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1 ## Copyright (C) 1996, 1997 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 |
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7 ## the Free Software Foundation; either version 2, or (at your option) |
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8 ## any later version. |
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9 ## |
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10 ## Octave is distributed in the hope that it will be useful, but |
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11 ## WITHOUT ANY WARRANTY; without even the implied warranty of |
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12 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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13 ## General Public License 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} {} logspace (@var{base}, @var{limit}, @var{n}) |
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22 ## Similar to @code{linspace} except that the values are logarithmically |
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23 ## spaced from |
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24 ## @iftex |
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25 ## @tex |
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26 ## $10^{base}$ to $10^{limit}$. |
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27 ## @end tex |
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28 ## @end iftex |
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29 ## @ifinfo |
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30 ## 10^base to 10^limit. |
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31 ## @end ifinfo |
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32 ## |
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33 ## If @var{limit} is equal to |
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34 ## @iftex |
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35 ## @tex |
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36 ## $\pi$, |
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37 ## @end tex |
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38 ## @end iftex |
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39 ## @ifinfo |
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40 ## pi, |
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41 ## @end ifinfo |
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42 ## the points are between |
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43 ## @iftex |
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44 ## @tex |
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45 ## $10^{base}$ and $\pi$, |
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46 ## @end tex |
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47 ## @end iftex |
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48 ## @ifinfo |
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49 ## 10^base and pi, |
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50 ## @end ifinfo |
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51 ## @emph{not} |
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52 ## @iftex |
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53 ## @tex |
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54 ## $10^{base}$ and $10^{\pi}$, |
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55 ## @end tex |
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56 ## @end iftex |
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57 ## @ifinfo |
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58 ## 10^base and 10^pi, |
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59 ## @end ifinfo |
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60 ## in order to be compatible with the corresponding @sc{Matlab} function. |
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61 ## @end deftypefn |
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62 ## |
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63 ## @seealso{linspace} |
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64 |
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65 ## Author: jwe |
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66 |
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67 function retval = logspace (x1, x2, n) |
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68 |
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69 if (nargin == 2) |
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70 npoints = 50; |
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71 elseif (nargin == 3) |
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72 if (length (n) == 1) |
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73 npoints = fix (n); |
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74 else |
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75 error ("logspace: arguments must be scalars"); |
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76 endif |
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77 else |
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78 usage ("logspace (x1, x2, n)"); |
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79 endif |
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80 |
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81 if (npoints < 2) |
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82 error ("logspace: npoints must be greater than 2"); |
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83 endif |
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84 |
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85 if (length (x1) == 1 && length (x2) == 1) |
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86 x2_tmp = x2; |
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87 if (x2 == pi) |
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88 x2_tmp = log10 (pi); |
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89 endif |
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90 retval = 10 .^ (linspace (x1, x2_tmp, npoints)); |
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91 else |
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92 error ("logspace: arguments must be scalars"); |
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93 endif |
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94 |
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95 endfunction |
