/usr/share/octave/packages/interval-2.1.0/@infsupdec/sqrrev.m is in octave-interval 2.1.0-2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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 59 60 61 62 63 64 65 66 67 68 | ## 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
## @deftypemethod {@@infsupdec} {@var{X} =} sqrrev (@var{C}, @var{X})
## @deftypemethodx {@@infsupdec} {@var{X} =} sqrrev (@var{C})
##
## Compute the reverse square function.
##
## That is, an enclosure of all @code{x ∈ @var{X}} where
## @code{sqr (x) ∈ @var{C}}.
##
## Accuracy: The result is a tight enclosure.
##
## @comment DO NOT SYNCHRONIZE DOCUMENTATION STRING
## No one way of decorating this operations gives useful information in all
## contexts. Therefore, the result will carry a @code{trv} decoration at best.
##
## @example
## @group
## sqrrev (infsupdec (-2, 1))
## @result{} ans = [-1, +1]_trv
## @end group
## @end example
## @seealso{@@infsupdec/sqr}
## @end deftypemethod
## Author: Oliver Heimlich
## Keywords: interval
## Created: 2014-10-19
function result = sqrrev (c, x)
if (nargin > 2)
print_usage ();
return
endif
if (nargin < 2)
x = infsupdec (-inf, inf);
endif
if (not (isa (c, "infsupdec")))
c = infsupdec (c);
endif
if (not (isa (x, "infsupdec")))
x = infsupdec (x);
endif
result = infsupdec (sqrrev (c.infsup, x.infsup), "trv");
result.dec(isnai (c) | isnai (x)) = _ill ();
endfunction
%!# from the documentation string
%!assert (isequal (sqrrev (infsupdec (-2, 1)), infsupdec (-1, 1, "trv")));
|