ROOT   6.10/09 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

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.

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

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

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

#include<TRInterface.h>
//in the next function the pointer *double must be changed by TVectorD, because the pointer has no
//sense in R's environment.
{
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;
}
{
const Double_t x = xx[0];
const Double_t y = xx[1];
grad[0]=-400 * x * (y - x * x) - 2 * (1 - x);
grad[1]=200 * (y - x * x);
}
{
//passing RosenBrock 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$par"); std::cout.precision(8); //printing results std::cout<<"-----------------------------------------"<<std::endl; std::cout<<"Minimum x="<<min[0]<<" y="<<min[1]<<std::endl; std::cout<<"Value at minimum ="<<RosenBrock(min)<<std::endl; //using the gradient r<<"optimHess(result$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<<"-----------------------------------------"<<std::endl;
std::cout<<"Minimum x="<<hmin[0]<<" y="<<hmin[1]<<std::endl;
std::cout<<"Value at minimum ="<<RosenBrock(hmin)<<std::endl;
}

Output

Processing Minimization.C...
-----------------------------------------
Minimum x=0.99980006 y=0.99960016
Value at minimum =3.9974288e-08
-----------------------------------------
Minimum x=0.99980443 y=0.99960838
Value at minimum =3.8273828e-08

## Users Guide

Definition at line 141 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...

Append graphics object to current pad. More...

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

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...

Bool_t IsOnHeap () const

virtual Bool_t IsSortable () const

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, Bool_t set)
Set or unset the user status bits as specified in f. More...

void SetBit (UInt_t f)

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...

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

TRInternalFunctionf

## Friends

SEXP Rcpp::wrap (const TRFunctionExport &f)

class TRInterface

Public Types inherited from TObject
enum  { kIsOnHeap = 0x01000000, kNotDeleted = 0x02000000, kZombie = 0x04000000, kBitMask = 0x00ffffff }

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

enum  EStatusBits {
kCanDelete = BIT(0), kMustCleanup = BIT(3), kObjInCanvas = 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 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:
[legend]

## ◆ TRFunctionExport() [1/3]

 TRFunctionExport::TRFunctionExport ( )

Default TRFunctionExport constructor.

Definition at line 15 of file TRFunctionExport.cxx.

## ◆ ~TRFunctionExport()

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

Default TRFunctionExport destructor.

Definition at line 155 of file TRFunctionExport.h.

## ◆ TRFunctionExport() [2/3]

 TRFunctionExport::TRFunctionExport ( const TRFunctionExport & fun )

TRFunctionExport copy constructor.

Parameters
 fun other TRFunctionExport

Definition at line 21 of file TRFunctionExport.cxx.

## ◆ TRFunctionExport() [3/3]

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

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

Parameters
 fun supported function to be wrapped by Rcpp

Definition at line 169 of file TRFunctionExport.h.

## ◆ SetFunction()

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

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

Parameters
 fun supported function to be wrapped by Rcpp

Definition at line 179 of file TRFunctionExport.h.

## ◆ Rcpp::wrap

 SEXP Rcpp::wrap ( const TRFunctionExport & f )
friend

## ◆ TRInterface

 friend class TRInterface
friend

Definition at line 142 of file TRFunctionExport.h.

## ◆ f

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

Definition at line 145 of file TRFunctionExport.h.

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