Configuration #

Math.js contains a number of configuration options. These options can be applied on a created mathjs instance and changed afterwards.

import { create, all } from 'mathjs'

// create a mathjs instance with configuration
const config = {
  relTol: 1e-12,
  absTol: 1e-15,
  matrix: 'Matrix',
  number: 'number',
  precision: 64,
  predictable: false,
  randomSeed: null
}
const math = create(all, config)

// read the applied configuration
console.log(math.config())

// change the configuration
math.config({
  number: 'BigNumber'
})

The following configuration options are available:

• relTol. The minimum relative difference used to test equality between two compared values. This value is used by all relational functions. Default value is 1e-12.

• absTol. The minimum absolute difference used to test equality between two compared values. This value is used by all relational functions. Default value is 1e-15.

• 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 type used to parse strings into a numeric value or create a new numeric value internally.

  For most functions, the type of output is determined from the input: a number as input will return a number as output, a BigNumber as input returns a BigNumber as output. But for example the functions math.evaluate('2+3'), math.parse('2+3'), math.range('1:10'), and math.unit('5cm') use the number configuration setting.

  Note that math.sqrt(4) will always return the number 2 regardless of the number configuration, because the numeric type can be determined from the input value.

  Available values are: 'number' (default), 'BigNumber', 'bigint', or 'Fraction'. BigNumbers have higher precision than the default numbers of JavaScript, bigint can represent large integer numbers, and Fractions store values in terms of a numerator and denominator.

• numberFallback. When number is configured for example with value 'bigint', and a value cannot be represented as bigint like in math.evaluate('2.3'), the value will be parsed in the type configured with numberFallback. Available values: 'number' (default) or 'BigNumber'.

• precision. The maximum number of significant digits for BigNumbers. This setting only applies to BigNumbers, not to numbers. Default value is 64.

• predictable. Predictable output type of functions. When true, output type depends only on the input types. When false (default), output type can vary depending on input values. For example math.sqrt(-4) returns complex('2i') when predictable is false, and returns NaN when true. Predictable output can be needed when programmatically handling the result of a calculation, but can be inconvenient for users when evaluating dynamic equations.

• randomSeed. Set this option to seed pseudo random number generation, making it deterministic. The pseudo random number generator is reset with the seed provided each time this option is set. For example, setting it to 'a' will cause math.random() to return 0.43449421599986604 upon the first call after setting the option every time. Set to null to seed the pseudo random number generator with a random seed. Default value is null.

Examples #

This section shows a number of configuration examples.

node.js #

import { create, all } from 'mathjs'

const config = {
  matrix: 'Array' // Choose 'Matrix' (default) or 'Array'
}
const math = create(all, config)

// range will output an Array
math.range(0, 4) // Array [0, 1, 2, 3]

// change the configuration from Arrays to Matrices
math.config({
  matrix: 'Matrix' // Choose 'Matrix' (default) or 'Array'
})

// range will output a Matrix
math.range(0, 4) // Matrix [0, 1, 2, 3]

// create an instance of math.js with BigNumber configuration
const bigmath = create(all, {
  number: 'BigNumber', // Choose 'number' (default), 'BigNumber', or 'Fraction'
  precision: 32        // 64 by default, only applicable for BigNumbers
})

// parser will parse numbers as BigNumber now:
bigmath.evaluate('1 / 3') // BigNumber, 0.33333333333333333333333333333333

browser #

<!DOCTYPE HTML>
<html>
<head>
  <script src="math.js" type="text/javascript"></script>
</head>
<body>
  <script type="text/javascript">
    // the default instance of math.js is available as 'math'

    // range will output a Matrix
    math.range(0, 4)          // Matrix [0, 1, 2, 3]

    // change the configuration of math from Matrices to Arrays
    math.config({
      matrix: 'Array'         // Choose 'Matrix' (default) or 'Array'
    })

    // range will output an Array
    math.range(0, 4)          // Array [0, 1, 2, 3]

    // create a new instance of math.js with bignumber configuration
    const bigmath = math.create({
      number: 'BigNumber',    // Choose 'number' (default), 'BigNumber', or 'Fraction'
      precision: 32           // 64 by default, only applicable for BigNumbers
    })

    // parser will parse numbers as BigNumber now:
    bigmath.evaluate('1 / 3') // BigNumber, 0.33333333333333333333333333333333
  </script>
</body>
</html>