function RHS = heat_mol_RHS(t,uInterior,N,deltax,ua,ub);
% 
% define end point values
%
u(1) = ua;
u(N+1) = ub;
%
% Construct the interior points from 3 to N-1
%
u(2:N) = uInterior;
%
% define RHS (AX is just a temporary
%
for j   = 2 :N
    AX(j)   =(1/deltax^2)*(u(j+1)-2*u(j)+u(j-1));
end
RHS=[AX(2:N)]';