getPoisson.cc

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#include <iostream>
#include <iomanip>
 
#include "TRandom3.h"
 
#include "JMath/JMathSupportkit.hh"
 
#include "Jeep/JParser.hh"
#include "Jeep/JMessage.hh"
 
 
/**
 * \file
 *
 * Auxiliary program to print random a number according Poisson statistics or the Poisson probability.
 * \author mdejong
 */
int main(int argc, char**argv)
{
  using namespace std;
  using namespace JPP;
 
  double  value;
  int     n;
  ULong_t seed;
  int     debug;
 
  try {
 
    JParser<> zap("Auxiliary program to print a random number according Poisson statistics or the Poisson probability."\
                  "\nIf the number of events is less than zero, the random number is printed, else the probability.");
 
    zap['e'] = make_field(value, "expectation value");
    zap['n'] = make_field(n,     "number of events")    = -1;
    zap['S'] = make_field(seed)              = 0;
    zap['d'] = make_field(debug)             = 3;
 
    zap(argc, argv);
  }
  catch(const exception &error) {
    FATAL(error.what() << endl);
  }
 
  if (n < 0) {
 
    gRandom->SetSeed(seed);
 
    cout << gRandom->Poisson(value) << endl;
 
  } else {
 
    cout << SCIENTIFIC(12,5) << poisson(n, value) << endl;
  }
}