def SipStrategy(query,
sipCollection,
factGraph,
derivedPreds,
bindings={},
processedRules=None,
network=None,
debug=False,
buildProof=False,
memoizeMemory=None,
proofLevel=1):
"""
Accordingly, we define a sip-strategy for computing the answers to a query
expressed using a set of Datalog rules, and a set of sips, one for each
adornment of a rule head, as follows...
Each evaluation uses memoization (via Python decorators) but also relies on well-formed
rewrites for using semi-naive bottom up method over large SPARQL data.
"""
memoizeMemory = memoizeMemory and memoizeMemory or {}
queryLiteral = BuildUnitermFromTuple(query)
processedRules = processedRules and processedRules or set()
if bindings:
#There are bindings. Apply them to the terms in the query
queryLiteral.ground(bindings)
if debug:
print("%sSolving" % ('\t' * proofLevel), queryLiteral, bindings)
# Only consider ground triple pattern isomorphism with matching bindings
goalRDFStatement = queryLiteral.toRDFTuple()
if queryLiteral in memoizeMemory:
if debug:
print("%sReturning previously calculated results for " % \
('\t' * proofLevel), queryLiteral)
for answers in memoizeMemory[queryLiteral]:
yield answers
elif AlphaNode(goalRDFStatement).alphaNetworkHash(
True,
skolemTerms=list(bindings.values())) in \
[AlphaNode(r.toRDFTuple()).alphaNetworkHash(True,
skolemTerms=list(bindings.values()))
for r in processedRules
if AdornLiteral(goalRDFStatement).adornment == \
r.adornment]:
if debug:
print("%s Goal already processed..." % \
('\t' * proofLevel))
else:
isGround = literalIsGround(queryLiteral)
if buildProof:
ns = NodeSet(goalRDFStatement, network=network, identifier=BNode())
else:
ns = None
# adornedProgram = factGraph.adornedProgram
queryPred = GetOp(queryLiteral)
if sipCollection is None:
rules = []
else:
#For every rule head matching the query, we invoke the rule,
#thus determining an adornment, and selecting a sip to follow
rules = sipCollection.headToRule.get(queryPred, set())
if None in sipCollection.headToRule:
#If there are second order rules, we add them
#since they are a 'wildcard'
rules.update(sipCollection.headToRule[None])
#maintained list of rules that haven't been processed before and
#match the query
validRules = []
#each subquery contains values for the bound arguments that are passed
#through the sip arcs entering the node corresponding to that literal. For
#each subquery generated, there is a set of answers.
answers = []
# variableMapping = {}
#Some TBox queries can be 'joined' together into SPARQL queries against
#'base' predicates via an RDF dataset
#These atomic concept inclusion axioms can be evaluated together
#using a disjunctive operator at the body of a horn clause
#where each item is a query of the form uniPredicate(?X):
#Or( uniPredicate1(?X1), uniPredicate2(?X), uniPredicate3(?X), ..)
#In this way massive, conjunctive joins can be 'mediated'
#between the stated facts and the top-down solver
@parameterizedPredicate([i for i in derivedPreds])
def IsAtomicInclusionAxiomRHS(rule, dPreds):
"""
This is an atomic inclusion axiom with
a variable (or bound) RHS: uniPred(?ENTITY)
"""
bodyList = list(iterCondition(rule.formula.body))
body = first(bodyList)
return GetOp(body) not in dPreds and \
len(bodyList) == 1 and \
body.op == RDF.type
atomicInclusionAxioms = list(filter(IsAtomicInclusionAxiomRHS, rules))
if atomicInclusionAxioms and len(atomicInclusionAxioms) > 1:
if debug:
print("\tCombining atomic inclusion axioms: ")
pprint(atomicInclusionAxioms, sys.stderr)
if buildProof:
factStep = InferenceStep(ns, source='some RDF graph')
ns.steps.append(factStep)
axioms = [rule.formula.body for rule in atomicInclusionAxioms]
#attempt to exaustively apply any available substitutions
#and determine if query if fully ground
vars = [
v for v in GetArgs(queryLiteral, secondOrder=True)
if isinstance(v, Variable)
]
openVars, axioms, _bindings = \
normalizeBindingsAndQuery(vars,
bindings,
axioms)
if openVars:
# mappings = {}
#See if we need to do any variable mappings from the query literals
#to the literals in the applicable rules
query, rt = EDBQuery(axioms, factGraph, openVars,
_bindings).evaluate(
debug, symmAtomicInclusion=True)
if buildProof:
factStep.groundQuery = subquery
for ans in rt:
if buildProof:
factStep.bindings.update(ans)
memoizeMemory.setdefault(queryLiteral, set()).add(
(prepMemiozedAns(ans), ns))
yield ans, ns
else:
#All the relevant derivations have been explored and the result
#is a ground query we can directly execute against the facts
if buildProof:
factStep.bindings.update(bindings)
query, rt = EDBQuery(axioms, factGraph, _bindings).evaluate(
debug, symmAtomicInclusion=True)
if buildProof:
factStep.groundQuery = subquery
memoizeMemory.setdefault(queryLiteral, set()).add(
(prepMemiozedAns(rt), ns))
yield rt, ns
rules = filter(lambda i: not IsAtomicInclusionAxiomRHS(i), rules)
for rule in rules:
#An exception is the special predicate ph; it is treated as a base
#predicate and the tuples in it are those supplied for qb by unification.
