array, list or matrix



Hi all

I am writing some routines that
do something with matrices and 
in order to do this
I don't know whether I should use
(1) lists
(2) arrays
(3) matrices (are they still supported?)

If I have understood well, arrays
should allow me to select elements
in constant time.
Is it always so? Even for arrays
defined as make_array('any,size)?

Lists, instead, are implemented
as linked lists and selecting one
element takes linear time.

Maxima also has a built-in type
for matrices but I haven't been
able to find much about it 
in the in line documentation.
For instance I don't know how
to read off the size of matrix.
Is there anything like arrayinfo
that works for matrices?
As a consequence I don't know
how to convert an uknown size 
matrix into a list of lists.

   Regards

   Fabrizio