mathjs/lib/function/arithmetic/round.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';

var isInteger = require('../../utils/number').isInteger;

var toFixed = require('../../utils/number').toFixed;

var deepMap = require('../../utils/collection/deepMap');

var NO_INT = 'Number of decimals in function round must be an integer';

function factory(type, config, load, typed) {
  var matrix = load(require('../../type/matrix/function/matrix'));
  var equalScalar = load(require('../relational/equalScalar'));
  var zeros = load(require('../matrix/zeros'));
  var algorithm11 = load(require('../../type/matrix/utils/algorithm11'));
  var algorithm12 = load(require('../../type/matrix/utils/algorithm12'));
  var algorithm14 = load(require('../../type/matrix/utils/algorithm14'));
  /**
   * Round a value towards the nearest integer.
   * For matrices, the function is evaluated element wise.
   *
   * Syntax:
   *
   *    math.round(x)
   *    math.round(x, n)
   *
   * Examples:
   *
   *    math.round(3.2)              // returns number 3
   *    math.round(3.8)              // returns number 4
   *    math.round(-4.2)             // returns number -4
   *    math.round(-4.7)             // returns number -5
   *    math.round(math.pi, 3)       // returns number 3.142
   *    math.round(123.45678, 2)     // returns number 123.46
   *
   *    const c = math.complex(3.2, -2.7)
   *    math.round(c)                // returns Complex 3 - 3i
   *
   *    math.round([3.2, 3.8, -4.7]) // returns Array [3, 4, -5]
   *
   * See also:
   *
   *    ceil, fix, floor
   *
   * @param  {number | BigNumber | Fraction | Complex | Array | Matrix} x  Number to be rounded
   * @param  {number | BigNumber | Array} [n=0]                            Number of decimals
   * @return {number | BigNumber | Fraction | Complex | Array | Matrix} Rounded value
   */

  var round = typed('round', {
    'number': function number(x) {
      return _round(x, 0);
    },
    'number, number': function numberNumber(x, n) {
      if (!isInteger(n)) {
        throw new TypeError(NO_INT);
      }

      if (n < 0 || n > 15) {
        throw new Error('Number of decimals in function round must be in te range of 0-15');
      }

      return _round(x, n);
    },
    'Complex': function Complex(x) {
      return x.round();
    },
    'Complex, number': function ComplexNumber(x, n) {
      if (n % 1) {
        throw new TypeError(NO_INT);
      }

      return x.round(n);
    },
    'Complex, BigNumber': function ComplexBigNumber(x, n) {
      if (!n.isInteger()) {
        throw new TypeError(NO_INT);
      }

      var _n = n.toNumber();

      return x.round(_n);
    },
    'number, BigNumber': function numberBigNumber(x, n) {
      if (!n.isInteger()) {
        throw new TypeError(NO_INT);
      }

      return new type.BigNumber(x).toDecimalPlaces(n.toNumber());
    },
    'BigNumber': function BigNumber(x) {
      return x.toDecimalPlaces(0);
    },
    'BigNumber, BigNumber': function BigNumberBigNumber(x, n) {
      if (!n.isInteger()) {
        throw new TypeError(NO_INT);
      }

      return x.toDecimalPlaces(n.toNumber());
    },
    'Fraction': function Fraction(x) {
      return x.round();
    },
    'Fraction, number': function FractionNumber(x, n) {
      if (n % 1) {
        throw new TypeError(NO_INT);
      }

      return x.round(n);
    },
    'Array | Matrix': function ArrayMatrix(x) {
      // deep map collection, skip zeros since round(0) = 0
      return deepMap(x, round, true);
    },
    'SparseMatrix, number | BigNumber': function SparseMatrixNumberBigNumber(x, y) {
      return algorithm11(x, y, round, false);
    },
    'DenseMatrix, number | BigNumber': function DenseMatrixNumberBigNumber(x, y) {
      return algorithm14(x, y, round, false);
    },
    'number | Complex | BigNumber, SparseMatrix': function numberComplexBigNumberSparseMatrix(x, y) {
      // check scalar is zero
      if (equalScalar(x, 0)) {
        // do not execute algorithm, result will be a zero matrix
        return zeros(y.size(), y.storage());
      }

      return algorithm12(y, x, round, true);
    },
    'number | Complex | BigNumber, DenseMatrix': function numberComplexBigNumberDenseMatrix(x, y) {
      // check scalar is zero
      if (equalScalar(x, 0)) {
        // do not execute algorithm, result will be a zero matrix
        return zeros(y.size(), y.storage());
      }

      return algorithm14(y, x, round, true);
    },
    'Array, number | BigNumber': function ArrayNumberBigNumber(x, y) {
      // use matrix implementation
      return algorithm14(matrix(x), y, round, false).valueOf();
    },
    'number | Complex | BigNumber, Array': function numberComplexBigNumberArray(x, y) {
      // use matrix implementation
      return algorithm14(matrix(y), x, round, true).valueOf();
    }
  });
  round.toTex = {
    1: "\\left\\lfloor${args[0]}\\right\\rceil",
    2: undefined // use default template

  };
  return round;
}
/**
 * round a number to the given number of decimals, or to zero if decimals is
 * not provided
 * @param {number} value
 * @param {number} decimals       number of decimals, between 0 and 15 (0 by default)
 * @return {number} roundedValue
 * @private
 */


function _round(value, decimals) {
  return parseFloat(toFixed(value, decimals));
}

exports.name = 'round';
exports.factory = factory;