problem with Matrix Multiplication

I have a matrix D which is 10x2, and a center Cent is 2x2 and a w diagonal matrix which is 2x2 , i have an equation:

Result = 1/W^2*(sqrt(w*(X-Y)*SIGMA^(-1)*w*(X-Y)'));

the code which i used is:

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

    D= [0.1 0.2 ; 0.3 0.4
        0.03  0.7; 0.1 0.7
         0.08 0.06; 0.04 0.9
         0.11 0.13; 0.12 0.32
         0.21  0.71; 1.01 0.33
         ];

    Sigma= cov(D);

    Cnt=[-1.982,1.278;0.431,-0.278]

   k=2;
   w=[0.6 0; 0 0.4];
   Wp= 0.6^2 +0.4^2;
   N=length(D); 
   dist=zeros(k,1);  
        for l=1:N  
            for i=1:k  
                dist(i) = 1/Wp*(sqrt( w*(D(l,:)-Cnt(i,:)) * inv(Sigma) * W*(D(l,:)-Cnt(i,:))'));
            end  
        end

iam receiving error : Error using * Inner matrix dimensions must agree.

any help please

Answer 1

[Are Mjaavatten]

Note that in Matlab, vectors are matrices of column or row shape and. A 2 by 2 matrix can only be multiplied by a column vector, not by a row vector.

x = (D(l,:)-Cnt(i,:)) is a 1 by 2 matrix ( row vector)

w is a 2 by 2 matrix, so w*x will result in an error

Maybe what you want to do is to replace the content of the innermost loop by:

                x = (D(l,:)-Cnt(i,:));
                dist(i) = 1/Wp*(sqrt( x*W * inv(Sigma) * W'*x'));