template<typename T>
class ROOT::VecOps::RVec< T >

A "std::vector"-like collection of values implementing handy operation to analyse them.

Template Parameters

T	The type of the contained objects

A RVec is a container designed to make analysis of values' collections fast and easy. Its storage is contiguous in memory and its interface is designed such to resemble to the one of the stl vector. In addition the interface features methods and external functions to ease the manipulation and analysis of the data in the RVec.

Example

Suppose to have an event featuring a collection of muons with a certain pseudorapidity, momentum and charge, e.g.:

std::vector<short> mu_charge {1, 1, -1, -1, -1, 1, 1, -1};
std::vector<float> mu_pt {56, 45, 32, 24, 12, 8, 7, 6.2};
std::vector<float> mu_eta {3.1, -.2, -1.1, 1, 4.1, 1.6, 2.4, -.5};

Suppose you want to extract the transverse momenta of the muons satisfying certain criteria, for example consider only negatively charged muons with a pseudorapidity smaller or equal to 2 and with a transverse momentum greater than 10 GeV. Such a selection would require, among the other things, the management of an explicit loop, for example:

std::vector<float> goodMuons_pt;
const auto size = mu_charge.size();
for (size_t i=0; i < size; ++i) {
   if (mu_pt[i] > 10 && abs(mu_eta[i]) <= 2. &&  mu_charge[i] == -1) {
      goodMuons_pt.emplace_back(mu_pt[i]);
   }
}

These operations become straightforward with RVec - we just need to write what we mean:

RVec<short> mu_charge {1, 1, -1, -1, -1, 1, 1, -1};
RVec<float> mu_pt {56, 45, 32, 24, 12, 8, 7, 6.2};
RVec<float> mu_eta {3.1, -.2, -1.1, 1, 4.1, 1.6, 2.4, -.5};
auto goodMuons_pt = mu_pt[ (mu_pt > 10.f && abs(mu_eta) <= 2.f && mu_charge == -1)

Now the clean collection of transverse momenta can be used within the rest of the data analysis, for example to fill a histogram.

Owning and adopting memory

RVec has contiguous memory associated to it. It can own it or simply adopt it. In the latter case, it can be constructed with the address of the memory associated to it and its lenght. For example:

std::vector<int> myStlVec {1,2,3};

RVec<int> myRVec(myStlVec.data(), myStlVec.size());

In this case, the memory associated to myStlVec and myRVec is the same, myRVec simply "adopted it". If any method which implies a re-allocation is called, e.g. emplace_back or resize, the adopted memory is released and new one is allocated. The previous content is copied in the new memory and preserved.

Usage in combination with TDataFrame

TDataFrame leverages internally RVecs. Suppose to have a dataset stored in a TTree which holds these columns (here we choose C arrays to represent the collections, they could be as well std::vector instances):

nPart            "nPart/I"            An integer representing the number of particles
px               "px[nPart]/D"        The C array of the particles' x component of the momentum
py               "py[nPart]/D"        The C array of the particles' y component of the momentum
E                "E[nPart]/D"         The C array of the particles' Energy

Suppose you'd like to plot in a histogram the transverse momenta of all particles for which the energy is greater than 200 MeV. The code required would just be:

TDataFrame d("mytree", "myfile.root");
using doubles = RVec<double>;
auto cutPt = [](doubles &pxs, doubles &pys, doubles &Es) {
   auto all_pts = sqrt(pxs * pxs + pys * pys);
   auto good_pts = all_pts[Es > 200.];
   return good_pts;
   };
auto hpt = d.Define("pt", cutPt, {"px", "py", "E"})
            .Histo1D("pt");
hpt->Draw();

And if you'd like to express your selection as a string:

TDataFrame d("mytree", "myfile.root");
auto hpt = d.Define("pt", "sqrt(pxs * pxs + pys * pys)[E>200]")
            .Histo1D("pt");
hpt->Draw();

Definition at line 146 of file RVec.hxx.

