/usr/share/octave/packages/interval-2.1.0/@infsup/sdist.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 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 | ## Copyright 2015-2016 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
## @defmethod {@@infsup} sdist (@var{X}, @var{Y})
##
## Compute the signed distance between two intervals as sets.
##
## The signed distance for closed real intervals is the minimum distance
## between each pair of numbers, where the result's sign indicates whether
## @var{x} precedes @var{y} (negative), @var{y} precedes @var{x} (positive), or
## @var{x} intersects @var{y} (zero). That is, the signed distance equals zero
## if a number can be found in both intervals. Otherwise the signed distance
## is the positive or negative size of the gap between both intervals on the
## real number lane.
##
## If any interval is empty, the result is NaN. For interval matrices the
## result is computed entry-wise.
##
## Accuracy: The result is correctly-rounded (away from zero).
##
## @example
## @group
## sdist (infsup (0, 6), infsup (7, 20))
## @result{} ans = -1
## sdist (infsup (3, 5), infsup (0, 1))
## @result{} ans = 2
## @end group
## @end example
## @seealso{@@infsup/idist, @@infsup/hdist}
## @end defmethod
## Author: Oliver Heimlich
## Keywords: interval
## Created: 2015-06-11
function result = sdist (x, y)
if (nargin ~= 2)
print_usage ();
return
endif
if (not (isa (x, "infsup")))
x = infsup (x);
endif
if (not (isa (y, "infsup")))
y = infsup (y);
endif
## Resize, if scalar × matrix
if (not (size_equal (x.inf, y.inf)))
x.inf = ones (size (y.inf)) .* x.inf;
x.sup = ones (size (y.inf)) .* x.sup;
y.inf = ones (size (x.inf)) .* y.inf;
y.sup = ones (size (x.inf)) .* y.sup;
endif
result = zeros (size (x.inf));
select = x.sup < y.inf;
if (any (select(:)))
result(select) = ...
mpfr_function_d ('minus', -inf, x.sup(select), y.inf(select));
endif
select = x.inf > y.sup;
if (any (select(:)))
result(select) = max (result(select), ...
mpfr_function_d ('minus', +inf, x.inf(select), y.sup(select)));
endif
result(isempty (x) | isempty (y)) = nan ();
endfunction
%!# from the documentation string
%!assert (sdist (infsup (0, 6), infsup (7, 20)), -1);
%!assert (sdist (infsup (3, 5), infsup (0, 1)), 2);
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