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"""Learning problem in Ontolearn."""
import logging
import random
from typing import Set, Optional
from owlapy.render import DLSyntaxObjectRenderer
from ontolearn.abstracts import AbstractLearningProblem, EncodedLearningProblem, EncodedPosNegLPStandardKind, \
AbstractKnowledgeBase
from owlapy.owl_individual import OWLNamedIndividual
logger = logging.getLogger(__name__)
[docs]
class EncodedPosNegLPStandard(EncodedPosNegLPStandardKind):
"""Encoded learning problem standard.
Attributes:
kb_pos (set): Positive examples.
kb_neg (set): Negative examples.
kb_diff (set): kb_all - (kb_pos + kb_neg).
kb_all (set): All examples/ all individuals set.
"""
__slots__ = 'kb_pos', 'kb_neg', 'kb_diff', 'kb_all'
kb_pos: set
kb_neg: set
kb_diff: set
kb_all: set
def __init__(self, kb_pos, kb_neg, kb_diff, kb_all):
"""Create a new instance of EncodedPosNegLPStandard.
Args:
kb_pos (set): Positive examples.
kb_neg (set): Negative examples.
kb_diff (set): kb_all - (kb_pos + kb_neg).
kb_all (set): All examples/ all individuals set.
"""
self.kb_pos = kb_pos
self.kb_neg = kb_neg
self.kb_diff = kb_diff
self.kb_all = kb_all
[docs]
class PosNegLPStandard(AbstractLearningProblem):
"""Positive-Negative learning problem standard.
Attributes:
pos: Positive examples.
neg: Negative examples.
all: All examples.
"""
__slots__ = 'pos', 'neg', 'all'
def __init__(self,
pos: Set[OWLNamedIndividual],
neg: Set[OWLNamedIndividual],
all_instances: Optional[Set[OWLNamedIndividual]] = None):
"""
Determine the learning problem and initialize the search.
1) Convert the string representation of an individuals into the owlready2 representation.
2) Sample negative examples if necessary.
3) Initialize the root and search tree.
Args:
pos: Positive examples.
neg: Negative examples.
all_instances: All examples.
"""
assert isinstance(pos, set) and isinstance(neg, set)
self.pos = frozenset(pos)
self.neg = frozenset(neg)
if all_instances is None:
self.all = None
else:
self.all = frozenset(all_instances)
# def encode_kb(self, knowledge_base: 'KnowledgeBase') -> EncodedPosNegLPStandard:
# return knowledge_base.encode_learning_problem(self)
[docs]
def encode_kb(self, kb: 'AbstractKnowledgeBase') -> EncodedPosNegLPStandard:
"""
Provides the encoded learning problem (lp), i.e. the class containing the set of OWLNamedIndividuals
as follows:
kb_pos --> the positive examples set,
kb_neg --> the negative examples set,
kb_all --> all lp individuals / all individuals set,
kb_diff --> kb_all - (kb_pos + kb_neg).
Args:
kb (PosNegLPStandard): The knowledge base to encode the learning problem.
Return:
EncodedPosNegLPStandard: The encoded learning problem.
"""
if self.all is None:
kb_all = set(kb.individuals())
else:
kb_all = set(kb.individuals_set(self.all))
assert 0 < len(self.pos) < len(kb_all) and len(kb_all) > len(self.neg)
if logger.isEnabledFor(logging.INFO):
r = DLSyntaxObjectRenderer()
logger.info('E^+:[ {0} ]'.format(', '.join(map(r.render, self.pos))))
logger.info('E^-:[ {0} ]'.format(', '.join(map(r.render, self.neg))))
kb_pos = kb.individuals_set(self.pos)
if len(self.neg) == 0: # if negatives are not provided, randomly sample.
kb_neg = type(kb_all)(random.sample(list(kb_all), len(kb_pos)))
else:
kb_neg = kb.individuals_set(self.neg)
try:
assert len(kb_pos) == len(self.pos)
except AssertionError:
print(self.pos)
print(kb_pos)
print(kb_all)
print('Assertion error. Exiting.')
raise
if self.neg:
assert len(kb_neg) == len(self.neg)
return EncodedPosNegLPStandard(
kb_pos=kb_pos,
kb_neg=kb_neg,
kb_all=kb_all,
kb_diff=kb_all.difference(kb_pos.union(kb_neg)))
[docs]
class EncodedPosNegUndLP(EncodedLearningProblem):
"""To be implemented."""
...
# XXX: TODO
[docs]
class PosNegUndLP(AbstractLearningProblem):
"""To be implemented."""
...
# XXX: TODO