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SNNS

Name

SNNS (Stuttgart Neural Network Simulator) Version 2.0

Source

Dr. Andreas Zell, Universität Stuttgart, Institute for Parallel and Distributed High Performance Systems

Price

Not public domain but `free software', distributed in a licensing agreement free of charge.

Target usage

education, experimentation, research; advanced beginners, experts

Model

Network Architecture

The units are distinguished by the values of several attributes (number, name, io-type, activation, output, bias, activation function, output function, position, subnet number, etc.). The connections to a unit can be grouped by sites and treated differently.

Paradigms

Five network update-modes are implemented. One training method used is online Backpropagation, also known as stochastic gradient method; two versions are available, one without and one with momentum. Furthermore, Quickprop, Counterpropagation, and Backpercolation are implemented. A few examples are included.

Limitations

The net executes in update-steps synchronized by a discrete clock.

Implementation

Display

Visualization is by means of XGUI, it has a manager window containing all elements needed for working with the interface, several displays to show the network in two dimensions, a 3D-view panel, a panel for simulator operations, a special purpose window for the creation of big regular feedforward-nets, and several windows to display help information. Additionally, there are several popup windows. A graphical network editor provides means to generate or modify networks in various ways.

User Interface

Medium sized nets (up to 10.000 units) can be created by XGUI, a high level network description language Nessus for the generation of large nets (10.000 to 1.000.000 units) is available.

Execution

Interactive and batch exexcution is possible. Networks can be saved and loaded, as well as activation values and displays with all setup parameters.

Data Format

The format of the file interface to the kernel is described in the appendix of the user manual. Files of this format may be generated by any other program.

Evaluation

The sum of the squared error over output units and the average error per output unit are reported.

Performance

information not available

System Requirements

Hardware

SUN 3/50, 3/60; SUN SparcSt. SLC, ELC; SUN SparcSt. 2 GX, GS; DECstation 2100, 3100; DECstation 5000/200; IBM-PC 80386; IBM RS 6000/320, 320H; HP 9000/845; HP 9000/720, 730.

Operating System

SunOS 4.1.1, Ultrix V4.2, Interactive Unix, AIX V3.1, HP/UX

Display

monochrome as well as color, X-Windows X11R4 and X11R5, Sun OpenWindows 3.0

Language

C

Installation and Documentation

Installation

Procedures for supported machine architectures are included.

Sources available

yes

Implementation language

C

Documentation

On-line help available, examples and user manual (Report No. 3/92) are included in the distribution.

Support

None, but users are encouraged to send back changes and improvements. Distribution of modified copies is not allowed. There is no warranty of any kind.

User Groups

Mailing list snns@informatik.uni-stuttgart.de