diff options
Diffstat (limited to 'extractor/target_phrase_extractor.cc')
| -rw-r--r-- | extractor/target_phrase_extractor.cc | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/extractor/target_phrase_extractor.cc b/extractor/target_phrase_extractor.cc index 9f8bc6e2..2b8a2e4a 100644 --- a/extractor/target_phrase_extractor.cc +++ b/extractor/target_phrase_extractor.cc @@ -43,11 +43,13 @@ vector<pair<Phrase, PhraseAlignment> > TargetPhraseExtractor::ExtractPhrases( int target_x_low = target_phrase_low, target_x_high = target_phrase_high; if (!require_tight_phrases) { + // Extend loose target phrase to the left. while (target_x_low > 0 && target_phrase_high - target_x_low < max_rule_span && target_low[target_x_low - 1] == -1) { --target_x_low; } + // Extend loose target phrase to the right. while (target_x_high < target_sent_len && target_x_high - target_phrase_low < max_rule_span && target_low[target_x_high] == -1) { @@ -59,10 +61,12 @@ vector<pair<Phrase, PhraseAlignment> > TargetPhraseExtractor::ExtractPhrases( for (size_t i = 0; i < gaps.size(); ++i) { gaps[i] = target_gaps[target_gap_order[i]]; if (!require_tight_phrases) { + // Extend gap to the left. while (gaps[i].first > target_x_low && target_low[gaps[i].first - 1] == -1) { --gaps[i].first; } + // Extend gap to the right. while (gaps[i].second < target_x_high && target_low[gaps[i].second] == -1) { ++gaps[i].second; @@ -70,6 +74,9 @@ vector<pair<Phrase, PhraseAlignment> > TargetPhraseExtractor::ExtractPhrases( } } + // Compute the range in which each chunk may start or end. (Even indexes + // represent the range in which the chunk may start, odd indexes represent the + // range in which the chunk may end.) vector<pair<int, int> > ranges(2 * gaps.size() + 2); ranges.front() = make_pair(target_x_low, target_phrase_low); ranges.back() = make_pair(target_phrase_high, target_x_high); @@ -101,6 +108,7 @@ void TargetPhraseExtractor::GeneratePhrases( vector<int> symbols; unordered_map<int, int> target_indexes; + // Construct target phrase chunk by chunk. int target_sent_start = target_data_array->GetSentenceStart(sentence_id); for (size_t i = 0; i * 2 < subpatterns.size(); ++i) { for (size_t j = subpatterns[i * 2]; j < subpatterns[i * 2 + 1]; ++j) { @@ -115,6 +123,7 @@ void TargetPhraseExtractor::GeneratePhrases( } } + // Construct the alignment between the source and the target phrase. vector<pair<int, int> > links = alignment->GetLinks(sentence_id); vector<pair<int, int> > alignment; for (pair<int, int> link: links) { @@ -133,6 +142,7 @@ void TargetPhraseExtractor::GeneratePhrases( if (index > 0) { subpatterns[index] = max(subpatterns[index], subpatterns[index - 1]); } + // Choose every possible combination of [start, end) for the current chunk. while (subpatterns[index] <= ranges[index].second) { subpatterns[index + 1] = max(subpatterns[index], ranges[index + 1].first); while (subpatterns[index + 1] <= ranges[index + 1].second) { |