headBindings = getBindingsFromLiteral(goalRDFStatement,
rule.formula.head)
# comboBindings = dict([(k, v) for k, v in itertools.chain(
# bindings.items(),
# headBindings.items())])
varMap = rule.formula.head.getVarMapping(queryLiteral)
if headBindings and\
[term for term in rule.formula.head.getDistinguishedVariables(True)
if varMap.get(term, term) not in headBindings]:
continue
# subQueryAnswers = []
# dontStop = True
# projectedBindings = comboBindings.copy()
if debug:
print("%sProcessing rule" % \
('\t' * proofLevel), rule.formula)
if debug and sipCollection:
print("Sideways Information Passing (sip) graph for %s: " %
queryLiteral)
print(sipCollection.serialize(format='n3'))
for sip in SIPRepresentation(sipCollection):
print(sip)
try:
# Invoke the rule
if buildProof:
step = InferenceStep(ns, rule.formula)
else:
step = None
for rt, step in\
invokeRule([headBindings],
iter(iterCondition(rule.formula.body)),
rule.sip,
(proofLevel + 1,
memoizeMemory,
sipCollection,
factGraph,
derivedPreds,
processedRules.union([
AdornLiteral(query)])),
step=step,
debug=debug):
if rt:
if isinstance(rt, dict):
#We received a mapping and must rewrite it via
#correlation between the variables in the rule head
#and the variables in the original query (after applying
#bindings)
varMap = rule.formula.head.getVarMapping(
queryLiteral)
if varMap:
rt = MakeImmutableDict(
refactorMapping(varMap, rt))
if buildProof:
step.bindings = rt
else:
if buildProof:
step.bindings = headBindings
validRules.append(rule)
if buildProof:
ns.steps.append(step)
if isGround:
yield True, ns
else:
memoizeMemory.setdefault(queryLiteral, set()).add(
(prepMemiozedAns(rt), ns))
yield rt, ns
except RuleFailure:
# Clean up failed antecedents
if buildProof:
if ns in step.antecedents:
step.antecedents.remove(ns)
if not validRules:
#No rules matching, query factGraph for answers
successful = False
if buildProof:
factStep = InferenceStep(ns, source='some RDF graph')
ns.steps.append(factStep)
if not isGround:
subquery, rt = EDBQuery([queryLiteral], factGraph, [
v for v in GetArgs(queryLiteral, secondOrder=True)
if isinstance(v, Variable)
], bindings).evaluate(debug)
if buildProof:
factStep.groundQuery = subquery
for ans in rt:
successful = True
if buildProof:
factStep.bindings.update(ans)
memoizeMemory.setdefault(queryLiteral, set()).add(
(prepMemiozedAns(ans), ns))
yield ans, ns
if not successful and queryPred not in derivedPreds:
#Open query didn't return any results and the predicate
#is ostensibly marked as derived predicate, so we have failed
memoizeMemory.setdefault(queryLiteral, set()).add(
(False, ns))
yield False, ns
else:
#All the relevant derivations have been explored and the result
#is a ground query we can directly execute against the facts
if buildProof:
factStep.bindings.update(bindings)
subquery, rt = EDBQuery([queryLiteral], factGraph,
bindings).evaluate(debug)
if buildProof:
factStep.groundQuery = subquery
memoizeMemory.setdefault(queryLiteral, set()).add(
(prepMemiozedAns(rt), ns))
yield rt, ns
def sparql_query(self,
queryString,
queryObj,
graph,
dataSetBase,
extensionFunctions,
initBindings={},
initNs={},
DEBUG=False):
"""
The default 'native' SPARQL implementation is based on sparql-p's expansion trees
layered on top of the read-only RDF APIs of the underlying store
"""
from rdflib.sparql.Algebra import TopEvaluate
from rdflib.QueryResult import QueryResult
from rdflib import plugin
