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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
http://root.cern.ch/root/html/tutorials/fit/NumericalMinimization.C.html
http://stat.ethz.ch/R-manual/R-devel/library/stats/html/optim.html

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.

#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.
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
r["RosenBrock"]<<ROOT::R::TRFunctionExport(RosenBrock);
//passing RosenBrockGrad function to R
r["RosenBrockGrad"]<<ROOT::R::TRFunctionExport(RosenBrockGrad);
//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<<"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;
}

Output

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

Users Guide

http://oproject.org/tiki-index.php?page=ROOT+R+Users+Guide
https://root.cern.ch/drupal/content/how-use-r-root-root-r-interface

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...
 
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, 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...
 
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

TRInternalFunctionf
 

Friends

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 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]

Constructor & Destructor Documentation

◆ 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
funother TRFunctionExport

Definition at line 21 of file TRFunctionExport.cxx.

◆ TRFunctionExport() [3/3]

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


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

Parameters
funsupported function to be wrapped by Rcpp

Definition at line 169 of file TRFunctionExport.h.

Member Function Documentation

◆ SetFunction()

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


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

Parameters
funsupported function to be wrapped by Rcpp

Definition at line 179 of file TRFunctionExport.h.

Friends And Related Function Documentation

◆ Rcpp::wrap

SEXP Rcpp::wrap ( const TRFunctionExport f)
friend

◆ TRInterface

friend class TRInterface
friend

Definition at line 142 of file TRFunctionExport.h.

Member Data Documentation

◆ f

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

Definition at line 145 of file TRFunctionExport.h.

Libraries for ROOT::R::TRFunctionExport:
[legend]

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