Array dimensions must match for binary array op.

How to map these array to perform the function as, size of array A and B

size(A)

ans =

   256   256     4

>> size(d)

ans =

     1     1
 inv = (eye(d) + 2*tau*gamma1*A)^(-1);

Answer 1

[Deepak]

Hi @ACHALA SHAKYA,

I understand that you are trying to perform a matrix operation involving arrays A and d, specifically computing an inverse expression like:

inv = (eye(d) + 2*tau*gamma1*A)^(-1);

However, your array A has size 256×256×4 and d is 1×1, which suggests a dimension mismatch — eye(d) creates a 1×1 identity matrix, but you likely want an identity matrix matching the first two dimensions of A.

To fix the dimension mismatch and perform the intended operation for each 2D slice of A, you can loop through the third dimension and compute the inverse per slice:

tau = 0.1;       % example scalar
gamma1 = 0.5;    % example scalar
A = rand(256,256,4);  % example A
inv_result = zeros(256,256,4);

for k = 1:size(A,3)
    inv_result(:,:,k) = inv(eye(256) + 2*tau*gamma1*A(:,:,k));
end

This way, you correctly apply the inverse operation to each 256×256 matrix slice in A.

Please find attached the documentation of functions used for reference:

inv: www.mathworks.com/help/matlab/ref/inv.html

eye: www.mathworks.com/help/fixedpoint/ref/eye.html

I hope this hleps.