    /*****************************************************************************
     * Project: RooFit                                                           *
     * Package: RooFitCore                                                       *
     *    File: $Id: RooGenericPdf.cc,v 1.27 2005/06/20 15:44:53 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] --
    // RooGenericPdf is a concrete implementation of a probability density function,
    // which takes a RooArgList of servers and a C++ expression string defining how
    // its value should be calculated from the given list of servers.
    // A fully numerical integration is automatically performed to normalize the given
    // expression. RooGenericPdf uses a RooFormula object to perform the expression evaluation
    //
    // The string expression can be any valid TFormula expression referring to the
    // listed servers either by name or by their ordinal list position:
    //
    //   RooGenericPdf("gen","x*y",RooArgList(x,y))  or
    //   RooGenericPdf("gen","@0*@1",RooArgList(x,y))
    //
    // The latter form, while slightly less readable, is more versatile because it
    // doesn't hardcode any of the variable names it expects

    #include "RooFit.h"

    #include "RooGenericPdf.h"
    #include "RooGenericPdf.h"
    #include "RooStreamParser.h"
    #include "RooArgList.h"

    ClassImp(RooGenericPdf)

     RooGenericPdf::RooGenericPdf(const char *name, const char *title, const RooArgList& dependents) :
      RooAbsPdf(name,title),
      _actualVars("actualVars","Variables used by PDF expression",this),
      _formula(name,title,dependents)
    {
      // Constructor with formula expression and list of input variables
      _actualVars.add(dependents) ;

      if (_actualVars.getSize()==0) _value = traceEval(0) ;
    }

     RooGenericPdf::RooGenericPdf(const char *name, const char *title,
    			     const char* formula, const RooArgList& dependents) :
      RooAbsPdf(name,title),
      _actualVars("actualVars","Variables used by PDF expression",this),
      _formula(name,formula,dependents)
    {
      _actualVars.add(dependents) ;

      if (_actualVars.getSize()==0) _value = traceEval(0) ;
    }

     RooGenericPdf::RooGenericPdf(const RooGenericPdf& other, const char* name) :
      RooAbsPdf(other, name),
      _actualVars("actualVars",this,other._actualVars),
      _formula(other._formula)
    {
      // Copy constructor
    }

     RooGenericPdf::~RooGenericPdf()
    {
      // Destructor
    }

     Double_t RooGenericPdf::evaluate() const
    {
      // Calculate current value of this object
      return _formula.eval(_normMgr.lastNormSet()) ;
    }

     Bool_t RooGenericPdf::setFormula(const char* formula)
    {
      // Change formula expression to given expression
      if (_formula.reCompile(formula)) return kTRUE ;

      SetTitle(formula) ;
      setValueDirty() ;
      return kFALSE ;
    }

     Bool_t RooGenericPdf::isValidReal(Double_t /*value*/, Bool_t /*printError*/) const {
      // Check if given value is valid
      return kTRUE ;
    }

     Bool_t RooGenericPdf::redirectServersHook(const RooAbsCollection& newServerList, Bool_t mustReplaceAll, Bool_t nameChange, Bool_t /*isRecursive*/)
    {
      // Propagate server changes to embedded formula objecy
      return _formula.changeDependents(newServerList,mustReplaceAll,nameChange) ;
    }

     void RooGenericPdf::printToStream(ostream& os, PrintOption opt, TString indent) const
    {
      // Print info about this object to the specified stream.
      RooAbsPdf::printToStream(os,opt,indent);
      if(opt >= Verbose) {
        indent.Append("  ");
        os << indent;
        _formula.printToStream(os,opt,indent);
      }
    }

     Bool_t RooGenericPdf::readFromStream(istream& is, Bool_t compact, Bool_t /*verbose*/)
    {
      // Read object contents from given stream
      if (compact) {
        cout << "RooGenericPdf::readFromStream(" << GetName() << "): can't read in compact mode" << endl ;
        return kTRUE ;
      } else {
        RooStreamParser parser(is) ;
        return setFormula(parser.readLine()) ;
      }
    }

     void RooGenericPdf::writeToStream(ostream& os, Bool_t compact) const
    {
      // Write object contents to given stream
      if (compact) {
        cout << getVal() << endl ;
      } else {
        os << GetTitle() ;
      }
    }