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RooStats::LikelihoodInterval Class Reference

LikelihoodInterval is a concrete implementation of the RooStats::ConfInterval interface.

It implements a connected N-dimensional intervals based on the contour of a likelihood ratio. The boundary of the interval is equivalent to a MINUIT/MINOS contour about the maximum likelihood estimator

The interval does not need to be an ellipse (eg. it is not the HESSE error matrix). The level used to make the contour is the same as that used in MINOS, eg. it uses Wilks' theorem, which states that under certain regularity conditions the function -2* log (profile likelihood ratio) is asymptotically distributed as a chi^2 with N-dof, where N is the number of parameters of interest.

Note, a boundary on the parameter space (eg. s>= 0) or a degeneracy (eg. mass of signal if Nsig = 0) can lead to violations of the conditions necessary for Wilks' theorem to be true.

Also note, one can use any RooAbsReal as the function that will be used in the contour; however, the level of the contour is based on Wilks' theorem as stated above.

#### References

1. F. James., Minuit.Long writeup D506, CERN, 1998.

Definition at line 34 of file LikelihoodInterval.h.

## Public Member Functions

LikelihoodInterval (const char *name, RooAbsReal *, const RooArgSet *, RooArgSet *=nullptr)
Alternate constructor taking a pointer to the profile likelihood ratio, parameter of interest and optionally a snapshot of best parameter of interest for interval.

LikelihoodInterval (const char *name=nullptr)
default constructor

~LikelihoodInterval () override
destructor

bool CheckParameters (const RooArgSet &) const override
check if parameters are correct (i.e. they are the POI of this interval)

double ConfidenceLevel () const override
return confidence level

bool FindLimits (const RooRealVar &param, double &lower, double &upper)
find both lower and upper interval boundaries for a given parameter return false if the bounds have not been found

const RooArgSetGetBestFitParameters () const
return a pointer to a snapshot with best fit parameter of interest

Int_t GetContourPoints (const RooRealVar &paramX, const RooRealVar &paramY, double *x, double *y, Int_t npoints=30)
return the 2D-contour points for the given subset of parameters by default make the contour using 30 points.

RooAbsRealGetLikelihoodRatio ()
return the profile log-likelihood ratio function

RooArgSetGetParameters () const override
return a cloned list of parameters of interest. User manages the return object

TClassIsA () const override

bool IsInInterval (const RooArgSet &) const override
check if given point is in the interval

double LowerLimit (const RooRealVar &param)
return the lower bound of the interval on a given parameter

double LowerLimit (const RooRealVar &param, bool &status)
Compute lower limit, check first if limit has been computed status is a boolean flag which will b set to false in case of error and is true if calculation is successful in case of error return also a lower limit value of zero.

void SetConfidenceLevel (double cl) override
set the confidence level for the interval (e.g 0.682 for a 1-sigma interval)

void Streamer (TBuffer &) override
Stream an object of class TObject.

void StreamerNVirtual (TBuffer &ClassDef_StreamerNVirtual_b)

double UpperLimit (const RooRealVar &param)
return the upper bound of the interval on a given parameter

double UpperLimit (const RooRealVar &param, bool &status)
Compute upper limit, check first if limit has been computed status is a boolean flag which will b set to false in case of error and is true if calculation is successful in case of error return also a lower limit value of zero.

Public Member Functions inherited from RooStats::ConfInterval
ConfInterval (const char *name=nullptr)
constructor given name and title

ConfIntervaloperator= (const ConfInterval &other)
operator=

void StreamerNVirtual (TBuffer &ClassDef_StreamerNVirtual_b)

Public Member Functions inherited from TNamed
TNamed ()

TNamed (const char *name, const char *title)

TNamed (const TNamed &named)
TNamed copy ctor.

TNamed (const TString &name, const TString &title)

virtual ~TNamed ()
TNamed destructor.

void Clear (Option_t *option="") override
Set name and title to empty strings ("").

