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update copyright notices
author John W. Eaton <jwe@octave.org>
date Sat, 07 Mar 2009 10:41:27 -0500
parents 70ae882c63cd
children 1bf0ce0930be
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John W. Eaton <jwe@octave.org>
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1 ## Copyright (C) 1999, 2000, 2002, 2004, 2005, 2006, 2007, 2008 Paul Kienzle
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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} {} mod (@var{x}, @var{y})
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21 ## Compute modulo function. Conceptually this is given by
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22 ##
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23 ## @example
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24 ## x - y .* floor (x ./ y)
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25 ## @end example
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26 ##
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27 ## and is written in a manner that the correct modulus is returned for
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28 ##integer types. This function handles negative values correctly. That
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29 ##is @code{mod (-1, 3)} is 2, not -1 as @code{rem (-1, 3)} returns.
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30 ## Also, @code{mod (@var{x}, 0)} returns @var{x}.
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31 ##
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32 ## An error message is printed if the dimensions of the arguments do not
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33 ## agree, or if either of the arguments is complex.
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34 ## @seealso{rem, round}
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35 ## @end deftypefn
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36
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37 ## Author: Paul Kienzle <pkienzle@kienzle.powernet.co.uk>
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38 ## Modified by: Teemu Ikonen <tpikonen@pcu.helsinki.fi>
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39 ## Adapted by: jwe
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40
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41 function r = mod (x, y)
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42
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43 if (nargin != 2)
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44 print_usage ();
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45 endif
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46
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47 if (! size_equal (x, y) && ! (isscalar (x) || isscalar (y)))
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48 error ("mod: argument sizes must agree");
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49 endif
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50
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51 if (isreal (x) && isreal (y))
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52 nz = y != 0.0;
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53 if (all (nz(:)))
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54 ## No elements of y are zero.
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55 if (isinteger(x) || isinteger(y))
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56 if (isinteger (x))
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57 typ = class (x);
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58 else
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59 typ = class (y);
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60 endif
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61 r = x - y .* cast (floor (double(x) ./ double(y)), typ);
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62 else
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63 r = x - y .* floor (x ./ y);
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64 endif
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65 elseif (isscalar (y))
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66 ## y must be zero.
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67 r = x;
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68 else
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69 ## Some elements of y are zero.
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70 if (isscalar (x))
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71 r = x * ones (size(y), class(y));
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72 else
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73 r = x;
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74 x = x(nz);
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75 endif
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76 y = y(nz);
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77 if (isinteger(x) || isinteger(y))
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78 if (isinteger (x))
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79 typ = class (x);
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80 else
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81 typ = class (y);
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82 endif
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83 r(nz) = x - y .* floor (double(x) ./ double(y));
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84 else
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85 r(nz) = x - y .* floor (x ./ y);
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86 endif
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87 endif
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88 else
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89 error ("mod: complex arguments are not allowed");
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90 endif
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91
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92 endfunction
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93
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94 ## empty input test
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95 %!assert (isempty(mod([], [])));
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96
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97 ## x mod y, y != 0 tests
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98 %!assert (mod(5, 3), 2);
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99 %!assert (mod(-5, 3), 1);
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100 %!assert (mod(0, 3), 0);
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101 %!assert (mod([-5, 5, 0], [3, 3, 3]), [1, 2, 0]);
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102 %!assert (mod([-5; 5; 0], [3; 3; 3]), [1; 2; 0]);
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103 %!assert (mod([-5, 5; 0, 3], [3, 3 ; 3, 1]), [1, 2 ; 0, 0]);
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104
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105 ## x mod 0 tests
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106 %!assert (mod(5, 0), 5);
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107 %!assert (mod(-5, 0), -5);
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108 %!assert (mod([-5, 5, 0], [3, 0, 3]), [1, 5, 0]);
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109 %!assert (mod([-5; 5; 0], [3; 0; 3]), [1; 5; 0]);
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110 %!assert (mod([-5, 5; 0, 3], [3, 0 ; 3, 1]), [1, 5 ; 0, 0]);
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111 %!assert (mod([-5, 5; 0, 3], [0, 0 ; 0, 0]), [-5, 5; 0, 3]);
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112
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113 ## mixed scalar/matrix tests
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114 %!assert (mod([-5, 5; 0, 3], 0), [-5, 5; 0, 3]);
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115 %!assert (mod([-5, 5; 0, 3], 3), [1, 2; 0, 0]);
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116 %!assert (mod(-5,[0,0; 0,0]), [-5, -5; -5, -5]);
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117 %!assert (mod(-5,[3,0; 3,1]), [1, -5; 1, 0]);
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118 %!assert (mod(-5,[3,2; 3,1]), [1, 1; 1, 0]);
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119
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120 ## integer types
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121 %!assert (mod(uint8(5),uint8(4)),uint8(1))
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122 %!assert (mod(uint8([1:5]),uint8(4)),uint8([1,2,3,0,1]))
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123 %!assert (mod(uint8([1:5]),uint8(0)),uint8([1:5]))
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124 %!error (mod(uint8(5),int8(4)))
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125
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126 ## mixed integer/real types
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127 %!assert (mod(uint8(5),4),uint8(1))
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128 %!assert (mod(5,uint8(4)),uint8(1))
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129 %!assert (mod(uint8([1:5]),4),uint8([1,2,3,0,1]))