diff scripts/specfun/realpow.m @ 7621:4682dda22527

Add the reallog, realsqrt and realpow functions
author David Bateman <dbateman@free.fr>
date Fri, 21 Mar 2008 16:09:01 +0100
parents
children 23c248d415b5
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--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/scripts/specfun/realpow.m	Fri Mar 21 16:09:01 2008 +0100
@@ -0,0 +1,45 @@
+## Copyright (C) 2008  David Bateman
+##
+## 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
+## <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## @deftypefn {Function File} {} realpow (@var{x}, @var{y})
+## Return the element by element power operator. This is equivalent to
+## @code{@var{x} .^ @var{y}), except that if the return value
+## is complex @code{realpow} produces an error.
+## @seealso{log, reallog, realsqrt}
+## @end deftypefn
+
+function z = realpow (x, y)
+  if (nargin != 2)
+    print_usage ();
+  else
+    z = x .^ y;
+    if (iscomplex (z))
+      error ("realpow: produced complex result");
+    endif
+  endif
+endfunction
+
+%!assert (power (1:10, 0.5:0.5:5), realpow (1:10, 0.5:0.5:5))
+%!assert ([1:10] .^ [0.5:0.5:5], realpow (1:10, 0.5:0.5:5))
+%!test
+%! x = rand (10,10);
+%! y = randn (10,10);
+%! assert (x.^y,realpow(x,y))
+%!assert (realpow(1i,2),-1)
+%!error (realpow(-1, 1/2))