1%% Copyright (C) 2014-2016, 2018 Colin B. Macdonald
2%%
3%% This file is part of OctSymPy.
4%%
5%% OctSymPy is free software; you can redistribute it and/or modify
6%% it under the terms of the GNU General Public License as published
7%% by the Free Software Foundation; either version 3 of the License,
8%% or (at your option) any later version.
9%%
10%% This software is distributed in the hope that it will be useful,
11%% but WITHOUT ANY WARRANTY; without even the implied warranty
12%% of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
13%% the GNU General Public License for more details.
14%%
15%% You should have received a copy of the GNU General Public
16%% License along with this software; see the file COPYING.
17%% If not, see <http://www.gnu.org/licenses/>.
18
19%% -*- texinfo -*-
20%% @documentencoding UTF-8
21%% @defop  Method   @@sym and {(@var{x}, @var{y})}
22%% @defopx Operator @@sym {@var{x} & @var{y}} {}
23%% Logical "and" of symbolic arrays.
24%%
25%% Examples:
26%% @example
27%% @group
28%% sym(false) & sym(true)
29%%   @result{} (sym) False
30%%
31%% syms x y z
32%% x & (y | z)
33%%   @result{} (sym) x ∧ (y ∨ z)
34%% @end group
35%% @end example
36%%
37%% @seealso{@@sym/or, @@sym/not, @@sym/xor, @@sym/eq, @@sym/ne,
38%%          @@sym/logical, @@sym/isAlways, @@sym/isequal}
39%% @end defop
40
41function r = and(x, y)
42
43  if (nargin ~= 2)
44    print_usage ();
45  end
46
47  r = elementwise_op ('And', sym(x), sym(y));
48
49end
50
51
52%!shared t, f
53%! t = sym(true);
54%! f = sym(false);
55
56%!test
57%! % simple
58%! assert (isequal (t & f, f))
59%! assert (isequal (t & t, t))
60
61%!test
62%! % mix wih nonsym
63%! assert (isequal (t & false, f))
64%! assert (isequal (t & true, t))
65%! assert (isequal (t & 0, f))
66%! assert (isequal (t & 1, t))
67%! assert (isa (t & false, 'sym'))
68%! assert (isa (t & 1, 'sym'))
69
70%!test
71%! % array
72%! w = [t t f f];
73%! z = [t f t f];
74%! assert (isequal (w & z, [t f f f]))
75
76%!test
77%! % number
78%! assert (isequal( sym(1) & t, t))
79%! assert (isequal( sym(0) & t, f))
80
81%!test
82%! % output is sym even for scalar t/f
83%! assert (isa (t & f, 'sym'))
84
85%!test
86%! % eqns, exclusive
87%! syms x
88%! e = (x == 3) & (x^2 == 9);
89%! assert (isequal (subs(e, x, [-3 0 3]), [f f t]))
90
91%!error and (sym('x'), 2, 3)
92