diff -u -r1.2 -r1.3
--- ExtendTrack.java	9 May 2012 11:52:05 -0000	1.2
+++ ExtendTrack.java	11 May 2012 13:07:44 -0000	1.3
@@ -1,129 +1,227 @@

 package org.lcsim.hps.users.omoreno;
 

+//--- hep ---//

 import hep.physics.vec.BasicHep3Vector;
 import hep.physics.vec.Hep3Vector;
 

+//--- org.lcsim ---//

 import org.lcsim.recon.tracking.seedtracker.SeedTrack;
 
 /**
  * 
  * @author Omar Moreno <[log in to unmask]>

- * @version $Id: ExtendTrack.java,v 1.2 2012/05/09 11:52:05 omoreno Exp $

+ * @version $Id: ExtendTrack.java,v 1.3 2012/05/11 13:07:44 omoreno Exp $

  */
 
 public class ExtendTrack {
 	
 	

-	public static final double ECAL_POSITION = 1470; // mm
-	public static final double DIPOLE_EDGE = 914.4; // mm

+	public static final double ECAL_FACE = 1450;  // mm
+	public static final double DIPOLE_EDGE = 914; // mm
+	
+	
+	SeedTrack track;
+	double[] trackParameters;
+	
+	boolean debug = true;

 	
 	/**
 	 * 
 	 */

-	public ExtendTrack(){ 

+	public ExtendTrack(){
+		track = null;

 	}

-

+	

 	/**
 	 * 
 	 */

-	public static double arcLengthToYPlane(SeedTrack track, double y){

+	public void setTrack(SeedTrack track){
+		this.track = track;
+		trackParameters = new double[9];
+		this.setTrackParameters(track);
+	}
+	
+	/**
+	 * 
+	 */
+	public void setTrackParameters(SeedTrack track){

-		// Get the track parameters
-		double doca = track.getTrackParameter(0);   
-		double phi0 = track.getTrackParameter(1);
-		double R    = 1/track.getTrackParameter(2);

+		// All track parameters are in LCSim coordinates system
+		trackParameters[0] = track.getTrackParameter(0);				// DOCA
+		trackParameters[1] = track.getTrackParameter(1);				// phi0
+		trackParameters[2] = 1/track.getTrackParameter(2);				// R
+		trackParameters[3] = -this.getDoca()*Math.sin(this.getPhi0());	// x0
+		trackParameters[4] = this.getDoca()*Math.cos(this.getPhi0());	// y0
+		trackParameters[5] = track.getTrackParameter(3);				// z0
+		trackParameters[6] = track.getTrackParameter(4);				// tan(Lambda)
+		trackParameters[7] = (this.getR() - this.getPhi0())*Math.sin(this.getPhi0());	// xc
+		trackParameters[8] = -(this.getR() - this.getPhi0())*Math.cos(this.getPhi0());	// yc
+	}
+	
+	/**
+	 * 
+	 */
+	public double getDoca(){
+		return trackParameters[0];
+	}
+	
+	/**
+	 * 
+	 */
+	public double getPhi0(){
+		return trackParameters[1];
+	}
+	
+	/**
+	 * 
+	 */
+	public double getR(){
+		return trackParameters[2];
+	}
+	
+	/**
+	 * 
+	 */
+	public double getX0(){
+		return trackParameters[3];
+	}
+	
+	/**
+	 * 
+	 */
+	public double getY0(){
+		return trackParameters[4];
+	}
+	/**
+	 * 
+	 */
+	public double getZ0(){
+		return trackParameters[5];
+	}
+	
+	/**
+	 * 
+	 */
+	public double getTanLambda(){
+		return trackParameters[6];
+	}
+	
+	/**
+	 * 
+	 */
+	public double getXC(){
+		return trackParameters[7];
+	}
+	
+	/**
+	 * 
+	 */
+	public double getYC(){
+		return trackParameters[8];
+	}
+	
+	/**
+	 * 
+	 */
+	public void printTrackParameters(){
+		System.out.println(" DOCA: " + this.getDoca() + 
+						   " phi0: " + this.getPhi0() + 
+						   " R: " 	 + this.getR()    +
+						   " x0: " 	 + this.getX0()   +
+						   " y0: "   + this.getY0()   + 
+						   " z0: " 	 + this.getZ0()   + 
+						   " tan(Lambda): " + this.getTanLambda() + 
+						   " xc: "   + this.getXC()   + 
+						   " yc: "   + this.getYC() );

-		// Get the coordinates of the distance of closest approach
-		double x0 = -doca*Math.sin(phi0);
-		double y0 = doca*Math.cos(phi0);

+	}

-		// Get the coordinates of the helix center
-		double xc = (R - doca)*Math.sin(phi0);
-		double yc = -(R - doca)*Math.cos(phi0);

+	/**
+	 * 
+	 */
+	public double getXOnHelixProjection(double y){

-		System.out.println("x0: " + x0 + " y0: " + y0);
-		System.out.println("Phi0: " + track.getTrackParameter(1));
-		System.out.println("xc: " + xc + " yc: " + yc);

+		// Check if a track has been set
+		if(track == null) throw new RuntimeException("Track has not been set!");

-		// Find the x-coor dinate 
-		double x = xc + Math.signum(R)*Math.sqrt(R*R - Math.pow(y-yc, 2));

+		// Find the x position
+		return this.getXC() 
+				+ Math.signum(this.getR())*Math.sqrt(this.getR()*this.getR() - Math.pow(y-this.getYC(), 2));
+	}
+	
+	/**
+	 * 
+	 */
+	public double getYOnHelixProjection(double x){

