diff -u -r1.3 -r1.4
--- AnalysisUtils.java	16 Sep 2008 01:03:10 -0000	1.3
+++ AnalysisUtils.java	28 Oct 2008 23:48:40 -0000	1.4
@@ -3,8 +3,6 @@

  *
  * Created on August 4, 2008, 11:00 AM
  *

- * To change this template, choose Tools | Template Manager
- * and open the template in the editor.

  */
 
 package org.lcsim.recon.tracking.seedtracker.analysis;

@@ -25,12 +23,13 @@

 import org.lcsim.event.MCParticle;
 import org.lcsim.event.RawTrackerHit;
 import org.lcsim.event.SimTrackerHit;

+import org.lcsim.event.TrackerHit;

 import org.lcsim.fit.helicaltrack.HelicalTrackHit;
 
 
 /**
  * This class contains utilities useful for seedtracker performance studies

- * @authors Richard Partridge,Pelham Keahey

+ * @authors Richard Partridge, Pelham Keahey

  * @version 1.0
  */
 public class AnalysisUtils {

@@ -38,6 +37,7 @@

     private static EventHeader currentEvent=null;
     //trkmap returned in the FindTrackMap method
     private static Map<MCParticle,Track> trkmap;

+

     /** Creates a new instance of AnalysisUtils */
     public AnalysisUtils() {
     }

@@ -92,52 +92,42 @@

         //  Done looping over all MCParticle candidates - return the list with any matches that were found
         return mcplist;
     }

+    

     /**
      * Finds the purity of the given track
      * @param trk find purity of this track
      * @return a double purity
      */
     public static double FindTrackPurity(Track trk){

-        double purity=0.;
-        //MCParticle and Int map, int will be the number of times this mcparticle shows up in the track
-        Map<MCParticle,Integer> occurrences = new HashMap<MCParticle,Integer>();
-        double mostoccured;
-        int index;
-        //creates a seedcandiate for the track
-        if (trk instanceof SeedTrack) {
-            SeedTrack strk = (SeedTrack) trk;
-            for (HelicalTrackHit h : strk.getSeedCandidate().getHits()){
-                //Create List of MCParticles in the SeedCandidate
-                List<MCParticle> mcpl = h.getMCParticles();
-                //loop through these mcparticles and count how many times that particle occurs
-                for(MCParticle part : mcpl){
-                    if(occurrences.containsKey(part)){
-                        index = occurrences.get(part);
-                        occurrences.put(part,index+1);
-                    } else {
-                        occurrences.put(part, 1);
-                    }
-                }
-                
-            }
-            //If only one MCParticle exsists in the map, then purity if perfect
-            if(occurrences.size()==1){
-                purity =1;
-            }
-            //otherwise save the value of the most occuring mcparticle against the total size of the track's hitlist
-            else{
-                mostoccured = -1;
-                for(MCParticle p : occurrences.keySet()){
-                    int occured = occurrences.get(p);
-                    if(occured>mostoccured){
-                        mostoccured = occured;
-                    }
-                }
-                purity = mostoccured / strk.getSeedCandidate().getHits().size();

+        
+        //  Create a map containing the number of hits for each MCParticle associated with the track
+        Map<MCParticle,Integer> mcmap = new HashMap<MCParticle,Integer>();
+        
+        //  Loop over the hits on the track and make sure we have HelicalTrackHits (which contain the MC particle)
+        for (TrackerHit hit : trk.getTrackerHits()) {
+            if (!(hit instanceof HelicalTrackHit)) throw new RuntimeException("AnalysisUtils found track with non-HelicalTrackHits");
+
+            //  Loop over the MCParticles for this hit and update their hit count
+            for (MCParticle mcp : ((HelicalTrackHit) hit).getMCParticles()) {
+                Integer mchits = 0;
+                if (mcmap.containsKey(mcp)) mchits = mcmap.get(mcp);
+                mcmap.put(mcp,  mchits++);

             }
         }

+        
+        //  Find the maximum purity among the MCParticles that contribute to the track
+        double nhits = trk.getTrackerHits().size();
+        double purity = 0;
+        for (Map.Entry entry : mcmap.entrySet()) {
+            int count = (Integer) entry.getValue();
+            purity = Math.max(purity, (double) count / (double) nhits);
+        }
+

         return purity;
     }

+
+    
+

     /**
      * @param event
      * @return a map of MCParticles and Integers.  The int is either 1 or 0, 1 being track found 0, track not found