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248 | class ProbLogCompiler(Compiler):
default_suffix: ClassVar[str] = "problog"
_predicate_mappings: Optional[Dict[str, str]] = None
def compile(self, theory: Theory, syntax: Optional[Union[str, ModelSyntax]] = None, **kwargs) -> str:
"""
Compile a Theory object into ProbLog code.
Example:
>>> from typedlogic import SentenceGroup, PredicateDefinition, Forall, Variable, Theory
>>> x = Variable('x')
>>> y = Variable('y')
>>> z = Variable('z')
>>> theory = Theory(
... predicate_definitions=[PredicateDefinition(predicate="AncestorOf", arguments={'ancestor': 'str', 'descendant': 'str'})],
... ground_terms=[Term('AncestorOf', 'p1', 'p1a'), Term('AncestorOf', 'p1a', 'p1aa')],
... )
>>> theory.add(Forall([x, y, z], (Term('AncestorOf', x, y) & Term('AncestorOf', y, z)) >> Term('AncestorOf', x, z)))
>>> theory.add(Probability(0.5, That(Term('AncestorOf', 'p1', 'p1a'))))
>>> theory.add(Probability(0.5, That(Term('AncestorOf', 'p1a', 'p1aa'))))
>>> compiler = ProbLogCompiler()
>>> print(compiler.compile(theory))
ancestorof(X, Z) :- ancestorof(X, Y), ancestorof(Y, Z).
0.5::ancestorof("p1", "p1a").
0.5::ancestorof("p1a", "p1aa").
ancestorof("p1", "p1a").
ancestorof("p1a", "p1aa").
query(ancestorof(Ancestor, Descendant)).
Note like most compilers, you don't need to use this directly. It is more common to use ProblogSolver, which takes care of
compiling the problog program, feeding it to problog, and parsing results.
:param theory:
:param syntax:
:param kwargs:
:return:
"""
include_queries = kwargs.get("include_queries", True)
prolog_config = self.prolog_config()
if not self._predicate_mappings:
self._predicate_mappings = {}
for pd in theory.predicate_definitions:
prolog_pd = as_prolog(Term(pd.predicate), config=prolog_config)
if "(" in prolog_pd:
prolog_pd = prolog_pd[: prolog_pd.index("(")]
self._predicate_mappings[prolog_pd] = pd.predicate
clauses = []
clauses.extend(self.false_predicate_declarations(theory, prolog_config))
for sentence in theory.sentences + theory.ground_terms:
clause = self._sentence_to_problog(sentence, prolog_config)
if clause:
clauses.append(clause)
if include_queries:
for pd in theory.predicate_definitions:
if pd.predicate in [Probability.__name__, That.__name__, Evidence.__name__]:
continue
query_vars = [Variable(a) for a in pd.arguments.keys()]
term = Term("query", Term(pd.predicate, *query_vars))
clause = self._sentence_to_problog(term, prolog_config)
clauses.append(clause)
return "\n".join(clauses)
@staticmethod
def prolog_config() -> PrologConfig:
"""Return Prolog rendering configuration for ProbLog syntax."""
return PrologConfig(
disjunctive_datalog=True,
double_quote_strings=True,
operator_map={"eq": "=", "ne": r"\="},
allow_nesting=False,
allow_ungrounded_vars_in_head=True,
)
@staticmethod
def false_predicate_declarations(theory: Theory, prolog_config: PrologConfig) -> List[str]:
"""Return false clauses for declared predicates that may otherwise be empty."""
declarations = []
seen: set[tuple[str, int]] = set()
for predicate_definition in theory.predicate_definitions:
if predicate_definition.predicate in [Probability.__name__, That.__name__, Evidence.__name__]:
continue
predicate = as_prolog(Term(predicate_definition.predicate), config=prolog_config)
if "(" in predicate:
predicate = predicate[: predicate.index("(")]
arity = len(predicate_definition.arguments)
key = (predicate, arity)
if key in seen:
continue
seen.add(key)
if arity == 0:
declarations.append(f"{predicate} :- fail.")
continue
args = ", ".join("_" for _ in range(arity))
declarations.append(f"{predicate}({args}) :- fail.")
