- # Method that finds all maximally expanded non-redundant matches shared
- # between two sequences inside a given search space.
- def matches_find(q_seq, s_seq, q_min, s_min, q_max, s_max, kmer)
- matches = []
- redundant = Hash.new { |h, k| h[k] = [] }
-
- s_index = index_seq(s_seq, s_min, s_max, kmer)
-
- q_pos = q_min
-
- while q_pos <= q_max - kmer + 1
- q_oligo = q_seq[q_pos ... q_pos + kmer]
-
- s_index[q_oligo].each do |s_pos|
- match = Match.new(q_pos, s_pos, kmer)
-
- unless match_redundant?(redundant, match)
- match_expand(match, q_seq, s_seq, q_min, s_min, q_max, s_max)
- matches << match
-
- match_redundant_add(redundant, match)
- end
- end
-
- q_pos += 1
- end
-
- matches
- end
-
- # Method that indexes a sequence within a given interval such that the
- # index contains all oligos of a given kmer size and the positions where
- # this oligo was located.
- def index_seq(seq, min, max, kmer)
- index_hash = Hash.new { |h, k| h[k] = [] }
-
- pos = min
-
- while pos <= max - kmer + 1
- oligo = seq[pos ... pos + kmer]
- index_hash[oligo] << pos
-
- pos += 1
- end
-
- index_hash
- end
-
- # Method to check if a match is redundant.
- def match_redundant?(redundant, match)
- redundant[match.q_beg].each do |s_interval|
- if s_interval.include? match.s_beg and s_interval.include? match.s_end
- return true
- end
- end
-
- false
- end
-
- # Method that adds a match to the redundancy index.
- def match_redundant_add(redundant, match)
- (match.q_beg .. match.q_end).each do |q|
- redundant[q] << (match.s_beg .. match.s_end)
- end
- end
-
- # Method that expands a match as far as possible to the left and right.
- def match_expand(match, q_seq, s_seq, q_min, s_min, q_max, s_max)
- match_expand_left(match, q_seq, s_seq, q_min, s_min)
- match_expand_right(match, q_seq, s_seq, q_max, s_max)
-
- match
- end
-
- # Method that expands a match as far as possible to the left.
- def match_expand_left(match, q_seq, s_seq, q_min, s_min)
- while match.q_beg > q_min and
- match.s_beg > s_min and
- q_seq[match.q_beg - 1] == s_seq[match.s_beg - 1]
- match.q_beg -= 1
- match.s_beg -= 1
- match.length += 1
- end
-
- match
- end
-
- # Method that expands a match as far as possible to the right.
- def match_expand_right(match, q_seq, s_seq, q_max, s_max)
- while match.q_end < q_max and
- match.s_end < s_max and
- q_seq[match.q_end + 1] == s_seq[match.s_end + 1]
- match.length += 1
- end
-
- match
- end
-