Public Types
using	const_iterator = typename Impl_t::const_iterator

using	const_pointer = typename Impl_t::const_pointer

using	const_reference = typename Impl_t::const_reference

using	const_reverse_iterator = typename Impl_t::const_reverse_iterator

using	difference_type = typename Impl_t::difference_type

using	Impl_t = typename std::vector< T, ::ROOT::Detail::VecOps::RAdoptAllocator< T > >

using	iterator = typename Impl_t::iterator

using	pointer = typename Impl_t::pointer

using	reference = typename Impl_t::reference

using	reverse_iterator = typename Impl_t::reverse_iterator

using	size_type = typename Impl_t::size_type

using	value_type = typename Impl_t::value_type

Public Member Functions
	RVec ()

	RVec (size_type count)

	RVec (size_type count, const T &value)

	RVec (const RVec< T > &v)

	RVec (RVec< T > &&v)

	RVec (const std::vector< T > &v)

	RVec (pointer p, size_type n)

template<class InputIt >
	RVec (InputIt first, InputIt last)

	RVec (std::initializer_list< T > init)

reference	at (size_type pos)

const_reference	at (size_type pos) const

reference	back ()

const_reference	back () const

iterator	begin () noexcept

const_iterator	begin () const noexcept

size_type	capacity () const noexcept

const_iterator	cbegin () const noexcept

const_iterator	cend () const noexcept

void	clear () noexcept

const_reverse_iterator	crbegin () const noexcept

const_reverse_iterator	crend () const noexcept

T *	data () noexcept

const T *	data () const noexcept

template<typename U = T, typename std::enable_if< std::is_arithmetic< U >::value, int > * = nullptr>
iterator	emplace (const_iterator pos, U value)
	This method is intended only for arithmetic types unlike the std::vector corresponding one which is generic. More...

template<class... Args>
reference	emplace_back (Args &&... args)

bool	empty () const noexcept

iterator	end () noexcept

const_iterator	end () const noexcept

iterator	erase (iterator pos)

iterator	erase (iterator first, iterator last)

reference	front ()

const_reference	front () const

size_type	max_size () const noexcept

template<typename U , typename = std::enable_if<std::is_convertible<T, U>::value>>
	operator RVec< U > () const

RVec< T > &	operator= (const RVec< T > &v)

RVec< T > &	operator= (RVec< T > &&v)

RVec< T > &	operator= (std::initializer_list< T > ilist)

reference	operator[] (size_type pos)

const_reference	operator[] (size_type pos) const

template<typename V , typename = std::enable_if<std::is_convertible<V, bool>::value>>
RVec	operator[] (const RVec< V > &conds) const

void	pop_back ()

void	push_back (T &&value)

reverse_iterator	rbegin () noexcept

const_reverse_iterator	rbegin () const noexcept

reverse_iterator	rend () noexcept

const_reverse_iterator	rend () const noexcept

void	reserve (size_type new_cap)

void	resize (size_type count)

void	resize (size_type count, const value_type &value)

void	shrink_to_fit ()

size_type	size () const noexcept

void	swap (RVec< T > &other)

Private Attributes
Impl_t	fData

#include <ROOT/RVec.hxx>

Member Typedef Documentation

◆ const_iterator

template<typename T>

using ROOT::VecOps::RVec< T >::const_iterator = typename Impl_t::const_iterator

Definition at line 157 of file RVec.hxx.

◆ const_pointer

template<typename T>

using ROOT::VecOps::RVec< T >::const_pointer = typename Impl_t::const_pointer

Definition at line 155 of file RVec.hxx.

◆ const_reference

template<typename T>

using ROOT::VecOps::RVec< T >::const_reference = typename Impl_t::const_reference

Definition at line 153 of file RVec.hxx.

◆ const_reverse_iterator

template<typename T>

using ROOT::VecOps::RVec< T >::const_reverse_iterator = typename Impl_t::const_reverse_iterator

Definition at line 159 of file RVec.hxx.

◆ difference_type

template<typename T>

using ROOT::VecOps::RVec< T >::difference_type = typename Impl_t::difference_type

Definition at line 151 of file RVec.hxx.

◆ Impl_t

template<typename T>

using ROOT::VecOps::RVec< T >::Impl_t = typename std::vector<T, ::ROOT::Detail::VecOps::RAdoptAllocator<T> >

Definition at line 148 of file RVec.hxx.

◆ iterator

template<typename T>

using ROOT::VecOps::RVec< T >::iterator = typename Impl_t::iterator

Definition at line 156 of file RVec.hxx.

◆ pointer

template<typename T>

using ROOT::VecOps::RVec< T >::pointer = typename Impl_t::pointer

Definition at line 154 of file RVec.hxx.

◆ reference

template<typename T>

using ROOT::VecOps::RVec< T >::reference = typename Impl_t::reference

Definition at line 152 of file RVec.hxx.

