diff -N ConeMIPReassignmentAlgorithm.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ ConeMIPReassignmentAlgorithm.java	15 Aug 2008 17:40:01 -0000	1.1
@@ -0,0 +1,80 @@

+package org.lcsim.contrib.uiowa;
+
+import java.util.*; 
+import org.lcsim.util.*;
+import org.lcsim.event.util.*;
+import org.lcsim.event.*;
+import hep.physics.vec.*;
+
+/**
+ * A class to calculate the cone angle for a track and a cluster.
+ * The apex of the cone is based on the showering point of the
+ * track, adjusted by an offset distance along the tangent of
+ * the track at its showering point. We then calculate the angle
+ * between the tangent and the vector from the apex to the cluster.
+ *
+ * @version $Id: ConeMIPReassignmentAlgorithm.java,v 1.1 2008/08/15 17:40:01 mcharles Exp $
+ */
+
+public class ConeMIPReassignmentAlgorithm implements ReassignClustersAlgorithm {
+
+    protected MIPGeometryHandler m_geom;
+    protected double m_distanceToGoBack = 0.0;
+    protected double m_limit = 0.0;
+
+    /** 
+     * Constructor.
+     *
+     * @param geomHandler       Helper class to calculate showering point and tangent of tracks.
+     * @param distanceToGoBack  Offset distance from showering point to cone apex.
+     * @param limit             If cone angle is bigger than this, the calculation will return null.
+     */
+    public ConeMIPReassignmentAlgorithm(MIPGeometryHandler geomHandler, double distanceToGoBack, double limit) {
+	m_geom = geomHandler;
+	m_distanceToGoBack = distanceToGoBack;
+	m_limit = limit;
+    }
+
+    /** Calculate cone angle. Returns null if angle is undefined or too large. */
+    public Double computeFigureOfMerit(Track tr, Cluster clus) {
+
+	// Check for case where track is a placeholder MultipleTrackTrack
+	if (tr.getTracks().size()!=0) {
+	    Double bestAmongDaughters = null;
+	    for (Track daughterTrack : tr.getTracks()) {
+		Double daughterFigureOfMerit = this.computeFigureOfMerit(daughterTrack, clus);
+		if (daughterFigureOfMerit != null) {
+		    if (daughterFigureOfMerit < m_limit) {
+			if (bestAmongDaughters==null || daughterFigureOfMerit<bestAmongDaughters) {
+			    bestAmongDaughters = daughterFigureOfMerit;
+			}
+		    }
+		}
+	    }
+	    return bestAmongDaughters;
+	}
+
+	Hep3Vector showerPoint = m_geom.getShowerPoint(tr);
+	Hep3Vector tangentUnit = m_geom.getTangentUnit(tr);
+	Hep3Vector clusterPosition = new BasicHep3Vector(clus.getPosition());
+
+	if (showerPoint == null || tangentUnit == null) {
+	    // Extrapolation failed
+	    return null;
+	} else {
+	    Hep3Vector coneOffset = VecOp.mult(m_distanceToGoBack, tangentUnit);
+	    Hep3Vector coneStartPoint = VecOp.sub(showerPoint, coneOffset);
+	    Hep3Vector displacement = VecOp.sub(clusterPosition, coneStartPoint);
+	    Hep3Vector displacementUnit = VecOp.unit(displacement);
+	    double cosTheta = VecOp.dot(tangentUnit, displacementUnit);
+	    double angle = Math.acos(cosTheta);
+	    if (angle < m_limit) {
+		return new Double(angle);
+	    } else {
+		// Outside cone
+		return null;
+	    }
+	}
+    }
+
+}