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1 ## Copyright (C) 1996, 2000, 2002, 2003, 2004, 2005, 2006, 2007 |
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2 ## Auburn University. All rights reserved. |
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3 ## |
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4 ## This file is part of Octave. |
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5 ## |
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6 ## Octave is free software; you can redistribute it and/or modify it |
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7 ## under the terms of the GNU General Public License as published by |
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8 ## the Free Software Foundation; either version 3 of the License, or (at |
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9 ## your option) any later version. |
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10 ## |
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11 ## Octave is distributed in the hope that it will be useful, but |
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12 ## WITHOUT ANY WARRANTY; without even the implied warranty of |
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13 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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14 ## General Public License for more details. |
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15 ## |
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16 ## You should have received a copy of the GNU General Public License |
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17 ## along with Octave; see the file COPYING. If not, see |
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18 ## <http://www.gnu.org/licenses/>. |
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19 |
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20 ## -*- texinfo -*- |
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21 ## @deftypefn {Function File} {} sysupdate (@var{sys}, @var{opt}) |
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22 ## Update the internal representation of a system. |
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23 ## |
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24 ## @strong{Inputs} |
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25 ## @table @var |
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26 ## @item sys: |
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27 ## system data structure |
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28 ## @item opt |
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29 ## string: |
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30 ## @table @code |
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31 ## @item "tf" |
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32 ## update transfer function form |
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33 ## @item "zp" |
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34 ## update zero-pole form |
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35 ## @item "ss" |
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36 ## update state space form |
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37 ## @item "all" |
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38 ## all of the above |
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39 ## @end table |
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40 ## @end table |
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41 ## |
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42 ## @strong{Outputs} |
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43 ## @table @var |
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44 ## @item retsys |
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45 ## Contains union of data in sys and requested data. |
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46 ## If requested data in @var{sys} is already up to date then @var{retsys}=@var{sys}. |
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47 ## @end table |
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48 ## |
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49 ## Conversion to @command{tf} or @command{zp} exits with an error if the system is |
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50 ## mixed continuous/digital. |
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51 ## @seealso{tf, ss, zp, sysout, sys2ss, sys2tf, sys2zp} |
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52 ## @end deftypefn |
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53 |
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54 ## Author: John Ingram <ingraje@eng.auburn.edu> |
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55 ## Created: July 9, 1996 |
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56 |
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57 function sys = sysupdate (sys, opt) |
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58 |
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59 ## check for correct number of inputs |
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60 if (nargin != 2) |
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61 print_usage (); |
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62 elseif (! isstruct (sys)) |
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63 error ("first argument must be system data structure"); |
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64 elseif (! (strcmp (opt, "tf") || strcmp (opt, "zp") |
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65 || strcmp (opt, "ss") || strcmp (opt, "all"))) |
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66 error ("second argument must be \"tf\", \"zp\", \"ss\", or \"all\""); |
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67 endif |
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68 |
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69 ## check to make sure not trying to make a SISO system out of a MIMO sys |
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70 if ((strcmp (opt, "tf") || strcmp(opt,"zp") || strcmp (opt, "all")) |
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71 && strcmp (sysgettype (sys), "ss") && ! is_siso (sys)) |
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72 error ("MIMO -> SISO update requested"); |
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73 endif |
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74 |
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75 ## update transfer function if desired |
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76 if ((strcmp (opt, "tf") || strcmp (opt, "all")) && (! sys.sys(2))) |
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77 ## check to make sure the system is not discrete and continuous |
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78 is_digital (sys); |
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79 |
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80 ## if original system zero-pole |
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81 if (strcmp (sysgettype (sys), "zp")) |
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82 [sys.num, sys.den] = zp2tf (sys.zer, sys.pol, sys.k); |
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83 sys.sys(2) = 1; |
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84 ## if original system is state-space |
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85 elseif (sys.sys(1) == 2) |
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86 [sys.num, sys.den] = ss2tf (sys.a, sys.b, sys.c, sys.d); |
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87 sys.sys(2) = 1; |
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88 endif |
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89 endif |
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90 |
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91 |
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92 ## update zero-pole if desired |
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93 if ((strcmp (opt, "zp") || strcmp (opt, "all")) && ! sys.sys(3)) |
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94 ## check to make sure the system is not discrete and continuous |
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95 is_digital (sys); |
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96 |
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97 ## original system is transfer function |
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98 if (sys.sys(1) == 0) |
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99 [sys.zer, sys.pol, sys.k] = tf2zp (sys.num, sys.den); |
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100 sys.sys(3) = 1; |
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101 ## original system is state-space |
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102 elseif (sys.sys(1) == 2) |
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103 [sys.zer, sys.pol, sys.k] = ss2zp (sys.a, sys.b, sys.c, sys.d); |
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104 sys.sys(3) = 1; |
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105 endif |
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106 endif |
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107 |
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108 ## update state-space if desired |
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109 if ((strcmp (opt, "ss") || strcmp (opt, "all")) && ! sys.sys(4)) |
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110 ## original system is transfer function |
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111 if (sys.sys(1) == 0) |
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112 [sys.a, sys.b, sys.c, sys.d] = tf2ss (sys.num, sys.den); |
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113 sys.sys(4) = 1; |
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114 ## original system is zero-pole |
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115 elseif (sys.sys(1) == 1) |
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116 [sys.a, sys.b, sys.c, sys.d] = zp2ss (sys.zer, sys.pol, sys.k); |
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117 sys.sys(4) = 1; |
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118 endif |
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119 |
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120 ## create new state names |
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121 sys.stname = __sysdefstname__ (sys.n, sys.nz); |
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122 endif |
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123 |
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124 endfunction |