TObjectClone (const char *newname="") const override
Make a clone of an object using the Streamer facility.

Int_t Compare (const TObject *obj) const override
Compare two TNamed objects.

void Copy (TObject &named) const override
Copy this to obj.

virtual void FillBuffer (char *&buffer)
Encode TNamed into output buffer.

const char * GetName () const override
Returns name of object.

const char * GetTitle () const override
Returns title of object.

ULong_t Hash () const override
Return hash value for this object.

TClassIsA () const override

Bool_t IsSortable () const override

void ls (Option_t *option="") const override
List TNamed name and title.

TNamedoperator= (const TNamed &rhs)
TNamed assignment operator.

void Print (Option_t *option="") const override
Print TNamed name and title.

virtual void SetName (const char *name)
Set the name of the TNamed.

virtual void SetNameTitle (const char *name, const char *title)
Set all the TNamed parameters (name and title).

virtual void SetTitle (const char *title="")
Set the title of the TNamed.

virtual Int_t Sizeof () const
Return size of the TNamed part of the TObject.

void Streamer (TBuffer &) override
Stream an object of class TObject.

void StreamerNVirtual (TBuffer &ClassDef_StreamerNVirtual_b)

Public Member Functions inherited from TObject
TObject ()
TObject constructor.

TObject (const TObject &object)
TObject copy ctor.

virtual ~TObject ()
TObject destructor.

void AbstractMethod (const char *method) const
Use this method to implement an "abstract" method that you don't want to leave purely abstract.

Append graphics object to current pad.

virtual void Browse (TBrowser *b)
Browse object. May be overridden for another default action.

ULong_t CheckedHash ()
Check and record whether this class has a consistent Hash/RecursiveRemove setup (*) and then return the regular Hash value for this object.

virtual const char * ClassName () const
Returns name of class to which the object belongs.

virtual void Delete (Option_t *option="")
Delete this object.

virtual Int_t DistancetoPrimitive (Int_t px, Int_t py)
Computes distance from point (px,py) to the object.

virtual void Draw (Option_t *option="")
Default Draw method for all objects.

virtual void DrawClass () const
Draw class inheritance tree of the class to which this object belongs.

virtual TObjectDrawClone (Option_t *option="") const
Draw a clone of this object in the current selected pad with: gROOT->SetSelectedPad(c1).

virtual void Dump () const
Dump contents of object on stdout.

virtual void Error (const char *method, const char *msgfmt,...) const
Issue error message.

virtual void Execute (const char *method, const char *params, Int_t *error=nullptr)
Execute method on this object with the given parameter string, e.g.

virtual void Execute (TMethod *method, TObjArray *params, Int_t *error=nullptr)
Execute method on this object with parameters stored in the TObjArray.

virtual void ExecuteEvent (Int_t event, Int_t px, Int_t py)
Execute action corresponding to an event at (px,py).

virtual void Fatal (const char *method, const char *msgfmt,...) const
Issue fatal error message.

virtual TObjectFindObject (const char *name) const
Must be redefined in derived classes.

virtual TObjectFindObject (const TObject *obj) const
Must be redefined in derived classes.

virtual Option_tGetDrawOption () const
Get option used by the graphics system to draw this object.

virtual const char * GetIconName () const
Returns mime type name of object.

virtual char * GetObjectInfo (Int_t px, Int_t py) const
Returns string containing info about the object at position (px,py).

virtual Option_tGetOption () const

virtual UInt_t GetUniqueID () const
Return the unique object id.

virtual Bool_t HandleTimer (TTimer *timer)
Execute action in response of a timer timing out.

