Mercurial > octave-nkf
view scripts/general/idivide.m @ 14138:72c96de7a403 stable
maint: update copyright notices for 2012
author | John W. Eaton <jwe@octave.org> |
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date | Mon, 02 Jan 2012 14:25:41 -0500 |
parents | c792872f8942 |
children | 4d917a6a858b |
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## Copyright (C) 2008-2012 David Bateman ## ## 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 {Function File} {} idivide (@var{x}, @var{y}, @var{op}) ## Integer division with different rounding rules. ## ## The standard behavior of integer division such as @code{@var{a} ./ @var{b}} ## is to round the result to the nearest integer. This is not always the ## desired behavior and @code{idivide} permits integer element-by-element ## division to be performed with different treatment for the fractional ## part of the division as determined by the @var{op} flag. @var{op} is ## a string with one of the values: ## ## @table @asis ## @item "fix" ## Calculate @code{@var{a} ./ @var{b}} with the fractional part rounded ## towards zero. ## ## @item "round" ## Calculate @code{@var{a} ./ @var{b}} with the fractional part rounded ## towards the nearest integer. ## ## @item "floor" ## Calculate @code{@var{a} ./ @var{b}} with the fractional part rounded ## towards negative infinity. ## ## @item "ceil" ## Calculate @code{@var{a} ./ @var{b}} with the fractional part rounded ## towards positive infinity. ## @end table ## ## @noindent ## If @var{op} is not given it defaults to @code{"fix"}. ## An example demonstrating these rounding rules is ## ## @example ## @group ## idivide (int8 ([-3, 3]), int8 (4), "fix") ## @result{} int8 ([0, 0]) ## idivide (int8 ([-3, 3]), int8 (4), "round") ## @result{} int8 ([-1, 1]) ## idivide (int8 ([-3, 3]), int8 (4), "floor") ## @result{} int8 ([-1, 0]) ## idivide (int8 ([-3, 3]), int8 (4), "ceil") ## @result{} int8 ([0, 1]) ## @end group ## @end example ## ## @seealso{ldivide, rdivide} ## @end deftypefn function z = idivide (x, y, op) if (nargin < 2 || nargin > 3) print_usage (); elseif (nargin == 2) op = "fix"; else op = tolower (op); endif if (strcmp (op, "round")) z = x ./ y; else if (isfloat (x)) typ = class (y); elseif (isfloat (y)) typ = class (x); else typ = class (x); if (!strcmp (class (x), class (y))) error ("idivide: incompatible types"); endif endif if (strcmp (op, "fix")) z = cast (fix (double (x) ./ double (y)), typ); elseif (strcmp (op, "floor")) z = cast (floor (double (x) ./ double (y)), typ); elseif (strcmp (op, "ceil")) z = cast (ceil (double (x) ./ double (y)), typ); else error ("idivide: unrecognized rounding type"); endif endif endfunction %!shared a, af, b, bf %! a = int8(3); %! af = 3; %! b = int8([-4, 4]); %! bf = [-4, 4]; %!assert (idivide (a, b), int8 ([0, 0])) %!assert (idivide (a, b, "floor"), int8([-1, 0])) %!assert (idivide (a, b, "ceil"), int8 ([0, 1])) %!assert (idivide (a, b, "round"), int8 ([-1, 1])) %!assert (idivide (af, b), int8 ([0, 0])) %!assert (idivide (af, b, "floor"), int8([-1, 0])) %!assert (idivide (af, b, "ceil"), int8 ([0, 1])) %!assert (idivide (af, b, "round"), int8 ([-1, 1])) %!assert (idivide (a, bf), int8 ([0, 0])) %!assert (idivide (a, bf, "floor"), int8([-1, 0])) %!assert (idivide (a, bf, "ceil"), int8 ([0, 1])) %!assert (idivide (a, bf, "round"), int8 ([-1, 1])) %!error (idivide (uint8(1), int8(1)))