mathjs/src/function/matrix/size.js

Math.js is an extensive math library for JavaScript and Node.js. It features a flexible expression parser with support for symbolic computation, comes with a large set of built-in functions and constants, and offers an integrated solution to work with dif

'use strict'

const array = require('../../utils/array')

function factory (type, config, load, typed) {
  const matrix = load(require('../../type/matrix/function/matrix'))

  /**
   * Calculate the size of a matrix or scalar.
   *
   * Syntax:
   *
   *     math.size(x)
   *
   * Examples:
   *
   *     math.size(2.3)                  // returns []
   *     math.size('hello world')        // returns [11]
   *
   *     const A = [[1, 2, 3], [4, 5, 6]]
   *     math.size(A)                    // returns [2, 3]
   *     math.size(math.range(1,6))      // returns [5]
   *
   * See also:
   *
   *     resize, squeeze, subset
   *
   * @param {boolean | number | Complex | Unit | string | Array | Matrix} x  A matrix
   * @return {Array | Matrix} A vector with size of `x`.
   */
  const size = typed('size', {
    'Matrix': function (x) {
      // TODO: return the same matrix type as the input
      return matrix(x.size())
    },

    'Array': array.size,

    'string': function (x) {
      return (config.matrix === 'Array') ? [x.length] : matrix([x.length])
    },

    'number | Complex | BigNumber | Unit | boolean | null': function (x) {
      // scalar
      return (config.matrix === 'Array') ? [] : matrix([])
    }
  })

  size.toTex = undefined // use default template

  return size
}

exports.name = 'size'
exports.factory = factory