Add a useful package (from Source forge) for octave

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

diff --git a/octave_packages/control-2.3.52/@lti/frdata.m b/octave_packages/control-2.3.52/@lti/frdata.m
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+## Copyright (C) 2010, 2011, 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 -*-
+## @deftypefn {Function File} {[@var{H}, @var{w}, @var{tsam}] =} frdata (@var{sys})
+## @deftypefnx {Function File} {[@var{H}, @var{w}, @var{tsam}] =} frdata (@var{sys}, @var{"vector"})
+## Access frequency response data.
+## Argument @var{sys} is not limited to frequency response data objects.
+## If @var{sys} is not a frd object, it is converted automatically.
+##
+## @strong{Inputs}
+## @table @var
+## @item sys
+## Any type of LTI model.
+## @item "v", "vector"
+## In case @var{sys} is a SISO model, this option returns the frequency response
+## as a column vector (lw-by-1) instead of an array (p-by-m-by-lw).
+## @end table
+##
+## @strong{Outputs}
+## @table @var
+## @item H
+## Frequency response array (p-by-m-by-lw).  H(i,j,k) contains the
+## response from input j to output i at frequency k.  In the SISO case,
+## a vector (lw-by-1) is possible as well.
+## @item w
+## Frequency vector (lw-by-1) in radian per second [rad/s].
+## Frequencies are in ascending order.
+## @item tsam
+## Sampling time in seconds.  If @var{sys} is a continuous-time model,
+## a zero is returned.
+## @end table
+## @end deftypefn
+
+## Author: Lukas Reichlin <lukas.reichlin@gmail.com>
+## Created: October 2010
+## Version: 0.3
+
+function [H, w, tsam] = frdata (sys, rtype = "array")
+
+  if (! isa (sys, "frd"))
+    sys = frd (sys);
+  endif
+
+  [H, w] = __sys_data__ (sys); 
+
+  tsam = sys.tsam;
+
+  if (strncmpi (rtype, "v", 1) && issiso (sys))
+    H = reshape (H, [], 1);
+  endif
+
+endfunction