lcsim/src/org/lcsim/recon/tracking/gtrfit
diff -N SimpleGTrackFitter.java
--- /dev/null 1 Jan 1970 00:00:00 -0000
+++ SimpleGTrackFitter.java 28 Oct 2005 04:53:10 -0000 1.1
@@ -0,0 +1,262 @@
+package org.lcsim.recon.tracking.gtrfit;
+
+import java.util.TreeSet;
+import java.util.List;
+import java.util.ArrayList;
+import java.util.Iterator;
+import java.util.Collections;
+
+import org.lcsim.recon.tracking.trfutil.Assert;
+
+import org.lcsim.recon.tracking.trfbase.Propagator;
+import org.lcsim.recon.tracking.trffit.AddFitter;
+import org.lcsim.recon.tracking.trffit.AddFitKalman;
+import org.lcsim.recon.tracking.gtrbase.GTrack;
+import org.lcsim.recon.tracking.gtrbase.GTrackState;
+import org.lcsim.recon.tracking.gtrbase.FitStatus;
+import org.lcsim.recon.tracking.trfbase.ETrack;
+import org.lcsim.recon.tracking.trfbase.PropStat;
+import org.lcsim.recon.tracking.trfbase.Hit;
+import org.lcsim.recon.tracking.trfbase.TrackError;
+import org.lcsim.recon.tracking.trfbase.Surface;
+import org.lcsim.recon.tracking.trfbase.Cluster;
+import org.lcsim.recon.tracking.trfbase.PropDir;
+
+import org.lcsim.recon.tracking.trffit.HTrack;
+/**
+ * A class which fits a GTrack.
+ *
+ *@author Norman A. Graf
+ *@version 1.0
+ *
+ */
+public class SimpleGTrackFitter
+{
+
+ //**********************************************************************
+ // Local definitions.
+ //**********************************************************************
+
+ private static final int FORWARD = 1;
+ private static final int BACKWARD = -1;
+ private static final double ERRFAC = 10.;
+
+
+ // attributes
+
+ // Propagator.
+ private Propagator _prop;
+
+ // Fit order.
+ private int _order;
+
+ // Add fitter.
+ private AddFitter _fitter;
+
+ // Maximum chi-square.
+ private double _chsq_max;
+
+
+ // methods
+
+ /**
+ *Construct an instance from a propagator, the order in which to fit, and a
+ * chi-square value on which to cut.
+ * order = fit order (1 for going out, -1 for going in)
+ *
+ * @param prop The Propagator to use in the fit.
+ * @param order The order in wich to fit (1 for going out, -1 for going in).
+ * @param chsq_max The maximum value of chi-square to allow for a hit.
+ */
+ public SimpleGTrackFitter( Propagator prop, int order,
+ double chsq_max)
+ {
+ _prop = prop;
+ _order = order;
+ _fitter = new AddFitKalman();
+ _chsq_max = chsq_max;
+ if ( _order!=FORWARD && _order!=BACKWARD )
+ {
+ throw new IllegalArgumentException("Fit order must be FORWARD or BACKWARD!");
+ }
+ }
+
+
+ /**
+ *Fit a track.
+ *
+ * @param gtr The GTrack to fit.
+ * @return 0 for successful fit.
+ */
+ public int fit(GTrack gtr)
+ {
+
+ // Extract list of states.
+ TreeSet oldstates = gtr.states();
+
+ // Require track to have at least one valid state.
+ if ( oldstates.size() < 1 )
+ {
+ return 1;
+ }
+
+ // Extract starting track and error.
+ GTrackState state0 = new GTrackState();
+ if ( _order == FORWARD ) state0 = (GTrackState) oldstates.first();
+ if ( _order == BACKWARD ) state0 = (GTrackState) oldstates.last();
+
+ // The first state must be valid.
+ Assert.assertTrue( state0.isValid() );
+ if ( ! state0.isValid() )
+ {
+ return 2;
+ }
+
+ double s0 = state0.s();
+ ETrack tre0 = state0.track();
+ //Starting surface
+ Surface srf0 = tre0.surface();
+ // Increase error.
