95 lines
2.7 KiB
JavaScript
95 lines
2.7 KiB
JavaScript
import { factory } from '../../utils/factory.js';
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import { isInteger } from '../../utils/number.js';
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import { product } from '../../utils/product.js';
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var name = 'combinationsWithRep';
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var dependencies = ['typed'];
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export var createCombinationsWithRep = /* #__PURE__ */factory(name, dependencies, _ref => {
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var {
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typed
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} = _ref;
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/**
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* Compute the number of ways of picking `k` unordered outcomes from `n`
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* possibilities, allowing individual outcomes to be repeated more than once.
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*
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* CombinationsWithRep only takes integer arguments.
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* The following condition must be enforced: k <= n + k -1.
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*
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* Syntax:
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*
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* math.combinationsWithRep(n, k)
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*
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* Examples:
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*
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* math.combinationsWithRep(7, 5) // returns 462
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*
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* See also:
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*
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* combinations, permutations, factorial
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*
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* @param {number | BigNumber} n Total number of objects in the set
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* @param {number | BigNumber} k Number of objects in the subset
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* @return {number | BigNumber} Number of possible combinations with replacement.
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*/
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return typed(name, {
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'number, number': function numberNumber(n, k) {
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if (!isInteger(n) || n < 0) {
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throw new TypeError('Positive integer value expected in function combinationsWithRep');
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}
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if (!isInteger(k) || k < 0) {
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throw new TypeError('Positive integer value expected in function combinationsWithRep');
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}
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if (n < 1) {
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throw new TypeError('k must be less than or equal to n + k - 1');
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}
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if (k < n - 1) {
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var _prodrange = product(n, n + k - 1);
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return _prodrange / product(1, k);
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}
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var prodrange = product(k + 1, n + k - 1);
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return prodrange / product(1, n - 1);
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},
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'BigNumber, BigNumber': function BigNumberBigNumber(n, k) {
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var BigNumber = n.constructor;
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var result, i;
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var one = new BigNumber(1);
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var nMinusOne = n.minus(one);
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if (!isPositiveInteger(n) || !isPositiveInteger(k)) {
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throw new TypeError('Positive integer value expected in function combinationsWithRep');
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}
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if (n.lt(one)) {
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throw new TypeError('k must be less than or equal to n + k - 1 in function combinationsWithRep');
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}
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result = one;
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if (k.lt(nMinusOne)) {
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for (i = one; i.lte(nMinusOne); i = i.plus(one)) {
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result = result.times(k.plus(i)).dividedBy(i);
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}
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} else {
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for (i = one; i.lte(k); i = i.plus(one)) {
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result = result.times(nMinusOne.plus(i)).dividedBy(i);
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}
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}
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return result;
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}
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});
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});
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/**
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* Test whether BigNumber n is a positive integer
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* @param {BigNumber} n
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* @returns {boolean} isPositiveInteger
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*/
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function isPositiveInteger(n) {
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return n.isInteger() && n.gte(0);
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} |