1 function L = Ucomplap (nodes,Nnodes,elements,Nelements,coeff)
3 % L = Ucomplap (nodes,Nnode,elements,Nelements,coeff)
4 % Computes the P1 finite element approximation of the
5 % differential operator - d ( coeff d (.)\dx)\dx
7 ## This file is part of
9 ## SECS1D - A 1-D Drift--Diffusion Semiconductor Device Simulator
10 ## -------------------------------------------------------------------
11 ## Copyright (C) 2004-2007 Carlo de Falco
15 ## SECS1D is free software; you can redistribute it and/or modify
16 ## it under the terms of the GNU General Public License as published by
17 ## the Free Software Foundation; either version 2 of the License, or
18 ## (at your option) any later version.
20 ## SECS1D is distributed in the hope that it will be useful,
21 ## but WITHOUT ANY WARRANTY; without even the implied warranty of
22 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
23 ## GNU General Public License for more details.
25 ## You should have received a copy of the GNU General Public License
26 ## along with SECS1D; If not, see <http://www.gnu.org/licenses/>.
28 h = nodes(2:end)-nodes(1:end-1);
30 d0 = [ coeff(1)./h(1);
31 (coeff(1:end-1)./h(1:end-1))+(coeff(2:end)./h(2:end));
34 d1 = [1000; -coeff./h];
35 dm1 = [ -coeff./h;1000];
37 L = spdiags([dm1, d0, d1],-1:1,Nnodes,Nnodes);
42 % $Date: 2008-02-04 16:26:27 +0100 (man, 04 feb 2008) $