class Stats:
def __init__(self, matrix):
self.mx = matrix
self.N = 0
self.classes = {}
self.terms = SuperList()
for c in self.mx.classes:
self.classes[c] = {}
self.classes[c]['terms'] = self.mx.classes[c]
self.classes[c]['total'] = sum(self.classes[c]['terms'])
self.terms.add(self.classes[c]['terms'])
self.N += self.classes[c]['total']
self.mi_terms = []
def __str__(self):
s = 'Matrix Stats:'
s += '\n * Vocabulary/Terms: %d/%d' % (len(self.terms), self.N)
return s
def getN(self):
''' Get total number of terms, counting their frequencies too.
Notice: This is not the same as len(vocabulary)
'''
return self.N
def get_terms_freq(self, normalized=False):
''' Returns 2d matrix of vocabulary terms and their occurences
if normalized is True, devide by total number of terms
'''
terms = self.mx.terms
freq = self.terms.div(self.N) if normalized else self.terms
return [terms, freq]
def pr_term(self, t):
' Get probability of term t '
i = self.mx[t]
if i == -1:
return 0
return float(self.terms[i]) / self.N
def pr_class(self, c):
' Get probability of class c '
return float(self.classes[c]['total']) / self.N
def pr_joint(self, t, c):
'Get joint probability between term t and class c'
i = self.mx[t]
if i == -1:
return 0
return float(self.classes[c]['terms'][i]) / self.N
def mi(self):
for t in self.mx.vocabulary():
mi = 0
for c in self.classes:
try:
mi += self.pr_joint(t,c) * math.log10( self.pr_joint(t,c) / ( self.pr_term(t) * self.pr_class(c) ))
except:
# Oh, log(0), let's set mi = 0
mi = 0
self.mi_terms.append(mi)
print self.classes
print self.mi_terms
