Matrix multiplier

27 Nov 2012 Code on Github


This is my attempt to make a tool for quickly multiplying matrices, even when they contain expressions. It still needs a lot of work to be really useful.

The program

Click on the grey boxes to edit the matrices and their dimensions. Matrix values can be numbers or variables consisting of letters and parenthese. Dimensions are limited to the range 1-6.

Or try an example matrix: Integers Decimals Simple variables Complex variables
Matrix 1
( × )
Matrix 2
( × )
(2 × 2)

Notes, Bugs & Features

  • Don't use fractions. e.g. use 0.5a not a/2.
  • Don't leave a space between variables and coefficients, e.g. write "4a" not "4 a".
  • Variables must consist only of upper- or lower-case letters and parentheses.
  • cos(5) won't work, cos(pi) will.
  • θ won't work, theta will.
  • The dot notation is used for the output, so b.b means b2.
  • Expressions, such as a + b, cannot be used (yet).
  • The variable ab is assumed to be a single variable, not a × b.
  • Separated parts of expressions are not cancelled, e.g. 2a + b - 2a.