@beenotung/tslib/math.js

utils library in Typescript

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.reduceFraction = exports.numberToFraction = exports.lcm = exports.gcd = exports.math = exports.calcPhi = void 0;
function calcPhi() {
    let phi = 1;
    for (;;) {
        const x = 1 + 1 / phi;
        if (phi === x) {
            return x;
        }
        phi = x;
    }
}
exports.calcPhi = calcPhi;
let phi;
exports.math = {
    get phi() {
        return phi || (phi = calcPhi());
    },
    set phi(never) {
        throw new Error('unexpected assignment');
    },
};
function gcd(a, b) {
    a = Math.abs(a);
    b = Math.abs(b);
    if (b > a) {
        const t = a;
        a = b;
        b = t;
    }
    for (;;) {
        if (b === 0) {
            return a;
        }
        a %= b;
        if (a === 0) {
            return b;
        }
        b %= a;
    }
}
exports.gcd = gcd;
function lcm(a, b) {
    return !a || !b ? 0 : Math.abs(a * b) / gcd(a, b);
}
exports.lcm = lcm;
/**
 * input: x
 * output: [a, b], where x = a/b
 * */
function numberToFraction(x, error = 1e-12) {
    if (x === Math.round(x)) {
        return [x, 1];
    }
    if (x < 0) {
        const [a, b] = numberToFraction(-x, error);
        return [-a, b];
    }
    let a = 1;
    let b = 1;
    for (;;) {
        const y = a / b;
        // process.stdout.write(`\r diff=${y - x}, x=${x}, ${a}/${b}`);
        if (x === y || Math.abs(y - x) < error) {
            return [a, b];
        }
        if (y > x) {
            b++;
        }
        else {
            a++;
        }
    }
}
exports.numberToFraction = numberToFraction;
function reduceFraction([a, b]) {
    const c = gcd(a, b);
    a /= c;
    b /= c;
    return b < 0 ? [-a, -b] : [a, b];
}
exports.reduceFraction = reduceFraction;
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