Bool_t HasInconsistentHash () const
Return true is the type of this object is known to have an inconsistent setup for Hash and RecursiveRemove (i.e.

virtual void Info (const char *method, const char *msgfmt,...) const
Issue info message.

virtual Bool_t InheritsFrom (const char *classname) const
Returns kTRUE if object inherits from class "classname".

virtual Bool_t InheritsFrom (const TClass *cl) const
Returns kTRUE if object inherits from TClass cl.

virtual void Inspect () const
Dump contents of this object in a graphics canvas.

void InvertBit (UInt_t f)

Bool_t IsDestructed () const
IsDestructed.

virtual Bool_t IsEqual (const TObject *obj) const
Default equal comparison (objects are equal if they have the same address in memory).

virtual Bool_t IsFolder () const
Returns kTRUE in case object contains browsable objects (like containers or lists of other objects).

R__ALWAYS_INLINE Bool_t IsOnHeap () const

R__ALWAYS_INLINE Bool_t IsZombie () const

void MayNotUse (const char *method) const
Use this method to signal that a method (defined in a base class) may not be called in a derived class (in principle against good design since a child class should not provide less functionality than its parent, however, sometimes it is necessary).

virtual Bool_t Notify ()
This method must be overridden to handle object notification (the base implementation is no-op).

void Obsolete (const char *method, const char *asOfVers, const char *removedFromVers) const
Use this method to declare a method obsolete.

void operator delete (void *ptr)
Operator delete.

void operator delete (void *ptr, void *vp)
Only called by placement new when throwing an exception.

void operator delete[] (void *ptr)
Operator delete [].

void operator delete[] (void *ptr, void *vp)
Only called by placement new[] when throwing an exception.

void * operator new (size_t sz)

void * operator new (size_t sz, void *vp)

void * operator new[] (size_t sz)

void * operator new[] (size_t sz, void *vp)

TObjectoperator= (const TObject &rhs)
TObject assignment operator.

virtual void Paint (Option_t *option="")
This method must be overridden if a class wants to paint itself.

virtual void Pop ()
Pop on object drawn in a pad to the top of the display list.

virtual Int_t Read (const char *name)
Read contents of object with specified name from the current directory.

virtual void RecursiveRemove (TObject *obj)
Recursively remove this object from a list.

void ResetBit (UInt_t f)

virtual void SaveAs (const char *filename="", Option_t *option="") const
Save this object in the file specified by filename.

virtual void SavePrimitive (std::ostream &out, Option_t *option="")
Save a primitive as a C++ statement(s) on output stream "out".

void SetBit (UInt_t f)

void SetBit (UInt_t f, Bool_t set)
Set or unset the user status bits as specified in f.

virtual void SetDrawOption (Option_t *option="")
Set drawing option for object.

virtual void SetUniqueID (UInt_t uid)
Set the unique object id.

void StreamerNVirtual (TBuffer &ClassDef_StreamerNVirtual_b)

virtual void SysError (const char *method, const char *msgfmt,...) const
Issue system error message.

R__ALWAYS_INLINE Bool_t TestBit (UInt_t f) const

Int_t TestBits (UInt_t f) const

virtual void UseCurrentStyle ()
Set current style settings in this object This function is called when either TCanvas::UseCurrentStyle or TROOT::ForceStyle have been invoked.

virtual void Warning (const char *method, const char *msgfmt,...) const
Issue warning message.

virtual Int_t Write (const char *name=nullptr, Int_t option=0, Int_t bufsize=0)
Write this object to the current directory.

virtual Int_t Write (const char *name=nullptr, Int_t option=0, Int_t bufsize=0) const
Write this object to the current directory.

