/usr/share/octave/packages/interval-3.1.0/interval_bitpack.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 98 99 | ## 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
## @defun interval_bitpack (@var{X})
##
## Decode an interval from its interchange format.
##
## The input must either be a matrix of n × 128 bits for n bare intervals, or a
## matrix of n × 136 bits for n decorated intervals. Bits are in increasing
## order. Byte order depends on the system's endianness. First 8 bytes are
## used for the lower interval boundary, next 8 bytes are used for the upper
## interval boundary, (optionally) last byte is used for the decoration.
##
## The result is a row vector of intervals.
##
## Accuracy: For all valid interchange encodings the following equation holds:
## @code{@var{X} == bitunpack (interval_bitpack (@var{X}))}.
##
## @seealso{@@infsup/bitunpack, @@infsupdec/bitunpack}
## @end defun
## Author: Oliver Heimlich
## Keywords: interval
## Created: 2014-12-23
function result = interval_bitpack (x)
if (nargin ~= 1)
print_usage ();
return
endif
if (not (islogical (x)))
## Built-in function bitpack will fail on other data types
error ("interval:InvalidOperand", ...
['interval_bitpack: parameter must be a bool matrix, ' ...
'was: ' typeinfo(x)])
endif
switch size (x, 2)
case 128 # (inf, sup)
l = bitpack (x (:, 1 : 64)' (:), 'double');
u = bitpack (x (:, 65 : 128)' (:), 'double');
result = infsup (l, u);
case 136 # (inf, sup, dec)
l = bitpack (x (:, 1 : 64)' (:), 'double');
u = bitpack (x (:, 65 : 128)' (:), 'double');
d = bitpack (x (:, 129 : 136)' (:), 'uint8');
dec = cell (size (x, 1), 1);
dec (d == 4) = 'trv';
dec (d == 8) = 'def';
dec (d == 12) = 'dac';
dec (d == 16) = 'com';
result = infsupdec (l, u, dec);
otherwise
error ("interval:InvalidOperand", ...
['interval_bitpack: invalid bit-length, ' ...
'expected: 128 or 136, ' ...
'was: ' num2str(size (x, 2))])
endswitch
endfunction
%!test "bare";
%! littleendian = bitunpack (uint16 (1))(1);
%! b = zeros (1, 128);
%! if (littleendian)
%! b([52, 63, 117, 127]) = 1;
%! else
%! b([7, 12, 71, 77]) = 1;
%! endif
%! decoded = interval_bitpack (logical (b));
%! assert (eq (decoded, infsup (3, 4)));
%!test "decorated";
%! littleendian = bitunpack (uint16 (1))(1);
%! b = zeros (1, 136);
%! if (littleendian)
%! b([52, 63, 117, 127, 133]) = 1;
%! else
%! b([7, 12, 71, 77, 133]) = 1;
%! endif
%! decoded = interval_bitpack (logical (b));
%! assert (eq (decoded, infsupdec (3, 4)));
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