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Reference Guide
ROOT::R::TRFunctionExport Class Reference

This is a class to pass functions from ROOT to R.

TRFunctionExport class

The TRFunctionExport class lets you pass ROOT's functions to R's environment

The next example was based in

Let \( f(x,y)=(x-1)^{2} + 100(y-x^{2})^{2} \) , which is called the Rosenbrock function.

It's known that this function has a minimum when \( y = x^{2}\) , and \( x = 1.\) Let's get the minimum using R's optim package through ROOTR's interface. In the code this function was called "Double_t RosenBrock(const TVectorD xx )", because for optim, the input in your function deļ¬nition must be a single vector.

The Gradient is formed by

\( \frac{\partial f}{\partial x} = -400x(y - x^{2}) - 2(1 - x) \)

\( \frac{\partial f}{\partial y} = 200(y - x^{2}); \)

The "TVectorD RosenBrockGrad(const TVectorD xx )" function must have a single vector as the argument a it will return a single vetor.

//in the next function the pointer *double must be changed by TVectorD, because the pointer has no
//sense in R's environment.
Double_t RosenBrock(const TVectorD xx )
const Double_t x = xx[0];
const Double_t y = xx[1];
const Double_t tmp1 = y-x*x;
const Double_t tmp2 = 1-x;
return 100*tmp1*tmp1+tmp2*tmp2;
TVectorD RosenBrockGrad(const TVectorD xx )
const Double_t x = xx[0];
const Double_t y = xx[1];
TVectorD grad(2);
grad[0]=-400 * x * (y - x * x) - 2 * (1 - x);
grad[1]=200 * (y - x * x);
return grad;
//passing RosenBrock function to R
//passing RosenBrockGrad function to R
//the option "method" could be "Nelder-Mead", "BFGS", "CG", "L-BFGS-B", "SANN","Brent"
//the option "control" lets you put some constraints like:
//"maxit" The maximum number of iterations
//"abstol" The absolute convergence tolerance.
//"reltol" Relative convergence tolerance.
r<<"result <- optim( c(0.01,0.01), RosenBrock,method='BFGS',control = list(maxit = 1000000) )";
//Getting results from R
TVectorD min=r.Eval("result$par");
//printing results
std::cout<<"Minimum x="<<min[0]<<" y="<<min[1]<<std::endl;
std::cout<<"Value at minimum ="<<RosenBrock(min)<<std::endl;
//using the gradient
r<<"optimHess(result$par, RosenBrock, RosenBrockGrad)";
r<<"hresult <- optim(c(-1.2,1), RosenBrock, NULL, method = 'BFGS', hessian = TRUE)";
//getting the minimum calculated with the gradient
TVectorD hmin=r.Eval("hresult$par");
//printing results
std::cout<<"Minimization with the Gradient"<<endl;
std::cout<<"Minimum x="<<hmin[0]<<" y="<<hmin[1]<<std::endl;
std::cout<<"Value at minimum ="<<RosenBrock(hmin)<<std::endl;
ROOT::R::TRInterface & r
Definition: Object.C:4
double Double_t
Definition: RtypesCore.h:57
This is a class to pass functions from ROOT to R.
ROOT R was implemented using the R Project library and the modules Rcpp and RInside
Definition: TRInterface.h:136
static TRInterface & Instance()
static method to get an TRInterface instance reference
Int_t Eval(const TString &code, TRObject &ans)
Method to eval R code and you get the result in a reference to TRObject.
Definition: TRInterface.cxx:78
Double_t y[n]
Definition: legend1.C:17
Double_t x[n]
Definition: legend1.C:17
@ Minimization
Definition: RooGlobalFunc.h:67


Processing Minimization.C...
Minimum x=0.99980006 y=0.99960016
Value at minimum =3.9974288e-08
Minimization with the Gradient
Minimum x=0.99980443 y=0.99960838
Value at minimum =3.8273828e-08
const T Minimum(const T &lhs, const T &rhs)
Definition: Functions.h:99

Users Guide

https://oproject.org/pages/ROOT R Users Guide

Definition at line 140 of file TRFunctionExport.h.

