elimination of rows and columns

Can anyone tell how do I eliminate rows and columns corresponding to a diagonal element of a symmetric matrix at a time?

Answer 1

[Walter Roberson]

Let the matrix be A. Then to remove the row and column K, corresponding to A(K,K), use

B = A([1:K-1, K+1:end], [1:K-1, K+1:end]);  %select all but row and column

or

B = A;
B(K,:) = [];  %remove row
B(:,K) = [];  %remove column