{require lib_matrix}

1) applying a matrix to a vector

{def M
 {M.new [[1,2,3],
         [4,5,6],
         [7,8,-9]]}}
-> M

{def V {M.new [1,2,3]} }
-> V

{M.multiply {M} {V}}
-> [14,32,-4]

2) matrix multiplication

{M.multiply {M} {M}}
-> [[ 30, 36,-12],
    [ 66, 81,-12],
    [-24,-18,150]]