// -*- mode: C++ -*-
/* Copyright (C) 2007 Christian Holm Christensen <cholm@nbi.dk>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public License
 * as published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
 * USA
 */
/** @file 
    @brief Declaration and implementation of classes to deal with a
    well-known event plane @f$ \Psi_R@f$. */
//____________________________________________________________________
//
//  AliFMDFlowTrueBin: 
//    A specialised AliFMDFlowBin of flow in case the event plane is
//    well-known.  
//  AliFMDFlowTrue1D: 
//    A specialised AliFMDFlowBinned1D histogram in case the event
//    plane is well-known.   
//
#ifndef ALIFMDFLOWTRUE_H
#define ALIFMDFLOWTRUE_H
#include <flow/AliFMDFlowStat.h>
#include <flow/AliFMDFlowBin.h>
#include <flow/AliFMDFlowBinned1D.h>


/** @defgroup x_true Classes for handling Flow when the event plane is
    known. 

    @ingroup FMD_flow */
/** @class TrueBin flow/True.h <flow/True.h>
    @brief A specialised Bin of flow in case the event plane is 
    well-known. 
    @ingroup x_true */
class AliFMDFlowTrueBin : public AliFMDFlowBin
{
public:
  /** Default constructor - do not use */
  AliFMDFlowTrueBin() : AliFMDFlowBin(), fPsiR(), fResReal() {}
  /** Constructor */ 
  AliFMDFlowTrueBin(UShort_t order) : 
    AliFMDFlowBin(order, 1), 
    fPsiR(0), 
    fResReal()
  {}
  /** Set the well-known event plane angle @f$ \Psi_R@f$ for this
      event. 
      @param psi @f$ \Psi_R@f$ */ 
  void SetPsi(Double_t psi) { fPsiR = psi; } 
  /** Should be called at the end of an event */ 
  virtual void End();
  /** Add a contribution @f$ \cos(n(\varphi-\Psi_R))@f$ where   
      @f$ \Psi_R@f$ is the previously set, well-known event plane
      angle. 
      @param wp  Weight of @a phi (only used in the calculation of
                 the event plane). 
      @param wh  Weight if the @f$ \varphi@f$ observation 
      @param phi @f$ \varphi@f$ */ 
  void AddToHarmonic(Double_t phi, Double_t wp, Double_t wh=1);
  /** Get the value in this bin 
      @param t  Which type of correction
      @return the value of the harmonic */
  virtual Double_t Value(CorType t=kNone) const;
  /** Get the value in this bin 
      @param e2 On return, the square error. 
      @param t  Which type of correction
      @return the value of the harmonic */
  Double_t Value(Double_t& e2, CorType t=kNone) const;
  /** Get the value in this bin 
      @param e2 On return, the square error. 
      @param t  Which type  of correction
      @return the value of the harmonic */
  Double_t Correction(Double_t& e2, CorType t=kNone) const;
  /** Print to standard out. */ 
  void Print(Option_t* option="s") const;
  /** get the event plane */ 
  Double_t Psi() const { return fPsiR; }
protected:
  /** The well-known event plane */ 
  Double_t fPsiR;  // The well-known event plane 
  /** True resolution */ 
  AliFMDFlowStat fResReal; // True resolution
  /** define for ROOT I/O */
  ClassDef(AliFMDFlowTrueBin,1);
  
}; 
/** @brief A "histogram" of objects of class TrueBin in case the
    event plane angle @f$ \Psi_R@f$ is well known. 
    @ingroup x_true */
struct AliFMDFlowTrue1D : public AliFMDFlowBinned1D
{
public:
  /** Default constructor - do not use */
  AliFMDFlowTrue1D() {}
  /** Constructor */ 
  AliFMDFlowTrue1D(const char* name, const char* title, 
		   UShort_t order, const AliFMDFlowAxis& xaxis);
  /** Set the well-known event plane angle @f$ \Psi_R@f$ for this
      event. 
      @param psi @f$ \Psi_R@f$ */ 
  void SetPsi(Double_t psi);
  /** Print to standard out */ 
  virtual void Print(Option_t* option="") const;
  /** define for ROOT I/O */
  ClassDef(AliFMDFlowTrue1D,1);
};


#endif
//
// EOF
//