function out=r2(A,i,j)
%
% Anew=r2(A,i,j)
% interchanges the i-th row and the j-th row of the matrix 
% Aold and assigns the new value to the matrix Anew.
%
% Note: Anew may be equal to Aold. In this case the old
% matrix is overwritten.
%
% Author: M. Kawski, September 1996
%
b=A(j,:);
A(j,:)=A(i,:);
A(i,:)=b;
out=A;