nonlinear 2D elliptic problem u_xx+u_yy= f(x,y)

x is in (0,1) , y (0,1) and u =0 pn boundaries.

My problem is equivalent to this matrix formulation: (attached).

However, I am stuck on the last part of my code! If anyone can take look and tell me, how to correct it,

Answer 1

[Torsten]

f=reshape(f',(Nx+1)*(Ny+1),1);

Best wishes

Torsten.

[nandine]

Thank you, butI still get the same error. It's weird cause I am pretty sure the number of elements has not changed, so don't understand how the number of elements has changed.

[Torsten]

Report the dimension of the f-array, e.g. by the command "size(f)".

Best wishes

Torsten.

[nandine]

Actually, your earlier suggestion worked! thank you so much!