MATRIXDEF
Syntax
MATRIXDEF symbol
@label@ { options } MATRIXDEF [*] symbol = expression
Implemented in iMath since version 2.2.0 or earlier.
Explanation
Declares the symbol to be a (two-dimensional) matrix. This is important because matrices are non-commutative when evaluating an expression.
The second form is a shortcut for the combination of MATRIXDEF and EQDEF. It defines the symbol and creates an equation defining its value.
Note that the matrix symbol is not identical with another symbol that has the same name but a different commutativity. To avoid confusion, always define your symbols as matrices before you use them for the first time.
Example
MATRIXDEF M
@matrix@ MATRIXDEF M = left(MATRIX{ a # b # c ## d # e # f ## g# h# i }right)
Declares two matrices M and N and assigns a value to N. In expression evaluation, iMath will treat the matrices as non-commutative, that is, M N ≠ N M.