Add a useful package (from Source forge) for octave

[CreaPhase.git] / octave_packages / control-2.3.52 / @lti / series.m

diff --git a/octave_packages/control-2.3.52/@lti/series.m b/octave_packages/control-2.3.52/@lti/series.m
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+## Copyright (C) 2009, 2010   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 -*-
+## @deftypefn {Function File} {@var{sys} =} series (@var{sys1}, @var{sys2})
+## @deftypefnx {Function File} {@var{sys} =} series (@var{sys1}, @var{sys2}, @var{outputs1}, @var{inputs2})
+## Series connection of two LTI models.
+##
+## @strong{Block Diagram}
+## @example
+## @group
+##     .....................................
+##  u  :  +--------+ y1    u2  +--------+  :  y
+## ------>|  sys1  |---------->|  sys2  |------->
+##     :  +--------+           +--------+  :
+##     :................sys.................
+##
+## sys = series (sys1, sys2)
+## @end group
+## @end example
+## @example
+## @group
+##     .....................................
+##     :                   v2  +--------+  :
+##     :            ---------->|        |  :  y
+##     :  +--------+ y1    u2  |  sys2  |------->
+##  u  :  |        |---------->|        |  :
+## ------>|  sys1  |       z1  +--------+  :
+##     :  |        |---------->            :
+##     :  +--------+                       :
+##     :................sys.................
+##
+## outputs1 = [1]
+## inputs2 = [2]
+## sys = series (sys1, sys2, outputs1, inputs2)
+## @end group
+## @end example
+## @end deftypefn
+
+## Author: Lukas Reichlin <lukas.reichlin@gmail.com>
+## Created: September 2009
+## Version: 0.2
+
+function sys = series (sys1, sys2, out1, in2)
+
+  if (nargin == 2)
+    sys = sys2 * sys1;
+  elseif (nargin == 4)
+    [p1, m1] = size (sys1);
+    [p2, m2] = size (sys2);
+
+    if (! is_real_vector (out1))
+      error ("series: argument 3 (outputs1) invalid");
+    endif
+
+    if (! is_real_vector (in2))
+      error ("series: argument 4 (inputs2) invalid");
+    endif
+
+    l_out1 = length (out1);
+    l_in2 = length (in2);
+
+    if (l_out1 > p1)
+      error ("series: outputs1 has too many indices for sys1");
+    endif
+
+    if (l_in2 > m2)
+      error ("series: inputs2 has too many indices for sys2");
+    endif
+
+    if (l_out1 != l_in2)
+      error ("series: number of outputs1 and inputs2 indices must be equal");
+    endif
+
+    if (any (out1 > m1 | out1 < 1))
+      error ("series: range of outputs1 indices exceeds dimensions of sys1");
+    endif
+
+    if (any (in2 > p1 | in2 < 1))
+      error ("series: range of inputs2 indices exceeds dimensions of sys2");
+    endif
+
+    out_scl = full (sparse (1:l_out1, out1, 1, l_out1, p1));
+    in_scl = full (sparse (in2, 1:l_out1, 1, m2, l_in2));
+    
+    ## NOTE: for-loop does NOT the same as
+    ##       out_scl(1:l_out1, out1) = 1;
+    ##       in_scl(in2, 1:l_out1) = 1;
+    ##
+    ## out_scl = zeros (l_out1, p1);
+    ## in_scl = zeros (m2, l_in2);
+    ##
+    ## for k = 1 : l_out1
+    ##   out_scl(k, out1(k)) = 1;
+    ##   in_scl(in2(k), k) = 1;
+    ## endfor
+
+    scl = in_scl * out_scl;
+    sys = sys2 * scl * sys1;
+  else
+    print_usage ();
+  endif
+
+endfunction