1 function S = Uscharfettergummel3(mesh,alpha,gamma,eta,beta)
5 ## @deftypefn {Function File} @
6 ## {@var{S}} = Uscharfettergummel3 (@var{mesh}, @var{alpha}, @
7 ## @var{gamma}, @var{eta}, @var{beta})
10 ## Builds the Scharfetter-Gummel matrix for the
11 ## discretization of the LHS
16 ## $ -div ( \alpha \gamma ( \eta \vect{\nabla} u - \vect{beta} u )) = f $
20 ## -div (@var{alpha} * @var{gamma} (@var{eta} grad u - @var{beta} u )) = f
25 ## @item @var{alpha} is an element-wise constant scalar function
26 ## @item @var{eta}, @var{gamma} are piecewise linear conforming
28 ## @item @var{beta} is an element-wise constant vector function
31 ## Instead of passing the vector field @var{beta} directly
32 ## one can pass a piecewise linear conforming scalar function
33 ## @var{phi} as the last input. In such case @var{beta} = grad @var{phi}
34 ## is assumed. If @var{phi} is a single scalar value @var{beta}
35 ## is assumed to be 0 in the whole domain.
39 ## [mesh.p,mesh.e,mesh.t] = Ustructmesh([0:1/3:1],[0:1/3:1],1,1:4);
40 ## mesh = Umeshproperties(mesh);
42 ## Dnodes = Unodesonside(mesh,[2,4]);
43 ## Nnodes = columns(mesh.p); Nelements = columns(mesh.t);
44 ## Varnodes = setdiff(1:Nnodes,Dnodes);
45 ## alpha = ones(Nelements,1); eta = .1*ones(Nnodes,1);
46 ## beta = [ones(1,Nelements);zeros(1,Nelements)];
47 ## gamma = ones(Nnodes,1);
48 ## f = Ucompconst(mesh,ones(Nnodes,1),ones(Nelements,1));
49 ## S = Uscharfettergummel3(mesh,alpha,gamma,eta,beta);
50 ## u = zeros(Nnodes,1);
51 ## u(Varnodes) = S(Varnodes,Varnodes)\f(Varnodes);
52 ## uex = x - (exp(10*x)-1)/(exp(10)-1);
56 ## @seealso{Ucomplap, Ucompconst, Ucompmass2, Uscharfettergummel}
60 %% This file is part of
62 %% SECS2D - A 2-D Drift--Diffusion Semiconductor Device Simulator
63 %% -------------------------------------------------------------------
64 %% Copyright (C) 2004-2006 Carlo de Falco
68 %% SECS2D is free software; you can redistribute it and/or modify
69 %% it under the terms of the GNU General Public License as published by
70 %% the Free Software Foundation; either version 2 of the License, or
71 %% (at your option) any later version.
73 %% SECS2D is distributed in the hope that it will be useful,
74 %% but WITHOUT ANY WARRANTY; without even the implied warranty of
75 %% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
76 %% GNU General Public License for more details.
78 %% You should have received a copy of the GNU General Public License
79 %% along with SECS2D; If not, see <http://www.gnu.org/licenses/>.
82 Nnodes = columns(mesh.p);
83 Nelements = columns(mesh.t);
85 alphaareak = reshape (alpha.*sum( mesh.wjacdet,1)',1,1,Nelements);
86 shg = mesh.shg(:,:,:);
89 % build local Laplacian matrix
91 Lloc=zeros(3,3,Nelements);
95 ginode(inode,jnode,:)=mesh.t(inode,:);
96 gjnode(inode,jnode,:)=mesh.t(jnode,:);
