Add a useful package (from Source forge) for octave

[CreaPhase.git] / octave_packages / secs2d-0.0.8 / Utilities / Udriftdiffusion.m

diff --git a/octave_packages/secs2d-0.0.8/Utilities/Udriftdiffusion.m b/octave_packages/secs2d-0.0.8/Utilities/Udriftdiffusion.m
new file mode 100644 (file)
index 0000000..602a48f
--- /dev/null
+++ b/octave_packages/secs2d-0.0.8/Utilities/Udriftdiffusion.m
@@ -0,0 +1,95 @@
+function c=Udriftdiffusion(mesh,Dsides,guess,M,U,V,u)
+
+%%
+%  c=Udriftdiffusion(mesh,Dsides,guess,M,U,V,u)
+% solves the drift diffusion equation
+% $ -div ( u ( \nabla n - n \nabla V)) + M = U $
+%%
+
+% This file is part of 
+%
+%            SECS2D - A 2-D Drift--Diffusion Semiconductor Device Simulator
+%         -------------------------------------------------------------------
+%            Copyright (C) 2004-2006  Carlo de Falco
+%
+%
+%
+%  SECS2D is free software; you can redistribute it and/or modify
+%  it under the terms of the GNU General Public License as published by
+%  the Free Software Foundation; either version 2 of the License, or
+%  (at your option) any later version.
+%
+%  SECS2D is distributed in the hope that it will be useful,
+%  but WITHOUT ANY WARRANTY; without even the implied warranty of
+%  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+%  GNU General Public License for more details.
+%
+%  You should have received a copy of the GNU General Public License
+%  along with SECS2D; If not, see <http://www.gnu.org/licenses/>.
+
+global DDG_RHS DDG_MASS %DEBUG_SGM
+
+
+if (Ucolumns(guess)>Urows(guess))
+    guess=guess';
+end
+
+if (Ucolumns(V)>Urows(V))
+    V=V';
+end
+
+if (Ucolumns(U)>Urows(U))
+    U=U';
+end
+Nnodes    = max(size(mesh.p));
+Nelements = max(size(mesh.t));
+
+
+% Set list of nodes with Dirichelet BCs
+Dnodes=Unodesonside(mesh,Dsides);
+
+% Set values of Dirichelet BCs
+Bc     = guess(Dnodes);
+% Set list of nodes without Dirichelet BCs
+Varnodes = setdiff([1:Nnodes],Dnodes);
+
+
+% Build LHS matrix and RHS
+A = Uscharfettergummel(mesh,V,u);
+if (isempty(DDG_MASS))
+  DDG_MASS=Ucompmass2(mesh,ones(Nnodes,1),ones(Nelements,1));
+end
+A = A + DDG_MASS.*spdiag(M,0);
+
+if (isempty(DDG_RHS))
+       DDG_RHS=Ucompconst(mesh,ones(Nnodes,1),ones(Nelements,1));
+end
+b = DDG_RHS.*U;
+
+
+
+%%%%%%%%DEBUG%%%%%%%%%%%
+%DEBUG_SGM = A;
+
+%% Apply boundary conditions
+A (Dnodes,:) = 0;
+b (Dnodes)   = 0;
+b = b - A (:,Dnodes) * Bc;
+
+A(Dnodes,:)= [];
+A(:,Dnodes)= [];
+
+b(Dnodes)      = [];
+
+% Enforce positivity
+% dA = abs(diag(A));
+% edA= abs(sum(triu(A,1)+tril(A,-1),1));
+% nondominant = find(dA < edA');
+% for ii=1:length(nondominant)
+%     A(nondominant(ii),nondominant(ii)) = edA(ii);
+% end
+
+c = guess;
+
+c(Varnodes) = A \ b;
+