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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 3 of the License, or (at |
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8 ## your option) 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, see |
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17 ## <http://www.gnu.org/licenses/>. |
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18 |
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19 ## -*- texinfo -*- |
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20 ## @deftypefn {Mapping Function} {} lcm (@var{x}, @dots{}) |
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21 ## Compute the least common multiple of the elements of @var{x}, or |
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22 ## the list of all the arguments. For example, |
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23 ## |
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24 ## @example |
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25 ## lcm (a1, ..., ak) |
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26 ## @end example |
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27 ## |
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28 ## @noindent |
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29 ## is the same as |
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30 ## |
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31 ## @example |
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32 ## lcm ([a1, ..., ak]). |
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33 ## @end example |
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34 ## |
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35 ## All elements must be the same size or scalar. |
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36 ## @seealso{gcd, min, max, ceil, floor} |
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37 ## @end deftypefn |
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38 |
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39 ## Author: KH <Kurt.Hornik@wu-wien.ac.at> |
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40 ## Created: 16 September 1994 |
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41 ## Adapted-By: jwe |
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42 |
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43 function l = lcm (varargin) |
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44 |
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45 if (nargin == 0) |
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46 print_usage (); |
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47 endif |
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48 |
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49 if (nargin == 1) |
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50 a = varargin{1}; |
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51 |
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52 if (round (a) != a) |
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53 error ("lcm: all arguments must be integer"); |
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54 endif |
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55 |
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56 if (any (a) == 0) |
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57 l = 0; |
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58 else |
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59 a = abs (a); |
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60 l = a (1); |
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61 for k = 1:(length (a) - 1) |
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62 l = l * a(k+1) / gcd (l, a(k+1)); |
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63 endfor |
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64 endif |
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65 else |
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66 |
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67 l = varargin{1}; |
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68 sz = size (l); |
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69 nel = numel (l); |
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70 |
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71 for i=2:nargin |
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72 a = varargin{i}; |
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73 |
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74 if (size (a) != sz) |
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75 if (nel == 1) |
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76 sz = size (a); |
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77 nel = numel (a); |
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78 elseif (numel (a) != 1) |
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79 error ("lcm: all arguments must be the same size or scalar"); |
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80 endif |
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81 endif |
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82 |
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83 if (round (a) != a) |
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84 error ("lcm: all arguments must be integer"); |
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85 endif |
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86 |
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87 idx = find (l == 0 || a == 0); |
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88 a = abs (a); |
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89 l = l .* a ./ gcd (l, a); |
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90 l(idx) = 0; |
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91 endfor |
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92 endif |
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93 |
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94 endfunction |
