text: 'use strict';
  
  function factory (type, config, load, typed) {
    var combinations = load(require('../probability/combinations'));
    var add = load(require('../arithmetic/addScalar'));
    var isPositive = load(require('../utils/isPositive'));
    var isInteger = load(require('../utils/isInteger'));
    var larger = load(require('../relational/larger'));
  
    /**
     * The composition counts of n into k parts.
     *
     * composition only takes integer arguments.
     * The following condition must be enforced: k <= n.
     *
     * Syntax:
     *
     *   math.composition(n, k)
     *
     * Examples:
     *
     *    math.composition(5, 3); // returns 6
     *
     * See also:
     *
     *    combinations
     *
     * @param {Number | BigNumber} n    Total number of objects in the set
     * @param {Number | BigNumber} k    Number of objects in the subset
     * @return {Number | BigNumber}     Returns the composition counts of n into k parts.
     */
    var composition =  typed('composition', {
      'number | BigNumber, number | BigNumber': function (n, k) {
        if (!isInteger(n) || !isPositive(n) || !isInteger(k) || !isPositive(k)) {
          throw new TypeError('Positive integer value expected in function composition');
        }
        else if (larger(k, n)) {
          throw new TypeError('k must be less than or equal to n in function composition');
        }
  
        return combinations(add(n, -1), add(k, -1));
      }
    });
  
    composition.toTex = undefined; // use default template
  
    return composition;
  }
  
  exports.name = 'composition';
  exports.factory = factory;
  