Changeset 174

Timestamp:

Sep 29, 2004, 2:54:38 PM (19 years ago)

Author:

Jari Häkkinen

Message:

Added checks on perfect match rows, i.e. avoid zero (distance) division.

Location:

trunk/src

Files:

• WeNNI.cc (modified) (1 diff)
• kNNI.cc (modified) (1 diff)

trunk/src/WeNNI.cc

@@ -37 +37 @@
         double norm=0.0;
         for (vector<u_int>::const_iterator k=knn.begin(); k!=knn.end(); k++) {
-          new_value+=1.0*data_(distance[*k].first,j)/(distance[*k].second);
-          norm+=1.0/(distance[*k].second);
+          // Jari, a small number needed here, use something standardized.
+          // Avoid division with zero (perfect match vectors)
+          double d=(distance[*k].second ? distance[*k].second : 1e-10);
+          new_value+=1.0*data_(distance[*k].first,j)/d;
+          norm+=1.0/d;
         }
         // No impute if no contributions from neighbours.

trunk/src/kNNI.cc

@@ -44 +44 @@
           double norm=0.0;
           for (vector<u_int>::const_iterator k=knn.begin(); k!=knn.end(); k++) {
-            new_value+=data_(distance[*k].first,j)/(distance[*k].second);
-            norm+=1.0/(distance[*k].second);
+            // Jari, a small number needed here, use something standardized.
+            // Avoid division with zero (perfect match vectors)
+            double d=(distance[*k].second ? distance[*k].second : 1e-10);
+            new_value+=data_(distance[*k].first,j)/d;
+            norm+=1.0/d;
           }
           // No impute if no contributions from neighbours.