changelog shortlog tags changeset files revisions annotate raw

scripts/specfun/reallog.m

changeset 10289: 4b124317dc38
parent:c1fff751b5a8
author: John W. Eaton <jwe@octave.org>
date: Tue Feb 09 20:58:55 2010 -0500 (31 minutes ago)
permissions: -rw-r--r--
description: base_properties::set_children: account for hidden children 
     1## Copyright (C) 2008, 2009 David Bateman

     2##

     3## This file is part of Octave.

     4##

     5## Octave is free software; you can redistribute it and/or modify it

     6## under the terms of the GNU General Public License as published by

     7## the Free Software Foundation; either version 3 of the License, or (at

     8## your option) any later version.

     9##

    10## Octave is distributed in the hope that it will be useful, but

    11## WITHOUT ANY WARRANTY; without even the implied warranty of

    12## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

    13## General Public License for more details.

    14##

    15## You should have received a copy of the GNU General Public License

    16## along with Octave; see the file COPYING.  If not, see

    17## <http://www.gnu.org/licenses/>.

    18

    19## -*- texinfo -*-

    20## @deftypefn {Function File} {} reallog (@var{x})

    21## Return the real-valued natural logarithm of each element of @var{x}.  Report 

    22## an error if any element results in a complex return value.

    23## @seealso{log, realpow, realsqrt}

    24## @end deftypefn

    25

    26function y = reallog (x)

    27  if (nargin != 1)

    28    print_usage ();

    29  elseif (iscomplex (x) || any (x(:) < 0))

    30    error ("reallog: produced complex result");

    31  else    

    32    y = log (x);

    33  endif

    34endfunction

    35

    36%!assert (log(1:5),reallog(1:5))

    37%!test

    38%! x = rand (10,10);

    39%! assert (log(x),reallog(x))

    40%!error (reallog(-1))