Feed-forward ANN have become increasingly popular over the
last couple of years in feature recognition and function mapping problems
in a wide area of applications. High energy physics (** HEP**) is no
exception with its demanding on-line and off-line analysis tasks. To date,
the most commonly used architectures and procedures are the Multilayer
Perceptron (** MLP**) with backpropagation updating and self-organizing
networks. Both these approaches were implemented in ` JETNET 2.0`.
For the self-organizing networks nothing is changed in ` JETNET 3.0`
and we refer the reader to refs. [1,4] for information on this
part. For the MLP the most important additions and changes concern additional
** learning algorithm** variants, ** learning parameters** and various
tools for gauging performance and estimating error surfaces.

The following learning algorithms are included in ` JETNET 3.0`:

- Standard Gradient Descent (back-propagation) [5]
- Langevin Updating [6]
- Conjugate Gradient [7]
- Scaled Conjugate Gradient [8]
- ``Quickprop'' [9]
- ``Rprop'' [10]

- Dynamic Learning Rates
- Saturation Measurement
- Computation and Monitoring of Hessian Eigenvalues
- Limited Precision

Besides a full description of the functionality and the use of the various
` JETNET 3.0` subroutines this writeup also contains a set of
``rules-of-thumb'' and guidelines on how to use the package in
different situations.

However, we emphasize that in addition to feature recognition and function mapping there are ANN applications in HEP that require feed-back networks, which are not included in this package. In particular, we think of optimization networks used for track finding [11,12,13,14,15,16].

This write-up is organized as follows. In Sect. 2 we very briefly discuss
the basic steps and variants when using feed-forward networks for learning.
Discussions and prescriptions on what methods to use in various situations
are found in Sect. 3. Some implementation issues with respect to
` JETNET 3.0` are contained in Sect. 4. The program components together
with switch and parameter descriptions are listed in Sect. 5. Finally Sect. 6 contains
a list of technical restricions and Sect. 7 a sample program.

Fri Feb 24 11:28:59 MET 1995