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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, 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{zer}, @var{pol}]=} pzmap (@var{sys}) |
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21 ## Plots the zeros and poles of a system in the complex plane. |
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22 ## @strong{Inputs} |
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23 ## @var{sys} system data structure |
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24 ## |
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25 ## @strong{Outputs} |
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26 ## if omitted, the poles and zeros are plotted on the screen. |
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27 ## otherwise, pol, zer are returned as the system poles and zeros. |
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28 ## (see sys2zp for a preferable function call) |
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29 ## @end deftypefn |
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30 |
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31 function [zer, pol]=pzmap (sys) |
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32 |
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33 save_emp = empty_list_elements_ok; |
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34 |
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35 empty_list_elements_ok = 1; |
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36 |
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37 if(nargin != 1) |
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38 usage("pzmap(sys) or [zer,pol] = pzmap(sys)"); |
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39 elseif (!is_struct(sys)); |
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40 error("sys must be in system format"); |
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41 endif |
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42 |
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43 [zer,pol] = sys2zp(sys); |
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44 |
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45 ## force to column vectors, split into real, imaginary parts |
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46 zerdata = poldata = []; |
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47 if(length(zer)) |
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48 zer = reshape(zer,length(zer),1); |
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49 zerdata = [real(zer(:,1)), imag(zer(:,1))]; |
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50 endif |
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51 if(length(pol)) |
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52 pol = reshape(pol,length(pol),1); |
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53 poldata = [real(pol(:,1)), imag(pol(:,1))]; |
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54 endif |
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55 |
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56 ## determine continuous or discrete plane |
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57 vars = "sz"; |
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58 varstr = vars(is_digital(sys) + 1); |
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59 |
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60 ## Plot the data |
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61 gset nologscale xy; |
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62 if(is_siso(sys)) |
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63 title(sprintf("Pole-zero map from %s to %s", ... |
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64 sysgetsignals(sys,"in",1,1), sysgetsignals(sys,"out",1,1) )); |
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65 endif |
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66 xlabel(["Re(",varstr,")"]); |
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67 ylabel(["Im(",varstr,")"]); |
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68 grid; |
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69 |
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70 ## compute axis limits |
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71 axis(axis2dlim([zerdata;poldata])); |
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72 grid |
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73 ## finally, plot the data |
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74 if(length(zer) == 0) |
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75 plot(poldata(:,1), poldata(:,2),"@12 ;poles (no zeros);"); |
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76 elseif(length(pol) == 0) |
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77 plot(zerdata(:,1), zerdata(:,2),"@31 ;zeros (no poles);"); |
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78 else |
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79 plot(zerdata(:,1), zerdata(:,2),"@31 ;zeros;", ... |
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80 poldata(:,1), poldata(:,2),"@12 ;poles;"); |
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81 endif |
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82 replot |
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83 |
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84 empty_list_elements_ok = save_emp; |
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85 |
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86 endfunction |
