package org.lcsim.analysis;
   
   import hep.aida.IHistogram1D;
   
   import org.lcsim.event.EventHeader;
   import org.lcsim.event.Track;
   import org.lcsim.util.Driver;
   import org.lcsim.util.aida.AIDA;
   
  /**
   * This is a very simple analysis driver used for grid production tests on LCIO data.
   * 
   * @author Jeremy McCormick <jeremym@slac.stanford.edu>
   * @version $Id: SimpleTrackAnalysis.java,v 1.2 2013/04/26 22:44:38 jeremy Exp $
   */
  public class SimpleTrackAnalysis extends Driver {
  	AIDA aida = AIDA.defaultInstance();
  	IHistogram1D h = aida.histogram1D("Track Momentum", 100, 0., 100.);
  	public void process(EventHeader event) {
  		for (Track track : event.get(Track.class, "Tracks")) {
  			double[] p = track.getTrackStates().get(0).getMomentum();
  			h.fill(computeMomentum(p));
  		}
  	}	
  	private double computeMomentum(double[] p) {
  		return Math.sqrt(p[0]*p[0]+p[1]*p[1]+p[2]*p[2]);
  	}
  }