CHREST Code - Centre for Research in Development, Instruction and Training

The CHREST Code Home Page

This page provides pointers to a generic implementation of the CHREST model; a detailed description of the implementation is provided in a technical report.

Note: the technical report is currently not complete, and the distributions are all being added to almost daily.

Each distribution is accompanied by a set of system tests. The tests should be fairly self-explanatory, and give enough details to illustrate how the code works. Some of the distributions also include demonstrations, and some graphical tools, to aid in visualising the behaviour of CHREST.

At present, we provide distributions for Common Lisp, PLT Scheme and Java:

Common Lisp

Due to the specificity of separate compilers, we provide separate versions for the PC and Apple Macintosh. Apart from the graphical elements (mostly in the MCL version), the code is written generically in ANSI Common Lisp, and should be readily adaptable to alternative Lisp compilers.

PC - CLISP

The PC distribution has been developed using CLISP. When running, you should include utilities.lisp at startup, e.g. test clisp as follows:

clisp -i utilities.lisp -f run-tests.lisp -x (run-tests)

Download: chrest.zip

The PC distribution includes the network and STM learning mechanisms, as well as a simple GrowNetwork demo, which illustrates how a CHREST network is trained and grows in response to simple list patterns. Use the .bat files in the CHREST folder to run the demos, as the home directory for CLISP must be the CHREST folder itself.

Apple Macintosh - MCL

The Mac distribution has been developed using Digitool's MCL 4.2; a demo version of MCL is available from the Digitool web site, which should be sufficient to try the CHREST Demos.

Download: CHREST.sit

Note, because the Mac version does not get run from a command line, you must modify the run-*.lisp files to recognise the home directory for the distribution.

The Mac distribution includes two demonstrations at present:

run-mcl-grow-network.lisp, which provides a simple interface to a CHREST network, where you can enter lists of numbers or symbols and observe how the network grows, with or without chunking.
run-numbers-demo.lisp, which provides a similar demonstration, but training proceeds with several lists of numbers.

PLT Scheme

PLT Scheme is a cross-platform environment for developing Scheme programs: the environment includes many useful extensions, including a GUI library, object-orientation, and parallel threading. PLT Scheme is recommended for its cross-platform compatibility and ease-of-use.

Note: The downloadable files here are still incomplete.

Also, for compatibility with the MacOS, these files use the older version 103p1.

Download: CHREST-PLT.zip

Java

SHORTLY TO BE UPLOADED.

Last updated: 20th June 2002

All comments on the code, please email pcl@psyc.nott.ac.uk