diff -N TrackAnalysis.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ TrackAnalysis.java	20 Aug 2009 17:22:04 -0000	1.1
@@ -0,0 +1,87 @@

+/*
+ * TrackAnalysis.java
+ *
+ * Created on October 16, 2008, 6:09 PM
+ *
+ */
+
+package org.lcsim.contrib.sATLAS;
+
+import org.lcsim.contrib.mgraham.sATLASDigi.*;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Set;
+
+import org.lcsim.event.MCParticle;
+import org.lcsim.event.RelationalTable;
+import org.lcsim.event.Track;
+import org.lcsim.event.TrackerHit;
+
+/**
+ *
+ * @author Richard Partridge
+ */
+public class TrackAnalysis {
+    private enum HelixPar {Curvature, Phi0, DCA, Z0, Slope};
+    private MCParticle _mcp = null;
+    private int _nhits;
+    private int _nbadhits;
+    private double _purity;
+    
+    /** Creates a new instance of TrackAnalysis */
+    public TrackAnalysis(Track trk, RelationalTable hittomc) {
+        
+        //  Get the number of hits on the track
+        _nhits = trk.getTrackerHits().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()) {
+    
+            //  get the set of MCParticles associated with this hit and update the hit count for each MCParticle
+            Set<MCParticle> mclist = hittomc.allFrom(hit);
+            for (MCParticle mcp : mclist) {
+                Integer mchits = 0;
+                if (mcmap.containsKey(mcp)) mchits = mcmap.get(mcp);
+                mchits++;
+                mcmap.put(mcp,  mchits);
+            }
+        }
+        
+        //  Find the MCParticle that has the most hits on the track
+        
+        int nbest = 0;
+        MCParticle mcbest = null;
+        for (MCParticle mcp : mcmap.keySet()) {
+            int count = mcmap.get(mcp);
+            if (count > nbest) {
+                nbest = count;
+                mcbest = mcp;
+            }
+        }
+        
+        if (nbest > 0) _mcp = mcbest;
+        _purity = (double) nbest / (double) _nhits;
+        _nbadhits = _nhits - nbest;
+        
+    }
+    
+    public MCParticle getMCParticle() {
+        return _mcp;
+    }
+    
+    public int getNHits() {
+        return _nhits;
+    }
+    
+    public int getNBadHits() {
+        return _nbadhits;
+    }
+    
+    public double getPurity() {
+        return _purity;
+    }
+    
+}