//--------------------------------------------------------------------
//
//  Play around with some random number generators.
//
//--------------------------------------------------------------------


#include "HepTuple/HepHBookHist1D.h"
#include "HepTuple/TupleManager.h"
#include "HepTuple/HBookFile.h"

#include "CLHEP/Random/DRand48Engine.h"
#include "CLHEP/Random/RandFlat.h"
#include "CLHEP/Random/RandGauss.h"
#include "CLHEP/Random/RandExponential.h"

ZM_USING_NAMESPACE( zmht )

#include <cstdlib>
#include "ZMutility/iostream"
#include <cmath>

USING( namespace std )

DRand48Engine someEngine;
RandFlat Rflat(someEngine);
RandGauss Rgauss(someEngine);
RandExponential Rexp(someEngine);

//  Declare the pointer to the file manager at this level to
//  make it available at file scope.

HBookFile * tManager;

int  main()  {

  int nsamp=10000;
  void generate(long);

  tManager = new HBookFile( "x1.rz" );

//  Book and fill some histograms in a function named generate.
  generate(nsamp);

//  Write out the corresponding RZ file, clean up and bail out.
  delete tManager;

  return 0;
}

void generate(long samples)  {

  double x;
  double mu=-0.5;
  double sig=0.9;
  double lambda = 2.0;

  cout << "Function generate called to produce " << samples << " events." << endl;

//  Book a gang of histograms.

  cout << "\n>>> Populate some 1D histograms." << endl;
  HepHist1D & rflat = tManager->hist1D("Flat distribution",       10, 0.0f,10.0f);
  HepHist1D & rgaus = tManager->hist1D("Gauss distribution",      50,-6.0f, 6.0f);
  HepHist1D & rexp  = tManager->hist1D("Exponential distribution",50, 0.0f,10.0f);

//  Make some entries.  Fill with random numbers from a flat distributions.

  for( int j=0; j<samples; j++ ) {
    x = Rflat.fireInt(10);
    rflat.accumulate((float)x);

    x = Rgauss.fire( mu, sig );
    rgaus.accumulate((float)x);

    x = Rexp.fire( lambda );
    rexp.accumulate((float)x);

  }
  rflat.release();
  rgaus.release();
  rexp.release();

//  Write out the histograms and bail out
  cout << "\n>>> Histograms filled.  Write the file." << endl;
  tManager->write();

  return;
}