Package clingo

Module providing functions and classes to control the grounding and solving process.

Next follow some concepts used throughout the modules of the clingo package.

Terms

Terms without variables and interpreted functions are called symbols in the following. They are wrapped in the Symbol class.

Atoms And Literals

Atoms are also captured using the Symbol class. They must be of type SymbolType.Function. Some functions accept literals in form of pairs of symbols and Booleans. The Boolean stands for the sign of the literal (True for positive and False for negative).

Program Literals

Program literals are non-zero integers associated with symbolic atoms, theory atoms, and also without any association if they are used to translate complex language constructs. The sign of a program literal is used to represent default negation. Symbolic atoms can be mapped to program literals using the clingo.symbolic_atoms module, theory atoms using the clingo.theory_atoms module, and the clingo.backend can also be used to introduce fresh program literals.

Solver Literals

Furthermore, there are non-zero integer solver literals. There is a surjective mapping from program atoms to solver literals. The PropagateInit.solver_literal() function can be used to map program literals to solver literals.

Embedded Python Code

If the clingo application is build with Python support, clingo will also be able to execute Python code embedded in logic programs. Functions defined in a Python script block are callable during the instantiation process using @-syntax. The default grounding/solving process can be customized if a main function is provided.

Examples

The first example shows how to use the clingo module from Python.

>>> from clingo.symbol import Number
>>> from clingo.control import Control
>>>
>>> class Context:
...     def inc(self, x):
...         return Number(x.number + 1)
...     def seq(self, x, y):
...         return [x, y]
...
>>> def on_model(m):
...     print (m)
...
>>> ctl = Control()
>>> ctl.add("base", [], """\
... p(@inc(10)).
... q(@seq(1,2)).
... """)
>>> ctl.ground([("base", [])], context=Context())
>>> print(ctl.solve(on_model=on_model))
p(11) q(1) q(2)
SAT

The second example shows how to use Python code from clingo.

#script (python)

from clingo.symbol import Number

class Context:
    def inc(x):
        return Number(x.number)

    def seq(x, y):
        return [x, y]

def main(prg):
    prg.ground([("base", [])], context=Context())
    prg.solve()

#end.

p(@inc(10)).
q(@seq(1,2)).
Expand source code
'''
Module providing functions and classes to control the grounding and solving
process.

Next follow some concepts used throughout the modules of the clingo package.

Terms
-----
Terms without variables and interpreted functions are called symbols in the
following. They are wrapped in the `clingo.symbol.Symbol` class.

Atoms and Literals
------------------
Atoms are also captured using the `clingo.symbol.Symbol` class. They must be of
type `clingo.symbol.SymbolType.Function`. Some functions accept literals in
form of pairs of symbols and Booleans. The Boolean stands for the sign of the
literal (`True` for positive and `False` for negative).

Program Literals
----------------
*Program literals* are non-zero integers associated with symbolic atoms, theory
atoms, and also without any association if they are used to translate complex
language constructs. The sign of a program literal is used to represent default
negation. Symbolic atoms can be mapped to program literals using the
`clingo.symbolic_atoms` module, theory atoms using the `clingo.theory_atoms`
module, and the `clingo.backend` can also be used to introduce fresh program
literals.

Solver Literals
---------------
Furthermore, there are non-zero integer *solver literals*. There is a
surjective mapping from program atoms to solver literals. The
`clingo.propagator.PropagateInit.solver_literal` function can be used to map
program literals to solver literals.

Embedded Python Code
--------------------
If the clingo application is build with Python support, clingo will also be
able to execute Python code embedded in logic programs.  Functions defined in a
Python script block are callable during the instantiation process using
`@`-syntax.  The default grounding/solving process can be customized if a main
function is provided.

## Examples

The first example shows how to use the clingo module from Python.

    >>> from clingo.symbol import Number
    >>> from clingo.control import Control
    >>>
    >>> class Context:
    ...     def inc(self, x):
    ...         return Number(x.number + 1)
    ...     def seq(self, x, y):
    ...         return [x, y]
    ...
    >>> def on_model(m):
    ...     print (m)
    ...
    >>> ctl = Control()
    >>> ctl.add("base", [], """\\
    ... p(@inc(10)).
    ... q(@seq(1,2)).
    ... """)
    >>> ctl.ground([("base", [])], context=Context())
    >>> print(ctl.solve(on_model=on_model))
    p(11) q(1) q(2)
    SAT

The second example shows how to use Python code from clingo.

    #script (python)

    from clingo.symbol import Number

    class Context:
        def inc(x):
            return Number(x.number)

        def seq(x, y):
            return [x, y]

    def main(prg):
        prg.ground([("base", [])], context=Context())
        prg.solve()

    #end.

    p(@inc(10)).
    q(@seq(1,2)).
'''

from .core import *
from .symbol import *
from .symbolic_atoms import *
from .theory_atoms import *
from .solving import *
from .propagator import *
from .backend import *
from .configuration import *
from .statistics import *
from .control import *
from .application import *

__version__ = '.'.join(map(str, version()))

Sub-modules

clingo.application

Functions and classes to implement applications based on clingo …

clingo.ast

Module to work with clingo's non-ground program representation …

clingo.backend

Functions and classes to observe or add ground statements …

clingo.configuration

Functions and classes related to configuration …

clingo.control

This module contains the Control class responsible for controling grounding and solving …

clingo.core

Core functionality used throught the clingo package.

clingo.propagator

Functions and classes to implement custom propagators …

clingo.script

This module contains functions to add custom scripts, which can be embedded into logic programs …

clingo.solving

Functions and classes related to solving …

clingo.statistics

Functions and classes related to statistics …

clingo.symbol

Functions and classes for symbol manipulation …

clingo.symbolic_atoms

Functions and classes to work with symbolic atoms …

clingo.theory

This module defines the Theory class for using a [CFFI] based module with clingo's Python package …

clingo.theory_atoms

Functions and classes to work with theory atoms …

clingo.util

Utility functions and classes.