def open_string_alexander(crossings):
crossings_copy = pickle.loads(pickle.dumps(crossings))
loose = []
for c in crossings_copy:
for i in range(4):
if c.adjacent[i] is None:
loose.append(c.crossing_strands()[i])
connect_loose_strands(crossings_copy, loose[0], loose[1])
K = Link(crossings_copy)
K.simplify(mode='level')
return K.alexander_polynomial() if len(K) > 0 else 1
def open_string_evaluation(crossings, function, simplify='level'):
crossings_copy = pickle.loads(pickle.dumps(crossings))
loose = []
for c in crossings_copy:
for i in range(4):
if c.adjacent[i] is None:
loose.append(c.crossing_strands()[i])
connect_loose_strands(crossings_copy, loose[0], loose[1])
K = Link(crossings_copy)
if simplify:
K.simplify(mode=simplify)
if len(K) > 0:
return function(K)