improve checks for `don't-care`s
@@ -161,7 +161,7 @@ class TruthTableOracle(Oracle):
ones = [i for i, v in enumerate(bitmap) if v == '1']
if not ones:
return Expr(0)
- dcs = [i for i, v in enumerate(bitmap) if v == 'x']
+ dcs = [i for i, v in enumerate(bitmap) if v == '*' or v == '-' or v.lower() == 'x']
pis = get_prime_implicants(ones=ones, dcs=dcs)
cover = get_exact_covers(ones, pis)[-1]
clauses = []
