2 files changed, 16 insertions, 15 deletions

diff --git a/extractor/backoff_sampler.cc b/extractor/backoff_sampler.cc
index 28b12909..891276c6 100644
--- a/extractor/backoff_sampler.cc
+++ b/extractor/backoff_sampler.cc
@@ -16,47 +16,47 @@ PhraseLocation BackoffSampler::Sample(
     const unordered_set<int>& blacklisted_sentence_ids) const {
   vector<int> samples;
   int low = GetRangeLow(location), high = GetRangeHigh(location);
-  int last_position = low - 1;
+  int last = low - 1;
   double step = max(1.0, (double) (high - low) / max_samples);
   for (double num_samples = 0, i = low;
        num_samples < max_samples && i < high;
        ++num_samples, i += step) {
-    int position = GetPosition(location, round(i));
+    int sample = round(i);
+    int position = GetPosition(location, sample);
     int sentence_id = source_data_array->GetSentenceId(position);
     bool found = false;
-    if (last_position >= position ||
+    if (last >= sample ||
         blacklisted_sentence_ids.count(sentence_id)) {
       for (double backoff_step = 1; backoff_step < step; ++backoff_step) {
         double j = i - backoff_step;
-        if (round(j) >= 0) {
-          position = GetPosition(location, round(j));
+        sample = round(j);
+        if (sample >= 0) {
+          position = GetPosition(location, sample);
           sentence_id = source_data_array->GetSentenceId(position);
-          if (position > last_position &&
-              !blacklisted_sentence_ids.count(sentence_id)) {
+          if (sample > last && !blacklisted_sentence_ids.count(sentence_id)) {
             found = true;
-            last_position = position;
             break;
           }
         }
 
         double k = i + backoff_step;
-        if (round(k) < high) {
-          position = GetPosition(location, round(k));
+        sample = round(k);
+        if (sample < high) {
+          position = GetPosition(location, sample);
           sentence_id = source_data_array->GetSentenceId(position);
           if (!blacklisted_sentence_ids.count(sentence_id)) {
             found = true;
-            last_position = position;
             break;
           }
         }
       }
     } else {
       found = true;
-      last_position = position;
     }
 
     if (found) {
-      AppendMatching(samples, position, location);
+      last = sample;
+      AppendMatching(samples, sample, location);
     }
   }
 
diff --git a/extractor/matchings_sampler.cc b/extractor/matchings_sampler.cc
index bb916e49..75a62366 100644
--- a/extractor/matchings_sampler.cc
+++ b/extractor/matchings_sampler.cc
@@ -30,8 +30,9 @@ int MatchingsSampler::GetPosition(const PhraseLocation& location,
 
 void MatchingsSampler::AppendMatching(vector<int>& samples, int index,
                                       const PhraseLocation& location) const {
-  copy(location.matchings->begin() + index,
-       location.matchings->begin() + index + location.num_subpatterns,
+  int start = index * location.num_subpatterns;
+  copy(location.matchings->begin() + start,
+       location.matchings->begin() + start + location.num_subpatterns,
        back_inserter(samples));
 }