X-Git-Url: https://git.creatis.insa-lyon.fr/pubgit/?p=CreaPhase.git;a=blobdiff_plain;f=octave_packages%2Fnnet-0.1.13%2Flogsig.m;fp=octave_packages%2Fnnet-0.1.13%2Flogsig.m;h=a21cf4c15f2579266d7e5092eba9f39bc65606e3;hp=0000000000000000000000000000000000000000;hb=f5f7a74bd8a4900f0b797da6783be80e11a68d86;hpb=1705066eceaaea976f010f669ce8e972f3734b05

diff --git a/octave_packages/nnet-0.1.13/logsig.m b/octave_packages/nnet-0.1.13/logsig.m
new file mode 100644
index 0000000..a21cf4c
--- /dev/null
+++ b/octave_packages/nnet-0.1.13/logsig.m
@@ -0,0 +1,41 @@
+## Copyright (C) 2007 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{a} = logsig (@var{n})
+## @code{logsig} is a non-linear transfer function used to train
+## neural networks.
+## This function can be used in newff(...) to create a new feed forward
+## multi-layer neural network.
+##
+## @end deftypefn
+
+## @seealso{purelin,tansig}
+
+## Author: Michel D. Schmid
+
+
+function a = logsig(n)
+
+
+  a = 1 ./ (1 + exp(-n));
+  ## attention with critical values ==> infinite values
+  ## must be set to 1! Still the same problem as in "tansig"
+  i = find(!finite(a));
+  a(i) = sign(n(i));
+
+endfunction
\ No newline at end of file