Public Member Functions

 TRFunctionExport ()
 Default TRFunctionExport constructor. More...
 TRFunctionExport (const TRFunctionExport &fun)
 TRFunctionExport copy constructor. More...
template<class T >
 TRFunctionExport (T fun)
 TRFunctionExport template constructor that supports a lot of function's prototypes. More...
 ~TRFunctionExport ()
 Default TRFunctionExport destructor. More...
template<class T >
void SetFunction (T fun)
 function to assign function to export, template method that supports a lot of function's prototypes More...
- Public Member Functions inherited from TObject
 TObject ()
 TObject constructor. More...
 TObject (const TObject &object)
 TObject copy ctor. More...
virtual ~TObject ()
 TObject destructor. More...
void AbstractMethod (const char *method) const
 Use this method to implement an "abstract" method that you don't want to leave purely abstract. More...
virtual void AppendPad (Option_t *option="")
 Append graphics object to current pad. More...
virtual void Browse (TBrowser *b)
 Browse object. May be overridden for another default action. More...
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. More...
virtual const char * ClassName () const
 Returns name of class to which the object belongs. More...
virtual void Clear (Option_t *="")
virtual TObjectClone (const char *newname="") const
 Make a clone of an object using the Streamer facility. More...
virtual Int_t Compare (const TObject *obj) const
 Compare abstract method. More...
virtual void Copy (TObject &object) const
 Copy this to obj. More...
virtual void Delete (Option_t *option="")
 Delete this object. More...
virtual Int_t DistancetoPrimitive (Int_t px, Int_t py)
 Computes distance from point (px,py) to the object. More...
virtual void Draw (Option_t *option="")
 Default Draw method for all objects. More...
virtual void DrawClass () const
 Draw class inheritance tree of the class to which this object belongs. More...
virtual TObjectDrawClone (Option_t *option="") const
 Draw a clone of this object in the current selected pad for instance with: gROOT->SetSelectedPad(gPad). More...
virtual void Dump () const
 Dump contents of object on stdout. More...
virtual void Error (const char *method, const char *msgfmt,...) const
 Issue error message. More...
virtual void Execute (const char *method, const char *params, Int_t *error=0)
 Execute method on this object with the given parameter string, e.g. More...
virtual void Execute (TMethod *method, TObjArray *params, Int_t *error=0)
 Execute method on this object with parameters stored in the TObjArray. More...
virtual void ExecuteEvent (Int_t event, Int_t px, Int_t py)
 Execute action corresponding to an event at (px,py). More...
virtual void Fatal (const char *method, const char *msgfmt,...) const
 Issue fatal error message. More...
virtual TObjectFindObject (const char *name) const
 Must be redefined in derived classes. More...
virtual TObjectFindObject (const TObject *obj) const
 Must be redefined in derived classes. More...
virtual Option_tGetDrawOption () const
 Get option used by the graphics system to draw this object. More...
virtual const char * GetIconName () const
 Returns mime type name of object. More...
virtual const char * GetName () const
 Returns name of object. More...
virtual char * GetObjectInfo (Int_t px, Int_t py) const
 Returns string containing info about the object at position (px,py). More...
virtual Option_tGetOption () const
virtual const char * GetTitle () const
 Returns title of object. More...
virtual UInt_t GetUniqueID () const
 Return the unique object id. More...
virtual Bool_t HandleTimer (TTimer *timer)
 Execute action in response of a timer timing out. More...
virtual ULong_t Hash () const
 Return hash value for this object. More...
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. More...
virtual void Info (const char *method, const char *msgfmt,...) const
 Issue info message. More...
virtual Bool_t InheritsFrom (const char *classname) const
 Returns kTRUE if object inherits from class "classname". More...
virtual Bool_t InheritsFrom (const TClass *cl) const
 Returns kTRUE if object inherits from TClass cl. More...
virtual void Inspect () const
 Dump contents of this object in a graphics canvas. More...
void InvertBit (UInt_t f)
virtual Bool_t IsEqual (const TObject *obj) const
 Default equal comparison (objects are equal if they have the same address in memory). More...
virtual Bool_t IsFolder () const
 Returns kTRUE in case object contains browsable objects (like containers or lists of other objects). More...
R__ALWAYS_INLINE Bool_t IsOnHeap () const
virtual Bool_t IsSortable () const
R__ALWAYS_INLINE Bool_t IsZombie () const
virtual void ls (Option_t *option="") const
 The ls function lists the contents of a class on stdout. More...
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). More...
virtual Bool_t Notify ()
 This method must be overridden to handle object notification. More...
void Obsolete (const char *method, const char *asOfVers, const char *removedFromVers) const
 Use this method to declare a method obsolete. More...
void operator delete (void *ptr)
 Operator delete. More...
void operator delete[] (void *ptr)
 Operator delete []. More...
voidoperator new (size_t sz)
voidoperator new (size_t sz, void *vp)
voidoperator new[] (size_t sz)
voidoperator new[] (size_t sz, void *vp)
TObjectoperator= (const TObject &rhs)
 TObject assignment operator. More...
virtual void Paint (Option_t *option="")
 This method must be overridden if a class wants to paint itself. More...
virtual void Pop ()
 Pop on object drawn in a pad to the top of the display list. More...
virtual void Print (Option_t *option="") const
 This method must be overridden when a class wants to print itself. More...
virtual Int_t Read (const char *name)
 Read contents of object with specified name from the current directory. More...
virtual void RecursiveRemove (TObject *obj)
 Recursively remove this object from a list. More...
void ResetBit (UInt_t f)
virtual void SaveAs (const char *filename="", Option_t *option="") const
 Save this object in the file specified by filename. More...
virtual void SavePrimitive (std::ostream &out, Option_t *option="")
 Save a primitive as a C++ statement(s) on output stream "out". More...
void SetBit (UInt_t f)
void SetBit (UInt_t f, Bool_t set)
 Set or unset the user status bits as specified in f. More...
virtual void SetDrawOption (Option_t *option="")
 Set drawing option for object. More...
virtual void SetUniqueID (UInt_t uid)
 Set the unique object id. More...
virtual void SysError (const char *method, const char *msgfmt,...) const
 Issue system error message. More...
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. More...
virtual void Warning (const char *method, const char *msgfmt,...) const
 Issue warning message. More...
virtual Int_t Write (const char *name=0, Int_t option=0, Int_t bufsize=0)
 Write this object to the current directory. More...
virtual Int_t Write (const char *name=0, Int_t option=0, Int_t bufsize=0) const
 Write this object to the current directory. More...

