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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 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, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
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18 ## 02110-1301 USA. |
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19 |
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20 save_var = page_screen_output (); |
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21 page_screen_output (1); |
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22 disp("Description of system data structure:") |
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23 disp("A linear system is stored in a structure, and may be represented in") |
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24 disp("ss (state space), tf (transfer function), and/or zp (zero-pole-gain)") |
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25 disp("form.") |
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26 disp(" ") |
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27 disp("variables in all representations:") |
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28 disp("inname: list of signal names (strings) containing name(s) of system ") |
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29 disp(" inputs; see is_signal_list"); |
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30 disp("n: number of continuous states") |
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31 disp("nz: number of discrete states") |
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32 disp("outname: list of signal names (strings) containing name(s) of system ") |
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33 disp(" outputs"); |
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34 disp(" ") |
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35 disp("variables in all representations:(cont'd)") |
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36 disp("sys: system status vector. This vector indicates both what") |
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37 disp(" representation was used to initialize the system data structure") |
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38 disp(" (called the primary system type) and which other representations") |
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39 disp(" are currently up-to-date with the primary system type.") |
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40 disp(" sys(0): primary system type") |
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41 disp(" =0 for tf form") |
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42 disp(" =1 for zp form") |
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43 disp(" =2 for ss form") |
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44 disp(" sys(1:3): indicate whether tf, zp, or ss, respectively, are") |
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45 disp(" \"up to date\" (whether it is safe to use the variables") |
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46 disp(" associated with these representations)") |
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47 disp(" sys(1): = 1 if tf variables are up to date") |
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48 disp(" = 0 else"); |
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49 disp(" sys(2): = 1 if zp variables are up to date") |
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50 disp(" = 0 else"); |
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51 disp(" sys(3): = 1 if ss variables are up to date") |
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52 disp(" = 0 else"); |
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53 disp("You can update alternative representations internally with the") |
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54 disp("sysupdate command:") |
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55 disp(" ") |
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56 help sysupdate |
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57 disp("===============================") |
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58 disp("More variables common to all representations in system data structures:"); |
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59 disp("tsam: discrete time sampling interval ") |
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60 disp(" =0 if system is purely continuous"); |
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61 disp(" >0 if system has discrete-time states or outputs"); |
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62 disp("yd: vector indicating which outputs are discrete time (i.e.,") |
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63 disp(" produced by D/A converters) and which are continuous time.") |
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64 disp(" yd(ii) = 0 if output ii is continuous, = 1 if discrete.") |
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65 disp(" ") |
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66 disp("===============================") |
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67 disp("variables in tf representations (SISO only):") |
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68 disp("num: vector of numerator coefficients") |
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69 disp("den: vector of denominator coefficients") |
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70 disp(" ") |
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71 disp("===============================") |
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72 disp("variables in zp representations (SISO only):") |
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73 disp("zer: vector of system zeros") |
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74 disp("pol: vector of system poles") |
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75 disp("k: system leading coefficient") |
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76 disp(" ") |
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77 disp("===============================") |
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78 disp("variables in ss representations:") |
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79 disp("a,b,c,d: usual state-space matrices. If a system has both") |
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80 disp(" continuous and discrete states, they are sorted so that") |
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81 disp(" continuous states come first, then discrete states") |
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82 disp(" ") |
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83 disp("WARNING: some functions (e.g., bode) will not accept systems") |
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84 disp("with both discrete and continuous states/outputs") |
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85 disp("stname: list of signal names (strings) containing name(s) of system ") |
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86 disp(" states"); |
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87 disp("===============================") |
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88 disp("Object oriented programming:") |
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89 disp("It is recommended that users do not directly access the internal") |
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90 disp("variables themselves, but use the interface functions") |
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91 disp(" fir ss tf sys2fir") |
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92 disp(" sys2ss sys2tf sys2zp syschtsam") |
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93 disp(" sysdimensions sysgetsignals syssetsignals sysgettype") |
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94 disp(" zp ") |
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95 disp("to create/access internal variables. "); |
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96 page_screen_output (save_var); |
