def getValue(self, variable):
"""Defuzzyfication using center of gravity method."""
sum_1, sum_2 = 0., 0.
for adjective in variable.adjectives.values():
# get precomputed adjective set
set = adjective.set
if not isinstance(set, fuzzy.set.Singleton.Singleton):
raise DefuzzificationException(
"Only Singleton for COGS defuzzification allowed.")
a = (self.INF or self._INF)(set(set.x), adjective.getMembership())
sum_1 += set.x * a
sum_2 += a
try:
if sum_2 == 0.:
raise DefuzzificationException(
"No result, all singletons set to 0.")
return sum_1 / sum_2
except:
# was not to calculate
if self.failsafe is not None:
# user gave us a value to return
return self.failsafe
else:
# forward exception
raise
def getValue(self, variable):
"""Defuzzyfication."""
try:
temp = self.accumulate(variable)
# get polygon representation
table = list(self.value_table(temp))
if len(table) == 0:
raise DefuzzificationException(
"no value calculable: complete undefined set")
y = table[0][1]
x = float('-inf') # left end of polygon is always -infinity
for (x_, y_) in table[1:]:
if y_ > y:
y = y_
x = x_
return x
except:
# was not to calculate
if self.failsafe is not None:
# user gave us a value to return
return self.failsafe
else:
raise