Protected Attributes



SEXP Rcpp::wrap (const TRFunctionExport &f)
class TRInterface

Additional Inherited Members

- Public Types inherited from TObject
enum  {
  kIsOnHeap = 0x01000000 , kNotDeleted = 0x02000000 , kZombie = 0x04000000 , kInconsistent = 0x08000000 ,
  kBitMask = 0x00ffffff
enum  { kSingleKey = BIT(0) , kOverwrite = BIT(1) , kWriteDelete = BIT(2) }
enum  EDeprecatedStatusBits { kObjInCanvas = BIT(3) }
enum  EStatusBits {
  kCanDelete = BIT(0) , kMustCleanup = BIT(3) , kIsReferenced = BIT(4) , kHasUUID = BIT(5) ,
  kCannotPick = BIT(6) , kNoContextMenu = BIT(8) , kInvalidObject = BIT(13)
- Static Public Member Functions inherited from TObject
static Long_t GetDtorOnly ()
 Return destructor only flag. More...
static Bool_t GetObjectStat ()
 Get status of object stat flag. More...
static void SetDtorOnly (void *obj)
 Set destructor only flag. More...
static void SetObjectStat (Bool_t stat)
 Turn on/off tracking of objects in the TObjectTable. More...
- Protected Types inherited from TObject
enum  { kOnlyPrepStep = BIT(3) }
- 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). More...
void MakeZombie ()

#include <TRFunctionExport.h>

Inheritance diagram for ROOT::R::TRFunctionExport:

Constructor & Destructor Documentation

◆ TRFunctionExport() [1/3]

TRFunctionExport::TRFunctionExport ( )

Default TRFunctionExport constructor.

Definition at line 15 of file TRFunctionExport.cxx.

◆ ~TRFunctionExport()

ROOT::R::TRFunctionExport::~TRFunctionExport ( )

Default TRFunctionExport destructor.

Definition at line 154 of file TRFunctionExport.h.

◆ TRFunctionExport() [2/3]

TRFunctionExport::TRFunctionExport ( const TRFunctionExport fun)

TRFunctionExport copy constructor.

funother TRFunctionExport

Definition at line 21 of file TRFunctionExport.cxx.

◆ TRFunctionExport() [3/3]

template<class T >
ROOT::R::TRFunctionExport::TRFunctionExport ( fun)

TRFunctionExport template constructor that supports a lot of function's prototypes.

funsupported function to be wrapped by Rcpp

Definition at line 168 of file TRFunctionExport.h.

Member Function Documentation

◆ SetFunction()

template<class T >
void ROOT::R::TRFunctionExport::SetFunction ( fun)

function to assign function to export, template method that supports a lot of function's prototypes

funsupported function to be wrapped by Rcpp

Definition at line 178 of file TRFunctionExport.h.

Friends And Related Function Documentation

◆ Rcpp::wrap

SEXP Rcpp::wrap ( const TRFunctionExport f)

◆ TRInterface

friend class TRInterface

Definition at line 141 of file TRFunctionExport.h.

Member Data Documentation

◆ f

TRInternalFunction* ROOT::R::TRFunctionExport::f

Definition at line 144 of file TRFunctionExport.h.

Libraries for ROOT::R::TRFunctionExport:

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