/usr/share/octave/packages/interval-2.1.0/@infsup/uminus.m is in octave-interval 2.1.0-2.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 | ## Copyright 2014-2016 Oliver Heimlich
##
## This program 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.
##
## This program 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 this program; if not, see <http://www.gnu.org/licenses/>.
## -*- texinfo -*-
## @documentencoding UTF-8
## @defop Method {@@infsup} uminus (@var{X})
## @defopx Operator {@@infsup} {-@var{X}}
##
## Negate all numbers in the interval.
##
## Accuracy: The result is exact.
##
## @example
## @group
## x = infsup (2, 3);
## -x
## @result{} ans = [-3, -2]
## @end group
## @end example
## @seealso{@@infsup/uplus}
## @end defop
## Author: Oliver Heimlich
## Keywords: interval
## Created: 2014-09-30
function x = uminus (x)
if (nargin ~= 1)
print_usage ();
return
endif
## This also works for empty / entire intervals
[x.inf, x.sup] = deal (-x.sup, -x.inf);
endfunction
%!# from the documentation string
%!assert (-infsup (2, 3) == infsup (-3, -2));
%!# correct use of signed zeros
%!test
%! x = uminus (infsup (0));
%! assert (signbit (inf (x)));
%! assert (not (signbit (sup (x))));
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