function [ res ] = DBDUX_BNDRY(t,x,u,ux)
% 
% Checked (WWX): 2005-11-19 (One error found!)
% 
% Written by:
% -- 
% John L. Weatherwax                2005-06-15
% 
% email: wax@alum.mit.edu
% 
% Please send comments and especially bug reports to the
% above email address.
% 
%-----
  
if( x == 0.0 )
  res = [ 0 0; 0 0 ]; 
else
  res = [ 1 0; 0 1 ]; 
end