## Static Public Member Functions

static TClassClass ()

static const char * Class_Name ()

static constexpr Version_t Class_Version ()

static const char * DeclFileName ()

Static Public Member Functions inherited from RooStats::ConfInterval
static TClassClass ()

static const char * Class_Name ()

static constexpr Version_t Class_Version ()

static const char * DeclFileName ()

Static Public Member Functions inherited from TNamed
static TClassClass ()

static const char * Class_Name ()

static constexpr Version_t Class_Version ()

static const char * DeclFileName ()

Static Public Member Functions inherited from TObject
static TClassClass ()

static const char * Class_Name ()

static constexpr Version_t Class_Version ()

static const char * DeclFileName ()

static Longptr_t GetDtorOnly ()
Return destructor only flag.

static Bool_t GetObjectStat ()
Get status of object stat flag.

static void SetDtorOnly (void *obj)
Set destructor only flag.

static void SetObjectStat (Bool_t stat)
Turn on/off tracking of objects in the TObjectTable.

## Protected Member Functions

bool CreateMinimizer ()
internal function to create the minimizer for finding the contours

void ResetLimits ()
reset the cached limit values

Protected Member Functions inherited from TObject
virtual void DoError (int level, const char *location, const char *fmt, va_list va) const
Interface to ErrorHandler (protected).

void MakeZombie ()

## Private Attributes

RooArgSetfBestFitParams
snapshot of the model parameters with best fit value (managed internally)

double fConfidenceLevel
Requested confidence level (eg. 0.95 for 95% CL)

std::shared_ptr< RooFunctorfFunctor
! transient pointer to functor class used by the minimizer

RooAbsRealfLikelihoodRatio
likelihood ratio function used to make contours (managed internally)

std::map< std::string, doublefLowerLimits
map with cached lower bound values

std::shared_ptr< ROOT::Math::IMultiGenFunctionfMinFunc
! transient pointer to the minimization function

std::shared_ptr< ROOT::Math::MinimizerfMinimizer
! transient pointer to minimizer class used to find limits and contour

RooArgSet fParameters
parameters of interest for this interval

std::map< std::string, doublefUpperLimits
map with cached upper bound values

Public Types inherited from TObject
enum  {
kIsOnHeap = 0x01000000 , kNotDeleted = 0x02000000 , kZombie = 0x04000000 , kInconsistent = 0x08000000 ,
}

enum  { kSingleKey = (1ULL << ( 0 )) , kOverwrite = (1ULL << ( 1 )) , kWriteDelete = (1ULL << ( 2 )) }

enum  EDeprecatedStatusBits { kObjInCanvas = (1ULL << ( 3 )) }

enum  EStatusBits {
kCanDelete = (1ULL << ( 0 )) , kMustCleanup = (1ULL << ( 3 )) , kIsReferenced = (1ULL << ( 4 )) , kHasUUID = (1ULL << ( 5 )) ,
kCannotPick = (1ULL << ( 6 )) , kNoContextMenu = (1ULL << ( 8 )) , kInvalidObject = (1ULL << ( 13 ))
}

Protected Types inherited from TObject
enum  { kOnlyPrepStep = (1ULL << ( 3 )) }

Protected Attributes inherited from TNamed
TString fName

TString fTitle

#include <RooStats/LikelihoodInterval.h>

Inheritance diagram for RooStats::LikelihoodInterval:
[legend]

## ◆ LikelihoodInterval() [1/2]

 LikelihoodInterval::LikelihoodInterval ( const char * name = nullptr )
explicit

default constructor

Default constructor with name and title.

Definition at line 77 of file LikelihoodInterval.cxx.

## ◆ LikelihoodInterval() [2/2]

 LikelihoodInterval::LikelihoodInterval ( const char * name, RooAbsReal * lr, const RooArgSet * params, RooArgSet * bestParams = nullptr )

Alternate constructor taking a pointer to the profile likelihood ratio, parameter of interest and optionally a snapshot of best parameter of interest for interval.

Definition at line 86 of file LikelihoodInterval.cxx.

## ◆ ~LikelihoodInterval()

 LikelihoodInterval::~LikelihoodInterval ( )
override

destructor

Destructor.

Definition at line 99 of file LikelihoodInterval.cxx.

## ◆ CheckParameters()

 bool LikelihoodInterval::CheckParameters ( const RooArgSet & parameterPoint ) const
overridevirtual

check if parameters are correct (i.e. they are the POI of this interval)

check that the parameters are correct

Implements RooStats::ConfInterval.

