RooUniformBinning.cxx

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/*****************************************************************************
 * Project: RooFit                                                           *
 * Package: RooFitCore                                                       *
 * @(#)root/roofitcore:$Id$
 * Authors:                                                                  *
 *   WV, Wouter Verkerke, UC Santa Barbara, verkerke@slac.stanford.edu       *
 *   DK, David Kirkby,    UC Irvine,         dkirkby@uci.edu                 *
 *                                                                           *
 * Copyright (c) 2000-2005, Regents of the University of California          *
 *                          and Stanford University. All rights reserved.    *
 *                                                                           *
 * Redistribution and use in source and binary forms,                        *
 * with or without modification, are permitted according to the terms        *
 * listed in LICENSE (http://roofit.sourceforge.net/license.txt)             *
 *****************************************************************************/
 
/**
\file RooUniformBinning.cxx
\class RooUniformBinning
\ingroup Roofitcore
 
Implementation of RooAbsBinning that provides
a uniform binning in 'n' bins between the range end points. A RooUniformBinning
is 'elastic': if the range changes the binning will change accordingly, unlike
e.g. the binning of class RooBinning.
**/
 
#include "RooUniformBinning.h"
#include "RooMsgService.h"
 
#include "Riostream.h"
 
 
using std::endl;
 
ClassImp(RooUniformBinning);
 
////////////////////////////////////////////////////////////////////////////////
/// Construct range [xlo,xhi] with 'nBins' bins
 
RooUniformBinning::RooUniformBinning(double xlo, double xhi, Int_t nBins, const char* name) :
  RooAbsBinning(name),
  _nbins(nBins)
{
  setRange(xlo,xhi) ;
}
 
////////////////////////////////////////////////////////////////////////////////
/// Copy constructor
 
RooUniformBinning::RooUniformBinning(const RooUniformBinning &other, const char *name)
   : RooAbsBinning(name), _xlo(other._xlo), _xhi(other._xhi), _nbins(other._nbins), _binw(other._binw)
{
}
 
 
 
////////////////////////////////////////////////////////////////////////////////
/// Change range to [xlo,xhi]. A changes in range automatically
/// adjusts the binning as well to nBins bins in the new range
 
void RooUniformBinning::setRange(double xlo, double xhi)
{
  if (xlo>xhi) {
    coutE(InputArguments) << "RooUniformBinning::setRange: ERROR low bound > high bound" << endl ;
    return ;
  }
 
  _xlo = xlo ;
  _xhi = xhi ;
  _binw = (xhi-xlo)/_nbins ;
 
  // Delete any out-of-date boundary arrays at this point
  _array.clear();
}
 
 
 
////////////////////////////////////////////////////////////////////////////////
/// Return the index of the bin that encloses 'x'
 
void RooUniformBinning::binNumbers(double const * x, int * bins, std::size_t n, int coef) const
{
  const double oneOverW = 1./_binw;
 
  for(std::size_t i = 0; i < n; ++i) {
    bins[i] += coef * (x[i] >= _xhi ? _nbins - 1 : std::max(0, int((x[i] - _xlo)*oneOverW)));
  }
}
 
 
 
////////////////////////////////////////////////////////////////////////////////
/// Return the central value of the 'i'-th fit bin
 
double RooUniformBinning::binCenter(Int_t i) const
{
  if (i<0 || i>=_nbins) {
    coutE(InputArguments) << "RooUniformBinning::binCenter ERROR: bin index " << i
           << " is out of range (0," << _nbins-1 << ")" << endl ;
    return 0 ;
  }
 
  return _xlo + (i + 0.5) * _binw;
}
 
 
 
 
////////////////////////////////////////////////////////////////////////////////
/// Return the bin width (same for all bins)
 
double RooUniformBinning::binWidth(Int_t /*bin*/) const
{
  return _binw ;
}
 
 
 
////////////////////////////////////////////////////////////////////////////////
/// Return the low edge of the 'i'-th fit bin
 
double RooUniformBinning::binLow(Int_t i) const
{
  if (i<0 || i>=_nbins) {
    coutE(InputArguments) << "RooUniformBinning::binLow ERROR: bin index " << i
           << " is out of range (0," << _nbins-1 << ")" << endl ;
    return 0 ;
  }
 
  return _xlo + i*_binw ;
}
 
 
 
////////////////////////////////////////////////////////////////////////////////
/// Return the high edge of the 'i'-th fit bin
 
double RooUniformBinning::binHigh(Int_t i) const
{
  if (i<0 || i>=_nbins) {
    coutE(InputArguments) << "RooUniformBinning::fitBinHigh ERROR: bin index " << i
           << " is out of range (0," << _nbins-1 << ")" << endl ;
    return 0 ;
  }
 
  return _xlo + (i + 1)*_binw ;
}
 
 
 
////////////////////////////////////////////////////////////////////////////////
/// Return an array of doubles with the bin boundaries
 
double* RooUniformBinning::array() const
{
  _array.resize(_nbins+1);
 
  Int_t i ;
  for (i=0 ; i<=_nbins ; i++) {
    _array[i] = _xlo + i*_binw ;
  }
  return _array.data();
}