I can not create a matrix.

a =[ 7
     7
     7
    11
    11
    11]

b =[ 4
     4
     4
     4
     4
     4]

c =[11
    11
    11]

d =[ 4
     4
     4
     7
     7
     7]

for i = 1:length(a)
    for j = 1:(length(c))
        if (b(i) == d(j))
            A(i,j) = [0]
        elseif (a(i) == c(j)) 
             A(j,j) = [-1]
        end
    end
end

A = [0     0     0
     0     0     0
     0     0     0
     0     0     0
     0     0     0
     0     0     0] % This matrix is forming.

% The matrix to form:
A = [0     0     0
     0     0     0
     0     0     0
    -1     0     0
     0     -1    0
     0     0     -1]

[Stephen23]

What is wrong with the (several) answers to your previous identical question?:

https://www.mathworks.com/matlabcentral/answers/337360-i-can-not-create-a-matrix

Answer 1

[Honglei Chen]

I don't know what your logic is but the code is behaving as expected. The first condition (b(i)==c(j)) is always satisfied so the second branch is never executed.

HTH

[Muhendisleksi]

I was trying to create this matrix.

[Honglei Chen]

If the matrix is constant, what's wrong just typing is out, say

A = [zeros(3);-1*eye(3)]