def norris(context):
# To be more efficient we store intent (as Python set) of every
# object to the list
# TODO: Move to Context class?
examples = []
for ex in context.examples():
examples.append(ex)
cs = [Concept([], context.attributes)]
for i in range(len(context)):
# TODO:
cs_for_loop = cs[:]
for c in cs_for_loop:
if c.intent.issubset(examples[i]):
c.extent.add(context.objects[i])
else:
new_intent = c.intent & examples[i]
new = True
for j in range(i):
if new_intent.issubset(examples[j]) and\
context.objects[j] not in c.extent:
new = False
break
if new:
cs.append(Concept(set([context.objects[i]]) | c.extent,
new_intent))
cs = ConceptSystem(cs)
return (cs, cs.compute_covering_relation())
def closeByOne(context):
alg = CbO(context)
extent = context.down([])
intent = context.up(extent)
concept = Concept(extent, intent)
alg.generate_from(concept, 0)
return alg.result
def upperNeighbors(self, concept):
A = concept.extent
M = set(self._objectsIterator()) - A
neighbors = set()
for x in list(M):
B1 = self.up(A | {x})
A1 = self.down(B1)
if (M & ((A1 - A) - {x})) == set():
neighbors.add(Concept(A1, B1))
else:
M = M - {x}
return neighbors
def lowerNeighbors(self, concept):
B = concept.intent
M = set(self._attributesIterator()) - B
neighbors = set()
for x in list(M):
A1 = self.down(B | {x})
B1 = self.up(A1)
increased = ((B1 - B) - {x})
if (M & increased) == set():
neighbors.add(Concept(A1, B1))
else:
M = M - {x}
return neighbors
def generate_from(self, concept, y):
self.result.append(concept)
A = set(concept.extent)
B = set(concept.intent)
n = self.context.width - 1
if B == set(range(n + 1)) or y > n:
return
for j in range(y, n + 1):
if not (j in B):
Yj = set(range(j))
C = A & self.context.down({j})
D = self.context.up(C)
if B & Yj == D & Yj:
self.generate_from(Concept(C, D), j + 1)
def getSearchConceptByObjects(self, context, objects):
sConcept = Concept()
sConcept.intent = context.up(objects)
sConcept.extent = context.down(sConcept.intent)
return sConcept
def _getSearchConceptByAttr(self, context, attributes):
sConcept = Concept()
sConcept.extent = context.down(attributes)
sConcept.intent = context.up(sConcept.extent)
return sConcept
def getSearchConceptByObjects(self, context, objects): sConcept = Concept() sConcept.intent = context.up(objects) sConcept.extent = context.down(sConcept.intent) return sConcept
def _getSearchConceptByAttr(self, context, attributes): sConcept = Concept() sConcept.extent = context.down(attributes) sConcept.intent = context.up(sConcept.extent) return sConcept
