The Project

DLV-EX is an Answer Set Programming System extending [http://www.dlvsystem.com DLV] by External Predicates, which features a framework aimed at enabling ASP to deal with external sources of computation. This feature is realized by the introduction of “parametric” external predicates, whose extension is not specified by means of a logic program but implicitly computed through external code. It is explicitly addressed the issue of invention of new information coming from external predicates, in form of new, and possibly infinite, constant symbols.

DLV-EX is based on the [http://www.dlvsystem.com DLV] system.

The Team

Core

Francesco Calimeri ([calimeri@mat.unical.it]), Giovambattista Ianni ([ianni@mat.unical.it]), Susanna Cozza ([cozza@mat.unical.it])

Former team members

Adriana Pietramala (student), Maria Carmela Santoro (student)

Prompters and helpers

[http://www.wfaber.com Wolfgang Faber], [http://www.pfeifer.com/gerald/ Gerald Pfeifer]

Download

DLV-EX is actively developed. To receive notifications about new releases and other important events regarding DLV-EX, just have a look at this page, or drop us a note here.

Please always use the most current version of DLV-EX (cf. version history).

We offer a command-line version in binary form for i586-linux-elf-static (please have a look at the notes below). We plan to release binaries for other platforms as soon as an official release will be ready.

Notes: Please note that the .tar.gz archive consists of the executable plus a folder, namely "LIB", containing headers and scripts needed in order to create new External Builtins libraries. For further information, have a look at the documentation.

Libraries

Some (compiled) dynamic libraries can be downloaded here. They have to be considered as "betas", since they are currently developed and tested. Feedbacks are useful and welcome, so please download them freely. For further information on how to exploit libraries have a look at the documentation. Please note that updates will be available later on, so come back to this page.

String Library (linux) and related documentation. Integers Library (linux) and related documentation. Reals Library (linux) and related documentation.

Utilities

DEBT - We have developed an integrated command-line environment aimed at helping in testing external built-ins predicates. This may be very useful for users who define their own built-ins. DEBT can be downloaded here, and it is gathered with its related documentation.

Documentation & Examples

We provide an online manual and an online tutorial; they are updated accordingly to the evolution of the system, so check them.

For a full documentation on DLV please check the official web page.

Related Work

It is worth noting that our work shares many aspects with the work carried out by Thomas Eiter, Giovambattista Ianni, Roman Schindlauer, and Hans Tompits. They introduce HEX programs, which are nonmonotonic logic programs admitting higher-order atoms as well as external atoms, and extend the answer-set semantics accordingly. A web page with a very preliminar prototype and some references is available here.

* DLV is the system into which DLV-EX is implemented.

* DLT is an extension to the DLV system providing reusable template predicate definitions. It is maintained by members of the DLV team from Università della Calabria.

* James Delgrande, Torsten Schaub and Hans Tompits have created an external frontend for prioritized logic programs.

* Vladimir Sarsakov, Torsten Schaub, Hans Tompits and Stefan Woltran have created an external frontend for logic programs with nested expressions.

* A-POL, a partial order programming extension for Answer Set Programming, by Mauricio Osorio Galindo and Enrique R. Corona D.

History

* September 28th, 2005 "Beta" version, much improved. Carries many bugfixes and improvements.

* March 28th, 2005 First stable version, even if still a "beta".

* October 17th, 2004 First working version, experimental.

* Previous versions ...did not carry a real version identification.

Selected Publications

[1] F. Calimeri, G. Ianni, "External sources of computation for Answer Set Solvers", Proceedings of the 8th International Conference on Logic Programming and Nonmonotonic Reasoning (LPNMR-05), Diamante, Italy, 5-8 September 2005, Springer Verlag.