97 Lloc(inode,jnode,:) = sum( shg(:,inode,:) .* shg(:,jnode,:),1)...
104 x = x(mesh.t(1:3,:));
106 y = y(mesh.t(1:3,:));
108 if all(size(beta)==1)
110 elseif all(size(beta)==[2,Nelements])
111 v12 = beta(1,:) .* (x(2,:)-x(1,:)) + beta(2,:) .* (y(2,:)-y(1,:));
112 v23 = beta(1,:) .* (x(3,:)-x(2,:)) + beta(2,:) .* (y(3,:)-y(2,:));
113 v31 = beta(1,:) .* (x(1,:)-x(3,:)) + beta(2,:) .* (y(1,:)-y(3,:));
114 elseif all(size(beta)==[Nnodes,1])
115 betaloc = beta(mesh.t(1:3,:));
116 v12 = betaloc(2,:)-betaloc(1,:);
117 v23 = betaloc(3,:)-betaloc(2,:);
118 v31 = betaloc(1,:)-betaloc(3,:);
121 etaloc = eta(mesh.t(1:3,:));
123 eta12 = etaloc(2,:)-etaloc(1,:);
124 eta23 = etaloc(3,:)-etaloc(2,:);
125 eta31 = etaloc(1,:)-etaloc(3,:);
127 etalocm1 = Utemplogm(etaloc(2,:),etaloc(3,:));
128 etalocm2 = Utemplogm(etaloc(3,:),etaloc(1,:));
129 etalocm3 = Utemplogm(etaloc(1,:),etaloc(2,:));
131 gammaloc = gamma(mesh.t(1:3,:));
132 geloc = gammaloc.*etaloc;
134 gelocm1 = Utemplogm(geloc(2,:),geloc(3,:));
135 gelocm2 = Utemplogm(geloc(3,:),geloc(1,:));
136 gelocm3 = Utemplogm(geloc(1,:),geloc(2,:));
138 [bp12,bm12] = Ubern( (v12 - eta12)./etalocm3);
139 [bp23,bm23] = Ubern( (v23 - eta23)./etalocm1);
140 [bp31,bm31] = Ubern( (v31 - eta31)./etalocm2);
142 bp12 = reshape(gelocm3.*etalocm3.*bp12,1,1,Nelements).*Lloc(1,2,:);
143 bm12 = reshape(gelocm3.*etalocm3.*bm12,1,1,Nelements).*Lloc(1,2,:);
144 bp23 = reshape(gelocm1.*etalocm1.*bp23,1,1,Nelements).*Lloc(2,3,:);
145 bm23 = reshape(gelocm1.*etalocm1.*bm23,1,1,Nelements).*Lloc(2,3,:);
146 bp31 = reshape(gelocm2.*etalocm2.*bp31,1,1,Nelements).*Lloc(3,1,:);
147 bm31 = reshape(gelocm2.*etalocm2.*bm31,1,1,Nelements).*Lloc(3,1,:);
149 Sloc(1,1,:) = (-bm12-bp31)./reshape(etaloc(1,:),1,1,Nelements);
150 Sloc(1,2,:) = bp12./reshape(etaloc(2,:),1,1,Nelements);
151 Sloc(1,3,:) = bm31./reshape(etaloc(3,:),1,1,Nelements);
153 Sloc(2,1,:) = bm12./reshape(etaloc(1,:),1,1,Nelements);
154 Sloc(2,2,:) = (-bp12-bm23)./reshape(etaloc(2,:),1,1,Nelements);
155 Sloc(2,3,:) = bp23./reshape(etaloc(3,:),1,1,Nelements);
157 Sloc(3,1,:) = bp31./reshape(etaloc(1,:),1,1,Nelements);
158 Sloc(3,2,:) = bm23./reshape(etaloc(2,:),1,1,Nelements);
159 Sloc(3,3,:) = (-bm31-bp23)./reshape(etaloc(3,:),1,1,Nelements);
161 S = sparse(ginode(:),gjnode(:),Sloc(:));
166 %! [mesh.p,mesh.e,mesh.t] = Ustructmesh([0:1/3:1],[0:1/3:1],1,1:4);
