Re: [Maxima-discuss] matrix problem

[Barton W. <wi...@un...>]

Try this:


    (%i7) M : genmatrix(A[phi],3,1);
    (%o7) matrix([A[phi](1,1)],[A[phi](2,1)],[A[phi](3,1)])


Nice way to locally define function A[phi]

    (%i8) M, A[phi](i,j) := cos(phi);
    (%o8) matrix([cos(phi)],[cos(phi)],[cos(phi)])


In Maxima, A[phi](i,j) := cos(phi) defines a memoizing function--there are some things about memoizing functions

can be a tricky--be careful.


Alternatively, you could simply do


    (%i9) M : genmatrix(lambda([i,j], cos(phi)),3,1);
    (%o9) matrix([cos(phi)],[cos(phi)],[cos(phi)])


--Barton



________________________________
From: Jan Brosius <bro...@gm...>
Sent: Tuesday, July 8, 2014 11:17
To: max...@li...
Subject: [Maxima-discuss] matrix problem

Hi,

I can define

genmatrix(A[phi],3,1}

but how do I assign a value to e.g. A[phi][2,1]. See below the maxima output

(%i1) genmatrix(A[phi],3,1);
                                [ A   (1, 1) ]
                                [  phi       ]
                                [            ]
(%o1)                           [ A   (2, 1) ]
                                [  phi       ]
                                [            ]
                                [ A   (3, 1) ]
                                [  phi       ]
(%i2) A[phi][2,1]:=cos(phi);

define: argument cannot be an atom or a subscripted memoizing function; found:
                                                                     (A   )
                                                                       phi
                                                                           2, 1
 -- an error. To debug this try: debugmode(true);

(%i3) A[phi][2,1]:cos(phi);

assignment: cannot assign to (A   )
                               phi
                                   2, 1
 -- an error. To debug this try: debugmode(true);

thx for any help
Jan