Writing your own program - Merlin++ user script fundamentals

Merlin++ follows a relatively simple overarching design in that a user script can be thought of in just five parts.

1. Defining the lattice
2. Defining the beam
3. Defining the tracker
4. Running the simulation
5. Post-processing & output of results

The following provides a code snippet corresponding to each part. Note that this is simply an example of the most basic implementation and more advanced methods can be found in the tutorials.

• Defining the Lattice (A or B)

  A) Define lattice apertures manually within Merlin++

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  AcceleratorModelConstructor newModel();
  newModel.NewModel();
  newModel.AppendComponent(new Quadrupole( QF ,1.0,5.5));
  newModel.AppendComponent(new Drift( D1 ,12.55));
  newModel.AppendComponent(new SectorBend( BFD ,5.0,0.0255,11.23));
  newModel.AppendComponent(new Drift( D1 ,12.55));
  newModel.AppendComponent(new Quadrupole( QD ,1.0,-5.5));
  // etc..
  AcceleratorModel* theModel = newModel.GetModel();
  

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  B) Importing MAD optices/lattice apertures file

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  MADInterface madInterface("/path/to/lattice.tfs", beamenergy);
  AcceleratorModel* theModel = madInterface.ConstructModel();

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• Defining the Beam

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  ParticleBunch* theBunch = new ParticleBunch(beamenergy);
  particleBunch->AddParticle(co);

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• Defining the Tracker

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  ParticleTracker tracker(theModel->GetBeamline(), theBunch);

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• Running the Simulation

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  tracker.Run();

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• Processing & Output of Results

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  // Prior to running the tracker:
  ofstream trackingLog("build/trackinginfo.out");
  // Post running the tracker:
  ParticleBunch& tracked = tracker.GetTrackedBunch();
  tracked.Output(trackingLog);
  // Tracking data can be imported and plotted in python/octave etc

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