return declarations
def _sentence_to_problog(self, sentence: Sentence, prolog_config: PrologConfig) -> str:
if isinstance(sentence, Forall):
if isinstance(sentence.sentence, Term):
if sentence.sentence.predicate == "eq":
vals = sentence.sentence.values
if len(vals) != 2:
raise ValueError(f"Invalid equality sentence: {sentence}")
first = vals[0]
if isinstance(first, Term) and first.predicate == "probability":
inner_expr = first.values[0]
pr = vals[1]
return self._sentence_to_problog(
Term(Probability.__name__, pr, That(inner_expr).to_model_object()), prolog_config
)
def _to_rules(s: Sentence) -> List[Sentence]:
rules = []
try:
for rule in to_horn_rules(s, allow_disjunctions_in_head=False, allow_goal_clauses=True):
rewritten_rule = self._comparison_head_to_constraint(rule)
if rewritten_rule is None:
continue
rules.append(rewritten_rule)
except NotInProfileError as e:
logger.info(f"Skipping sentence {s} due to {e}")
return rules
pr_sent = self._sentence_probability(sentence)
if pr_sent:
pr, inner = pr_sent
inner_rules = _to_rules(inner)
strs = []
for r in inner_rules:
rendered = self._rule_to_problog(r, prolog_config)
if rendered:
strs.append(f"{pr}::{rendered}")
return "\n".join(strs)
elif isinstance(sentence, Term) and sentence.predicate == Evidence.__name__:
# special treatment for evidence sentences
if len(sentence.values) != 2:
raise ValueError(f"Invalid evidence sentence: {sentence}")
inner = sentence.values[0]
inner_prolog = as_prolog(inner, config=prolog_config, strict=True)
if not inner_prolog:
raise ValueError(f"Invalid evidence inner sentence: {inner}")
truth_value = sentence.values[1]
return f"evidence({inner_prolog}, {'true' if truth_value else 'false'})."
else:
rules = _to_rules(sentence)
return "\n".join([rendered for r in rules if (rendered := self._rule_to_problog(r, prolog_config))])
def _sentence_probability(self, sentence: Sentence) -> Optional[Tuple[Union[float, int], Sentence]]:
if isinstance(sentence, Forall):
return self._sentence_probability(sentence.sentence)
if isinstance(sentence, Term):
if sentence.predicate == PROBABILITY_PREDICATE:
if len(sentence.values) != 2:
raise ValueError(f"Invalid probability sentence: {sentence}")
pr = sentence.values[0]
inner = sentence.values[1]
if not isinstance(pr, (float, int)):
raise ValueError(f"Invalid probability: {pr}")
if not isinstance(inner, Sentence):
raise ValueError(f"Invalid inner sentence: {inner}")
if isinstance(inner, Extension):
inner = inner.to_model_object()
if not isinstance(inner, Term):
raise ValueError(f"Invalid inner term: {inner}")
if inner.predicate != THAT_PREDICATE:
raise ValueError(f"Invalid inner predicate: {inner.predicate}")
inner_ref = inner.values[0]
if not isinstance(inner_ref, Sentence):
raise ValueError(f"Invalid inner reference: {inner_ref}")
return pr, inner_ref
return None
@staticmethod
def _comparison_head_to_constraint(rule: Sentence) -> Optional[Sentence]:
"""Convert implication heads like ``X != Y`` into ProbLog constraints."""
if not isinstance(rule, Implies):
return rule
head = rule.consequent
if not isinstance(head, Term) or head.predicate not in NAME_TO_INFIX_OP:
return rule
negated_predicate = NEGATED_COMPARISON_PREDICATES.get(head.predicate)
if not negated_predicate:
logger.info(f"Skipping rule with built-in predicate in head: {rule}")
return None
negated_comparison = Term(negated_predicate, *head.values)
return Implies(And(rule.antecedent, negated_comparison), Or())
@staticmethod
def _rule_to_problog(rule: Sentence, prolog_config: PrologConfig) -> str:
"""Render one rule, encoding goal clauses as ProbLog evidence."""
if isinstance(rule, Implies) and isinstance(rule.consequent, Or) and not rule.consequent.operands:
violation = Implies(rule.antecedent, Term(CONSTRAINT_VIOLATION_PREDICATE))
return (
f"{as_prolog(violation, config=prolog_config, strict=False)}\n"
f"evidence({CONSTRAINT_VIOLATION_PREDICATE}, false)."
)
return as_prolog(rule, config=prolog_config, strict=False)
def decompile_term(self, compiled_term: Any) -> Term:
if isinstance(compiled_term, pl.Term):
pms = self._predicate_mappings or {}
functor = pms.get(compiled_term.functor, compiled_term.functor)
def _decompile_const(a: Any) -> Any:
if isinstance(a, pl.Constant):
v = a.value
if isinstance(v, str):
if v.startswith('"') and v.endswith('"'):
v = v[1:-1]
return v
return str(a)
vals = [_decompile_const(a) for a in compiled_term.args]
plt_term = Term(functor, *vals)
return plt_term
raise ValueError(f"Expected a Prolog term, got {compiled_term}")
|