Hi everyone ! can anyone help me to do this , thank you

% I'd like to take the first 4x4 block of X and put it in Xa and Xb

% in such a way as to take the first and second column of X and put it in the first and second column in Xa

% and take the third column and the fourth column of X and put it in the third and fourth column of Xb

% second block 4x4 of X

% the (5,6) column of X in the (5,6) column of Xa

% the (7,8) column of X in the (5,6) column of Xb

clear all

clc

P=2;

M=4;

X=rand(M,P*M);

Xa=zeros(M,P*M);

Xb=zeros(M,P*M);

[Fangjun Jiang]

double check all the column numbers in your question and make sure they are correct.

[mina massoud]

yes you are wright becasue at the end i need to make somthing like this for P=4:-

Xa(:,1:2)= X(:,1:2)

Xb(:,3:4)= X(:,3:4)

Xa(:,5:6)= X(:,5:6)

Xb(:,7:8)= X(:,7:8)

Xa(:,9:10)= X(:,9:10)

Xb(:,11:12)= X(:,11:12)

Xa(:,13:14)= X(:,13:14)

Xb(:,15:16)= X(:,15:16)

so can i do it with somthing more general , thank u

Answer 1

[madhan ravi]

[~,n]=size(X);
xai=[1:4:n,2:4:n];
xbi=[3:4:n,4:4:n];
Xa(:,xai)=X(:,xai)
Xb(:,xbi)=X(:,xbi)

[Fangjun Jiang]

this would be my guess. n=size(X,2), sort() is not needed.

[madhan ravi]

Thank you :) Fangjun , you’re totally right.

[mina massoud]

thank you guys very much , i really appreciate it :)