| 1 | /*
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| 2 | Fraction.js v5.0.0 10/1/2024
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| 3 | https://raw.org/article/rational-numbers-in-javascript/
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| 4 |
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| 5 | Copyright (c) 2024, Robert Eisele (https://raw.org/)
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| 6 | Licensed under the MIT license.
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| 7 | */
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| 8 | const Fraction = require('fraction.js');
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| 9 |
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| 10 | // NOTE: This is a nice example, but a stable version of this is served with Polynomial.js:
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| 11 | // https://github.com/rawify/Polynomial.js
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| 12 |
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| 13 | function integrate(poly) {
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| 14 |
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| 15 | poly = poly.replace(/\s+/g, "");
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| 16 |
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| 17 | var regex = /(\([+-]?[0-9/]+\)|[+-]?[0-9/]+)x(?:\^(\([+-]?[0-9/]+\)|[+-]?[0-9]+))?/g;
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| 18 | var arr;
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| 19 | var res = {};
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| 20 | while (null !== (arr = regex.exec(poly))) {
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| 21 |
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| 22 | var a = (arr[1] || "1").replace("(", "").replace(")", "").split("/");
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| 23 | var b = (arr[2] || "1").replace("(", "").replace(")", "").split("/");
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| 24 |
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| 25 | var exp = new Fraction(b).add(1);
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| 26 | var key = "" + exp;
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| 27 |
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| 28 | if (res[key] !== undefined) {
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| 29 | res[key] = { x: new Fraction(a).div(exp).add(res[key].x), e: exp };
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| 30 | } else {
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| 31 | res[key] = { x: new Fraction(a).div(exp), e: exp };
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| 32 | }
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| 33 | }
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| 34 |
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| 35 | var str = "";
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| 36 | var c = 0;
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| 37 | for (var i in res) {
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| 38 | if (res[i].x.s !== -1n && c > 0) {
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| 39 | str += "+";
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| 40 | } else if (res[i].x.s === -1n) {
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| 41 | str += "-";
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| 42 | }
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| 43 | if (res[i].x.n !== res[i].x.d) {
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| 44 | if (res[i].x.d !== 1n) {
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| 45 | str += res[i].x.n + "/" + res[i].x.d;
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| 46 | } else {
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| 47 | str += res[i].x.n;
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| 48 | }
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| 49 | }
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| 50 | str += "x";
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| 51 | if (res[i].e.n !== res[i].e.d) {
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| 52 | str += "^";
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| 53 | if (res[i].e.d !== 1n) {
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| 54 | str += "(" + res[i].e.n + "/" + res[i].e.d + ")";
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| 55 | } else {
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| 56 | str += res[i].e.n;
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| 57 | }
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| 58 | }
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| 59 | c++;
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| 60 | }
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| 61 | return str;
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| 62 | }
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| 63 |
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| 64 | var poly = "-2/3x^3-2x^2+3x+8x^3-1/3x^(4/8)";
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| 65 |
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| 66 | console.log("f(x): " + poly);
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| 67 | console.log("F(x): " + integrate(poly));
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