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changeset 7621:4682dda22527

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Add the reallog, realsqrt and realpow functions
author David Bateman <dbateman@free.fr>
date Fri, 21 Mar 2008 16:09:01 +0100
parents 36594d5bbe13
children c195bd0a5c64
files scripts/ChangeLog scripts/specfun/Makefile.in scripts/specfun/reallog.m scripts/specfun/realpow.m scripts/specfun/realsqrt.m
diffstat 5 files changed, 131 insertions(+), 1 deletions(-) [+]
line wrap: on
line diff
--- a/scripts/ChangeLog	Fri Mar 21 00:08:24 2008 +0100
+++ b/scripts/ChangeLog	Fri Mar 21 16:09:01 2008 +0100
@@ -1,3 +1,8 @@
+2008-03-21  David Bateman  <dbateman@free.fr>
+
+	* specfun/reallog.m, specfun/realpow.m, specfun/realsqrt.m: New
+	functions.
+
 2008-03-20  David Bateman  <dbateman@free.fr>
 
 	* general/tril.m, general/triu.m: Fail if input is a structure.
--- a/scripts/specfun/Makefile.in	Fri Mar 21 00:08:24 2008 +0100
+++ b/scripts/specfun/Makefile.in	Fri Mar 21 16:09:01 2008 +0100
@@ -35,7 +35,7 @@
 
 SOURCES = bessel.m beta.m betai.m betaln.m erfinv.m factor.m \
   factorial.m gammai.m isprime.m legendre.m log2.m nchoosek.m \
-  perms.m pow2.m primes.m
+  perms.m pow2.m primes.m reallog.m realpow.m realsqrt.m
 
 DISTFILES = $(addprefix $(srcdir)/, Makefile.in $(SOURCES))
 
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/scripts/specfun/reallog.m	Fri Mar 21 16:09:01 2008 +0100
@@ -0,0 +1,40 @@
+## 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} {} realsqrt (@var{x})
+## Return the real natural logarithm of @var{x}. If any element results in the
+## return value being complex @code{reallog} produces an error.
+## @seealso{log, realsqrt, realpow}
+## @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 (log(1:5),reallog(1:5))
+%!test
+%! x = rand (10,10);
+%! assert (log(x),reallog(x))
+%!error (reallog(-1))
--- /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))
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/scripts/specfun/realsqrt.m	Fri Mar 21 16:09:01 2008 +0100
@@ -0,0 +1,40 @@
+## 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} {} realsqrt (@var{x})
+## Return the real sqrt of @var{x}. If any element results in the
+## return value being complex @code{realsqrt} produces an error.
+## @seealso{sqrt, reallog, realpow}
+## @end deftypefn
+
+function y = realsqrt (x)
+  if (nargin != 1)
+    print_usage ();
+  elseif (iscomplex (x) || any (x(:) < 0))
+    error ("realsqrt: produced complex result");
+  else    
+    y = sqrt (x);
+  endif
+endfunction
+
+%!assert (sqrt(1:5),realsqrt(1:5))
+%!test
+%! x = rand (10,10);
+%! assert (sqrt(x),realsqrt(x))
+%!error (realsqrt(-1))