◆ reverse_iterator

template<typename T>

using ROOT::VecOps::RVec< T >::reverse_iterator = typename Impl_t::reverse_iterator

Definition at line 158 of file RVec.hxx.

◆ size_type

template<typename T>

using ROOT::VecOps::RVec< T >::size_type = typename Impl_t::size_type

Definition at line 150 of file RVec.hxx.

◆ value_type

template<typename T>

using ROOT::VecOps::RVec< T >::value_type = typename Impl_t::value_type

Definition at line 149 of file RVec.hxx.

Constructor & Destructor Documentation

◆ RVec() [1/9]

template<typename T>

ROOT::VecOps::RVec< T >::RVec ( )

inline

Definition at line 166 of file RVec.hxx.

◆ RVec() [2/9]

template<typename T>

ROOT::VecOps::RVec< T >::RVec ( size_type count )

inlineexplicit

Definition at line 168 of file RVec.hxx.

◆ RVec() [3/9]

template<typename T>

ROOT::VecOps::RVec< T >::RVec	(	size_type	count,
		const T &	value
	)

inline

Definition at line 170 of file RVec.hxx.

◆ RVec() [4/9]

template<typename T>

ROOT::VecOps::RVec< T >::RVec ( const RVec< T > & v )

inline

Definition at line 172 of file RVec.hxx.

◆ RVec() [5/9]

template<typename T>

ROOT::VecOps::RVec< T >::RVec ( RVec< T > && v )

inline

Definition at line 174 of file RVec.hxx.

◆ RVec() [6/9]

template<typename T>

ROOT::VecOps::RVec< T >::RVec ( const std::vector< T > & v )

inline

Definition at line 176 of file RVec.hxx.

◆ RVec() [7/9]

template<typename T>

ROOT::VecOps::RVec< T >::RVec	(	pointer	p,
		size_type	n
	)

inline

Definition at line 178 of file RVec.hxx.

◆ RVec() [8/9]

template<typename T>

template<class InputIt >

ROOT::VecOps::RVec< T >::RVec	(	InputIt	first,
		InputIt	last
	)

inline

Definition at line 181 of file RVec.hxx.

◆ RVec() [9/9]

template<typename T>

ROOT::VecOps::RVec< T >::RVec ( std::initializer_list< T > init )

inline

Definition at line 183 of file RVec.hxx.

Member Function Documentation

◆ at() [1/2]

template<typename T>

reference ROOT::VecOps::RVec< T >::at ( size_type pos )

inline

Definition at line 214 of file RVec.hxx.

◆ at() [2/2]

template<typename T>

const_reference ROOT::VecOps::RVec< T >::at ( size_type pos ) const

inline

Definition at line 215 of file RVec.hxx.

◆ back() [1/2]

template<typename T>

reference ROOT::VecOps::RVec< T >::back ( )

inline

Definition at line 237 of file RVec.hxx.

◆ back() [2/2]

template<typename T>

const_reference ROOT::VecOps::RVec< T >::back ( ) const

inline

Definition at line 238 of file RVec.hxx.

◆ begin() [1/2]

template<typename T>

iterator ROOT::VecOps::RVec< T >::begin ( )

inlinenoexcept

Definition at line 242 of file RVec.hxx.

◆ begin() [2/2]

template<typename T>

const_iterator ROOT::VecOps::RVec< T >::begin ( ) const

inlinenoexcept

Definition at line 243 of file RVec.hxx.

◆ capacity()

template<typename T>

size_type ROOT::VecOps::RVec< T >::capacity ( ) const

inlinenoexcept

Definition at line 259 of file RVec.hxx.

◆ cbegin()

template<typename T>

const_iterator ROOT::VecOps::RVec< T >::cbegin ( ) const

inlinenoexcept

Definition at line 244 of file RVec.hxx.

◆ cend()

template<typename T>

const_iterator ROOT::VecOps::RVec< T >::cend ( ) const

inlinenoexcept

Definition at line 247 of file RVec.hxx.

◆ clear()

template<typename T>

void ROOT::VecOps::RVec< T >::clear ( )

inlinenoexcept

Definition at line 262 of file RVec.hxx.

◆ crbegin()

template<typename T>

const_reverse_iterator ROOT::VecOps::RVec< T >::crbegin ( ) const

inlinenoexcept

Definition at line 250 of file RVec.hxx.

