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1 # Copyright (C) 1996 A. Scottedward Hodel |
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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, 675 Mass Ave, Cambridge, MA 02139, USA. |
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18 |
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19 function sys = sysadd(Gsys,Hsys) |
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20 # |
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21 # [sys] = sysadd(Gsys,Hsys) |
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22 # |
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23 # |
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24 # returns transfer function sys = Gsys + Hsys |
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25 # |
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26 # Method: Gsys and Hsys are connected in parallel |
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27 # The vector are connected to both systems; the outputs will be |
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28 # added. The names given to the system will be the G systems names. |
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29 # |
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30 # ________ |
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31 # ----| Gsys |--- |
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32 # u | ---------- +| |
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33 # ----- (_)----> y |
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34 # | ________ +| |
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35 # ----| Hsys |--- |
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36 # -------- |
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37 |
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38 # Written by John Ingram July 1996 |
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39 # $Revision: 2.0.0.2 $ |
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40 |
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41 save_val = implicit_str_to_num_ok; # save for later |
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42 implicit_str_to_num_ok = 1; |
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43 |
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44 if(nargin != 2) |
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45 usage("sysadd: [sys] = sysysadd(Gsys,Hsys)"); |
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46 endif |
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47 |
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48 # check inputs |
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49 if(!is_struct(Gsys) | !is_struct(Hsys)) |
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50 error("Both Gsys and Hsys must be in system data structure form"); |
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51 endif |
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52 |
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53 # check for compatibility |
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54 [n,nz,mg,pg] = sysdimensions(Gsys); |
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55 [n,nz,mh,ph] = sysdimensions(Hsys); |
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56 if(mg != mh) |
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57 error(sprintf("Gsys inputs(%d) != Hsys inputs (%d)",mg,mh)); |
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58 elseif(pg != ph) |
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59 error(sprintf("Gsys outputs(%d) != Hsys outputs (%d)",pg,ph)); |
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60 endif |
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61 |
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62 [Gst, Gin, Gout, Gyd] = sysgetsignals(Gsys); |
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63 [Hst, Hin, Hout, Hyd] = sysgetsignals(Hsys); |
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64 |
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65 # check for digital to continuous addition |
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66 if (Gyd != Hyd) |
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67 error("can not add a discrete output to a continuous output"); |
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68 endif |
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69 |
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70 if( strcmp(sysgettype(Gsys),"tf") | strcmp(sysgettype(Hsys),"tf") ) |
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71 # see if adding transfer functions with identical denominators |
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72 [Gnum,Gden,GT,Gin,Gout] = sys2tf(Gsys); |
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73 [Hnum,Hden,HT,Hin,Hout] = sys2tf(Hsys); |
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74 if( (Hden == Gden) & (HT == GT) ) |
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75 sys = tf2sys(Gnum+Hnum,Gden,GT,Gin,Gout); |
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76 return |
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77 endif |
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78 # if not, we go on and do the usual thing... |
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79 endif |
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80 |
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81 # make sure in ss form |
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82 Gsys = sysupdate(Gsys,"ss"); |
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83 Hsys = sysupdate(Hsys,"ss"); |
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84 |
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85 sys = sysgroup(Gsys,Hsys); |
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86 |
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87 eyin = eye(mg); |
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88 eyout = eye(pg); |
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89 |
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90 |
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91 inname = Gin; |
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92 outname = Gout; |
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93 |
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94 sys = sysscale(sys,[eyout eyout],[eyin;eyin],outname,inname); |
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95 |
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96 endfunction |
