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
|
########################################################################
##
## Copyright (C) 2008-2024 The Octave Project Developers
##
## See the file COPYRIGHT.md in the top-level directory of this
## distribution or <https://octave.org/copyright/>.
##
## This file is part of Octave.
##
## Octave 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.
##
## Octave 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 Octave; see the file COPYING. If not, see
## <https://www.gnu.org/licenses/>.
##
########################################################################
## -*- texinfo -*-
## @deftypefn {} {@var{y} =} reallog (@var{x})
## Return the real-valued natural logarithm of each element of @var{x}.
##
## If any element results in a complex return value @code{reallog} aborts and
## issues an error.
## @seealso{log, realpow, realsqrt}
## @end deftypefn
function y = reallog (x)
if (nargin < 1)
print_usage ();
elseif (iscomplex (x) || any (x(:) < 0))
error ("reallog: produced complex result");
else
y = log (x);
endif
endfunction
%!assert (reallog (1:5), log (1:5))
%!test
%! x = rand (10, 10);
%! assert (reallog (x), log (x));
%!error <Invalid call> reallog ()
%!error <produced complex result> reallog (2i)
%!error <produced complex result> reallog (-1)
|
