LP2NORMAL and LP2NORMAL2

This tool transforms an smodels program into a normal logic program by translating away extended rule types (choice rules, cardinality rules, and weight rules).

Implementation

• For the moment, we provide two mainstream versions LP2NORMAL (v. 1.14) as reported in [JN10] and a new prototype LP2NORMAL2 (v. 2.27, v. 2.10 [BGJ14], v. 2.1 [BJ13]) based on merger and sorting circuits.
• Benchmark instances (168 MB) for rewriting optimization statements along with callscripts [BGJ16].
• Benchmark instances (12.1 MB) for the normalization of weight rules [BGJ14].
• Benchmark instances for which normalized programs are faster than native ones when solved with clasp (v. 2.1.3) [BJ13]. The respective ASP encoding is available under the second ASP Competition (ASPCOMP-2) files.

Simple Example

The tool is compatible with an extended smodels-format (with a support for input atoms) and can be used as part of command lines such as:

$ gringo file.lp | lp2normal | igen | clasp 0

See the --help option of lp2normal for a wide variety of options controlling the result of normalization. The intermediate filter IGEN (v. 1.7) expresses input atoms using a choice rules (for backward compatibility and is not needed with latest versions of clasp).

Related Publications

J. Bomanson, M. Gebser, and T. Janhunen. Rewriting Optimization Statements in Answer-Set Programs. In Technical Commmunications of ICLP'16, OASIcs, to appear, 2016.

J. Bomanson, M. Gebser, and T. Janhunen. Improving the Normalization of Weight Rules in Answer Set Programs. In the Proceedings of JELIA'14, 166—180. Springer LNCS 8761.

J. Bomanson and T. Janhunen. Normalizing Cardinality Rules using Merging and Sorting Constructions. In the Proceedings of LPNMR'13, 187—199. Springer LNCS 8148.

T. Janhunen and I. Niemelä. Compact Translations of Non-Disjunctive Answer Set Programs to Propositional Clauses. In Gelfond Festschrift, 2010, 111—130. Springer LNCS 6565.