Add a useful package (from Source forge) for octave

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

diff --git a/octave_packages/secs2d-0.0.8/Utilities/Urrextrapolation.m b/octave_packages/secs2d-0.0.8/Utilities/Urrextrapolation.m
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index 0000000..3058538
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+++ b/octave_packages/secs2d-0.0.8/Utilities/Urrextrapolation.m
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+function s = Urrextrapolation(X)
+  
+%  s = Urrextrapolation(X)
+%  RRE vector extrapolation see 
+%  Smith, Ford & Sidi SIREV 29 II 06/1987
+  
+% 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/>.
+
+  if (Ucolumns(X)>Urows(X))
+    X=X';
+  end
+  
+  % compute first and second variations
+  U = X(:,2:end) - X(:,1:end-1);
+  V = U(:,2:end) - U(:,1:end-1);
+  
+  % eliminate unused u_k column
+  U(:,end) = [];
+  
+  s = X(:,1) - U * pinv(V) * U(:,1);
+