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1 ## Copyright (C) 1993, 1994, 1995 John W. Eaton |
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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 ## -*- texinfo -*- |
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21 ## @deftypefn {Function File} {} damp (@var{p}, @var{tsam}) |
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22 ## Displays eigenvalues, natural frequencies and damping ratios |
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23 ## of the eigenvalues of a matrix @var{p} or the @math{A} matrix of a |
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24 ## system @var{p}, respectively. |
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25 ## If @var{p} is a system, @var{tsam} must not be specified. |
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26 ## If @var{p} is a matrix and @var{tsam} is specified, eigenvalues |
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27 ## of @var{p} are assumed to be in @var{z}-domain. |
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28 ## @end deftypefn |
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29 ## |
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30 ## @seealso{eig} |
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31 |
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32 ## Author: Kai P. Mueller <mueller@ifr.ing.tu-bs.de> |
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33 ## Created: September 29, 1997. |
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34 |
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35 function damp (p, tsam) |
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36 |
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37 ## assume a continuous system |
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38 DIGITAL = 0; |
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39 if(nargin < 1 || nargin > 2) |
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40 usage("damp(p,[ tsamp])") |
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41 endif |
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42 if(isstruct(p)) |
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43 if (nargin != 1) |
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44 error("damp: when p is a system, tsamp parameter is not allowed."); |
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45 endif |
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46 [aa, b, c, d, t_samp] = sys2ss(p); |
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47 DIGITAL = is_digital(p); |
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48 else |
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49 aa = p; |
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50 if (nargin == 2) |
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51 DIGITAL = 1; |
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52 t_samp = tsam; |
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53 endif |
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54 endif |
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55 if (!issquare(aa)) |
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56 error("damp: Matrix p is not square.") |
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57 endif |
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58 if (DIGITAL && t_samp <= 0.0) |
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59 error("damp: Sampling time tsam must not be <= 0.") |
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60 endif |
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61 |
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62 ## all checks done. |
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63 e = eig(aa); |
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64 [n, m] = size(aa); |
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65 if (DIGITAL) |
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66 printf(" (discrete system with sampling time %f)\n", t_samp); |
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67 endif |
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68 printf("............... Eigenvalue ........... Damping Frequency\n"); |
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69 printf("--------[re]---------[im]--------[abs]----------------------[Hz]\n"); |
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70 for i = 1:n |
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71 pole = e(i); |
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72 cpole = pole; |
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73 if (DIGITAL) |
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74 cpole = log(pole) / t_samp; |
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75 endif |
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76 d0 = -cos(atan2(imag(cpole), real(cpole))); |
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77 f0 = 0.5 / pi * abs(cpole); |
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78 if (abs(imag(cpole)) < eps) |
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79 printf("%12f --- %12f %10f %12f\n", |
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80 real(pole), abs(pole), d0, f0); |
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81 else |
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82 printf("%12f %12f %12f %10f %12f\n", |
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83 real(pole), imag(pole), abs(pole), d0, f0); |
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84 endif |
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85 endfor |
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86 |
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87 endfunction |
