Mercurial > octave
view scripts/general/mod.m @ 9141:c1fff751b5a8
Update section 17.1 (Utility Functions) of arith.txi
Split section into "Exponents and Logarithms" and "Utility Functions"
Use Tex in many more of the doc strings for pretty printing in pdf format.
author | Rik <rdrider0-list@yahoo.com> |
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date | Mon, 20 Apr 2009 17:16:09 -0700 |
parents | 1bf0ce0930be |
children | 16f53d29049f |
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## Copyright (C) 1999, 2000, 2002, 2004, 2005, 2006, 2007, 2008 Paul Kienzle ## ## This file is part of Octave. ## ## Octave is free software; you can redistribute it and/or modify it ## under the terms of the GNU General Public License as published by ## the Free Software Foundation; either version 3 of the License, or (at ## your option) any later version. ## ## Octave is distributed in the hope that it will be useful, but ## WITHOUT ANY WARRANTY; without even the implied warranty of ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU ## General Public License for more details. ## ## You should have received a copy of the GNU General Public License ## along with Octave; see the file COPYING. If not, see ## <http://www.gnu.org/licenses/>. ## -*- texinfo -*- ## @deftypefn {Mapping Function} {} mod (@var{x}, @var{y}) ## Compute the modulo of @var{x} and @var{y}. Conceptually this is given by ## ## @example ## x - y .* floor (x ./ y) ## @end example ## ## and is written such that the correct modulus is returned for ## integer types. This function handles negative values correctly. That ## is, @code{mod (-1, 3)} is 2, not -1, as @code{rem (-1, 3)} returns. ## @code{mod (@var{x}, 0)} returns @var{x}. ## ## An error results if the dimensions of the arguments do not agree, or if ## either of the arguments is complex. ## @seealso{rem, fmod} ## @end deftypefn ## Author: Paul Kienzle <pkienzle@kienzle.powernet.co.uk> ## Modified by: Teemu Ikonen <tpikonen@pcu.helsinki.fi> ## Adapted by: jwe function r = mod (x, y) if (nargin != 2) print_usage (); endif if (! size_equal (x, y) && ! (isscalar (x) || isscalar (y))) error ("mod: argument sizes must agree"); endif if (isreal (x) && isreal (y)) nz = y != 0.0; if (all (nz(:))) ## No elements of y are zero. if (isinteger(x) || isinteger(y)) if (isinteger (x)) typ = class (x); else typ = class (y); endif r = x - y .* cast (floor (double(x) ./ double(y)), typ); else r = x - y .* floor (x ./ y); endif elseif (isscalar (y)) ## y must be zero. r = x; else ## Some elements of y are zero. if (isscalar (x)) r = x * ones (size(y), class(y)); else r = x; x = x(nz); endif y = y(nz); if (isinteger(x) || isinteger(y)) if (isinteger (x)) typ = class (x); else typ = class (y); endif r(nz) = x - y .* floor (double(x) ./ double(y)); else r(nz) = x - y .* floor (x ./ y); endif endif else error ("mod: complex arguments are not allowed"); endif endfunction ## empty input test %!assert (isempty(mod([], []))); ## x mod y, y != 0 tests %!assert (mod(5, 3), 2); %!assert (mod(-5, 3), 1); %!assert (mod(0, 3), 0); %!assert (mod([-5, 5, 0], [3, 3, 3]), [1, 2, 0]); %!assert (mod([-5; 5; 0], [3; 3; 3]), [1; 2; 0]); %!assert (mod([-5, 5; 0, 3], [3, 3 ; 3, 1]), [1, 2 ; 0, 0]); ## x mod 0 tests %!assert (mod(5, 0), 5); %!assert (mod(-5, 0), -5); %!assert (mod([-5, 5, 0], [3, 0, 3]), [1, 5, 0]); %!assert (mod([-5; 5; 0], [3; 0; 3]), [1; 5; 0]); %!assert (mod([-5, 5; 0, 3], [3, 0 ; 3, 1]), [1, 5 ; 0, 0]); %!assert (mod([-5, 5; 0, 3], [0, 0 ; 0, 0]), [-5, 5; 0, 3]); ## mixed scalar/matrix tests %!assert (mod([-5, 5; 0, 3], 0), [-5, 5; 0, 3]); %!assert (mod([-5, 5; 0, 3], 3), [1, 2; 0, 0]); %!assert (mod(-5,[0,0; 0,0]), [-5, -5; -5, -5]); %!assert (mod(-5,[3,0; 3,1]), [1, -5; 1, 0]); %!assert (mod(-5,[3,2; 3,1]), [1, 1; 1, 0]); ## integer types %!assert (mod(uint8(5),uint8(4)),uint8(1)) %!assert (mod(uint8([1:5]),uint8(4)),uint8([1,2,3,0,1])) %!assert (mod(uint8([1:5]),uint8(0)),uint8([1:5])) %!error (mod(uint8(5),int8(4))) ## mixed integer/real types %!assert (mod(uint8(5),4),uint8(1)) %!assert (mod(5,uint8(4)),uint8(1)) %!assert (mod(uint8([1:5]),4),uint8([1,2,3,0,1]))