def createInputAlteringSIDTrans(n, sigmaSet):
"""Create an input-altering SID transducer based
:param int n: max number of errors
:param set sigmaSet: alphabet
:return: a transducer representing the SID channel
:rtype: SFT"""
new = SFT()
new.setSigma(sigmaSet)
new.setOutput(sigmaSet)
init = new.stateIndex((0, None), True)
new.addInitial(init)
for sy in new.Sigma:
new.addTransition(init, sy, sy, init)
i = 1
while i <= n:
d1 = new.stateIndex((i, None), True)
new.addFinal(d1)
for s in new.Sigma:
new.addTransition(d1, s, s, d1)
d = new.stateIndex((i, s), True)
new.addFinal(d)
if i == 1:
new.addTransition(init, s, Epsilon, d)
for s1 in new.Sigma - {s}:
new.addTransition(init, s, s1, d1)
else:
bar = new.stateIndex((i - 1, None))
new.addTransition(bar, s, Epsilon, d1)
new.addTransition(bar, Epsilon, s, d1)
for s1 in new.Sigma:
foo = new.stateIndex((i - 1, s))
new.addTransition(foo, s1, Epsilon, d)
if s1 != s:
new.addTransition(bar, s, s1, d1)
new.addTransition(foo, Epsilon, s1, d1)
for s2 in new.Sigma:
new.addTransition(foo, s2, s1, d1)
for s1 in new.Sigma - {s}:
new.addTransition(d, s1, s1, d1)
i += 1
return new
def notSatisfiesW(self, aut):
"""Test whether the language is a code.
:param DFA|NFA aut: the automaton
:return: two different factorizations of the same word
:rtype: tuple of list"""
def _findFactors(w, m):
l = []
i1 = 0
while True:
j = m.find('1', i1)
if j < 0:
break
l.append(w[i1:j + 1])
i1 = j + 1
return l
n = aut.toNFA() # .eliminateEpsilonTransitions()
for i in n.Initial:
if i in n.Final:
return [Epsilon], [Epsilon, Epsilon]
t = SFT()
t.States = copy.deepcopy(n.States)
t.setInitial(n.Initial)
t.setFinal(n.Initial)
t.setSigma(n.Sigma)
t.setOutput(['1', '0'])
for si in n.delta:
for sym in n.delta[si]:
for so in n.delta[si][sym]:
if so not in n.Final:
t.addTransition(si, sym, '0', so)
else:
t.addTransition(si, sym, '0', so)
for ss in t.Initial:
t.addTransition(si, sym, '1', ss)
t.trim()
foo = t.nonFunctionalW()
if foo == (None, None, None):
return None, None
else:
return _findFactors(foo[0], foo[1]), _findFactors(foo[0], foo[2])
