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