function ty=scode(u,y,sim)
global y u my t s 

% coding

%  ty=(1+(-1)^(sim+1))*u(s,t-(sim-1)/2)/2+(1-(-1)^(sim+1))*y(s,t-sim/2)/2;


  ty=1+(y(s,t-sim)-1)+my*(u(s,t-sim)-1);