hps-java/src/main/java/org/lcsim/hps/users/phansson

diff -u -r1.1 -r1.2
--- ParticleHelixProducer.java	9 Oct 2012 01:22:28 -0000	1.1
+++ ParticleHelixProducer.java	10 Oct 2012 18:53:10 -0000	1.2
@@ -51,7 +51,6 @@

     Hep3Matrix detToTrk;
     SvtTrackExtrapolator extrapolator = new SvtTrackExtrapolator();
     Hep3Vector _bfield;

-    WTrackUtils wutils = new WTrackUtils();

     TrackerHitType trackerType = new TrackerHitType(TrackerHitType.CoordinateSystem.GLOBAL, TrackerHitType.MeasurementType.STRIP_1D);
     CoordinateSystem coordinate_system =  trackerType.getCoordinateSystem();
     

@@ -87,7 +86,6 @@

         Hep3Vector IP = new BasicHep3Vector(0., 0., 1.);
         _bfield = new BasicHep3Vector(0,0,detector.getFieldMap().getField(IP).y());
         detToTrk = trackerhitutils.detToTrackRotationMatrix();

-        this.wutils.setDebug(true);

         
         
     }

@@ -115,6 +113,22 @@

                     Hep3Vector p = part.getMomentum();
                     Hep3Vector org = part.getOrigin();
                     double q = -1*part.getCharge(); //since I flipped the B-field I need to flip the charge

+
+                    //propagate to start of field region if needed
+                    double dz = 0-org.z();
+                    if(dz>0) {
+                        System.out.print(this.getClass().getSimpleName() + ": Propagate MC particle to field region from org=" + org.toString());
+                        double tanPxPz = p.x()/p.z();
+                        double tanPyPz = p.y()/p.z();
+                        double dx = dz*tanPxPz;
+                        double dy = dz*tanPyPz;
+                        
+                        org = new BasicHep3Vector(org.x()+dx,org.y()+dy,org.z()+dz);
+                        
+                        System.out.println( " to   org=" + org.toString() + " (p=" + p.toString()+ ")");
+                        
+                    }          
+                    

                     //if(debug) System.out.println(this.getClass().getSimpleName() + ": MC particle p=" + p.toString() +" org=" + org.toString() +" q = " + q);
                     p = VecOp.mult(detToTrk, p);
                     org = VecOp.mult(detToTrk, org);

@@ -129,24 +143,19 @@

                         double Rman = q*pt/(Constants.fieldConversion*bfield); 
                         double phi = Math.atan2(p.y(),p.x());
                         double xc = org.x() + Rman*Math.sin(phi);

-                        double yc = org.y() - Rman*Math.cos(phi);

+                        double yc = org.y() - Rman*Math.cos(phi);                      

                         double Rc = Math.sqrt(xc*xc+yc*yc);
                         double dca = q >0 ? (Rman - Rc) : (Rman + Rc);

-                        System.out.println(this.getClass().getSimpleName() + ": pt " + pt +" R " + Rman + " phi " + phi + " xc " + xc + " yc " + yc + " Rc " + Rc + " DCA " + dca );

+                        System.out.println(this.getClass().getSimpleName() + ": manual calcualtion gives pt " + pt +" R " + Rman + " phi " + phi + " xc " + xc + " yc " + yc + " Rc " + Rc + " DCA " + dca );

                     }
                     //HelixParamCalculator hpc = new HelixParamCalculator(part,bfield);
                     HelixParamCalculator hpc = new  HelixParamCalculator(p, org, (int)q,bfield); //remove sign from b-field

-                    double R = hpc.getRadius();
-                    double slope = hpc.getSlopeSZPlane();
-                    double d0 = hpc.getDCA();
-                    double phi0 = hpc.getPhi0();
-                    double z0 = hpc.getZ0();

                     double[] pars = new double[5];

-                    pars[0] = d0;
-                    pars[1] = phi0;
-                    pars[2] = 1/R;
-                    pars[3] = z0;
-                    pars[4] = slope;

+                    pars[0] = hpc.getDCA();
+                    pars[1] = hpc.getPhi0();
+                    pars[2] = 1/hpc.getRadius();
+                    pars[3] = hpc.getZ0();
+                    pars[4] = hpc.getSlopeSZPlane();

                     HelicalTrackFit htf = this.trackUtils.makeHelicalTrackFit(pars);
                     tracks.add(htf);
                     if(debug) {