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1 ## Copyright (C) 1996 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 the |
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7 ## Free Software Foundation; either version 2, or (at your option) any |
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8 ## later version. |
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9 ## |
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10 ## Octave is distributed in the hope that it will be useful, but WITHOUT |
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11 ## ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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12 ## FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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13 ## 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, write to the Free |
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17 ## Software Foundation, 59 Temple Place, Suite 330, Boston, MA 02111 USA. |
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18 |
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19 ## -*- texinfo -*- |
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20 ## @deftypefn {Function File} {[@var{csys}, @var{acd}, @var{ccd}] =} syscont (@var{sys}) |
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21 ## Extract the purely continuous subsystem of an input system. |
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22 ## |
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23 ## @strong{Inputs} |
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24 ## @var{sys} is a system data structure |
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25 ## |
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26 ## @strong{Outputs} |
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27 ## @table @var |
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28 ## @item csys |
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29 ## is the purely continuous input/output connections of @var{sys} |
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30 ## @item acd |
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31 ## @itemx ccd |
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32 ## connections from discrete states to continuous states, |
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33 ## discrete states to continuous outputs, respectively. |
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34 ## |
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35 ## returns @var{csys} empty if no continuous/continous path exists |
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36 ## @end table |
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37 ## @end deftypefn |
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38 |
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39 ## Author: John Ingram <ingraje@eng.auburn.edu> |
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40 ## Created: August 1996 |
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41 |
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42 function [csys, Acd, Ccd] = syscont (sys) |
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43 |
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44 save_empty = empty_list_elements_ok; |
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45 empty_list_elements_ok = 1; |
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46 |
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47 if (nargin != 1) |
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48 usage("[csys,Acd,Ccd,Dcd] = syscont(sys)"); |
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49 elseif (!is_struct(sys)) |
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50 error("sys must be in system data structure form"); |
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51 endif |
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52 |
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53 sys = sysupdate (sys, "ss"); |
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54 [n_tot, st_c, st_d, y_c, y_d] = __syscont_disc__ (sys); # get ranges |
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55 |
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56 ## assume there's nothing there; build partitions as appropriate |
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57 Acc = Acd = Bcc = Ccc = Ccd = Dcc = []; |
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58 |
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59 if(isempty(st_c) & isempty(y_c)) |
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60 error("syscont: expecting continous states and/or continous outputs"); |
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61 elseif (isempty(st_c)) |
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62 warning("syscont: no continuous states"); |
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63 elseif(isempty(y_c)) |
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64 warning("syscont: no continuous outputs"); |
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65 endif |
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66 |
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67 [sys_a, sys_b, sys_c, sys_d ] = sys2ss(sys); |
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68 [sys_stname, sys_inname, sys_outname] = sysgetsignals(sys); |
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69 [sys_n, sys_nz, sys_m, sys_p] = sysdimensions(sys); |
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70 if(!isempty(st_c)) |
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71 Acc = sys_a(st_c,st_c); |
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72 stname = sys_stname(st_c); |
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73 Bcc = sys_b(st_c,:); |
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74 Ccc = sys_c(y_c,st_c); |
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75 Acd = sys_a(st_c,st_d); |
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76 else |
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77 stname=[]; |
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78 endif |
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79 outname = sys_outname(y_c); |
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80 Dcc = sys_d(y_c,:); |
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81 Ccd = sys_c(y_c,st_d); |
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82 inname = sys_inname; |
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83 |
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84 csys = ss2sys(Acc,Bcc,Ccc,Dcc,0,sys_n,0,stname,inname,outname); |
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85 |
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86 empty_list_elements_ok = save_empty; |
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87 |
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88 endfunction |
