Add a useful package (from Source forge) for octave

[CreaPhase.git] / octave_packages / control-2.3.52 / __frequency_response__.m

diff --git a/octave_packages/control-2.3.52/__frequency_response__.m b/octave_packages/control-2.3.52/__frequency_response__.m
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+## Copyright (C) 2009, 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 -*-
+## Return frequency response H and frequency vector w.
+## If w is empty, it will be calculated by __frequency_vector__.
+
+## Author: Lukas Reichlin <lukas.reichlin@gmail.com>
+## Created: November 2009
+## Version: 0.4
+
+function [H, w] = __frequency_response__ (sys, w = [], mimoflag = 0, resptype = 0, wbounds = "std", cellflag = false)
+
+  ## check arguments
+  if(! isa (sys, "lti"))
+    error ("frequency_response: first argument sys must be an LTI system");
+  endif
+
+  if (! mimoflag && ! issiso (sys))
+    error ("frequency_response: require SISO system");
+  endif
+
+  if (isa (sys, "frd"))
+    if (! isempty (w))
+      warning ("frequency_response: second argument w is ignored");
+    endif
+    w = get (sys, "w");
+    H = __freqresp__ (sys, [], resptype, cellflag);
+  elseif (isempty (w))  # find interesting frequency range w if not specified
+    w = __frequency_vector__ (sys, wbounds);
+    H = __freqresp__ (sys, w, resptype, cellflag);
+  elseif (iscell (w) && numel (w) == 2 && issample (w{1}) && issample (w{2}))
+    w = __frequency_vector__ (sys, wbounds, w{1}, w{2});
+    H = __freqresp__ (sys, w, resptype, cellflag);
+  elseif (! is_real_vector (w))
+    error ("frequency_response: second argument w must be a vector of frequencies");
+  else
+    H = __freqresp__ (sys, w, resptype, cellflag);
+  endif
+
+endfunction