This is a short example on how to run the MCFast tool, generate a list of reconstructed particles and run a Jet Cluster
Requirements
- JAS3 must be installed
- Get a stdhep file, Z Pole stdhep from the SLAC HEP repository
- Select sid01 as detector version when JAS3 prompts you
The Code
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import java.io.File;
import java.util.List;
import java.util.ArrayList;
import org.lcsim.mc.fast.MCFast;
import org.lcsim.util.Driver;
import org.lcsim.util.loop.LCIODriver;
import org.lcsim.event.EventHeader;
import org.lcsim.event.ReconstructedParticle;
import org.lcsim.event.util.JetDriver;
import hep.physics.jet.*;
public class SimpleEventSim extends Driver
{
int ievt=0;
String LCIOoutputfilename="fastmcZuds.slcio";
String jetlistname = "Jets";
public SimpleEventSim()
{
// Create MCFast with standard options
Driver fast = new MCFast();
// Turn on diagnostic histograms
fast.setHistogramLevel(HLEVEL_NORMAL);
// Add as sub-driver
add(fast);
// set up Jet Finder
JetDriver j = new JetDriver();
j.setInputCollectionName("MCFastReconstructedParticles");
j.setOutputCollectionName(jetlistname);
JetFinder twojet = new FixNumberOfJetsFinder(2);
j.setFinder(twojet);
add(j);
// write lcio files
File output = new File(System.getProperty("user.home"),LCIOoutputfilename);
add(new LCIODriver(output));
}
protected void process(EventHeader event)
{
// call other driver process methods
super.process(event);
// give some status on events
if (ievt%50==0)
{
System.out.println("Processed Events " + ievt);
}
ievt++;
}
}
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Loading this code into JAS will run over the stdhep file and generate and output LCIO file for analysis later
MCFAST
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// Create MCFast with standard options
Driver fast = new MCFast();
// Turn on diagnostic histograms
fast.setHistogramLevel(HLEVEL_NORMAL);
// Add as sub-driver
add(fast);
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This initializes the fast Monte-Carlo Generator and adds it to the event loop
JET Clustering
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// set up Jet Finder
JetDriver j = new JetDriver();
j.setInputCollectionName("MCFastReconstructedParticles");
j.setOutputCollectionName(jetlistname);
JetFinder twojet = new FixNumberOfJetsFinder(2);
j.setFinder(twojet);
add(j);
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The JetDriver needs an input and output collection and a separate JetFinder, which in this example is a FixNumberOfJetsFinder finder. The JetFinder Object is then added to the JetDriver. For details see the FreeHep JetFinder documentation.
LCIO output
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// write lcio files
File output = new File(System.getProperty("user.home"),LCIOoutputfilename);
add(new LCIODriver(output));
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This opens a new file and writes all LCIO Collections into the file.