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1 ## Copyright (C) 1995, 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{y} =} polyout (@var{c}@{, @var{x}@}) |
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21 ## write formatted polynomial |
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22 ## @example |
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23 ## c(x) = c(1) * x^n + ... + c(n) x + c(n+1) |
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24 ## @end example |
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25 ## to string @var{y} or to the screen (if @var{y} is omitted) |
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26 ## @var{x} defaults to the string @code{"s"} |
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27 ## @end deftypefn |
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28 ## @seealso{polyval, polyvalm, poly, roots, conv, deconv, residue, |
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29 ## filter, polyderiv, and polyinteg} |
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30 |
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31 ## Author: A. S. Hodel <a.s.hodel@eng.auburn.edu> |
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32 ## Created: May 1995 |
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33 ## Nov 1998: Correctly handles complex coefficients |
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34 |
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35 function y = polyout (c, x) |
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36 |
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37 if (nargin < 1 ) || (nargin > 2) || (nargout < 0 ) || (nargout > 1) |
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38 usage("[y = ] polyout(c,[x])"); |
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39 endif |
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40 |
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41 if (!is_vector(c)) |
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42 error("polyout: first argument must be a vector"); |
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43 endif |
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44 |
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45 if (nargin == 1) |
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46 x = "s"; |
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47 elseif( ! isstr(x) ) |
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48 error("polyout: second argument must be a string"); |
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49 endif |
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50 |
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51 n = length(c); |
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52 if(n > 0) |
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53 n1 = n+1; |
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54 |
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55 if( imag(c(1)) ) tmp = com2str(c(1)) |
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56 else tmp = num2str(c(1)); endif |
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57 |
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58 for ii=2:n |
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59 if(real(c(ii)) < 0) ns = " - "; c(ii) = -c(ii); |
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60 else ns = " + "; endif |
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61 |
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62 if( imag(c(ii)) ) nstr = sprintf("(%s)",com2str(c(ii)) ); |
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63 else nstr = num2str(c(ii)); endif |
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64 |
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65 tmp = sprintf("%s*%s^%d%s%s",tmp,x,n1-ii,ns,nstr); |
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66 |
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67 endfor |
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68 else |
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69 tmp = " "; |
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70 endif |
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71 |
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72 if(nargout == 0) |
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73 disp(tmp) |
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74 else |
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75 y = tmp; |
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76 endif |
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77 |
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78 endfunction |