-		System.out.println("X Position: " + x);

+		// Check if a track has been set
+		if(track == null) throw new RuntimeException("Track has not been set!");
+		
+		return this.getYC() 
+				+ Math.signum(this.getR())*Math.sqrt(this.getR()*this.getR() - Math.pow(x-this.getXC(), 2));

-		return arcLength(R, x0, y0, x, y, xc, yc);

 	}

-	

+

 	/**
 	 * 
 	 */

-	public static double arcLength(double R,  double x1, double y1, double x2, double y2,
-								   double xc, double yc){

+	public double arcLength(double x, double y){

-        //  Find the angle between these points measured wrt the circle center
-        double phi1 = Math.atan2(y1 - yc, x1 - xc);
-		System.out.println("Phi 1: " + phi1);

+        double phi0 = Math.atan2(this.getY0() - this.getYC(), this.getX0() - this.getXC());
+        double phi = Math.atan2(y - this.getYC(), x - this.getXC());
+        double dphi = phi - phi0;        

-        double phi2 = Math.atan2(y2 - yc, x2 - xc);
-        System.out.println("Phi 2: " + phi2);
-        double dphi = phi2 - phi1;
-        
-        //  Make sure dphi is in the valid range (-pi, pi)

         if (dphi >  Math.PI) dphi -= 2. * Math.PI;
         if (dphi < -Math.PI) dphi += 2. * Math.PI;
         

-        System.out.println("phi: " + dphi);
-        
-        //  Return the arc length
-        return -R * dphi;

+        return -this.getR()*dphi;

 	}
 
 	/**
 	 * 
 	 */

-	public static Hep3Vector positionOnHelix(SeedTrack track, double s){

+	public Hep3Vector positionAtEcal(){

-		// Get the track parameters
-		double doca = track.getTrackParameter(0);   
-		double phi0 = track.getTrackParameter(1);
-		double R    = 1/track.getTrackParameter(2);
-		double z0 = track.getTrackParameter(3);
-		double tanLambda = track.getTrackParameter(4);

+		// Check if a track has been set
+		if(track == null) throw new RuntimeException("Track has not been set!");

-		// Find the azimuthal angle at this position
-		double phi = phi0 - s/R;
-		
-		// Get the coordinates of the helix center
-		double xc = (R - doca)*Math.sin(phi0);
-		double yc = -(R - doca)*Math.cos(phi0);
-		
-		// Find the position on the helix
-		double x = xc - R*Math.sin(phi);
-		double y = yc - R*Math.cos(phi);
-		double z = z0 + s*tanLambda;
-	
-		return new BasicHep3Vector(x, y, z);

+		return this.extrapolateTrack(ECAL_FACE);

 	}
 	
 	/**
 	 * 
 	 */

-	public static Hep3Vector positionAtEcal(SeedTrack track){
-		
-		double arcLengthDPEdge = arcLengthToYPlane(track, DIPOLE_EDGE);
-		Hep3Vector position = positionOnHelix(track, arcLengthDPEdge);
-		
-		// Get the track parameters
-		double phi0 = track.getTrackParameter(1);
-		double R    = 1/track.getTrackParameter(2);
-		double tanTheta = 1/track.getTrackParameter(4);

+	public Hep3Vector extrapolateTrack(double x){

-		// Find the azimuthal angle at this position
-		double phi = phi0 - arcLengthDPEdge/R;
-		
-		double xEcal = position.x() + (ECAL_POSITION - DIPOLE_EDGE)/Math.tan(phi);
-		double zEcal = position.z() + (ECAL_POSITION - DIPOLE_EDGE)/tanTheta;
-		
-		return new BasicHep3Vector(xEcal, ECAL_POSITION, zEcal);

+		if(x > DIPOLE_EDGE){
+
+			double yDipole = this.getYOnHelixProjection(DIPOLE_EDGE);
+			double s = this.arcLength(DIPOLE_EDGE, yDipole);
+			double zDipole = this.getZ0() + s*this.getTanLambda();
+			double phi = this.getPhi0() - s/this.getR();
+			
+			double dx = x - DIPOLE_EDGE;
+			double r = dx/(Math.cos(phi)*(1/Math.sqrt(1 + Math.pow(this.getTanLambda(), 2))));
+			double dy = r*Math.sin(phi)*(1/Math.sqrt(1 + Math.pow(this.getTanLambda(), 2)));
+			double dz = r*(this.getTanLambda()/Math.sqrt(1 + Math.pow(this.getTanLambda(), 2)));
+			
+			double y = yDipole + dy;
+			double z = zDipole + dz;
+			
+			return new BasicHep3Vector(x, y, z);
+		} else if(x < 0){ 
+			double dx = x - this.getX0();
+			double r = dx/(Math.cos(this.getPhi0())*(1/Math.sqrt(1 + Math.pow(this.getTanLambda(), 2))));
+			double dy = r*Math.sin(this.getPhi0())*(1/Math.sqrt(1 + Math.pow(this.getTanLambda(), 2)));
+			double dz = r*(this.getTanLambda()/Math.sqrt(1 + Math.pow(this.getTanLambda(), 2)));
+			
+			double y = this.getY0() + dy;
+			double z = this.getZ0() + dz;
+			
+			return new BasicHep3Vector(x, y, z);
+		} else  throw new RuntimeException(x + " value is invalid! x-coodinate must be outside of dipole volume!");

 	}
 

+
+

 }