Rivet analyses

title: MC_OPTIONS

Experiment: ()

Status: VALIDATED

Authors: - Christian Bierlich

References: none listed

Beams: * *

Beam energies: ANY

Run details: none listed

Just an example of the options system in action.

Source code:MC_OPTIONS.cc

```c++ // -- C++ --

include "Rivet/Analysis.hh"

namespace Rivet { using std::istream; using std::ostream;

// Example analysis to show how to use options in an analysis // Example of a custom class to be read in from an option. class A { public:

A()
    : a(-1.0) { }

private:

double a;
// Custom class must be streamable.
friend istream& operator>>(istream& is, A& a);
friend ostream& operator<<(ostream& os, const A& a);

};

// Custom class must be streamable. istream& operator>>(istream& is, A& a) { is >> a.a; return is; } ostream& operator<<(ostream& os, const A& a) { os << a.a; return os; }

class MC_OPTIONS : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(MC_OPTIONS);

/// @name Analysis methods
/// @{

/// Book histograms and initialise projections before the run
void init() {


  // Parameters read in.
  // A double.
  double f = getOption<double>("foo", 1.0);
  // A string.
  string s = getOption<string>("bar", "");
  // A custom object.
  A a = getOption<A>("baz", A());

  cout << "foo = " << f << endl;
  cout << "bar = " << s << endl;
  cout << "baz = " << a << endl;
  value = f;
  book(h, "hist", 10, 0, 10);
}

// Perform the per-event analysis
void analyze(const Event&) {
  h->fill(value);
}


/// Finalize
void finalize() { }

/// @}

private:

/// @name Histograms
/// @{
Histo1DPtr h;
/// @}
double value;

};

RIVET_DECLARE_PLUGIN(MC_OPTIONS);

} ```