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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
21class RooArgSet ;
22namespace RooBatchCompute {
23 struct RunContext;
24}
25
26class RooConstVar final : public RooAbsReal {
27public:
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
57protected:
58
60 return _value;
61 }
62
63 ClassDef(RooConstVar,2) // Constant RooAbsReal value object
64};
65
66#endif
bool Bool_t
Definition: RtypesCore.h:63
double Double_t
Definition: RtypesCore.h:59
#define ClassDef(name, id)
Definition: Rtypes.h:325
char name[80]
Definition: TGX11.cxx:110
RooAbsReal is the common abstract base class for objects that represent a real value and implements f...
Definition: RooAbsReal.h:61
Double_t _value
Definition: RooAbsReal.h:477
RooArgSet is a container object that can hold multiple RooAbsArg objects.
Definition: RooArgSet.h:35
RooConstVar represent a constant real-valued object.
Definition: RooConstVar.h:26
void writeToStream(std::ostream &os, Bool_t compact) const
Write object contents to stream.
Definition: RooConstVar.cxx:69
virtual ~RooConstVar()=default
RooSpan< const double > getValues(RooBatchCompute::RunContext &evalData, const RooArgSet *) const
Return batch with 1 constant element.
Definition: RooConstVar.cxx:57
virtual TObject * clone(const char *newname) const
Definition: RooConstVar.h:32
virtual Double_t getValV(const RooArgSet *) const
Return (constant) value.
Definition: RooConstVar.h:36
Double_t evaluate() const
Evaluate this PDF / function / constant. Needs to be overridden by all derived classes.
Definition: RooConstVar.h:59
virtual Bool_t isDerived() const
Returns false, as the value of the constant doesn't depend on other objects.
Definition: RooConstVar.h:45
void changeVal(double value)
Change the value of this constant.
Definition: RooConstVar.h:53
A simple container to hold a batch of data values.
Definition: RooSpan.h:34
Mother of all ROOT objects.
Definition: TObject.h:37
Namespace for dispatching RooFit computations to various backends.
This struct enables passing computation data around between elements of a computation graph.
Definition: RunContext.h:31