Compute Engine Forms

A given mathematical expression can be represented in multiple equivalent ways as a MathJSON expression. A form is used to specify a representation:

  • 'full': only transformations applied are those necessary to make it valid JSON (for example making sure that Infinity and NaN are represented as strings)
  • 'flatten': associative functions are combined, e.g. f(f(a, b), c) -> f(a, b, c)
  • 'sorted': the arguments of commutative functions are sorted such that: - numbers are first, sorted numerically - complex numbers are next, sorted numerically by imaginary value - symbols are next, sorted lexicographically - add functions are next - multiply functions are next - power functions are next, sorted by their first argument, then by their second argument - other functions follow, sorted lexicographically
  • 'stripped-metadata': any metadata associated with elements of the expression is removed.
  • 'object-literal': each term of an expression is expressed as an object literal: no shorthand representation is used.
  • 'canonical-add': `addition of 0 is simplified, associativity rules are applied, unnecessary groups are moved, single argument ‘add’ are simplified
  • 'canonical-divide': divide is replaced with multiply and `power’, division by 1 is simplified,
  • 'canonical-exp': exp is replaced with power
  • 'canonical-multiply': multiplication by 1 or -1 is simplified
  • 'canonical-power': power with a first or second argument of 1 is simplified
  • 'canonical-negate': real or complex number is replaced by the negative of that number. Negation of negation is simplified.
  • 'canonical-number': complex numbers with no imaginary compnents are simplified
  • 'canonical-root': root is replaced with power
  • 'canonical-subtract': subtract is replaced with add and negate
  • 'canonical': the following transformations are performed, in this order:
    • 'canonical-number', -> simplify number
    • 'canonical-exp', -> power
    • 'canonical-root', -> power, divide
    • 'canonical-subtract', -> add, negate, multiply,
    • 'canonical-divide', -> multiply, power
    • 'canonical-power', -> simplify power
    • 'canonical-multiply', -> multiply, power
    • 'canonical-negate', -> simplify negate
    • 'canonical-add', -> simplify add
    • 'flatten', simplify associative, idempotent, involution and groups
    • 'sorted',
    • 'full',

To transform an expression using the rules for a particular form, use the format() function.

import { format } from 'math-json';

console.log(format(["Add", 2, "x", 3], 'canonical');
// ➔ ["Add", 2, 3, "x"]

BaseForm

["BaseForm", _value_, _base_]

Format a value in a specific base, such as hexadecimal or binary.

  • value should be an integer.
  • base should be an integer from 2 to 36.
["Latex", ["BaseForm", 42, 16]]
// ➔ (\mathtt(2a))_{16}
Latex(BaseForm(42, 16))
// ➔ (\mathtt(2a))_{16}
BaseForm(42, 16)
// ➔ 0x2a

Derivative

["Derivative", _expression_, _order_]

  • order: default value is 1.
MathJSONLatex
["Derivative", "f"]f^\prime
["Derivative", "f", 2]f^\doubleprime
["Derivative", "f", "n"]f^{(n)}