+ {
+ TrackError err = tre0.error();
+ for ( int j=0; j<5; ++j )
+ {
+ for ( int i=0; i<=j; ++i )
+ {
+ err.set(i,j, err.get(i,j)*ERRFAC );
+ }
+ }
+ tre0.setError(err);
+ }
+
+ // Build list of clusters, preserving or reversing order.
+
+ List clusters = new ArrayList();
+
+ for ( Iterator istate=oldstates.iterator(); istate.hasNext(); )
+ {
+ clusters.add( ((GTrackState) istate.next() ).cluster() );
+ }
+ if ( _order == BACKWARD ) Collections.reverse(clusters);
+
+ // Build starting HTrack.
+ HTrack trh = new HTrack(tre0);
+
+ // New GTrack state list.
+ TreeSet newstates = new TreeSet();
+
+ //
+ // Loop over states and add each cluster in turn to the fit.
+ // If cluster does not exist, interact track at the state surface
+ //
+ double spath = 0.0;
+ boolean first = true;
+ for ( Iterator clusit = clusters.iterator(); clusit.hasNext(); )
+ {
+
+ // Get the TRF++ cluster.
+
+ Cluster clus = (Cluster) clusit.next();
+ double ds1 = 0;
+ double ds2 = 0;
+
+ // Propagate the fitted track to the cluster surface.
+ Surface srf = clus.surface().newSurface();
+ Assert.assertTrue( srf != null );
+ if( !first || !srf.pureEqual(srf0) )
+ {
+ PropStat pstat =
+ trh.propagate( _prop, srf, PropDir.NEAREST );
+ if ( ! pstat.success())
+ {
+ return 3;
+ }
+ ds1 = pstat.pathDistance();
+ }
+
+ // Extract the hit.
+ List hits = clus.predict( trh.newTrack(), clus );
+ Assert.assertTrue( hits.size() == 1 );
+ Hit hit = (Hit) hits.get(0);
+
+ // Propagate the fitted track to the hit surface.
+ Surface srf2 = (hit.surface()).newSurface();
+ if( !srf2.pureEqual(srf) )
+ {
+ Assert.assertTrue( srf2 != null );
+ PropStat pstat = trh.propagate( _prop, srf2, PropDir.NEAREST );
+ if ( ! pstat.success())
+ {
+ return 4;
+ }
+ ds2 = pstat.pathDistance();
+ }
+
+ // Update the path distance.
+ double ds = ds1 + ds2;
+ boolean ds_ok = ( _order == FORWARD && ds >= 0.0) ||
+ ( _order == BACKWARD && ds <= 0.0);
+ if ( ! ds_ok )
+ {
+ return 5;
+ }
+ spath += ds;
+
+ // Fit with the new hit.
+ int stat = _fitter.addHit(trh,hit);
+
+ // bad fit
+ if ( stat != 0 )
+ {
+ return 6;
+ }
+ // good fit, but bad chi-squared
+ if ( trh.chisquared() > _chsq_max )
+ {
+ return 7;
+ }
+
+ // Add new GTrackState.
+
+ FitStatus fstat = FitStatus.INVALID;
+ // If there are no more clusters this fit is OPTIMAL at this state
+ if ( ! clusit.hasNext() )
+ {
+ fstat = FitStatus.OPTIMAL;
+ }
+ else
+ {
+ if ( _order == 1 ) fstat = FitStatus.FORWARD;
+ if ( _order == -1 )fstat = FitStatus.BACKWARD;
+ }
+
+ ETrack tre = trh.newTrack();
+ double chsq = trh.chisquared();
+ newstates.add( new GTrackState( spath, tre, fstat, chsq, clus ));
+
+ // }
+
+ first = false;
+
+ } // end loop over clusters.
+
+ // Construct new GTrack.
+ gtr.update(newstates);
+
+ return 0;
+ }
+
+
+ /**
+ *output stream
+ *
+ * @return A String representation of this instance.
+ */
+ public String toString()
+ {
+ return "SimpleGTrackFitter: " +
+ "\nPropagator: " + _prop +
+ "\nFitter: " + _fitter +
+ "\n with chsq_max = " + _chsq_max;
+ }
+}
\ No newline at end of file
