Elements of Array Should not be the Same

Hello,

I have this value for element of my list:

And I have this code:

function [A,B] = CHSHmeasurement(d)
    A=zeros(d,d,2,d);
    B=A;
    projectors_of_sigma_x = [1/sqrt(2)*[1;1],1/sqrt(2)*[1;-1]];
    for k = 1:d
        for l =1:length(projectors_of_sigma_x)
            %A(k,k,1,k)=projectors_of_sigma_x(l);
            A(:,:,1,k)=projectors_of_sigma_x(l);
        end
    end
end    
    

However I have the same element for A although I have the different elements in the projectors_of_sigma_x

[madhan ravi]

Please provide the full error message. And d?

[Gözde Üstün]

There is no error message but as you can see I have different value for projectors_of_sigma_x = [1/sqrt(2)*[1;1],1/sqrt(2)*[1;-1]]; (v1 and v2 you can see from the images clearly) but for the A(:,:1,1) and A(:,:,1,2) I have the same matrix and d is = 2

Answer 1

[madhan ravi]

 for k = 1:d
        for l =1:d
            A(:,:,1,k) = repmat(projectors_of_sigma_x(:,k), 1, d);
        end
 end

I suggest you to read https://www.mathworks.com/company/newsletters/articles/matrix-indexing-in-matlab.html , first deal with 2D matrices before dealing with higher dimension matrices.

[Gözde Üstün]

Ahh thank you very much I just saw your answer now !

[Gözde Üstün]

Then we dont need to second for loop right?? or should I change k as l in this line repmat(projectors_of_sigma_x(:,k), 1, d); ?? @madhan ravi

I have a problem for d>2 (and d should be even) For d >2 the result should be block diagonal like that:

0.7071    0.7071    0        0
0.7071    0.7071    0        0
0         0         0.7071   0.7071
0         0         0.7071   0.7071

And I tried almost all combinations with blkdiag but I can't cope with it

for k = 1:d
        for l =1:d
            A(:,:,1,k) = repmat(projectors_of_sigma_x(:,k), 1, d);
            if k > 2 
              A(:,:,1,k) = repmat({A(:,:,1,k)}, 1, d/2); %This line and the following line I am trying to create a matrix which is a blog diagonal of the previous result for even d and of course d>2
              A(:,:,1,k) = blkdiag(A{:,:,1,k});
           end
        end
 end

[madhan ravi]

When do you need ? I don't have time to analyse that sorry :( . I see that you have asked the same question already!

[Gözde Üstün]

Ahh no worries! I can wait (till the tuesday) Yeah I asked and each question includes different version of my combination because I have tried too many combiations