using parts of matrix with different sub-vectors (Matlab)

Dear members

I have a vector V divided on sub-vectors

And I have also a matrix H divided on sub-matrices

I want shifting the sub matrices at each time with the sub-vectors

[Rik]

I'm glad my answer helped you solve the problem. I'm less glad you decided to edit away parts of your question. I have put a copy of it below. Feel free to put it back the way it was.

using parts of matrix with different sub-vectors (Matlab)

Dear members

I have this vector V divided on sub-vectors:

And I have also this matrix H:

I have this parameters:

T=5, M=5, N=10

For the first part of the matrix which is in the green screen, I use the vector [V0 V1].

For the second part of the matrix which is in the orange screen, I use the vector [V1 V2].

For the third part of the matrix which is in the black screen, I use the vector [V2 V3].

It means for the first step I always work on the first N rows and N*2 columns. Then I shif the screen with M columns and N rows.

I tried to program that like this:

sz=numel(V);
q=sz/N;
for ess=1:q  % q here = 3
    if ess == 1
        Hc = H(1:T*2,1:N*2); % Hc=H(1:10,1:20)
    else if ess ==2
        Hc = H(T+1:(T*2)+M,(T*2)+1:(T*2)+(N*2)); % Hc=H(6:15,11:30)
    else
        Hc = H((T*2)+1:end,(N*2)+1:end); % Hc=H(11:20,21:40)
    end

But how can I program this loop in general way if I have a long vector V

Answer 1

[Rik]

Shouldn't something like this work?

Hc = H((T*(ess-1))+1:end,((N*2)*(ess-1)+1:N);

[Afluo Raoual]

@Rik Unfortunately not !

[Rik]

It should be possible to find a formula to generate the correct indices.

Can you come up with a formula to find the upper left corner of the sub-matrix?

[Afluo Raoual]

@Rik The only formula is to work firstly on the first sub matrix using the first N rows and the first N*2 columns. Then, at each time we shift the previous sub matrix with M columns and N rows.

[Rik]

So what about this:

r=(ess-1)*N;c=(ess-1)*M
H( r+(1:N) , c+(1:2*N) )

[Afluo Raoual]

@Rik what is r and c !!!!

I don't understand what you wrote

[Rik]

Since we were talking about rows and columns, and they are used to index the rows and columns I thought the names would be clear.