ROOT R was implemented using the R Project library and the modules Rcpp and RInside

TRInterface class

The TRInterface class lets you process R code from ROOT.
You can call R libraries and their functions, plot results in R or ROOT,
and use the power of ROOT and R at the same time.
It also lets you pass scalars, vectors and matrices from ROOT to R
and from R to ROOT using TRObject; but you can to use overloaded operators [],<< and >>
to work with ROOTR like work with streams of data.

TRInterface class can not be instantiated directly, but you can create objects using the static methods TRInterface& Instance() and TRInterface* InstancePtr() to create your own objects.

Show an example below: Create an exponential fit, the idea is to create a set of numbers x,y with noise from ROOT, pass them to R and fit the data to \( x^3 \), get the fitted coefficient(power) and plot the data, the known function and the fitted function.

TCanvas *c1 = new TCanvas("c1","Curve Fit",700,500);
c1->SetGrid();
 
// draw a frame for multiples graphs
TMultiGraph *mg = new TMultiGraph();
 
// create the first graph (points with gaussian noise)
const Int_t n = 24;
Double_t x[n] ;
Double_t y[n] ;
//Generate points along a X^3 with noise
TRandom rg;
rg.SetSeed(520);
for (Int_t i = 0; i < n; i++) {
   x[i] = rg.Uniform(0, 1);
   y[i] = TMath::Power(x[i], 3) + rg.Gaus() * 0.06;
}
 
TGraph *gr1 = new TGraph(n,x,y);
gr1->SetMarkerColor(kBlue);
gr1->SetMarkerStyle(8);
gr1->SetMarkerSize(1);
mg->Add(gr1);
 
   // create second graph
TF1 *f_known=new TF1("f_known","pow(x,3)",0,1);
TGraph *gr2 = new TGraph(f_known);
gr2->SetMarkerColor(kRed);
gr2->SetMarkerStyle(8);
gr2->SetMarkerSize(1);
mg->Add(gr2);
 
//passing x and y values to R for fitting
ROOT::R::TRInterface &r=ROOT::R::TRInterface::Instance();
r["x"]<<TVectorD(n, x);
r["y"]<<TVectorD(n, y);
//creating a R data frame
r<<"ds<-data.frame(x=x,y=y)";
//fitting x and y to X^power using Nonlinear Least Squares
r<<"m <- nls(y ~ I(x^power),data = ds, start = list(power = 1),trace = T)";
//getting the fitted value (power)
Double_t power;
r["summary(m)$coefficients[1]"]>>power;
 
TF1 *f_fitted=new TF1("f_fitted","pow(x,[0])",0,1);
f_fitted->SetParameter(0,power);
//plotting the fitted function
TGraph *gr3 = new TGraph(f_fitted);
gr3->SetMarkerColor(kGreen);
gr3->SetMarkerStyle(8);
gr3->SetMarkerSize(1);
 
mg->Add(gr3);
mg->Draw("ap");
 
//displaying basic results
TPaveText *pt = new TPaveText(0.1,0.6,0.5,0.9,"brNDC");
pt->SetFillColor(18);
pt->SetTextAlign(12);
pt->AddText("Fitting x^power ");
pt->AddText(" \"Blue\"   Points with gaussian noise to be fitted");
pt->AddText(" \"Red\"    Known function x^3");
TString fmsg;
fmsg.Form(" \"Green\"  Fitted function with power=%.4lf",power);
pt->AddText(fmsg);
pt->Draw();
c1->Update();

Users Guide

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

Definition at line 136 of file TRInterface.h.

Classes
class	Binding

Public Member Functions
	~TRInterface ()

template<typename T >
void	Assign (const T &var, const TString &name)
	Template method to assign C++ variables into R environment.

void	Assign (const TRDataFrame &df, const TString &name)
	Method to assign TRDataFrame in R's environment.

void	Assign (const TRFunctionExport &fun, const TString &name)
	Method to assign TRFunctionExport in R's environment.

TRObject	Eval (const TString &code)
	Method to eval R code and you get the result in a TRObject.

Int_t	Eval (const TString &code, TRObject &ans)
	Method to eval R code and you get the result in a reference to TRObject.

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.

void	Execute (const TString &code)
	Method to eval R code.

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

Bool_t	Install (TString pkg, TString repos="http://cran.r-project.org")
	Method to install an R's package.

void	Interactive ()
	Method to get a R prompt to work interactively with tab completion support.

virtual TClass *	IsA () const

Bool_t	IsInstalled (TString pkg)
	Method to verify if a package is installed.

Binding	operator[] (const TString &name)

void	ProcessEventsLoop ()
	Init event loop in a thread to support actions in windows from R graphics system.

