IMPORTANT: THIS VERSION OF POPPER IS ONLY AVAILABLE FOR ARCHIVAL PURPOSES. See https://github.com/logic-and-learning-lab/Popper for the actively maintained version.
An Inductive Logic Programming system that learns Prolog/Datalog programs from examples by learning constraints. See the paper 'Learning programs by learning from failures', on arXiv.
Currently the system relies on being run from the repository folder.
The python interface to clingo, an Answer Set Programming environment, is required.
Test if the python library was installed with clingo by trying to run import clingo in your python interpreter.
The pyswip python library is used as an interface to swi-prolog.
Check the requirements.txt file for version numbers of these libraries that are confirmed to work.
One option is to use the command line interface by invoking python popper.py:
usage: popper.py [-h] [--no-pruning] [--ground-constraints] [--timeout TIMEOUT] [--eval-timeout EVAL_TIMEOUT]
[-n MAX_LITERALS] [--debug]
EXAMPLES_FILE MODES_FILE BK_FILE
The EXAMPLES_FILE consists of ground facts representing the positive and negative examples, respectively wrapped in pos(FACT). and neg(FACT).
The MODES_FILE is for predicate declarations, as used in the ASP encoding. A mode declaration has the form modeh(PRED,ARITY) or modeb(PRED,ARITY), respectively for predicates that may occur in heads and bodies. The predicate direction(PRED,POSITION,DIRECTION) is used to indicate a Prolog 'mode' for a predicate, i.e.~for each argument position Position indicate whether it works as an input, DIRECTION=in, or as an output DIRECTION=out.
(Additional parameters for the ASP encoding can also be placed in this file.)
The BK_FILE should include the Prolog predicate definitions for the predicates declared to be allowed to occur as predicates in bodies, but not in heads in the MODES_FILE.
The examples folder contains multiple examples of the EXAMPLES_FILE, ASP MODES_FILE and Prolog BK_FILE.
The system can also be used as a library:
import popper.entry_point
program, context = popper.entry_point.run_experiment('modes.pl', 'bk.pl', 'exampes.pl', MAX_LITERALS, EVAL_TIMEOUT, GROUND_CONSTRAINTS, NO_PRUNING, TIMEOUT, DEBUG)
Take a look at the popper/entry_point.py and popper/input.py files to understand the different parameters.