def optimal_t(self, seq_p, seq_ch, pattern_multiplicity=None, ignore_gaps=False):
seq_pair, multiplicity = self.compress_sequence_pair(seq_p, seq_ch,<EOL>pattern_multiplicity = pattern_multiplicity,<EOL>ignore_gaps=ignore_gaps)<EOL>return self.optimal_t_compressed(seq_pair, multiplicity)<EOL>
Find the optimal distance between the two sequences

Parameters
----------

 seq_p : character array
    Parent sequence

 seq_c : character array
    Child sequence

 pattern_multiplicity : numpy array
    If sequences are reduced by combining identical alignment patterns,
    these multplicities need to be accounted for when counting the number
    of mutations across a branch. If None, all pattern are assumed to
    occur exactly once.

 ignore_gaps : bool
    If True, ignore gaps in distance calculations