function [ dudt ] = F(t,x,y,u,ux,uy,duxx,duyy)
% 
% Written by:
% -- 
% John L. Weatherwax                2006-03-11
% 
% email: wax@alum.mit.edu
% 
% Please send comments and especially bug reports to the
% above email address.
% 
%-----

dudt = duxx + duyy - 6*x*y*exp(x)*exp(y)*(x*y+x+y-3);