Resolve "Revisit demos (formerly called examples) and update them"

Closes #209 (closed)

src/processor/processor_tracker_feature.cpp

@@ -144,6 +144,9 @@ void ProcessorTrackerFeature::resetDerived()
 
 void ProcessorTrackerFeature::establishFactors()
 {
+    if (origin_ptr_ == last_ptr_)
+        return;
+
     TrackMatches matches_origin_last = track_matrix_.matches(origin_ptr_, last_ptr_);
 
     for (auto const & pair_trkid_pair : matches_origin_last)