from rdflib.sparql.bison.Query import AskQuery
_expr = self.isaBaseQuery(None, queryObj)
if isinstance(queryObj.query, AskQuery) and \
_expr.name == 'BGP':
# isinstance(_expr, BasicGraphPattern):
#This is a ground, BGP, involving IDB and can be solved directly
#using top-down decision procedure
#First separate out conjunct into EDB and IDB predicates
#(solving the former first)
from FuXi.SPARQL import EDBQuery
groundConjunct = []
derivedConjunct = []
for s, p, o, func in _expr.patterns:
if self.derivedPredicateFromTriple((s, p, o)) is None:
groundConjunct.append(BuildUnitermFromTuple((s, p, o)))
else:
derivedConjunct.append(BuildUnitermFromTuple((s, p, o)))
if groundConjunct:
baseEDBQuery = EDBQuery(groundConjunct, self.edb)
subQuery, ans = baseEDBQuery.evaluate(DEBUG)
assert isinstance(ans, bool), ans
if groundConjunct and not ans:
askResult = False
else:
askResult = True
for derivedLiteral in derivedConjunct:
goal = derivedLiteral.toRDFTuple()
#Solve ground, derived goal directly
SetupDDLAndAdornProgram(
self.edb,
self.idb, [goal],
derivedPreds=self.derivedPredicates,
ignoreUnboundDPreds=True,
hybridPreds2Replace=self.hybridPredicates)
if self.hybridPredicates:
lit = BuildUnitermFromTuple(goal)
op = GetOp(lit)
if op in self.hybridPredicates:
lit.setOperator(URIRef(op + u'_derived'))
goal = lit.toRDFTuple()
sipCollection = PrepareSipCollection(
self.edb.adornedProgram)
if self.DEBUG and sipCollection:
for sip in SIPRepresentation(sipCollection):
print(sip)
pprint(list(self.edb.adornedProgram))
elif self.DEBUG:
print("No SIP graph.")
rt, node = first(
self.invokeDecisionProcedure(goal, self.edb, {},
self.DEBUG,
sipCollection))
if not rt:
askResult = False
break
return plugin.get('SPARQLQueryResult', QueryResult)(askResult)
else:
rt = TopEvaluate(queryObj,
graph,
initBindings,
DEBUG=self.DEBUG,
dataSetBase=dataSetBase,
extensionFunctions=extensionFunctions)
return plugin.get('SPARQLQueryResult', QueryResult)(rt)
def MagicSetTransformation(factGraph,
rules,
GOALS,
derivedPreds=None,
strictCheck=DDL_STRICTNESS_FALLBACK_DERIVED,
noMagic=None,
defaultPredicates=None):
"""
Takes a goal and a ruleset and returns an iterator
over the rulest that corresponds to the magic set
transformation:
"""
noMagic = noMagic and noMagic or []
magicPredicates = set()
# replacement = {}
adornedProgram = SetupDDLAndAdornProgram(
factGraph,
rules,
GOALS,
derivedPreds=derivedPreds,
strictCheck=strictCheck,
defaultPredicates=defaultPredicates)
newRules = []
for rule in adornedProgram:
if rule.isSecondOrder():
import warnings
warnings.warn("Second order rule no supported by GMS: %s" % rule,
RuntimeWarning)
magicPositions = {}
#Generate magic rules
for idx, pred in enumerate(iterCondition(rule.formula.body)):
# magicBody = []
if isinstance(pred,
AdornedUniTerm): # and pred not in magicPredicates:
# For each rule r in Pad, and for each occurrence of an adorned
# predicate p a in its body, we generate a magic rule defining magic_p a
prevPreds = [
item for _idx, item in enumerate(rule.formula.body)
if _idx < idx
]
if 'b' not in pred.adornment:
import warnings
warnings.warn(
"adorned predicate w/out any bound arguments (%s in %s)"
% (pred, rule.formula), RuntimeWarning)
if GetOp(pred) not in noMagic:
magicPred = pred.makeMagicPred()
magicPositions[idx] = (magicPred, pred)
inArcs = [(N, x) for (
N,
x) in IncomingSIPArcs(rule.sip, getOccurrenceId(pred))
if not set(x).difference(GetArgs(pred))]
if len(inArcs) > 1:
# If there are several arcs entering qi, we define the
# magic rule defining magic_qi in two steps. First,
# for each arc Nj --> qi with label cj , we define a
# rule with head label_qi_j(cj ). The body of the rule
# is the same as the body of the magic rule in the
# case where there is a single arc entering qi
# (described above). Then the magic rule is defined as
# follows. The head is magic_q(0). The body contains
# label_qi_j(cj) for all j (that is, for all arcs
# entering qi ).
#
# We combine all incoming arcs into a single list of
# (body) conditions for the magic set
PrettyPrintRule(rule)
SIPRepresentation(rule.sip)
print(pred, magicPred)
_body = []
additionalRules = []
for idxSip, (N, x) in enumerate(inArcs):
newPred = pred.clone()
SetOp(newPred,
URIRef('%s_label_%s' % (newPred.op, idxSip)))
ruleBody = And(
buildMagicBody(N, prevPreds, rule.formula.head,
derivedPreds))
additionalRules.append(
Rule(Clause(ruleBody, newPred)))
_body.extend(newPred)
# _body.extend(ruleBody)
additionalRules.append(
Rule(Clause(And(_body), magicPred)))
newRules.extend(additionalRules)
for i in additionalRules:
print(i)
raise NotImplementedError()
else:
for idxSip, (N, x) in enumerate(inArcs):
ruleBody = And(
buildMagicBody(N, prevPreds, rule.formula.head,
derivedPreds, noMagic))
newRule = Rule(Clause(ruleBody, magicPred))
newRules.append(newRule)
magicPredicates.add(magicPred)
# Modify rules
# we modify the original rule by inserting
# occurrences of the magic predicates corresponding
# to the derived predicates of the body and to the head
# If there are no bound arguments in the head, we don't modify the rule
idxIncrement = 0
newRule = copy.deepcopy(rule)
for idx, (magicPred, origPred) in list(magicPositions.items()):
newRule.formula.body.formulae.insert(idx + idxIncrement, magicPred)
idxIncrement += 1
if 'b' in rule.formula.head.adornment and GetOp(
rule.formula.head) not in noMagic:
headMagicPred = rule.formula.head.makeMagicPred()
if isinstance(newRule.formula.body, Uniterm):
newRule.formula.body = And(
[headMagicPred, newRule.formula.body])
else:
newRule.formula.body.formulae.insert(0, headMagicPred)
newRules.append(newRule)
if not newRules:
newRules.extend(AdditionalRules(factGraph))
for rule in newRules:
if rule.formula.body:
yield rule
def conjunctiveSipStrategy(self, goalsRemaining, factGraph, bindings=None):
"""
Given a conjunctive set of triples, invoke sip-strategy passing
on intermediate solutions to facilitate 'join' behavior
"""
bindings = bindings if bindings else {}
try:
tp = next(goalsRemaining)
assert isinstance(bindings, dict)
dPred = self.derivedPredicateFromTriple(tp)
if dPred is None:
baseEDBQuery = EDBQuery([BuildUnitermFromTuple(tp)],
self.edb,
bindings=bindings)
if self.DEBUG:
print("Evaluating TP against EDB:%s" %
baseEDBQuery.asSPARQL())
query, rt = baseEDBQuery.evaluate()
# _vars = baseEDBQuery.returnVars
for item in rt:
bindings.update(item)
for ansDict in self.conjunctiveSipStrategy(
goalsRemaining, factGraph, bindings):
yield ansDict
else:
queryLit = BuildUnitermFromTuple(tp)
currentOp = GetOp(queryLit)
queryLit.setOperator(currentOp)
query = EDBQuery([queryLit], self.edb, bindings=bindings)
if bindings:
tp = first(query.formulae).toRDFTuple()
if self.DEBUG:
print("Goal/Query: ", query.asSPARQL())
SetupDDLAndAdornProgram(
self.edb,
self.idb, [tp],
derivedPreds=self.derivedPredicates,
ignoreUnboundDPreds=True,
hybridPreds2Replace=self.hybridPredicates)
if self.hybridPredicates:
lit = BuildUnitermFromTuple(tp)
op = GetOp(lit)
if op in self.hybridPredicates:
lit.setOperator(URIRef(op + u'_derived'))
tp = lit.toRDFTuple()
sipCollection = PrepareSipCollection(self.edb.adornedProgram)
if self.DEBUG and sipCollection:
for sip in SIPRepresentation(sipCollection):
print(sip)
pprint(list(self.edb.adornedProgram), sys.stderr)
elif self.DEBUG:
print("No SIP graph.")
for nextAnswer, ns in self.invokeDecisionProcedure(
tp, factGraph, bindings, self.DEBUG, sipCollection):
nonGroundGoal = isinstance(nextAnswer, dict)
if nonGroundGoal or nextAnswer:
#Either we recieved bindings from top-down evaluation
#or we (successfully) proved a ground query
if not nonGroundGoal:
#Attempt to prove a ground query, return the response
rt = nextAnswer
else:
#Recieved solutions to 'open' query, merge with given bindings
#and continue
rt = mergeMappings1To2(bindings, nextAnswer)
#either answers were provided (the goal wasn't grounded) or
#the goal was ground and successfully proved
for ansDict in self.conjunctiveSipStrategy(
goalsRemaining, factGraph, rt):
yield ansDict
except StopIteration:
yield bindings