Definition at line 166 of file LikelihoodInterval.cxx.

## ◆ Class()

 static TClass * RooStats::LikelihoodInterval::Class ( )
static
Returns
TClass describing this class

## ◆ Class_Name()

 static const char * RooStats::LikelihoodInterval::Class_Name ( )
static
Returns
Name of this class

## ◆ Class_Version()

 static constexpr Version_t RooStats::LikelihoodInterval::Class_Version ( )
inlinestaticconstexpr
Returns
Version of this class

Definition at line 109 of file LikelihoodInterval.h.

## ◆ ConfidenceLevel()

 double RooStats::LikelihoodInterval::ConfidenceLevel ( ) const
inlineoverridevirtual

return confidence level

Implements RooStats::ConfInterval.

Definition at line 55 of file LikelihoodInterval.h.

## ◆ CreateMinimizer()

 bool LikelihoodInterval::CreateMinimizer ( )
protected

internal function to create the minimizer for finding the contours

Definition at line 217 of file LikelihoodInterval.cxx.

## ◆ DeclFileName()

 static const char * RooStats::LikelihoodInterval::DeclFileName ( )
inlinestatic
Returns
Name of the file containing the class declaration

Definition at line 109 of file LikelihoodInterval.h.

## ◆ FindLimits()

 bool LikelihoodInterval::FindLimits ( const RooRealVar & param, double & lower, double & upper )

find both lower and upper interval boundaries for a given parameter return false if the bounds have not been found

Definition at line 295 of file LikelihoodInterval.cxx.

## ◆ GetBestFitParameters()

 const RooArgSet * RooStats::LikelihoodInterval::GetBestFitParameters ( ) const
inline

return a pointer to a snapshot with best fit parameter of interest

Definition at line 87 of file LikelihoodInterval.h.

## ◆ GetContourPoints()

 Int_t LikelihoodInterval::GetContourPoints ( const RooRealVar & paramX, const RooRealVar & paramY, double * x, double * y, Int_t npoints = 30 )

return the 2D-contour points for the given subset of parameters by default make the contour using 30 points.

The User has to preallocate the x and y array which will return the set of x and y points defining the contour. The return value of the function specify the number of contour point found. In case of error a zero is returned

Definition at line 365 of file LikelihoodInterval.cxx.

## ◆ GetLikelihoodRatio()

 RooAbsReal * RooStats::LikelihoodInterval::GetLikelihoodRatio ( )
inline

return the profile log-likelihood ratio function

Definition at line 84 of file LikelihoodInterval.h.

## ◆ GetParameters()

 RooArgSet * LikelihoodInterval::GetParameters ( ) const
overridevirtual

return a cloned list of parameters of interest. User manages the return object

returns list of parameters

Implements RooStats::ConfInterval.

Definition at line 158 of file LikelihoodInterval.cxx.

## ◆ IsA()

 TClass * RooStats::LikelihoodInterval::IsA ( ) const
inlineoverridevirtual
Returns
TClass describing current object

Reimplemented from RooStats::ConfInterval.

Definition at line 109 of file LikelihoodInterval.h.

## ◆ IsInInterval()

 bool LikelihoodInterval::IsInInterval ( const RooArgSet & parameterPoint ) const
overridevirtual

check if given point is in the interval

This is the main method to satisfy the RooStats::ConfInterval interface.

It returns true if the parameter point is in the interval.

Implements RooStats::ConfInterval.

Definition at line 110 of file LikelihoodInterval.cxx.

## ◆ LowerLimit() [1/2]

 double RooStats::LikelihoodInterval::LowerLimit ( const RooRealVar & param )
inline

return the lower bound of the interval on a given parameter

Definition at line 65 of file LikelihoodInterval.h.

