RooConstVar.cxx

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/*****************************************************************************
 * Project: RooFit                                                           *
 * Package: RooFitCore                                                       *
 * @(#)root/roofitcore:$Id$
 * 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)             *
 *****************************************************************************/
 
/**
\file RooConstVar.cxx
\class RooConstVar
\ingroup Roofitcore
 
RooConstVar represent a constant real-valued object
**/
 
#include "RooConstVar.h"
#include "RunContext.h"
 
using namespace std;
 
ClassImp(RooConstVar);
 
 
 
////////////////////////////////////////////////////////////////////////////////
/// Constructor with value
RooConstVar::RooConstVar(const char *name, const char *title, Double_t value) : 
  RooAbsReal(name,title)
{
  _fast = true;
  _value = value;
  setAttribute("Constant",kTRUE) ;
}
 
 
 
////////////////////////////////////////////////////////////////////////////////
/// Copy constructor
RooConstVar::RooConstVar(const RooConstVar& other, const char* name) : 
  RooAbsReal(other, name)
{
  _fast = true;
}
 
 
////////////////////////////////////////////////////////////////////////////////
/// Return batch with 1 constant element.
RooSpan<const double> RooConstVar::getValues(RooBatchCompute::RunContext& evalData, const RooArgSet*) const {
  auto item = evalData.spans.find(this);
  if (item == evalData.spans.end()) {
    return evalData.spans[this] = {&_value, 1};
  }
 
  return evalData.spans[this];
}
 
////////////////////////////////////////////////////////////////////////////////
/// Write object contents to stream
 
void RooConstVar::writeToStream(ostream& os, Bool_t /*compact*/) const
{
  os << _value ;
}