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[u/mrichter/AliRoot.git] / PWG2 / RESONANCES / AliRsnPairDef.cxx

/**************************************************************************
 * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
 *                                                                        *
 * Author: The ALICE Off-line Project.                                    *
 * Contributors are mentioned in the code where appropriate.              *
 *                                                                        *
 * Permission to use, copy, modify and distribute this software and its   *
 * documentation strictly for non-commercial purposes is hereby granted   *
 * without fee, provided that the above copyright notice appears in all   *
 * copies and that both the copyright notice and this permission notice   *
 * appear in the supporting documentation. The authors make no claims     *
 * about the suitability of this software for any purpose. It is          *
 * provided "as is" without express or implied warranty.                  *
 **************************************************************************/

//
// ALIRSNPAIRDEF
//
// Definition of working parameters for a specific resonance analysis.
// This object allows to define the particles to be used for computation
// with respect to charge and PID type (included 'kUnknown'), and
// the binning of the output histogram.
// These definitions can then be used by many AliRsnPair objects
// which can operate on the same track samples under different conditions.
//
// author: A. Pulvirenti
// email : alberto.pulvirenti@ct.infn.it
//

#include <Riostream.h>

#include "AliLog.h"
#include "AliRsnDaughter.h"
#include "AliRsnPairDef.h"

ClassImp(AliRsnPairDef)

//_____________________________________________________________________________
AliRsnPairDef::AliRsnPairDef() :
  TObject(),
  fMotherPDG(0),
  fNBins(0),
  fMin(0.0),
  fMax(0.0)
{
//
// Empty constructor.
// Initializes the data members to default values:
//  - no definition of particles in the pair;
//  - histogram binning undefined.
// When using this constructor, all analysis elements (particles, histogram)
// must be defined before starting event processing.
//

    Int_t i;
    for (i = 0; i < 2; i++) {
        fCharge[i] = '0';
        fMass[i] = 0.0;
        fType[i] = AliRsnPID::kUnknown;
    }
}

//_____________________________________________________________________________
AliRsnPairDef::AliRsnPairDef
(Char_t sign1, AliRsnPID::EType type1, Char_t sign2, AliRsnPID::EType type2,
 Int_t nbins, Double_t min, Double_t max) :
  TObject(),
  fMotherPDG(0),
  fNBins(0),
  fMin(0.0),
  fMax(0.0)
{
//
// Constructor with arguments.
// This constructor allows to define all the working parameters.
//

    SetPair(sign1, type1, sign2, type2);
    SetBins(nbins, min, max);
}

//_____________________________________________________________________________
AliRsnPairDef::AliRsnPairDef(const AliRsnPairDef &copy) :
  TObject(copy),
  fMotherPDG(copy.fMotherPDG),
  fNBins(0),
  fMin(0.0),
  fMax(0.0)
{
//
// Copy constructor with standard behavior
//

    SetPair(copy.fCharge[0], copy.fType[0], copy.fCharge[1], copy.fType[1]);
    SetBins(copy.fNBins, copy.fMin, copy.fMax);
}

//_____________________________________________________________________________
const AliRsnPairDef& AliRsnPairDef::operator=(const AliRsnPairDef &copy)
{
//
// Assignment operator with standard behavior.
//

    fMotherPDG = copy.fMotherPDG;
    SetPair(copy.fCharge[0], copy.fType[0], copy.fCharge[1], copy.fType[1]);
    SetBins(copy.fNBins, copy.fMin, copy.fMax);

    return (*this);
}

//_____________________________________________________________________________
Bool_t AliRsnPairDef::SetPairElement(Int_t i, Char_t charge, AliRsnPID::EType type)
{
//
// Set one element of the pair
// and returns warnings if the type is not valid.
//
    if (i < 0 || i > 1) {
        AliError("Index out of range");
        return kFALSE;
    }
    if (charge != '+' && charge != '-') {
        AliError(Form("Character '%c' not recognized as charge sign"));
        return kFALSE;
    }
    if (type < AliRsnPID::kElectron && type > AliRsnPID::kUnknown) {
        AliError("Type index out of enumeration range");
        return kFALSE;
    }
    fCharge[i] = charge;
    fType[i] = type;
    fMass[i] = AliRsnPID::ParticleMass(type);
    return kTRUE;
}

//_____________________________________________________________________________
Bool_t AliRsnPairDef::SetPair
(Char_t charge1, AliRsnPID::EType type1, Char_t charge2, AliRsnPID::EType type2)
{
//
// Set both elements of the pair,
// returning logical AND of check for each one.
//

    Bool_t part1 = SetPairElement(0, charge1, type1);
    Bool_t part2 = SetPairElement(1, charge2, type2);
    return (part1 && part2);
}

//_____________________________________________________________________________
void AliRsnPairDef::CheckEdges()
{
//
// Checks that histogram edges are appropriate,
// otherwise swaps them.
//
    if (fMin > fMax) {
        AliWarning(Form("min = %f -- max = %f --> swapping", fMin, fMax));
        Double_t temp = fMin;
        fMin = fMax;
        fMax = temp;
    }
}

//_____________________________________________________________________________
Double_t AliRsnPairDef::ComputeWeight(AliRsnDaughter *d0, AliRsnDaughter *d1)
{
//
// Compute a weight for filling the histograms:
// probability of first track to be identified as 'type[0]' times
// the probability of second track to be identified as 'type[1]',
// according to the order of appearance in argument list.
//

    Double_t prob0 = d0->PIDProb()[fType[0]];
    Double_t prob1 = d1->PIDProb()[fType[1]];

    return prob0*prob1;
}