feat:node-modules

node_modules/mathjs/lib/cjs/function/probability/combinations.js

@@ -0,0 +1,75 @@
+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.createCombinations = void 0;
+var _factory = require("../../utils/factory.js");
+var _combinations = require("../../plain/number/combinations.js");
+const name = 'combinations';
+const dependencies = ['typed'];
+const createCombinations = exports.createCombinations = /* #__PURE__ */(0, _factory.factory)(name, dependencies, _ref => {
+  let {
+    typed
+  } = _ref;
+  /**
+   * Compute the number of ways of picking `k` unordered outcomes from `n`
+   * possibilities.
+   *
+   * Combinations only takes integer arguments.
+   * The following condition must be enforced: k <= n.
+   *
+   * Syntax:
+   *
+   *     math.combinations(n, k)
+   *
+   * Examples:
+   *
+   *    math.combinations(7, 5) // returns 21
+   *
+   * See also:
+   *
+   *    combinationsWithRep, permutations, factorial
+   *
+   * @param {number | BigNumber} n    Total number of objects in the set
+   * @param {number | BigNumber} k    Number of objects in the subset
+   * @return {number | BigNumber}     Number of possible combinations.
+   */
+  return typed(name, {
+    'number, number': _combinations.combinationsNumber,
+    'BigNumber, BigNumber': function (n, k) {
+      const BigNumber = n.constructor;
+      let result, i;
+      const nMinusk = n.minus(k);
+      const one = new BigNumber(1);
+      if (!isPositiveInteger(n) || !isPositiveInteger(k)) {
+        throw new TypeError('Positive integer value expected in function combinations');
+      }
+      if (k.gt(n)) {
+        throw new TypeError('k must be less than n in function combinations');
+      }
+      result = one;
+      if (k.lt(nMinusk)) {
+        for (i = one; i.lte(nMinusk); i = i.plus(one)) {
+          result = result.times(k.plus(i)).dividedBy(i);
+        }
+      } else {
+        for (i = one; i.lte(k); i = i.plus(one)) {
+          result = result.times(nMinusk.plus(i)).dividedBy(i);
+        }
+      }
+      return result;
+    }
+
+    // TODO: implement support for collection in combinations
+  });
+});
+
+/**
+ * Test whether BigNumber n is a positive integer
+ * @param {BigNumber} n
+ * @returns {boolean} isPositiveInteger
+ */
+function isPositiveInteger(n) {
+  return n.isInteger() && n.gte(0);
+}