Why does my matrix not change with each iteration?

In my code:

B = Bmat_4n(x,y,xi,eta);
for point = 1:length(xiList)
    xi = xiList(point);
    eta = etaList(point);
    strain = B*U;
    strainList(:, point) = strain;
    disp(B);
end

I run 4 iterations (length of xilist) and I get 4 different xi and eta values as intended. B here refers to a seperate function file which when tested by itself naturally gives different results for B for different xi and eta values but when I run the loop here I get 4 times the same B matrix? what am I missing?

The B is meant to draw the matrix B at the end of the function file

Answer 1

[Matt J]

I don't know why you think B should be changed by the loop when you generate it prior to the loop and never touch it again. Perhaps this is what you meant to have:

for point = 1:length(xiList)
    xi = xiList(point);
    eta = etaList(point);
    
    B = Bmat_4n(x,y,xi,eta);
    
    strain = B*U;
    strainList(:, point) = strain;
    disp(B);
end

[J]

Thank you! I knew it was something dumb like that