Add a useful package (from Source forge) for octave

[CreaPhase.git] / octave_packages / control-2.3.52 / @ss / __prescale__.m

diff --git a/octave_packages/control-2.3.52/@ss/__prescale__.m b/octave_packages/control-2.3.52/@ss/__prescale__.m
new file mode 100644 (file)
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+++ b/octave_packages/control-2.3.52/@ss/__prescale__.m
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+## Copyright (C) 2011   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 -*-
+## Prescale state-space model.
+## Uses SLICOT TB01ID and TG01AD by courtesy of
+## @uref{http://www.slicot.org, NICONET e.V.}
+
+## Author: Lukas Reichlin <lukas.reichlin@gmail.com>
+## Created: June 2011
+## Version: 0.1
+
+function [retsys, lscale, rscale] = __prescale__ (sys, optarg = 0.0)
+
+  if (isempty (sys.e))
+    [a, b, c, ~, scale] = sltb01id (sys.a, sys.b, sys.c, optarg);
+    retsys = ss (a, b, c, sys.d);
+    lscale = scale.^-1;
+    rscale = scale;
+  else
+    [a, e, b, c, lscale, rscale] = sltg01ad (sys.a, sys.e, sys.b, sys.c, optarg);
+    retsys = dss (a, b, c, sys.d, e);
+  endif
+  
+  retsys.scaled = true;
+  retsys.lti = sys.lti;  # retain i/o names and tsam
+
+endfunction