// ----------------------------------------------------------------------------
// Utility functions to fill histograms with user defined random distributions.
//
// The first function will fill a histogram referred to by HepHist1D& hist
// with num samplings drawn from the CLHEP Random distribution referred to
// by HepRandom& dist.  It is assumed that the user has already instantiated
// the HepRandom distribution with the desired shape parameters as well as
// the HepHist1D histogram with the desired range and binning.
//
// The second function will fill a histogram referred to by HepHist1D& subhist
// with num samplings drawn from the histogram referred to by HepHist1D&
// refhist.  It is assumed that the reference histogram exists and represents
// a reasonably high statistics thing with the desired shape parameters.
// Neither the range nor the binning of the subsample histogram is required to
// be the same as that for the reference histogram.
//
// A valid question here is, "Why is this thing in ZMtools and not in
// either CLHEP/Random or HepTuple?" The answer is that we don't want
// either of those to be dependent on the other.  That's a nice sentiment
// but putting it here makes ZMtools dependent on both CLHEP and HepTuple.
// Is that a good compromise? You should live so long!
//
// History:
//	21-Dec-1999	JMM	Initial draft.
//
// ----------------------------------------------------------------------------


#include "ZMtools/fillRandom.h"

ZM_BEGIN_NAMESPACE( zmht )	/*  namespace zmht  {	*/

void fillRandom( HepRandom& dist, HepHist1D& hist, int num )
{
  for( int i = 0; i < num; ++i ) hist.accumulate( (float)dist() );
}

void fillRandom( HepHist1D& refhist, HepHist1D& subhist, int num )
{
  TripleRand Triple;

// Collect the data from the reference histogram and feed it to RandGeneral

  int nbins = refhist.nBins();
  float refmin = refhist.min();
  float refmax = refhist.max();
  float range = refmax - refmin;
  float* contents = new float[nbins];
  refhist.getContents( contents );
  double* dcontents = new double[nbins];
  for( int i = 0; i < nbins; ++i ) dcontents[i] = (double)contents[i];
  delete [] contents;
  RandGeneral Reference( Triple, dcontents, nbins );

// RandGeneral produces samples scaled to the interval (0,1).
// Transform them back onto (refmin,refmax) and accumulate.

  double sample;
  for( int i = 0; i < num; ++i ) {
    sample = range*Reference() + refmin;
    subhist.accumulate( (float)sample );
  }
  delete [] dcontents;
}

ZM_END_NAMESPACE( zmht )	/*  } // namespace zmht	*/