◆ crend()

template<typename T>

const_reverse_iterator ROOT::VecOps::RVec< T >::crend ( ) const

inlinenoexcept

Definition at line 253 of file RVec.hxx.

◆ data() [1/2]

template<typename T>

T* ROOT::VecOps::RVec< T >::data ( )

inlinenoexcept

Definition at line 239 of file RVec.hxx.

◆ data() [2/2]

template<typename T>

const T* ROOT::VecOps::RVec< T >::data ( ) const

inlinenoexcept

Definition at line 240 of file RVec.hxx.

◆ emplace()

template<typename T>

template<typename U = T, typename std::enable_if< std::is_arithmetic< U >::value, int > * = nullptr>

iterator ROOT::VecOps::RVec< T >::emplace	(	const_iterator	pos,
		U	value
	)

inline

This method is intended only for arithmetic types unlike the std::vector corresponding one which is generic.

Definition at line 275 of file RVec.hxx.

◆ emplace_back()

template<typename T>

template<class... Args>

reference ROOT::VecOps::RVec< T >::emplace_back ( Args &&... args )

inline

Definition at line 267 of file RVec.hxx.

◆ empty()

template<typename T>

bool ROOT::VecOps::RVec< T >::empty ( ) const

inlinenoexcept

Definition at line 255 of file RVec.hxx.

◆ end() [1/2]

template<typename T>

iterator ROOT::VecOps::RVec< T >::end ( )

inlinenoexcept

Definition at line 245 of file RVec.hxx.

◆ end() [2/2]

template<typename T>

const_iterator ROOT::VecOps::RVec< T >::end ( ) const

inlinenoexcept

Definition at line 246 of file RVec.hxx.

◆ erase() [1/2]

template<typename T>

iterator ROOT::VecOps::RVec< T >::erase ( iterator pos )

inline

Definition at line 263 of file RVec.hxx.

◆ erase() [2/2]

template<typename T>

iterator ROOT::VecOps::RVec< T >::erase	(	iterator	first,
		iterator	last
	)

inline

Definition at line 264 of file RVec.hxx.

◆ front() [1/2]

template<typename T>

reference ROOT::VecOps::RVec< T >::front ( )

inline

Definition at line 235 of file RVec.hxx.

◆ front() [2/2]

template<typename T>

const_reference ROOT::VecOps::RVec< T >::front ( ) const

inline

Definition at line 236 of file RVec.hxx.

◆ max_size()

template<typename T>

size_type ROOT::VecOps::RVec< T >::max_size ( ) const

inlinenoexcept

Definition at line 257 of file RVec.hxx.

◆ operator RVec< U >()

template<typename T>

template<typename U , typename = std::enable_if<std::is_convertible<T, U>::value>>

ROOT::VecOps::RVec< T >::operator RVec< U > ( ) const

inline

Definition at line 206 of file RVec.hxx.

◆ operator=() [1/3]

template<typename T>

RVec<T>& ROOT::VecOps::RVec< T >::operator= ( const RVec< T > & v )

inline

Definition at line 186 of file RVec.hxx.

◆ operator=() [2/3]

template<typename T>

RVec<T>& ROOT::VecOps::RVec< T >::operator= ( RVec< T > && v )

inline

Definition at line 192 of file RVec.hxx.

◆ operator=() [3/3]

template<typename T>

RVec<T>& ROOT::VecOps::RVec< T >::operator= ( std::initializer_list< T > ilist )

inline

Definition at line 198 of file RVec.hxx.

◆ operator[]() [1/3]

template<typename T>

reference ROOT::VecOps::RVec< T >::operator[] ( size_type pos )

inline

Definition at line 216 of file RVec.hxx.

◆ operator[]() [2/3]

template<typename T>

const_reference ROOT::VecOps::RVec< T >::operator[] ( size_type pos ) const

inline

Definition at line 217 of file RVec.hxx.

◆ operator[]() [3/3]

template<typename T>

template<typename V , typename = std::enable_if<std::is_convertible<V, bool>::value>>

RVec ROOT::VecOps::RVec< T >::operator[] ( const RVec< V > & conds ) const

inline

Definition at line 220 of file RVec.hxx.

◆ pop_back()

template<typename T>

void ROOT::VecOps::RVec< T >::pop_back ( )

inline

Definition at line 279 of file RVec.hxx.

