java/trunk/tracking/src/main/java/org/hps/recon/tracking

--- java/trunk/tracking/src/main/java/org/hps/recon/tracking/HitCollectionUtilites.java	                        (rev 0)
+++ java/trunk/tracking/src/main/java/org/hps/recon/tracking/HitCollectionUtilites.java	2014-07-22 17:21:25 UTC (rev 817)
@@ -0,0 +1,71 @@

+package org.hps.recon.tracking;
+
+import java.util.ArrayList;
+import java.util.List;
+import org.lcsim.fit.helicaltrack.HelicalTrackHit;
+
+/**
+ * Some methods which manipulate hit collection in various ways
+ * --right now, uses HelicalTrackHits everywhere since I plan to
+ * use it for tracking...probably can use TrackerHits to make
+ * it more general
+ * @author mgraham  -- data created 7/9/2014
+ */
+public class HitCollectionUtilites {
+    /* return a list of hits sorted by there distance from the beam (in y) */
+
+    public static List<HelicalTrackHit> SortHitsByDistanceFromBeam(List<HelicalTrackHit> hits) {
+        List<HelicalTrackHit> sortedHits = new ArrayList<>();
+        while (!hits.isEmpty()) {
+            double minPosition = 999;
+            HelicalTrackHit minHit = null;
+            for (HelicalTrackHit hit : hits)
+                if (Math.abs(hit.getCorrectedPosition().y()) < minPosition) {
+                    minHit = hit;
+                    minPosition = hit.getCorrectedPosition().y();
+                }
+            if (minHit != null) {
+                sortedHits.add(minHit);
+                hits.remove(minHit);
+            }
+        }
+        return sortedHits;
+    }
+
+    /*
+     *  split the hit collection into top and bottom hit collections    
+     */
+    public static List<List<HelicalTrackHit>> SplitTopBottomHits(List<HelicalTrackHit> hits) {
+        List<List<HelicalTrackHit>> splitLists = new ArrayList<>();
+        List<HelicalTrackHit> topHits = new ArrayList<>();
+        List<HelicalTrackHit> bottomHits = new ArrayList<>();
+        for (HelicalTrackHit hit : hits)
+            if (hit.getPosition()[1] > 0)
+                topHits.add(hit);
+            else
+                bottomHits.add(hit);
+        splitLists.add(topHits);
+        splitLists.add(bottomHits);
+        
+        return splitLists;
+    }
+
+    /*
+     *  get the hits from a certain layer    
+     */
+    public static List<HelicalTrackHit> GetHitsFromLayer(List<HelicalTrackHit> hits, int nlayer) {
+        List<HelicalTrackHit> hitList = new ArrayList<>();
+        for (HelicalTrackHit hit : hits)           
+            if (hit.Layer() == nlayer)
+                hitList.add(hit);
+        return hitList;
+    }
+    
+     /*
+     *  get the hits from a certain layer sorted by distance from beamline  
+     */
+    public static List<HelicalTrackHit> GetSortedHits(List<HelicalTrackHit> hits, int nlayer) {
+       return SortHitsByDistanceFromBeam(GetHitsFromLayer(hits,nlayer));
+    }
+    
+}