Hi ;

I need your help to write the system contains all these equation:

# system 1

u[0,0]:=(1/2)*(u[1,0]+u[0,1]);

u[0,N+1]:=(1/2)*(u[0,N]+u[1,N+1]);

u[N+1,N+1]:=(1/2)*(u[N+1,N]+u[N,N+1]);

u[N+1,0]:=(1/2)*(u[N,0]+u[N+1,1]);

# system 2

for j from 1 to N do

u[0, j] := (1/4)*(u[1,j]+u[1,j]+u[0, j-1]+u[0,j+1]-f[0,j]*h^2);

end do;

# System 3

for j from 1 to N do

u[N+1, j] := (1/4)*(u[N, j]+u[N-1,j]+u[N+1, j-1]+u[N+1, j+1]-f[N+1,j]*h^2);

end do;

system4

eqs := [ seq(seq(Stencil[1](h,i,j,u,f),i=1..N),j=1..N)];

How can collect these system 1 system2, system3 ans system4 in a set with one name.

sys:=[eqs,system3,system2,system2]; ( sys: here contains all the equation).

Thanks you.