◆ push_back()

template<typename T>

void ROOT::VecOps::RVec< T >::push_back ( T && value )

inline

Definition at line 265 of file RVec.hxx.

◆ rbegin() [1/2]

template<typename T>

reverse_iterator ROOT::VecOps::RVec< T >::rbegin ( )

inlinenoexcept

Definition at line 248 of file RVec.hxx.

◆ rbegin() [2/2]

template<typename T>

const_reverse_iterator ROOT::VecOps::RVec< T >::rbegin ( ) const

inlinenoexcept

Definition at line 249 of file RVec.hxx.

◆ rend() [1/2]

template<typename T>

reverse_iterator ROOT::VecOps::RVec< T >::rend ( )

inlinenoexcept

Definition at line 251 of file RVec.hxx.

◆ rend() [2/2]

template<typename T>

const_reverse_iterator ROOT::VecOps::RVec< T >::rend ( ) const

inlinenoexcept

Definition at line 252 of file RVec.hxx.

◆ reserve()

template<typename T>

void ROOT::VecOps::RVec< T >::reserve ( size_type new_cap )

inline

Definition at line 258 of file RVec.hxx.

◆ resize() [1/2]

template<typename T>

void ROOT::VecOps::RVec< T >::resize ( size_type count )

inline

Definition at line 280 of file RVec.hxx.

◆ resize() [2/2]

template<typename T>

void ROOT::VecOps::RVec< T >::resize	(	size_type	count,
		const value_type &	value
	)

inline

Definition at line 281 of file RVec.hxx.

◆ shrink_to_fit()

template<typename T>

void ROOT::VecOps::RVec< T >::shrink_to_fit ( )

inline

Definition at line 260 of file RVec.hxx.

◆ size()

template<typename T>

size_type ROOT::VecOps::RVec< T >::size ( ) const

inlinenoexcept

Definition at line 256 of file RVec.hxx.

◆ swap()

template<typename T>

void ROOT::VecOps::RVec< T >::swap ( RVec< T > & other )

inline

Definition at line 282 of file RVec.hxx.

Member Data Documentation

◆ fData

template<typename T>

Impl_t ROOT::VecOps::RVec< T >::fData

private

Definition at line 162 of file RVec.hxx.

Libraries for ROOT::VecOps::RVec< T >:

[legend]

template<typename T> class ROOT::VecOps::RVec< T >

Table of Contents

Example

Owning and adopting memory

Usage in combination with TDataFrame

Public Types

Public Member Functions

Private Attributes

Member Typedef Documentation

◆ const_iterator

◆ const_pointer

◆ const_reference

◆ const_reverse_iterator

◆ difference_type

◆ Impl_t

◆ iterator

◆ pointer

◆ reference

◆ reverse_iterator

◆ size_type

◆ value_type

Constructor & Destructor Documentation

◆ RVec() [1/9]

◆ RVec() [2/9]

◆ RVec() [3/9]

◆ RVec() [4/9]

◆ RVec() [5/9]

◆ RVec() [6/9]

◆ RVec() [7/9]

◆ RVec() [8/9]

◆ RVec() [9/9]

Member Function Documentation

◆ at() [1/2]

◆ at() [2/2]

◆ back() [1/2]

◆ back() [2/2]

◆ begin() [1/2]

◆ begin() [2/2]

◆ capacity()

◆ cbegin()

◆ cend()

◆ clear()

◆ crbegin()

◆ crend()

◆ data() [1/2]

◆ data() [2/2]

◆ emplace()

◆ emplace_back()

◆ empty()

◆ end() [1/2]

◆ end() [2/2]

◆ erase() [1/2]

◆ erase() [2/2]

◆ front() [1/2]

◆ front() [2/2]

◆ max_size()

◆ operator RVec< U >()

◆ operator=() [1/3]

◆ operator=() [2/3]

◆ operator=() [3/3]

◆ operator[]() [1/3]

◆ operator[]() [2/3]

◆ operator[]() [3/3]

◆ pop_back()

◆ push_back()

◆ rbegin() [1/2]

◆ rbegin() [2/2]

◆ rend() [1/2]

◆ rend() [2/2]

◆ reserve()

◆ resize() [1/2]

◆ resize() [2/2]

◆ shrink_to_fit()

◆ size()

◆ swap()

Member Data Documentation

◆ fData

template<typename T>
class ROOT::VecOps::RVec< T >