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RooConstVar.h
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1 /*****************************************************************************
2  * Project: RooFit *
3  * Package: RooFitCore *
4  * File: $Id: RooConstVar.h,v 1.9 2007/05/11 09:11:30 verkerke Exp $
5  * Authors: *
6  * WV, Wouter Verkerke, UC Santa Barbara, verkerke@slac.stanford.edu *
7  * DK, David Kirkby, UC Irvine, dkirkby@uci.edu *
8  * *
9  * Copyright (c) 2000-2005, Regents of the University of California *
10  * and Stanford University. All rights reserved. *
11  * *
12  * Redistribution and use in source and binary forms, *
13  * with or without modification, are permitted according to the terms *
14  * listed in LICENSE (http://roofit.sourceforge.net/license.txt) *
15  *****************************************************************************/
16 #ifndef ROO_CONST_VAR
17 #define ROO_CONST_VAR
18 
19 #include "RooAbsReal.h"
20 
21 class RooArgSet ;
22 namespace RooBatchCompute {
23  struct RunContext;
24 }
25 
26 class RooConstVar final : public RooAbsReal {
27 public:
28  // Constructors, assignment etc
30  RooConstVar(const char *name, const char *title, Double_t value);
31  RooConstVar(const RooConstVar& other, const char* name=0);
32  virtual TObject* clone(const char* newname) const { return new RooConstVar(*this,newname); }
33  virtual ~RooConstVar() = default;
34 
35  /// Return (constant) value.
36  virtual Double_t getValV(const RooArgSet*) const {
37  return _value;
38  }
39 
41 
42  void writeToStream(std::ostream& os, Bool_t compact) const ;
43 
44  /// Returns false, as the value of the constant doesn't depend on other objects.
45  virtual Bool_t isDerived() const {
46  return false;
47  }
48 
49  /// Change the value of this constant.
50  /// On purpose, this is not `setVal`, as this could be confused with the `setVal`
51  /// that is available for variables. Constants, however, should remain mostly constant.
52  /// This function is e.g. useful when reading the constant from a file.
53  void changeVal(double value) {
54  _value = value;
55  }
56 
57 protected:
58 
59  Double_t evaluate() const {
60  return _value;
61  }
62 
63  ClassDef(RooConstVar,2) // Constant RooAbsReal value object
64 };
65 
66 #endif
RooAbsReal.h
RooConstVar::clone
virtual TObject * clone(const char *newname) const
Definition: RooConstVar.h:32
RooAbsReal
RooAbsReal is the common abstract base class for objects that represent a real value and implements f...
Definition: RooAbsReal.h:61
RooConstVar
RooConstVar represent a constant real-valued object.
Definition: RooConstVar.h:26
RooConstVar::evaluate
Double_t evaluate() const
Evaluate this PDF / function / constant. Needs to be overridden by all derived classes.
Definition: RooConstVar.h:59
RooConstVar::RooConstVar
RooConstVar()
Definition: RooConstVar.h:29
bool
RooConstVar::isDerived
virtual Bool_t isDerived() const
Returns false, as the value of the constant doesn't depend on other objects.
Definition: RooConstVar.h:45
RooConstVar::getValues
RooSpan< const double > getValues(RooBatchCompute::RunContext &evalData, const RooArgSet *) const
Return batch with 1 constant element.
Definition: RooConstVar.cxx:57
RooAbsReal::_value
Double_t _value
Definition: RooAbsReal.h:477
Double_t
double Double_t
Definition: RtypesCore.h:59
RooConstVar::~RooConstVar
virtual ~RooConstVar()=default
TObject
Mother of all ROOT objects.
Definition: TObject.h:37
ClassDef
#define ClassDef(name, id)
Definition: Rtypes.h:325
name
char name[80]
Definition: TGX11.cxx:110
RooBatchCompute
Namespace for dispatching RooFit computations to various backends.
Definition: BracketAdapter.h:24
RooConstVar::getValV
virtual Double_t getValV(const RooArgSet *) const
Return (constant) value.
Definition: RooConstVar.h:36
RooConstVar::writeToStream
void writeToStream(std::ostream &os, Bool_t compact) const
Write object contents to stream.
Definition: RooConstVar.cxx:69
RooBatchCompute::RunContext
This struct enables passing computation data around between elements of a computation graph.
Definition: RunContext.h:31
RooSpan
A simple container to hold a batch of data values.
Definition: RooSpan.h:34
RooConstVar::changeVal
void changeVal(double value)
Change the value of this constant.
Definition: RooConstVar.h:53
RooArgSet
RooArgSet is a container object that can hold multiple RooAbsArg objects.
Definition: RooArgSet.h:33