feat:node-modules

node_modules/mathjs/lib/cjs/function/combinatorics/stirlingS2.js

@@ -0,0 +1,92 @@
+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.createStirlingS2 = void 0;
+var _factory = require("../../utils/factory.js");
+var _is = require("../../utils/is.js");
+const name = 'stirlingS2';
+const dependencies = ['typed', 'addScalar', 'subtractScalar', 'multiplyScalar', 'divideScalar', 'pow', 'factorial', 'combinations', 'isNegative', 'isInteger', 'number', '?bignumber', 'larger'];
+const createStirlingS2 = exports.createStirlingS2 = /* #__PURE__ */(0, _factory.factory)(name, dependencies, _ref => {
+  let {
+    typed,
+    addScalar,
+    subtractScalar,
+    multiplyScalar,
+    divideScalar,
+    pow,
+    factorial,
+    combinations,
+    isNegative,
+    isInteger,
+    number,
+    bignumber,
+    larger
+  } = _ref;
+  const smallCache = [];
+  const bigCache = [];
+  /**
+   * The Stirling numbers of the second kind, counts the number of ways to partition
+   * a set of n labelled objects into k nonempty unlabelled subsets.
+   * stirlingS2 only takes integer arguments.
+   * The following condition must be enforced: k <= n.
+   *
+   *  If n = k or k = 1 <= n, then s(n,k) = 1
+   *  If k = 0 < n, then s(n,k) = 0
+   *
+   * Note that if either n or k is supplied as a BigNumber, the result will be
+   * as well.
+   *
+   * Syntax:
+   *
+   *   math.stirlingS2(n, k)
+   *
+   * Examples:
+   *
+   *    math.stirlingS2(5, 3) //returns 25
+   *
+   * See also:
+   *
+   *    bellNumbers
+   *
+   * @param {Number | BigNumber} n    Total number of objects in the set
+   * @param {Number | BigNumber} k    Number of objects in the subset
+   * @return {Number | BigNumber}     S(n,k)
+   */
+  return typed(name, {
+    'number | BigNumber, number | BigNumber': function (n, k) {
+      if (!isInteger(n) || isNegative(n) || !isInteger(k) || isNegative(k)) {
+        throw new TypeError('Non-negative integer value expected in function stirlingS2');
+      } else if (larger(k, n)) {
+        throw new TypeError('k must be less than or equal to n in function stirlingS2');
+      }
+      const big = !((0, _is.isNumber)(n) && (0, _is.isNumber)(k));
+      const cache = big ? bigCache : smallCache;
+      const make = big ? bignumber : number;
+      const nn = number(n);
+      const nk = number(k);
+      /* See if we already have the value: */
+      if (cache[nn] && cache[nn].length > nk) {
+        return cache[nn][nk];
+      }
+      /* Fill the cache */
+      for (let m = 0; m <= nn; ++m) {
+        if (!cache[m]) {
+          cache[m] = [m === 0 ? make(1) : make(0)];
+        }
+        if (m === 0) continue;
+        const row = cache[m];
+        const prev = cache[m - 1];
+        for (let i = row.length; i <= m && i <= nk; ++i) {
+          if (i === m) {
+            row[i] = 1;
+          } else {
+            row[i] = addScalar(multiplyScalar(make(i), prev[i]), prev[i - 1]);
+          }
+        }
+      }
+      return cache[nn][nk];
+    }
+  });
+});