Bool_t	Require (TString pkg)
	Method to load an R's package.

void	SetVerbose (Bool_t status)
	Method to set verbose mode, that produce extra output.

virtual void	Streamer (TBuffer &)
	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.

virtual void	AppendPad (Option_t *option="")
	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	Clear (Option_t *="")

virtual TObject *	Clone (const char *newname="") const
	Make a clone of an object using the Streamer facility.

virtual Int_t	Compare (const TObject *obj) const
	Compare abstract method.

virtual void	Copy (TObject &object) const
	Copy this to obj.

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 TObject *	DrawClone (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	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 TObject *	FindObject (const char *name) const
	Must be redefined in derived classes.

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

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

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

virtual const char *	GetName () const
	Returns 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_t *	GetOption () const

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

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.

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

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

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.

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)

TObject &	operator= (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 void	Print (Option_t *option="") const
	This method must be overridden when a class wants to print itself.

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 TClass *	Class ()

static const char *	Class_Name ()

static constexpr Version_t	Class_Version ()

static const char *	DeclFileName ()

static TRInterface &	Instance ()
	static method to get an TRInterface instance reference

static TRInterface *	InstancePtr ()
	static method to get an TRInterface instance pointer

Static Public Member Functions inherited from TObject
static TClass *	Class ()

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 Attributes
RInside *	fR

TThread *	th

Private Member Functions
	TRInterface (const Int_t argc=0, const Char_t *argv[]=NULL, const Bool_t loadRcpp=true, const Bool_t verbose=false, const Bool_t interactive=true)
	The command line arguments are by default argc=0 and argv=NULL, The verbose mode is by default disabled but you can enable it to show procedures information in stdout/stderr.

Additional Inherited Members
Public Types inherited from TObject
enum	{ kIsOnHeap = 0x01000000 , kNotDeleted = 0x02000000 , kZombie = 0x04000000 , kInconsistent = 0x08000000 , kBitMask = 0x00ffffff }

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 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 ()

#include <TRInterface.h>

Inheritance diagram for ROOT::R::TRInterface:

[legend]

Constructor & Destructor Documentation

◆ TRInterface()

TRInterface::TRInterface	(	const Int_t	argc = `0`,
		const Char_t *	argv[] = `NULL`,
		const Bool_t	loadRcpp = `true`,
		const Bool_t	verbose = `false`,
		const Bool_t	interactive = `true`
	)

private

The command line arguments are by default argc=0 and argv=NULL, The verbose mode is by default disabled but you can enable it to show procedures information in stdout/stderr.

Note: some time can produce so much noise in the output

Parameters

argc	default 0
argv	default null
loadRcpp	default true
verbose	default false
interactive	default true

Definition at line 33 of file TRInterface.cxx.

◆ ~TRInterface()

TRInterface::~TRInterface ( )

Definition at line 71 of file TRInterface.cxx.

Member Function Documentation

◆ Assign() [1/3]

template<typename T >

void ROOT::R::TRInterface::Assign	(	const T &	var,
		const TString &	name
	)

inline

Template method to assign C++ variables into R environment.

Parameters

var	any R wrappable datatype
name	name of the variable in R's environment

Definition at line 258 of file TRInterface.h.

◆ Assign() [2/3]

void TRInterface::Assign	(	const TRDataFrame &	df,
		const TString &	name
	)

Method to assign TRDataFrame in R's environment.

Parameters

df	TRDataFrame
name	name of the variable in R's environment

Definition at line 154 of file TRInterface.cxx.

◆ Assign() [3/3]

void TRInterface::Assign	(	const TRFunctionExport &	fun,
		const TString &	name
	)

Method to assign TRFunctionExport in R's environment.

Parameters

fun	TRFunctionExport
name	name of the variable in R's environment

Definition at line 148 of file TRInterface.cxx.

◆ Class()

static TClass * ROOT::R::TRInterface::Class ( )

static

Returns: TClass describing this class

◆ Class_Name()

static const char * ROOT::R::TRInterface::Class_Name ( )

static

Returns: Name of this class

◆ Class_Version()

static constexpr Version_t ROOT::R::TRInterface::Class_Version ( )

inlinestaticconstexpr

Returns: Version of this class

Definition at line 320 of file TRInterface.h.

◆ DeclFileName()

static const char * ROOT::R::TRInterface::DeclFileName ( )

inlinestatic

Returns: Name of the file containing the class declaration

Definition at line 320 of file TRInterface.h.

◆ Eval() [1/2]

TRObject TRInterface::Eval ( const TString & code )

Method to eval R code and you get the result in a TRObject.

Parameters

code R code

Returns: a TRObject with result

Definition at line 113 of file TRInterface.cxx.

◆ Eval() [2/2]

Int_t TRInterface::Eval	(	const TString &	code,
		TRObject &	ans
	)

Method to eval R code and you get the result in a reference to TRObject.

Parameters

code	R code
ans	reference to TRObject

Returns: an true or false if the execution was successful or not.

Definition at line 80 of file TRInterface.cxx.

