function g = matgcd(u)

% MATGCD Greatest common divisor
%	 G = MATGCD(U) is the greatest common divisor of 
%	 the entries in matrix U.
%	 G = MATGCD(0) is 0 by convention; all other GCDs
%	 are positive integers.
%
%	See also MATLCM

%	 Written by Serge Tchikanda 03/26/96.

u = u(:);
n=length(u);
u1 = u(1);

if n == 1
   g = u;
elseif n==2
  g = gcd(u(1),u(2));
else
  u(1)=[];
  g = gcd(u1,matgcd(u));
end