Code Results?

Hi,

I have the following code ,but I have a problem in the results,that Mz is just single value 17.619 ,despite it should be a matrix.Also Md is a matrix(1000*1000) but all elements in it has the same value.Can anybody help,please?

      clear all;
  clc
  load lab2_data;
  x = radar_noise;                %  input signal
  K = 1000;                       %  K CAPITAL is Block Size
  L = length(x) - mod(length(x),K);       %  only full blocks
  zkd = reshape(x(1:L), K, []);
    Md=zeros(L,L);                 %  M ZEROS covariance matrix L*L
  for i=1:size(zkd,1);            %  LOOP covariance matrix calculation
      Mz=zkd(i,:)*zkd(i,:)';
   Md=Md+Mz;
  end
  Md=Md/K;

Answer 1

[Sean de Wolski]

You duplicate question was answered here:

Walter's:Answer and in another thread that I answered but appears to have been deleted.

[zayed]

These results after your last answer.

[Sean de Wolski]

But you haven't changed anything!!!!!!!!

You're still multiplying a row vector by a column vector which will _always_ result in a scalar.

[zayed]

I have changed it but it gives error:

?? Error using ==> unknown

Matrix dimensions must agree.

Error in ==> cov3 at 12

Md=Md+Mz;

[Walter Roberson]

Your block size is larger than the number of blocks you have, so LL=length(zkd) is going to return the block size (K) rather than the number of blocks (L) . You then initialize Md to be LL by LL, which is going to be K by K. Your zkd(i,:)*zkd(i,:)' is going to result in L by L, and an L by L matrix is too small to add to a K by K matrix.

Drop the LL=length(zkd); line, and use Md=zeros(L,L)

Remember, length() does not give you the size of the second dimension of an array, it gives you the size of the _largest_ dimension of the array no matter which position it occurs in.

[zayed]

I used Md=zeros(L,L),but the same problem appears ,that Md (5000*5000) with all elements in the matrix equal to11.18040395640934 and Mz is a single value 17.61919686607911 but it should be amtrix

when I changed Mz=zkd(i,:)'*zkd(i,:);the following error appears :

??? Error using ==> unknown

Matrix dimensions must agree.

Error in ==> cov3 at 12

Md=Md+Mz;