Adding symbolic matrices along 3rd dimension

Hi,

I have a symbolic 3-by-3-by-3 matrix as:

Q(:,:,1) = 

[ a, b, c]
[ d, e, f]
[ g, h, i]

Q(:,:,2) = 

[ a, d, g]
[ b, e, h]
[ c, f, i]

I added by sum command and I need to do it along 3rd dimension; so I did:

W = sum(Q,3)

But it returns me the error:

Error using mupadmex
Error in MuPAD command: Unable to define matrix over Dom::ExpressionField().
[(Dom::Matrix(Dom::ExpressionField()))::new]

Error in sym/privUnaryOp (line 1700)
            Csym = mupadmex(op,args{1}.s,varargin{:});

Error in sym/sum (line 502)
            s = privUnaryOp(A, 'symobj::prodsumdim', num2str(dim), '_plus');

I tried it with numeric matrices and it works. How Can I do it with symbolic matrices ?

Answer 1

[Azzi Abdelmalek]

clear Q
syms a b c d e f g h i 
Q(:,:,1) = [ a b  c;d e  f;g  h  i]
Q(:,:,2) = [ a, d, g;b, e, h; c, f, i]
[n1,n2,n3]=size(Q);
out=0;
for k=1:n3
  out=out+Q(:,:,k)
end

[Marco]

Thanks