/usr/share/octave/packages/interval-3.1.0/@infsup/pow2.m is in octave-interval 3.1.0-5.
This file is owned by root:root, with mode 0o644.
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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 90 91 92 93 94 95 96 97 | ## 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
## @defmethod {@@infsup} pow2 (@var{X})
##
## Compute @code{2^x} for all numbers in @var{X}.
##
## Accuracy: The result is a tight enclosure.
##
## @example
## @group
## pow2 (infsup (5))
## @result{} ans = [32]
## @end group
## @end example
## @seealso{@@infsup/log2, @@infsup/pow, @@infsup/pow10, @@infsup/exp}
## @end defmethod
## Author: Oliver Heimlich
## Keywords: interval
## Created: 2014-09-30
function x = pow2 (x)
if (nargin ~= 1)
print_usage ();
return
endif
## pow2 is monotonically increasing from (-inf, 0) to (inf, inf)
l = mpfr_function_d ('pow2', -inf, x.inf); # this works for empty intervals
u = mpfr_function_d ('pow2', +inf, x.sup); # ... this does not
l(l == 0) = -0;
u(isempty (x)) = -inf;
x.inf = l;
x.sup = u;
endfunction
%!# from the documentation string
%! assert (pow2 (infsup (5)) == infsup (32));
%!# correct use of signed zeros
%!test
%! x = pow2 (infsup (-inf, -realmax));
%! assert (signbit (inf (x)));
%!shared testdata
%! # Load compiled test data (from src/test/*.itl)
%! testdata = load (file_in_loadpath ("test/itl.mat"));
%!test
%! # Scalar evaluation
%! testcases = testdata.NoSignal.infsup.exp2;
%! for testcase = [testcases]'
%! assert (isequaln (...
%! pow2 (testcase.in{1}), ...
%! testcase.out));
%! endfor
%!test
%! # Vector evaluation
%! testcases = testdata.NoSignal.infsup.exp2;
%! in1 = vertcat (vertcat (testcases.in){:, 1});
%! out = vertcat (testcases.out);
%! assert (isequaln (pow2 (in1), out));
%!test
%! # N-dimensional array evaluation
%! testcases = testdata.NoSignal.infsup.exp2;
%! in1 = vertcat (vertcat (testcases.in){:, 1});
%! out = vertcat (testcases.out);
%! # Reshape data
%! i = -1;
%! do
%! i = i + 1;
%! testsize = factor (numel (in1) + i);
%! until (numel (testsize) > 2)
%! in1 = reshape ([in1; in1(1:i)], testsize);
%! out = reshape ([out; out(1:i)], testsize);
%! assert (isequaln (pow2 (in1), out));
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