## Copyright (C) 2006 Michel D. Schmid  <michaelschmid@users.sourceforge.net>
##
##
## This program 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 2, or (at your option)
## any later version.
##
## This program 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 this program; see the file COPYING.  If not, see
## <http://www.gnu.org/licenses/>.

## -*- texinfo -*-
## @deftypefn {Function File} {}[@var{n} = __dtansig (@var{n})
## first derivative of @code{tansig}
##
## @example
##
## tansig is a symmetric non linear transfer function
## used by neural networks.
## Input n must be calculated with "n = tansig(n)".
## @end example
##
## @end deftypefn

## Author: Michel D. Schmid


function a = __dtansig(n)

  a = 1-(n.*n);

endfunction