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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 value);
31 RooConstVar(const RooConstVar& other, const char* name=0);
32 TObject* clone(const char* newname) const override { return new RooConstVar(*this,newname); }
33 ~RooConstVar() override = default;
34
35 /// Return (constant) value.
36 double getValV(const RooArgSet*) const override {
37 return _value;
38 }
39
41
42 void writeToStream(std::ostream& os, bool compact) const override ;
43
44 /// Returns false, as the value of the constant doesn't depend on other objects.
45 bool isDerived() const override {
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
59 double evaluate() const override {
60 return _value;
61 }
62
63 ClassDefOverride(RooConstVar,2) // Constant RooAbsReal value object
64};
65
66#endif
#define ClassDefOverride(name, id)
Definition: Rtypes.h:339
Option_t Option_t TPoint TPoint const char GetTextMagnitude GetFillStyle GetLineColor GetLineWidth GetMarkerStyle GetTextAlign GetTextColor GetTextSize void value
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:64
double _value
Cache for current value of object.
Definition: RooAbsReal.h:484
RooArgSet is a container object that can hold multiple RooAbsArg objects.
Definition: RooArgSet.h:57
RooConstVar represent a constant real-valued object.
Definition: RooConstVar.h:26
bool isDerived() const override
Returns false, as the value of the constant doesn't depend on other objects.
Definition: RooConstVar.h:45
~RooConstVar() override=default
double getValV(const RooArgSet *) const override
Return (constant) value.
Definition: RooConstVar.h:36
RooSpan< const double > getValues(RooBatchCompute::RunContext &evalData, const RooArgSet *) const override
Return batch with 1 constant element.
Definition: RooConstVar.cxx:57
TObject * clone(const char *newname) const override
Definition: RooConstVar.h:32
void writeToStream(std::ostream &os, bool compact) const override
Write object contents to stream.
Definition: RooConstVar.cxx:69
double evaluate() const override
Evaluate this PDF / function / constant. Needs to be overridden by all derived classes.
Definition: RooConstVar.h:59
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