function [ res ] = DBDU_BNDRY(t,x,u,ux)
% 
% Checked (WWX): 2005-11-19
%
% 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 == xleft )
if( x == 0.0 )
  res = [ 1 0; 0 1 ]; 
else
  res = [ u(2)*cos(u(1)*u(2)) u(1)*cos(u(1)*u(2)); ...
          u(2)*sin(u(1)*u(2)) u(1)*sin(u(1)*u(2)); ];
end