## ◆ LowerLimit() [2/2]

 double LikelihoodInterval::LowerLimit ( const RooRealVar & param, bool & status )

Compute lower limit, check first if limit has been computed status is a boolean flag which will b set to false in case of error and is true if calculation is successful in case of error return also a lower limit value of zero.

Definition at line 187 of file LikelihoodInterval.cxx.

## ◆ ResetLimits()

 void LikelihoodInterval::ResetLimits ( )
protected

reset the cached limit values

Definition at line 210 of file LikelihoodInterval.cxx.

## ◆ SetConfidenceLevel()

 void RooStats::LikelihoodInterval::SetConfidenceLevel ( double cl )
inlineoverridevirtual

set the confidence level for the interval (e.g 0.682 for a 1-sigma interval)

Implements RooStats::ConfInterval.

Definition at line 52 of file LikelihoodInterval.h.

## ◆ Streamer()

 void RooStats::LikelihoodInterval::Streamer ( TBuffer & R__b )
overridevirtual

Stream an object of class TObject.

Reimplemented from RooStats::ConfInterval.

## ◆ StreamerNVirtual()

 void RooStats::LikelihoodInterval::StreamerNVirtual ( TBuffer & ClassDef_StreamerNVirtual_b )
inline

Definition at line 109 of file LikelihoodInterval.h.

## ◆ UpperLimit() [1/2]

 double RooStats::LikelihoodInterval::UpperLimit ( const RooRealVar & param )
inline

return the upper bound of the interval on a given parameter

Definition at line 69 of file LikelihoodInterval.h.

## ◆ UpperLimit() [2/2]

 double LikelihoodInterval::UpperLimit ( const RooRealVar & param, bool & status )

Compute upper limit, check first if limit has been computed status is a boolean flag which will b set to false in case of error and is true if calculation is successful in case of error return also a lower limit value of zero.

Definition at line 201 of file LikelihoodInterval.cxx.

## ◆ fBestFitParams

 RooArgSet* RooStats::LikelihoodInterval::fBestFitParams
private

snapshot of the model parameters with best fit value (managed internally)

Definition at line 100 of file LikelihoodInterval.h.

## ◆ fConfidenceLevel

 double RooStats::LikelihoodInterval::fConfidenceLevel
private

Requested confidence level (eg. 0.95 for 95% CL)

Definition at line 102 of file LikelihoodInterval.h.

## ◆ fFunctor

 std::shared_ptr RooStats::LikelihoodInterval::fFunctor
private

! transient pointer to functor class used by the minimizer

Definition at line 106 of file LikelihoodInterval.h.

## ◆ fLikelihoodRatio

 RooAbsReal* RooStats::LikelihoodInterval::fLikelihoodRatio
private

likelihood ratio function used to make contours (managed internally)

Definition at line 101 of file LikelihoodInterval.h.

## ◆ fLowerLimits

 std::map RooStats::LikelihoodInterval::fLowerLimits
private

map with cached lower bound values

Definition at line 103 of file LikelihoodInterval.h.

## ◆ fMinFunc

 std::shared_ptr RooStats::LikelihoodInterval::fMinFunc
private

! transient pointer to the minimization function

Definition at line 107 of file LikelihoodInterval.h.

## ◆ fMinimizer

 std::shared_ptr RooStats::LikelihoodInterval::fMinimizer
private

! transient pointer to minimizer class used to find limits and contour

Definition at line 105 of file LikelihoodInterval.h.

## ◆ fParameters

 RooArgSet RooStats::LikelihoodInterval::fParameters
private

parameters of interest for this interval

Definition at line 99 of file LikelihoodInterval.h.

## ◆ fUpperLimits

 std::map RooStats::LikelihoodInterval::fUpperLimits
private

map with cached upper bound values

Definition at line 104 of file LikelihoodInterval.h.

Libraries for RooStats::LikelihoodInterval:

The documentation for this class was generated from the following files: