feat:node-modules

node_modules/mathjs/lib/cjs/function/arithmetic/invmod.js

@@ -0,0 +1,61 @@
+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.createInvmod = void 0;
+var _factory = require("../../utils/factory.js");
+const name = 'invmod';
+const dependencies = ['typed', 'config', 'BigNumber', 'xgcd', 'equal', 'smaller', 'mod', 'add', 'isInteger'];
+const createInvmod = exports.createInvmod = /* #__PURE__ */(0, _factory.factory)(name, dependencies, _ref => {
+  let {
+    typed,
+    config,
+    BigNumber,
+    xgcd,
+    equal,
+    smaller,
+    mod,
+    add,
+    isInteger
+  } = _ref;
+  /**
+   * Calculate the (modular) multiplicative inverse of a modulo b. Solution to the equation `ax ≣ 1 (mod b)`
+   * See https://en.wikipedia.org/wiki/Modular_multiplicative_inverse.
+   *
+   * Syntax:
+   *
+   *    math.invmod(a, b)
+   *
+   * Examples:
+   *
+   *    math.invmod(8, 12)             // returns NaN
+   *    math.invmod(7, 13)             // returns 2
+   *    math.invmod(15151, 15122)      // returns 10429
+   *
+   * See also:
+   *
+   *    gcd, xgcd
+   *
+   * @param {number | BigNumber} a  An integer number
+   * @param {number | BigNumber} b  An integer number
+   * @return {number | BigNumber }  Returns an integer number
+   *                              where `invmod(a,b)*a ≣ 1 (mod b)`
+   */
+  return typed(name, {
+    'number, number': invmod,
+    'BigNumber, BigNumber': invmod
+  });
+  function invmod(a, b) {
+    if (!isInteger(a) || !isInteger(b)) throw new Error('Parameters in function invmod must be integer numbers');
+    a = mod(a, b);
+    if (equal(b, 0)) throw new Error('Divisor must be non zero');
+    let res = xgcd(a, b);
+    res = res.valueOf();
+    let [gcd, inv] = res;
+    if (!equal(gcd, BigNumber(1))) return NaN;
+    inv = mod(inv, b);
+    if (smaller(inv, BigNumber(0))) inv = add(inv, b);
+    return inv;
+  }
+});