    /*****************************************************************************
     * Project: RooFit                                                           *
     * Package: RooFitCore                                                       *
     *    File: $Id: RooProduct.cc,v 1.8 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 [REAL] --
    //
    // RooProduct calculates the product of a set of RooAbsReal terms.
    // This class does not (yet) do any smart handling of integrals, i.e
    // all integrals of the product are handled numerically

    #include "RooFit.h"

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

    #include "RooProduct.h"
    #include "RooAbsReal.h"
    #include "RooErrorHandler.h"

    ClassImp(RooProduct)
    ;

     RooProduct::RooProduct()
    {
      _compIter = _compSet.createIterator() ;
    }

     RooProduct::RooProduct(const char* name, const char* title, const RooArgSet& prodSet) :
      RooAbsReal(name, title),
      _compSet("compSet","Set of product components",this)
    {
      // Constructor
      _compIter = _compSet.createIterator() ;

      TIterator* compIter = prodSet.createIterator() ;
      RooAbsArg* comp ;
      while((comp = (RooAbsArg*)compIter->Next())) {
        if (!dynamic_cast<RooAbsReal*>(comp)) {
          cout << "RooProduct::ctor(" << GetName() << ") ERROR: component " << comp->GetName()
    	   << " is not of type RooAbsReal" << endl ;
          RooErrorHandler::softAbort() ;
        }
        _compSet.add(*comp) ;
      }

      delete compIter ;
    }

     RooProduct::RooProduct(const RooProduct& other, const char* name) :
      RooAbsReal(other, name),
      _compSet("compSet",this,other._compSet)
    {
      // Copy constructor
      _compIter = _compSet.createIterator() ;
    }

     Double_t RooProduct::evaluate() const
    {
      Double_t prod(1) ;
      _compIter->Reset() ;

      RooAbsReal* comp ;
      const RooArgSet* nset = _compSet.nset() ;
      while((comp=(RooAbsReal*)_compIter->Next())) {
        prod *= comp->getVal(nset) ;
      }

      return prod ;
    }