◆ Execute() [1/3]

void TObject::Execute	(	const char *	method,
		const char *	params,
		Int_t *	error = `nullptr`
	)

virtual

Execute method on this object with the given parameter string, e.g.

"3.14,1,\"text\"".

Reimplemented from TObject.

Definition at line 130 of file TObject.cxx.

◆ Execute() [2/3]

void TRInterface::Execute ( const TString & code )

Method to eval R code.

Parameters

code R code

Definition at line 99 of file TRInterface.cxx.

◆ Execute() [3/3]

void TObject::Execute	(	TMethod *	method,
		TObjArray *	params,
		Int_t *	error = `nullptr`
	)

virtual

Execute method on this object with parameters stored in the TObjArray.

The TObjArray should contain an argv vector like:

argv[0] ... argv[n] = the list of TObjString parameters

TObjString

Collectable string class.

Definition TObjString.h:28

Reimplemented from TObject.

Definition at line 131 of file TObject.cxx.

◆ Install()

Bool_t TRInterface::Install	(	TString	pkg,
		TString	repos = `"http://cran.r-project.org"`
	)

Method to install an R's package.

Parameters

pkg	R's pkg name
repos	url for R's package repository

Returns: true or false if the package was installed or not

Definition at line 207 of file TRInterface.cxx.

◆ Instance()

TRInterface & TRInterface::Instance ( )

static

static method to get an TRInterface instance reference

Returns: TRInterface instance reference

Definition at line 187 of file TRInterface.cxx.

◆ InstancePtr()

TRInterface * TRInterface::InstancePtr ( )

static

static method to get an TRInterface instance pointer

Returns: TRInterface instance pointer

Definition at line 175 of file TRInterface.cxx.

◆ Interactive()

void TRInterface::Interactive ( )

Method to get a R prompt to work interactively with tab completion support.

Definition at line 161 of file TRInterface.cxx.

◆ IsA()

virtual TClass * ROOT::R::TRInterface::IsA ( ) const

inlinevirtual

Returns: TClass describing current object

Reimplemented from TObject.

Definition at line 320 of file TRInterface.h.

◆ IsInstalled()

Bool_t TRInterface::IsInstalled ( TString pkg )

Method to verify if a package is installed.

Parameters

pkg	R's pkg name

Returns: true or false if the package is installed or not

Definition at line 193 of file TRInterface.cxx.

◆ operator[]()

TRInterface::Binding TRInterface::operator[] ( const TString & name )

Definition at line 142 of file TRInterface.cxx.

◆ ProcessEventsLoop()

void TRInterface::ProcessEventsLoop ( )

Init event loop in a thread to support actions in windows from R graphics system.

Definition at line 219 of file TRInterface.cxx.

◆ Require()

Bool_t TRInterface::Require ( TString pkg )

Method to load an R's package.

Parameters

pkg	R's pkg name

Returns: true or false if the package was loaded or not

Definition at line 200 of file TRInterface.cxx.

◆ SetVerbose()

void TRInterface::SetVerbose ( Bool_t status )

Method to set verbose mode, that produce extra output.

Note: some time can produce so much noise in the output

Parameters

status boolean to enable of disable

Definition at line 134 of file TRInterface.cxx.

◆ Streamer()

virtual void ROOT::R::TRInterface::Streamer ( TBuffer & R__b )

virtual

Stream an object of class TObject.

Reimplemented from TObject.

◆ StreamerNVirtual()

void ROOT::R::TRInterface::StreamerNVirtual ( TBuffer & ClassDef_StreamerNVirtual_b )

inline

Definition at line 320 of file TRInterface.h.

Member Data Documentation

◆ fR

RInside* ROOT::R::TRInterface::fR

protected

Definition at line 138 of file TRInterface.h.

◆ th

TThread* ROOT::R::TRInterface::th

protected

Definition at line 139 of file TRInterface.h.

Libraries for ROOT::R::TRInterface:

[legend]

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

bindings/r/inc/TRInterface.h
bindings/r/src/TRInterface.cxx

TRInterface class

Users Guide

Classes

Public Member Functions

Static Public Member Functions

Protected Attributes

Private Member Functions

Additional Inherited Members

Constructor & Destructor Documentation

◆ TRInterface()

◆ ~TRInterface()

Member Function Documentation

◆ Assign() [1/3]

◆ Assign() [2/3]

◆ Assign() [3/3]

◆ Class()

◆ Class_Name()

◆ Class_Version()

◆ DeclFileName()

◆ Eval() [1/2]

◆ Eval() [2/2]

◆ Execute() [1/3]

◆ Execute() [2/3]

◆ Execute() [3/3]

◆ Install()

◆ Instance()

◆ InstancePtr()

◆ Interactive()

◆ IsA()

◆ IsInstalled()

◆ operator[]()

◆ ProcessEventsLoop()

◆ Require()

◆ SetVerbose()

◆ Streamer()

◆ StreamerNVirtual()

Member Data Documentation

◆ fR

◆ th