def get_qhull(self, neg_points=[]):
""" From a Petrinet, gets it's representationas a Convex Hull
"""
# Create an empty Convex Hull
qhull = Qhull(neg_points=neg_points)
# La normal por defaul para cada facet
dim = len(self.transitions)
tmpl_normal = [0]*dim
# Each transition corresponds to one dimension
# transition.label -> dimension number
transitions = self.event_dictionary
# Each facet corresponds to one place
# place.id -> {normal->[arc.value], offset->marking}
facets_dict = {}
# Iteramos sobre los arcos
for arc in self.arcs:
# No debería haber arcos nulos
if not arc.value:
logger.error('We found a zero arc: %s',arc)
raise Exception('We found a zero arc: %s',arc)
# NOTE recordar que nuestra representación interna de HS es
# al revés que el paper (usamos <= 0 en lguar de >= 0)
if isinstance(arc.source,Transition):
# Si el arco sale de una transition el coeficiente es < 0
coef = -1*arc.value
transition = arc.source
place = arc.destination
else:
# Si el arco sale de un place el coeficiente es > 0
coef = arc.value
place = arc.source
transition = arc.destination
x = transitions.setdefault(transition.label,len(transitions))
facet = facets_dict.setdefault(place.id,{'normal':list(tmpl_normal),
'in_transitions':[],
'out_transitions':[],
'offset': -1*place.marking,
'id':place.id})
if coef < 0:
facet['in_transitions'].append(transition.label)
else:
facet['out_transitions'].append(transition.label)
if facet['normal'][x]:
logger.debug('Coeficient already loaded. Dummy place')
coef = 0
facet['normal'][x] = coef
facets = []
for pl_id, facet in facets_dict.items():
# Do not create the facet for dummy places
if not any(facet['normal']):
continue
# Values are always integer
hs = Halfspace(facet['normal'], facet['offset'], integer_vals=False)
logger.debug('Adding facet %s',hs)
facets.append(hs)
qhull.dim = dim
qhull.facets = facets
return qhull
def get_qhull(self, neg_points=[], allow_dummy=False):
""" From a Petrinet, gets it's representationas a Convex Hull
"""
# Create an empty Convex Hull
qhull = Qhull(neg_points=neg_points)
# Default normal for every facet
dim = len(self.transitions)
tmpl_normal = [0]*dim
# Each transition corresponds to one dimension
# transition.label -> dimension number
transitions = self.event_dictionary
# Each facet corresponds to one place
# place.id -> {normal->[arc.value], offset->marking}
facets_dict = {}
for arc in self.arcs:
# No arc should have zero weight
if not arc.value:
logger.error('We found a zero arc: %s',arc)
raise Exception('We found a zero arc: %s'%arc)
# NOTE internal representation for Half Spaces
# is A.x <= 0 instead of A.x >= 0
if isinstance(arc.source,Transition):
# If the arc starts in a transition, coefficient should be < 0
coef = -1*arc.value
transition = arc.source
place = arc.destination
else:
# If the arc starts in a place, coefficient should be > 0
coef = arc.value
place = arc.source
transition = arc.destination
x = transitions.setdefault(transition.label,len(transitions))
facet = facets_dict.setdefault(place.id,{'normal':list(tmpl_normal),
'in_transitions':[],
'in_loop': False,
'out_transitions':[],
'offset': -1*place.marking,
'id':place.id})
if coef < 0:
facet['in_transitions'].append(transition.label)
else:
facet['out_transitions'].append(transition.label)
# If coefficient for this facet has already been loaded,
# It means we are in a loop. And once we go loop, we never go back
if (facet['normal'][x] and allow_dummy) or facet['in_loop']:
logger.debug('Coeficient already loaded. Loop found for place %s and transition %s! Dummy place?'%(place,transition))
facet['in_loop'] = True
coef = 0
elif facet['normal'][x]:
raise Exception('Loop found in place %s and transition %s'%(place,transition))
else:
facet['normal'][x] = coef
facets = []
for pl_id, facet in facets_dict.items():
# Do not create the facet for dummy places
if not any(facet['normal']):
continue
# Values are always integer
hs = Halfspace(facet['normal'], facet['offset'], integer_vals=False)
logger.debug('Adding facet %s',hs)
facets.append(hs)
# Remove duplicate facets
facets = list(set(facets))
qhull.dim = dim
qhull.facets = facets
return qhull
