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1 ## Copyright (C) 1996, 1998 Auburn University. All rights reserved. |
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2 ## |
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3 ## This file is part of Octave. |
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4 ## |
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5 ## Octave is free software; you can redistribute it and/or modify it |
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6 ## under the terms of the GNU General Public License as published by |
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7 ## the Free Software Foundation; either version 3 of the License, or (at |
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8 ## your option) any later version. |
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9 ## |
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10 ## Octave is distributed in the hope that it will be useful, but |
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11 ## WITHOUT ANY WARRANTY; without even the implied warranty of |
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12 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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13 ## General Public License for more details. |
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14 ## |
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15 ## You should have received a copy of the GNU General Public License |
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16 ## along with Octave; see the file COPYING. If not, see |
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17 ## <http://www.gnu.org/licenses/>. |
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18 |
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19 ## -*- texinfo -*- |
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20 ## @deftypefn {Function File} {[@var{a}, @var{b}, @var{c}, @var{d}, @var{tsam}, @var{n}, @var{nz}, @var{stname}, @var{inname}, @var{outname}, @var{yd}] =} sys2ss (@var{sys}) |
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21 ## Extract state space representation from system data structure. |
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22 ## |
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23 ## @strong{Input} |
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24 ## @table @var |
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25 ## @item sys |
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26 ## System data structure. |
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27 ## @end table |
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28 ## |
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29 ## @strong{Outputs} |
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30 ## @table @var |
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31 ## @item a |
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32 ## @itemx b |
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33 ## @itemx c |
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34 ## @itemx d |
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35 ## State space matrices for @var{sys}. |
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36 ## |
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37 ## @item tsam |
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38 ## Sampling time of @var{sys} (0 if continuous). |
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39 ## |
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40 ## @item n |
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41 ## @itemx nz |
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42 ## Number of continuous, discrete states (discrete states come |
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43 ## last in state vector @var{x}). |
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44 ## |
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45 ## @item stname |
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46 ## @itemx inname |
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47 ## @itemx outname |
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48 ## Signal names (lists of strings); names of states, |
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49 ## inputs, and outputs, respectively. |
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50 ## |
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51 ## @item yd |
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52 ## Binary vector; @var{yd}(@var{ii}) is 1 if output @var{y}(@var{ii}) |
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53 ## is discrete (sampled); otherwise @var{yd}(@var{ii}) is 0. |
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54 ## |
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55 ## @end table |
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56 ## A warning massage is printed if the system is a mixed |
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57 ## continuous and discrete system. |
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58 ## |
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59 ## @strong{Example} |
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60 ## @example |
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61 ## octave:1> sys=tf2sys([1 2],[3 4 5]); |
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62 ## octave:2> [a,b,c,d] = sys2ss(sys) |
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63 ## a = |
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64 ## 0.00000 1.00000 |
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65 ## -1.66667 -1.33333 |
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66 ## b = |
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67 ## 0 |
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68 ## 1 |
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69 ## c = 0.66667 0.33333 |
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70 ## d = 0 |
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71 ## @end example |
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72 ## @end deftypefn |
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73 |
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74 ## Author: David Clem |
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75 ## Created: August 19, 1994 |
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76 ## Updates by John Ingram July 14, 1996 |
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77 |
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78 function [a, b, c, d, tsam, n, nz, stname, inname, outname, yd] = sys2ss (sys) |
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79 |
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80 if(nargin != 1) |
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81 print_usage (); |
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82 endif |
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83 |
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84 if (nargout > 11) |
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85 warning(["sys2ss: ",num2str(nargout)," out arguments exceeds max=11"]) |
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86 print_usage (); |
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87 endif |
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88 |
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89 if( ! isstruct(sys) ) |
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90 error("input argument must be a system data structure"); |
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91 endif |
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92 |
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93 sys = sysupdate(sys,"ss"); # make sure state space data is there |
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94 [n,nz,m,p] = sysdimensions(sys); |
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95 [stname,inname,outname,yd] = sysgetsignals(sys); |
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96 tsam = sysgettsam(sys); |
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97 |
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98 cont = sum(yd == 0) + n; |
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99 dig = sum(yd != 0) + nz + tsam; |
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100 if(cont*dig) |
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101 warning("sys2ss: input system is mixed continuous/discrete"); |
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102 endif |
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103 |
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104 a = sys.a; |
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105 b = sys.b; |
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106 c = sys.c; |
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107 d = sys.d; |
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108 |
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109 endfunction |
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110 |
