% In HW3 we use the myBC=4 i.e. Ttop = Tbot = 303K and Tleft=293K

if(myBC == 1)
    Tleft = 393; Tright = 293; 

T(1,:) = T(2,:); T(Ny,:) = T(Ny-1,:); 
T(iny,1)= 2*Tleft - T(iny,2); T(iny,Nx)=2*Tright - T(iny,Nx-1);

elseif(myBC == 4)
    Tleft = 293; Ttop = 303; Tbot = 303;

% On these lines we copy to the ghost cells 
% rows Tghost = 2*Ttarget-Tinside to give exactly Ttarget between 
% ghost cell rows/columns and the first internal rows/columns

% use 2nd/Ny-1 row data to enforce Ttop/Tbot on top/bottom wall
T(1,:) = 2*Ttop - T(2,:); T(Ny,:) = 2*Tbot - T(Ny-1,:); 

% use 2nd column data (left end) to give Tleft at the inlet 
T(iny,1)= 2*Tleft - T(iny,2); 

% at the outlet, copy Nx-1 content to Nx row so dTdx = const
T(iny,Nx)= T(iny,Nx-1);
   
end