function [ ah, bh, ch ] = BNDRY_H(t,x,y,u)
% 
% Written by:
% -- 
% John L. Weatherwax                2006-07-06
% 
% email: wax@alum.mit.edu
% 
% Please send comments and especially bug reports to the
% above email address.
% 
%-----

  
if( y==0 )  
  ah = 0.0;
  bh = 1.0; 
else
  ah = 1.0;
  bh = 0.0; 
end

ch = 0.0;