How to create overlapping blocks using a matrix rows ?

Hello,

Suppose that we have the matrix A where:

A=[0 1 0 0 1 1 0 1 0 1 0 1 0]

now, we want to create 10 blocks where each block contains four bits and put it in the cell matrix B where:

B= {[0,1,0,0] [1,0,0,1] [0,0,1,1] [0,1,1,0] [1,1,0,1] [1,0,1,0] [0,1,0,1] ...
    [1,0,1,0] [0,1,0,1] [1,0,1,0] }

As you can see, each block is resulted by shifting a sliding window (of size four) by one bit each time, for example:

% the sequence 01001 will gives: 
% [0,1,0,0] and [1,0,0,1]

So how I can implement that?

[Stephan]

Are you sure that B looks like you want it to look?

[Sarah A]

yes. it supposed to be cell matrix. I editted the question.

Answer 1

[Star Strider]

Try this:

A=[0 1 0 0 1 1 0 1 0 1 0 1 0];
S = hankel(A, [0 1 1 1]);
S = S(1:10,:);
B = mat2cell(S, ones(1,size(S,1)), size(S,2))';

If you prefer a loop:

L = 4;
for k1 = 1:numel(A)-L
    S(k1,:) = A(k1:k1+L-1);
end
B = mat2cell(S, ones(1,size(S,1)), size(S,2))';
B{:}                                                           % Display Result (Delete Later)

[Sarah A]

Great ! Thanks alot.

[Star Strider]

As always, my pleasure!

[Sarah A]

@Star Strider

excuse me, what changes should I do on the loop of matrix A have several rows ?

regards,

[Star Strider]

The hankel code will likely not work in that event.

I would do something like this:

A = randi([0 1], 5, 13);                                        % Create ‘A’
L = 4;
for k1 = 1:size(A,1)
    for k2 = 1:size(A,2)-L+1
        S(k1,k2,:) = A(k1:k1+L-1);
    end
end
B = mat2cell(S, ones(1,size(S,1)), ones(1,size(S,2)), size(S,3));
B = cellfun(@squeeze, permute(B, [2,1,3]), 'Unif',0);

My code would require an extra loop for the rows.

[Star Strider]

Great!

I was not sure what result you wanted with a matrix (rather than a vector) for ‘A’.

[Sarah A]

This is the final form, I wasnt do it without your help so Thank you :)

matrix = [ 0 0 0 0 1 1 0 1 0 1 1 1 1; 0 1 0 1 1 1 0 0 1 1 1 0 1]
for i=1:size(matrix,1)
    A=matrix(i,:);
    S = hankel(A, [0 1 1 1]);
    L = 4; %sliding window size
    S = S(1:(size(A,2)-(L-1)),:);
    for k1 = 1:numel(A)-L
        S(k1,:) = A(k1:k1+L-1);
    end
    B = mat2cell(S, ones(1,size(S,1)), size(S,2))';
    C{i}=B; 
end

and the output will be:

C(1,1):
[0,0,0,0][0,0,0,1][0,0,1,1][0,1,1,0][1,1,0,1][1,0,1,0][0,1,0,1][1,0,1,1][0,1,1,1][1,1,1,1]
C(1,2):
[0,1,0,1][1,0,1,1][0,1,1,1][1,1,1,0][1,1,0,0][1,0,0,1][0,0,1,1][0,1,1,1][1,1,1,0][1,1,0,1]

[Star Strider]

As always, my pleasure!