changes: 35 additions & 0 deletions bessel.js
    View file
    Original file line number Diff line number Diff line change
    @@ -0,0 +1,35 @@
    const bessel = (x, alpha, n) => {
    if (n < 0) {
    throw new Error("n must be non-negative");
    }
    if (alpha < 0) {
    throw new Error("alpha must be non-negative");
    }

    let sum = 0;
    for (let m = 0; m <= n; m++) {
    const term =
    (Math.pow(-1, m) * Math.pow(x / 2, alpha + 2 * m)) /
    (factorial(m) * factorial(alpha + m));
    sum += term;
    }
    return sum;
    };

    const factorial = (n) => {
    if (n < 0) {
    throw new Error("n must be non-negative");
    }
    if (n === 0 || n === 1) {
    return 1;
    }
    let result = 1;
    for (let i = 2; i <= n; i++) {
    result *= i;
    }
    return result;
    };

    console.log(bessel(1, 0, 5));
    console.log(bessel(1, 1, 5));
    console.log(bessel(2, 0, 5));