    /*****************************************************************************
     * Project: RooFit                                                           *
     * Package: RooFitCore                                                       *
     *    File: $Id: RooPolyVar.cc,v 1.11 2005/06/20 15:44:56 wverkerke Exp $
     * 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)             *
     *****************************************************************************/

    // -- CLASS DESCRIPTION [PDF] --

    #include "RooFit.h"

    #include "Riostream.h"
    #include "Riostream.h"
    #include <math.h>
    #include "TMath.h"

    #include "RooPolyVar.h"
    #include "RooAbsReal.h"
    #include "RooRealVar.h"
    #include "RooArgList.h"
    #include "TMath.h"

    ClassImp(RooPolyVar)
    ;

     RooPolyVar::RooPolyVar()
    {
      _coefIter = _coefList.createIterator() ;
    }

     RooPolyVar::RooPolyVar(const char* name, const char* title,
    			     RooAbsReal& x, const RooArgList& coefList, Int_t lowestOrder) :
      RooAbsReal(name, title),
      _x("x", "Dependent", this, x),
      _coefList("coefList","List of coefficients",this),
      _lowestOrder(lowestOrder)
    {
      // Constructor
      _coefIter = _coefList.createIterator() ;

      // Check lowest order
      if (_lowestOrder<0) {
        cout << "RooPolyVar::ctor(" << GetName()
    	 << ") WARNING: lowestOrder must be >=1, setting value to 1" << endl ;
        _lowestOrder=0 ;
      }

      TIterator* coefIter = coefList.createIterator() ;
      RooAbsArg* coef ;
      while((coef = (RooAbsArg*)coefIter->Next())) {
        if (!dynamic_cast<RooAbsReal*>(coef)) {
          cout << "RooPolyVar::ctor(" << GetName() << ") ERROR: coefficient " << coef->GetName()
    	   << " is not of type RooAbsReal" << endl ;
          assert(0) ;
        }
        _coefList.add(*coef) ;
      }
      delete coefIter ;
    }

     RooPolyVar::RooPolyVar(const char* name, const char* title,
                               RooAbsReal& x) :
      RooAbsReal(name, title),
      _x("x", "Dependent", this, x),
      _coefList("coefList","List of coefficients",this),
      _lowestOrder(1)
    {
      _coefIter = _coefList.createIterator() ;
    }

     RooPolyVar::RooPolyVar(const RooPolyVar& other, const char* name) :
      RooAbsReal(other, name),
      _x("x", this, other._x),
      _coefList("coefList",this,other._coefList),
      _lowestOrder(other._lowestOrder)
    {
      // Copy constructor
      _coefIter = _coefList.createIterator() ;
    }

     Double_t RooPolyVar::evaluate() const
    {
      Double_t sum(0) ;
      Int_t order(_lowestOrder) ;
      _coefIter->Reset() ;

      RooAbsReal* coef ;
      const RooArgSet* nset = _coefList.nset() ;
      while((coef=(RooAbsReal*)_coefIter->Next())) {
        sum += coef->getVal(nset)*TMath::Power(_x,order++) ;
      }

      return sum;
    }

     Int_t RooPolyVar::getAnalyticalIntegral(RooArgSet& allVars, RooArgSet& analVars, const char* /*rangeName*/) const
    {
      if (matchArgs(allVars, analVars, _x)) return 1;
      return 0;
    }

     Double_t RooPolyVar::analyticalIntegral(Int_t code, const char* rangeName) const
    {
      assert(code==1) ;

      Double_t sum(0) ;

      const RooArgSet* nset = _coefList.nset() ;
      Int_t order(_lowestOrder) ;
      _coefIter->Reset() ;
      RooAbsReal* coef ;

      // Primitive = sum(k) coef_k * 1/(k+1) x^(k+1)
      while((coef=(RooAbsReal*)_coefIter->Next())) {
        sum += coef->getVal(nset)*(TMath::Power(_x.max(rangeName),order+1)-TMath::Power(_x.min(rangeName),order+1))/(order+1) ;
        order++ ;
      }

      return sum;

    }