167 %! mesh = Umeshproperties(mesh);
169 %! Dnodes = Unodesonside(mesh,[2,4]);
170 %! Nnodes = columns(mesh.p); Nelements = columns(mesh.t);
171 %! Varnodes = setdiff(1:Nnodes,Dnodes);
172 %! alpha = ones(Nelements,1); eta = .1*ones(Nnodes,1);
173 %! beta = [ones(1,Nelements);zeros(1,Nelements)];
174 %! gamma = ones(Nnodes,1);
175 %! f = Ucompconst(mesh,ones(Nnodes,1),ones(Nelements,1));
176 %! S = Uscharfettergummel3(mesh,alpha,gamma,eta,beta);
177 %! u = zeros(Nnodes,1);
178 %! u(Varnodes) = S(Varnodes,Varnodes)\f(Varnodes);
179 %! uex = x - (exp(10*x)-1)/(exp(10)-1);
180 %! assert(u,uex,1e-7)
183 %! [mesh.p,mesh.e,mesh.t] = Ustructmesh([0:1/3:1],[0:1/3:1],1,1:4);
184 %! mesh = Umeshproperties(mesh);
186 %! Dnodes = Unodesonside(mesh,[2,4]);
187 %! Nnodes = columns(mesh.p); Nelements = columns(mesh.t);
188 %! Varnodes = setdiff(1:Nnodes,Dnodes);
189 %! alpha = ones(Nelements,1); eta = .1*ones(Nnodes,1);
191 %! gamma = ones(Nnodes,1);
192 %! f = Ucompconst(mesh,ones(Nnodes,1),ones(Nelements,1));
193 %! S = Uscharfettergummel3(mesh,alpha,gamma,eta,beta);
194 %! u = zeros(Nnodes,1);
195 %! u(Varnodes) = S(Varnodes,Varnodes)\f(Varnodes);
196 %! uex = x - (exp(10*x)-1)/(exp(10)-1);
197 %! assert(u,uex,1e-7)
200 %! [mesh.p,mesh.e,mesh.t] = Ustructmesh([0:1/3:1],[0:1/3:1],1,1:4);
201 %! mesh = Umeshproperties(mesh);
203 %! Dnodes = Unodesonside(mesh,[2,4]);
204 %! Nnodes = columns(mesh.p); Nelements = columns(mesh.t);
205 %! Varnodes = setdiff(1:Nnodes,Dnodes);
206 %! alpha = 10*ones(Nelements,1); eta = .01*ones(Nnodes,1);
208 %! gamma = ones(Nnodes,1);
209 %! f = Ucompconst(mesh,ones(Nnodes,1),ones(Nelements,1));
210 %! S = Uscharfettergummel3(mesh,alpha,gamma,eta,beta);
211 %! u = zeros(Nnodes,1);
212 %! u(Varnodes) = S(Varnodes,Varnodes)\f(Varnodes);
213 %! uex = x - (exp(10*x)-1)/(exp(10)-1);
214 %! assert(u,uex,1e-7)
217 %! [mesh.p,mesh.e,mesh.t] = Ustructmesh([0:1/3:1],[0:1/3:1],1,1:4);
218 %! mesh = Umeshproperties(mesh);
220 %! Dnodes = Unodesonside(mesh,[2,4]);
221 %! Nnodes = columns(mesh.p); Nelements = columns(mesh.t);
222 %! Varnodes = setdiff(1:Nnodes,Dnodes);
223 %! alpha = 10*ones(Nelements,1); eta = .001*ones(Nnodes,1);
225 %! gamma = 10*ones(Nnodes,1);
226 %! f = Ucompconst(mesh,ones(Nnodes,1),ones(Nelements,1));
227 %! S = Uscharfettergummel3(mesh,alpha,gamma,eta,beta);
228 %! u = zeros(Nnodes,1);
