Annotated

From PIMC++

// ANNOTATED TUTORIAL INPUT FILE
// This file is still valid input; the parser will ignore all comments

double tau=.05; // 1/kT -- sets the time step and units

// Specify the parallelization strategy
Section (Parallel)
{
  int ProcsPerClone = 1;
  // For ProcsPerClone > 1, each clone will use 
  // ProcsPerClone processors for time-slice parallelization.
  // Otherwise, each processor will run an independent simulation with a different RNG seed.
}

// Description of physical system to be simulated
Section (System)
{
  int NumTimeSlices=12; // Inverse temperature beta = tau * NumTimeSlices
  Array<double,1> Box(3)=[10.0,10.0,10.0];  // dimensions of the simulation box -- make sure units are consistent
  Array<bool, 1 > IsPeriodic(3)=[true,true,true];  // Periodic boundary conditions for each dimension
  Section (Particles)
  {
    Section (Species)
    {
      string Name="free";  // arbitrary, but must be unique and used consistently
      string Type="free";  // H, O, Al, etc.
      double lambda=1.0;   // hbar^2/(2*m) in appropriate units
      string Statistics="BOLTZMANNON"; // other options are "BOSON" or "FERMION"
      int NumParticles=1;
      int NumDim=3; // dimensionality
      string InitPaths="BCC"; // See documentation on initialization options
    }
  } 
}

// Defines how to compute the action (tau * Energy) difference
// used to accept or reject moves
Section (Action)
{
  int NumImages=0;
  int MaxLevels = 2;
  Array<string,1> PairActionFiles(1) = ["zero.PairAction"];
  // These files define the action as a function of distance
  // between two particles of the given species.
  // Files must be provided for all relevant combinations.
  // The file zero.PairAction defines the (null) free-particle action
}

// Set up measurement of quantities of interest
Section (Observables)
{

  string OutFileBase = "SingleParticle"; // base name for output file

  // Basic energy observable  
  Section (Observable)
  {
    string Type = "Energy"; // specifies energy observable
    string Name = "Energy"; // arbitrary but must be unique and consistent
    string Description="Total Energy";
    int Frequency=1; // Accumulates every Frequency times it is called
   }
}   

// Define moves to update system configurations
Section (Moves){

  // See documentation for more information about this method
  Section (Move) {
    string Type="BisectionBlock";
    string Name="BisectionBlock";
    string PermuteType="NONE";
    string Species="free";
    int NumLevels=2;  
    int StepsPerBlock=2;
  }

  // This is a pseudo-move that is needed for technical reasons
  // when multiple time slices are used.
  // See documentation for more information.
  Section (Move)
  {
    string Type="ShiftMove";
    string Name="Shift";
  }
}  

// Define the sequence and frequency of events
// during the simulation
Section (Algorithm)
{
  Section (Loop)
  {
    int Steps=1000; // Do these events 1000 times
    Section (Loop)
    {
      int Steps=50; // Do these events 50 times
      Section (Move) {string Name="BisectionBlock";} // Make move; accept or reject
      Section (Observe) {string Name = "Energy"; }   // Accumulate energy of current configuration
      Section (Move) {string Name = "Shift"; }       // do Shift pseudo-move
    }
    Section (WriteData){} // Dump accumulated observable data to output file
  }
}