function E = EM3(n,c,i,k)
% EM2 elementary matrix of type III.
%
%   EM3(n,c,i,k) is an n-by-n matrix that muliplies the 
%   i-th row of any n-by-m matrix A by the scalar c and 
%   then adds the result to the k-th row of A (when mul-
%   tiplying A on the left).
%
%   Matt Kawski 7-10-99
%   http://math.la.asu.edu/~kawski
%   kawski@asu.edu
%
E = eye(n);
if ( i > n ) 
   disp('First index exceeds matrix dimension')
elseif ( k > n ) 
   disp('Second index exceeds matrix dimension')
else
   E(k,i) = c;   
end