229 %! u(Varnodes) = S(Varnodes,Varnodes)\f(Varnodes);
230 %! uex = x - (exp(10*x)-1)/(exp(10)-1);
231 %! assert(u,uex,1e-7)
234 %! [mesh.p,mesh.e,mesh.t] = Ustructmesh([0:1/1e3:1],[0:1/2:1],1,1:4);
235 %! mesh = Umeshproperties(mesh);
237 %! Dnodes = Unodesonside(mesh,[2,4]);
238 %! Nnodes = columns(mesh.p); Nelements = columns(mesh.t);
239 %! Varnodes = setdiff(1:Nnodes,Dnodes);
240 %! alpha = 3*ones(Nelements,1); eta = x+1;
241 %! beta = [ones(1,Nelements);zeros(1,Nelements)];
243 %! ff = 2*(6*x.^2+6*x) - (6*x+6).*(1-2*x)+6*(x-x.^2);
244 %! f = Ucompconst(mesh,ff,ones(Nelements,1));
245 %! S = Uscharfettergummel3(mesh,alpha,gamma,eta,beta);
246 %! u = zeros(Nnodes,1);
247 %! u(Varnodes) = S(Varnodes,Varnodes)\f(Varnodes);
249 %! assert(u,uex,5e-3)
252 %! [mesh.p,mesh.e,mesh.t] = Ustructmesh([0:1/1e3:1],[0:1/2:1],1,1:4);
253 %! mesh = Umeshproperties(mesh);
255 %! Dnodes = Unodesonside(mesh,[2,4]);
256 %! Nnodes = columns(mesh.p); Nelements = columns(mesh.t);
257 %! Varnodes = setdiff(1:Nnodes,Dnodes);
258 %! alpha = ones(Nelements,1); eta = ones(Nnodes,1);
262 %! f = Ucompconst(mesh,ff,ones(Nelements,1));
263 %! S = Uscharfettergummel3(mesh,alpha,gamma,eta,beta);
264 %! u = zeros(Nnodes,1);
265 %! u(Varnodes) = S(Varnodes,Varnodes)\f(Varnodes);
267 %! assert(u,uex,1e-7)
270 %! [mesh.p,mesh.e,mesh.t] = Ustructmesh([0:.1:1],[0:.1:1],1,1:4);
271 %! mesh = Umeshproperties(mesh);
272 %! x = mesh.p(1,:)';y = mesh.p(2,:)';
273 %! Dnodes = Unodesonside(mesh,[1:4]);
274 %! Nnodes = columns(mesh.p); Nelements = columns(mesh.t);
275 %! Varnodes = setdiff(1:Nnodes,Dnodes);
276 %! alpha = ones(Nelements,1); diff = 1e-2; eta=diff*ones(Nnodes,1);
277 %! beta =[ones(1,Nelements);ones(1,Nelements)];
279 %! ux = y.*(1-exp((y-1)/diff)) .* (1-exp((x-1)/diff)-x.*exp((x-1)/diff)/diff);
280 %! uy = x.*(1-exp((x-1)/diff)) .* (1-exp((y-1)/diff)-y.*exp((y-1)/diff)/diff);
281 %! uxx = y.*(1-exp((y-1)/diff)) .* (-2*exp((x-1)/diff)/diff-x.*exp((x-1)/diff)/(diff^2));
282 %! uyy = x.*(1-exp((x-1)/diff)) .* (-2*exp((y-1)/diff)/diff-y.*exp((y-1)/diff)/(diff^2));
283 %! ff = -diff*(uxx+uyy)+ux+uy;
284 %! f = Ucompconst(mesh,ff,ones(Nelements,1));
285 %! S = Uscharfettergummel3(mesh,alpha,gamma,eta,beta);
286 %! u = zeros(Nnodes,1);
287 %! u(Varnodes) = S(Varnodes,Varnodes)\f(Varnodes);
288 %! uex = x.*y.*(1-exp((x-1)/diff)).*(1-exp((y-1)/diff));
289 %! assert(u,uex,1e-7)