This class is unused and it has only been implemented as a proof of concept.

It shows how to implement the RDataSource API for a complex kind of source such as TTrees.

Definition at line 28 of file RRootDS.hxx.

Public Member Functions
	RRootDS (std::string_view treeName, std::string_view fileNameGlob)

	~RRootDS ()

void	FinaliseSlot (unsigned int slot)
	Convenience method called at the end of the data processing associated to a slot.

const std::vector< std::string > &	GetColumnNames () const
	Returns a reference to the collection of the dataset's column names.

std::vector< std::pair< ULong64_t, ULong64_t > >	GetEntryRanges ()
	Return ranges of entries to distribute to tasks.

std::string	GetLabel ()
	Return a string representation of the datasource type.

std::string	GetTypeName (std::string_view colName) const
	Type of a column as a string, e.g.

bool	HasColumn (std::string_view colName) const
	Checks if the dataset has a certain column.

void	Initialise ()
	Convenience method called before starting an event-loop.

void	InitSlot (unsigned int slot, ULong64_t firstEntry)
	Convenience method called at the start of the data processing associated to a slot.

bool	SetEntry (unsigned int slot, ULong64_t entry)
	Advance the "cursors" returned by GetColumnReaders to the selected entry for a particular slot.

void	SetNSlots (unsigned int nSlots)
	Inform RDataSource of the number of processing slots (i.e.

Public Member Functions inherited from ROOT::RDF::RDataSource
virtual	~RDataSource ()=default

virtual void	Finalise ()
	Convenience method called after concluding an event-loop.

template<typename T >
std::vector< T ** >	GetColumnReaders (std::string_view columnName)
	Called at most once per column by RDF.

virtual std::unique_ptr< ROOT::Detail::RDF::RColumnReaderBase >	GetColumnReaders (unsigned int, std::string_view, const std::type_info &)
	If the other GetColumnReaders overload returns an empty vector, this overload will be called instead.

Protected Member Functions
std::string	AsString ()

Private Member Functions
std::vector< void * >	GetColumnReadersImpl (std::string_view, const std::type_info &)
	type-erased vector of pointers to pointers to column values - one per slot

Private Attributes
std::vector< double * >	fAddressesToFree

std::vector< std::vector< void * > >	fBranchAddresses

std::vector< std::unique_ptr< TChain > >	fChains

std::vector< std::pair< ULong64_t, ULong64_t > >	fEntryRanges

std::string	fFileNameGlob

std::vector< std::string >	fListOfBranches

TChain	fModelChain

unsigned int	fNSlots = 0U

std::string	fTreeName

Additional Inherited Members
Protected Types inherited from ROOT::RDF::RDataSource
using	Record_t = std::vector< void * >

#include <ROOT/RRootDS.hxx>

Inheritance diagram for ROOT::Internal::RDF::RRootDS:

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Constructor & Destructor Documentation

◆ RRootDS()

ROOT::Internal::RDF::RRootDS::RRootDS	(	std::string_view	treeName,
		std::string_view	fileNameGlob
	)

Definition at line 48 of file RRootDS.cxx.

◆ ~RRootDS()

ROOT::Internal::RDF::RRootDS::~RRootDS ( )

Definition at line 60 of file RRootDS.cxx.

Member Function Documentation

◆ AsString()

std::string ROOT::Internal::RDF::RRootDS::AsString ( )

inlineprotectedvirtual

Reimplemented from ROOT::RDF::RDataSource.

Definition at line 43 of file RRootDS.hxx.

◆ FinaliseSlot()

void ROOT::Internal::RDF::RRootDS::FinaliseSlot ( unsigned int )

virtual

Convenience method called at the end of the data processing associated to a slot.

Parameters

[in] slot The data processing slot wihch needs to be finalised This method might be called multiple times per thread per event-loop.

Reimplemented from ROOT::RDF::RDataSource.

Definition at line 120 of file RRootDS.cxx.

◆ GetColumnNames()

const std::vector< std::string > & ROOT::Internal::RDF::RRootDS::GetColumnNames ( ) const

virtual

Returns a reference to the collection of the dataset's column names.

Implements ROOT::RDF::RDataSource.

Definition at line 83 of file RRootDS.cxx.

◆ GetColumnReadersImpl()

std::vector< void * > ROOT::Internal::RDF::RRootDS::GetColumnReadersImpl	(	std::string_view	name,
		const std::type_info &
	)

privatevirtual

type-erased vector of pointers to pointers to column values - one per slot

Implements ROOT::RDF::RDataSource.

Definition at line 26 of file RRootDS.cxx.

◆ GetEntryRanges()

std::vector< std::pair< ULong64_t, ULong64_t > > ROOT::Internal::RDF::RRootDS::GetEntryRanges ( )

virtual

Return ranges of entries to distribute to tasks.

They are required to be contiguous intervals with no entries skipped. Supposing a dataset with nEntries, the intervals must start at 0 and end at nEntries, e.g. [0-5],[5-10] for 10 entries. This function will be invoked repeatedly by RDataFrame as it needs additional entries to process. The same entry range should not be returned more than once. Returning an empty collection of ranges signals to RDataFrame that the processing can stop.

Implements ROOT::RDF::RDataSource.

Definition at line 125 of file RRootDS.cxx.

◆ GetLabel()

std::string ROOT::Internal::RDF::RRootDS::GetLabel ( )

virtual

Return a string representation of the datasource type.

The returned string will be used by ROOT::RDF::SaveGraph() to represent the datasource in the visualization of the computation graph. Concrete datasources can override the default implementation.

