How to multiply a vector of symbolic variables by a 3D matrix, for supplying to cvx?

I have a vector y:

y = [y1,y2..y25]

I also have a 3D matrix A, 10x10x25.

I need to create an expression B:

B = y1*A(:,:,1) + y2*(A:,:,2) + ... + y25*A(:,:,25)

I know that I can do this with a for loop, but I am doing this inside of cvx sdp solver, where the variables are defined separately (and I can't run a for loop in an equality statement).

I have tried using bsxfun, but that doesn't work with symbolics (whether standard MATLAB symbolics, or cvx variables).

Some of my reading suggests repmat or arrayfun could provide solutions but I am unclear on how to use them in this situation.

[Sheng Cheng]

I have a similar question on the realization of such LMI expression in MALTAB. Have you figured out how to do it in MATLAB?

Answer 1

[Azzi Abdelmalek]

y=sym('y',[1,3])
A=randi(4,5,5,3)
out=zeros(size(A,1),size(A,2))
for k=1:size(A,3)
  out=out+y(k)*A(:,:,k)
end

[LShaver]

Yes, I know this works, but it seems like there should be a way to do it in one line, or with some function such as bsxfun.

[Azzi Abdelmalek]

bsxfun doesn't work with symbolic variables

Answer 2

[Walter Roberson]

repmat(reshape(y,1,1,[]),size(A,1),size(A,2),1).*A