Add a useful package (from Source forge) for octave

[CreaPhase.git] / octave_packages / control-2.3.52 / @frd / __sys_group__.m

diff --git a/octave_packages/control-2.3.52/@frd/__sys_group__.m b/octave_packages/control-2.3.52/@frd/__sys_group__.m
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+## Copyright (C) 2010, 2012   Lukas F. Reichlin
+##
+## This file is part of LTI Syncope.
+##
+## LTI Syncope 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 3 of the License, or
+## (at your option) any later version.
+##
+## LTI Syncope 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 LTI Syncope.  If not, see <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## Block diagonal concatenation of two FRD models.
+## This file is part of the Model Abstraction Layer.
+## For internal use only.
+
+## Author: Lukas Reichlin <lukas.reichlin@gmail.com>
+## Created: October 2010
+## Version: 0.2
+
+function retsys = __sys_group__ (sys1, sys2)
+
+  if (! isa (sys1, "frd"))
+    sys1 = frd (sys1, sys2.w);
+  endif
+
+  if (! isa (sys2, "frd"))
+    sys2 = frd (sys2, sys1.w);
+  endif
+
+  retsys = frd ();
+  retsys.lti = __lti_group__ (sys1.lti, sys2.lti);
+
+  lw1 = length (sys1.w);
+  lw2 = length (sys2.w);
+
+  [p1, m1, l1] = size (sys1.H);
+  [p2, m2, l2] = size (sys2.H);
+
+  ## TODO: tolerances for frequencies, i.e. don't check for equality
+
+  ## find intersection of frequency vectors
+  if (lw1 == lw2 && all (sys1.w == sys2.w))  # identical frequency vectors
+    retsys.w = sys1.w;
+    H1 = sys1.H;
+    H2 = sys2.H;
+  else                                       # differing frequency vectors
+    ## find common frequencies
+    retsys.w = w = intersect (sys1.w, sys2.w);
+
+    ## indices of common frequencies
+    w1_idx = arrayfun (@(x) find (sys1.w == x), w);
+    w2_idx = arrayfun (@(x) find (sys2.w == x), w);
+
+    ## extract common responses
+    H1 = sys1.H(:, :, w1_idx);
+    H2 = sys2.H(:, :, w2_idx);
+  endif
+
+  ## block-diagonal concatenation
+  lw = length (retsys.w);
+  z12 = zeros (p1, m2);
+  z21 = zeros (p2, m1);
+  H1 = mat2cell (H1, p1, m1, ones (1, lw))(:);
+  H2 = mat2cell (H2, p2, m2, ones (1, lw))(:);
+
+  H = cellfun (@(x, y) [x, z12; z21, y], H1, H2, "uniformoutput", false);
+
+  retsys.H = cat (3, H{:});
+
+endfunction
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