Reimplemented from ROOT::RDF::RDataSource.

Definition at line 166 of file RRootDS.cxx.

◆ GetTypeName()

std::string ROOT::Internal::RDF::RRootDS::GetTypeName ( std::string_view colName ) const

virtual

Type of a column as a string, e.g.

GetTypeName("x") == "double". Required for jitting e.g. df.Filter("x>0").

Parameters

[in] colName The name of the column

Implements ROOT::RDF::RDataSource.

Definition at line 67 of file RRootDS.cxx.

◆ HasColumn()

bool ROOT::Internal::RDF::RRootDS::HasColumn ( std::string_view colName ) const

virtual

Checks if the dataset has a certain column.

Parameters

[in] colName The name of the column

Implements ROOT::RDF::RDataSource.

Definition at line 88 of file RRootDS.cxx.

◆ Initialise()

void ROOT::Internal::RDF::RRootDS::Initialise ( )

virtual

Convenience method called before starting an event-loop.

This method might be called multiple times over the lifetime of a RDataSource, since users can run multiple event-loops with the same RDataFrame. Ideally, Initialise should set the state of the RDataSource so that multiple identical event-loops will produce identical results.

Reimplemented from ROOT::RDF::RDataSource.

Definition at line 150 of file RRootDS.cxx.

◆ InitSlot()

void ROOT::Internal::RDF::RRootDS::InitSlot	(	unsigned int	,
		ULong64_t
	)

virtual

Convenience method called at the start of the data processing associated to a slot.

Parameters

[in]	slot	The data processing slot wihch needs to be initialised
[in]	firstEntry	The first entry of the range that the task will process. This method might be called multiple times per thread per event-loop.

Reimplemented from ROOT::RDF::RDataSource.

Definition at line 95 of file RRootDS.cxx.

◆ SetEntry()

bool ROOT::Internal::RDF::RRootDS::SetEntry	(	unsigned int	slot,
		ULong64_t	entry
	)

virtual

Advance the "cursors" returned by GetColumnReaders to the selected entry for a particular slot.

Parameters

[in]	slot	The data processing slot that needs to be considered
[in]	entry	The entry which needs to be pointed to by the reader pointers Slots are adopted to accommodate parallel data processing. Different workers will loop over different ranges and will be labelled by different "slot" values. Returns true if the entry has to be processed, false otherwise.

Implements ROOT::RDF::RDataSource.

Definition at line 131 of file RRootDS.cxx.

◆ SetNSlots()

void ROOT::Internal::RDF::RRootDS::SetNSlots ( unsigned int nSlots )

virtual

Inform RDataSource of the number of processing slots (i.e.

worker threads) used by the associated RDataFrame. Slots numbers are used to simplify parallel execution: RDataFrame guarantees that different threads will always pass different slot values when calling methods concurrently.

Implements ROOT::RDF::RDataSource.

Definition at line 137 of file RRootDS.cxx.

Member Data Documentation

◆ fAddressesToFree

std::vector<double *> ROOT::Internal::RDF::RRootDS::fAddressesToFree

private

Definition at line 34 of file RRootDS.hxx.

◆ fBranchAddresses

std::vector<std::vector<void *> > ROOT::Internal::RDF::RRootDS::fBranchAddresses

private

Definition at line 37 of file RRootDS.hxx.

◆ fChains

std::vector<std::unique_ptr<TChain> > ROOT::Internal::RDF::RRootDS::fChains

private

Definition at line 38 of file RRootDS.hxx.

◆ fEntryRanges

std::vector<std::pair<ULong64_t, ULong64_t> > ROOT::Internal::RDF::RRootDS::fEntryRanges

private

Definition at line 36 of file RRootDS.hxx.

◆ fFileNameGlob

std::string ROOT::Internal::RDF::RRootDS::fFileNameGlob

private

Definition at line 32 of file RRootDS.hxx.

◆ fListOfBranches

std::vector<std::string> ROOT::Internal::RDF::RRootDS::fListOfBranches

private

Definition at line 35 of file RRootDS.hxx.

◆ fModelChain

TChain ROOT::Internal::RDF::RRootDS::fModelChain

mutableprivate

Definition at line 33 of file RRootDS.hxx.

◆ fNSlots

unsigned int ROOT::Internal::RDF::RRootDS::fNSlots = 0U

private

Definition at line 30 of file RRootDS.hxx.

◆ fTreeName

std::string ROOT::Internal::RDF::RRootDS::fTreeName

private

Definition at line 31 of file RRootDS.hxx.

Libraries for ROOT::Internal::RDF::RRootDS:

[legend]

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

tree/dataframe/inc/ROOT/RRootDS.hxx
tree/dataframe/src/RRootDS.cxx

Public Member Functions

Protected Member Functions

Private Member Functions

Private Attributes

Additional Inherited Members

Constructor & Destructor Documentation

◆ RRootDS()

◆ ~RRootDS()

Member Function Documentation

◆ AsString()

◆ FinaliseSlot()

◆ GetColumnNames()

◆ GetColumnReadersImpl()

◆ GetEntryRanges()

◆ GetLabel()

◆ GetTypeName()

◆ HasColumn()

◆ Initialise()

◆ InitSlot()

◆ SetEntry()

◆ SetNSlots()

Member Data Documentation

◆ fAddressesToFree

◆ fBranchAddresses

◆ fChains

◆ fEntryRanges

◆ fFileNameGlob

◆ fListOfBranches

◆ fModelChain

◆ fNSlots

◆ fTreeName