# Configuration Math.js contains a number of configuration options. There are two ways to configure math.js: - Configure an existing instance of math.js using `math.config(options)`, for example `math.config({number: 'bignumber'})` to change to BigNumbers. - Create and configure a new instance of math.js using `math.create([options])`, for example `var bigmath = math.create({number: 'bignumber'})` to create a new instance configured to use BigNumbers. The following configuration options are available: - `epsilon`. The minimum relative difference used to test equality between two compared values. This value is used by all relational functions. Default value is `1e-14`. - `matrix`. The default type of matrix output for functions. Available values are: `'matrix'` (default) or `'array'`. Where possible, the type of matrix output from functions is determined from the function input: An array as input will return an Array, a Matrix as input will return a Matrix. In case of no matrix as input, the type of output is determined by the option `matrix`. In case of mixed matrix inputs, a matrix will be returned always. - `number`. The default type of numbers. This setting is used by functions like `eval `which cannot determine the correct type of output from the functions input. For most functions though, the type of output is determined from the the input: a number as input will return a number as output, a BigNumber as input returns a BigNumber as output. Available values are: `'number'` (default) or `'bignumber'`. BigNumbers have higher precision than the default numbers of JavaScript. - `precision`. The maximum number of significant digits for bigNumbers. This setting only applies to BigNumbers, not to numbers. Default value is `64`. ## Examples This section shows a number of configuration examples. ### node.js ```js // load the default instance of math.js var math = require('mathjs'); // range will output a Matrix math.range(0, 4); // Matrix [0, 1, 2, 3] // create a new instance configured to use Arrays var math2 = math.create({ matrix: 'array' // Choose 'matrix' (default) or 'array' }); // range will output an Array math2.range(0, 4); // Array [0, 1, 2, 3] // change the configuration of math2 from Arrays to Matrices math2.config({ matrix: 'matrix' // Choose 'matrix' (default) or 'array' }); // range will output a Matrix math2.range(0, 4); // Matrix [0, 1, 2, 3] // create an instance of math.js with bignumber configuration var bigmath = math.create({ number: 'bignumber', // Choose 'number' (default) or 'bignumber' precision: 32 // 64 by default, only applicable for BigNumbers }); // parser will parse numbers as BigNumber now: bigmath.eval('1 / 3'); // BigNumber, 0.33333333333333333333333333333333 ``` ### browser ```html ```