mathjs/src/function/arithmetic/floor.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 deepMap = require('../../utils/collection/deepMap')
const nearlyEqual = require('../../utils/number').nearlyEqual
const bigNearlyEqual = require('../../utils/bignumber/nearlyEqual')

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

  /**
   * Round a value towards minus infinity.
   * For matrices, the function is evaluated element wise.
   *
   * Syntax:
   *
   *    math.floor(x)
   *
   * Examples:
   *
   *    math.floor(3.2)              // returns number 3
   *    math.floor(3.8)              // returns number 3
   *    math.floor(-4.2)             // returns number -5
   *    math.floor(-4.7)             // returns number -5
   *
   *    const c = math.complex(3.2, -2.7)
   *    math.floor(c)                // returns Complex 3 - 3i
   *
   *    math.floor([3.2, 3.8, -4.7]) // returns Array [3, 3, -5]
   *
   * See also:
   *
   *    ceil, fix, round
   *
   * @param  {number | BigNumber | Fraction | Complex | Array | Matrix} x  Number to be rounded
   * @return {number | BigNumber | Fraction | Complex | Array | Matrix} Rounded value
   */
  const floor = typed('floor', {
    'number': function (x) {
      if (nearlyEqual(x, round(x), config.epsilon)) {
        return round(x)
      } else {
        return Math.floor(x)
      }
    },

    'Complex': function (x) {
      return x.floor()
    },

    'BigNumber': function (x) {
      if (bigNearlyEqual(x, round(x), config.epsilon)) {
        return round(x)
      } else {
        return x.floor()
      }
    },

    'Fraction': function (x) {
      return x.floor()
    },

    'Array | Matrix': function (x) {
      // deep map collection, skip zeros since floor(0) = 0
      return deepMap(x, floor, true)
    }
  })

  floor.toTex = { 1: `\\left\\lfloor\${args[0]}\\right\\rfloor` }

  return floor
}

exports.name = 'floor'
exports.factory = factory