The RDataSource implementation for RNTuple.

An RDataFrame that reads RNTuple data can be constructed using MakeNTupleDataFrame().

For each column containing an array or a collection, a corresponding column #colname is available to access colname.size() without reading and deserializing the collection values.

Definition at line 46 of file RNTupleDS.hxx.

Public Member Functions
	RNTupleDS (std::unique_ptr< ROOT::Experimental::Detail::RPageSource > pageSource)

	~RNTupleDS ()

void	Finalize () final
	Convenience method called after concluding an event-loop.

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

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

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

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

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

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

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

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

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

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

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

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

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

Protected Member Functions
Record_t	GetColumnReadersImpl (std::string_view name, const std::type_info &) final
	type-erased vector of pointers to pointers to column values - one per slot

Protected Member Functions inherited from ROOT::RDF::RDataSource
virtual std::string	AsString ()

Private Member Functions
void	AddField (const RNTupleDescriptor &desc, std::string_view colName, DescriptorId_t fieldId, std::vector< DescriptorId_t > skeinIDs)
	Provides the RDF column "colName" given the field identified by fieldID.

Private Attributes
std::vector< size_t >	fActiveColumns

std::vector< std::string >	fColumnNames

std::vector< std::unique_ptr< ROOT::Experimental::Internal::RNTupleColumnReader > >	fColumnReaderPrototypes
	We prepare a column reader prototype for every column.

std::vector< std::string >	fColumnTypes

bool	fHasSeenAllRanges = false

unsigned	fNSlots = 0

std::vector< std::unique_ptr< ROOT::Experimental::Detail::RPageSource > >	fSources
	Clones of the first source, one for each slot.

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

#include <ROOT/RNTupleDS.hxx>

Inheritance diagram for ROOT::Experimental::RNTupleDS:

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Constructor & Destructor Documentation

◆ RNTupleDS()

ROOT::Experimental::RNTupleDS::RNTupleDS ( std::unique_ptr< ROOT::Experimental::Detail::RPageSource > pageSource )

explicit

Definition at line 272 of file RNTupleDS.cxx.

◆ ~RNTupleDS()

ROOT::Experimental::RNTupleDS::~RNTupleDS ( )

default

Member Function Documentation

◆ AddField()

void ROOT::Experimental::RNTupleDS::AddField	(	const RNTupleDescriptor &	desc,
		std::string_view	colName,
		DescriptorId_t	fieldId,
		std::vector< DescriptorId_t >	skeinIDs
	)

private

Provides the RDF column "colName" given the field identified by fieldID.

For records and collections, AddField recurses into the sub fields. The skeinIDs is the list of field IDs of the outer collections of fieldId. For instance, if fieldId refers to an std::vector<Jet>, with struct Jet { float pt; float eta; }; AddField will recurse into Jet.pt and Jet.eta and provide the two inner fields as std::vector<float> each.

Definition at line 161 of file RNTupleDS.cxx.

◆ Finalize()

void ROOT::Experimental::RNTupleDS::Finalize ( )

finalvirtual

Convenience method called after concluding an event-loop.

See Initialize for more details.

Reimplemented from ROOT::RDF::RDataSource.

Definition at line 342 of file RNTupleDS.cxx.

◆ GetColumnNames()

const std::vector< std::string > & ROOT::Experimental::RNTupleDS::GetColumnNames ( ) const

inlinefinalvirtual

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

Implements ROOT::RDF::RDataSource.

Definition at line 78 of file RNTupleDS.hxx.

◆ GetColumnReaders()

std::unique_ptr< ROOT::Detail::RDF::RColumnReaderBase > ROOT::Experimental::RNTupleDS::GetColumnReaders	(	unsigned int	,
		std::string_view	,
		const std::type_info &
	)

finalvirtual

If the other GetColumnReaders overload returns an empty vector, this overload will be called instead.

Parameters

[in]	slot	The data processing slot that needs to be considered
[in]	name	The name of the column for which a column reader needs to be returned
[in]	tid	A type_info At least one of the two must return a non-empty/non-null value.

Reimplemented from ROOT::RDF::RDataSource.

Definition at line 288 of file RNTupleDS.cxx.

◆ GetColumnReadersImpl()

RDF::RDataSource::Record_t ROOT::Experimental::RNTupleDS::GetColumnReadersImpl	(	std::string_view	name,
		const std::type_info &
	)

finalprotectedvirtual

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

Implements ROOT::RDF::RDataSource.

Definition at line 281 of file RNTupleDS.cxx.

◆ GetEntryRanges()

std::vector< std::pair< ULong64_t, ULong64_t > > ROOT::Experimental::RNTupleDS::GetEntryRanges ( )

finalvirtual

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 303 of file RNTupleDS.cxx.

◆ GetLabel()

std::string ROOT::Experimental::RNTupleDS::GetLabel ( )

inlinefinalvirtual

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 82 of file RNTupleDS.hxx.

◆ GetTypeName()

std::string ROOT::Experimental::RNTupleDS::GetTypeName ( std::string_view colName ) const

finalvirtual

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 326 of file RNTupleDS.cxx.

◆ HasColumn()

bool ROOT::Experimental::RNTupleDS::HasColumn ( std::string_view colName ) const

finalvirtual

Checks if the dataset has a certain column.

Parameters

[in] colName The name of the column

Implements ROOT::RDF::RDataSource.

Definition at line 332 of file RNTupleDS.cxx.

◆ Initialize()

void ROOT::Experimental::RNTupleDS::Initialize ( )

finalvirtual

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, Initialize 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 337 of file RNTupleDS.cxx.

◆ SetEntry()

bool ROOT::Experimental::RNTupleDS::SetEntry	(	unsigned int	slot,
		ULong64_t	entry
	)

finalvirtual

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 298 of file RNTupleDS.cxx.

◆ SetNSlots()

void ROOT::Experimental::RNTupleDS::SetNSlots ( unsigned int nSlots )

finalvirtual

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 344 of file RNTupleDS.cxx.

Member Data Documentation

◆ fActiveColumns

std::vector<size_t> ROOT::Experimental::RNTupleDS::fActiveColumns

private

Definition at line 56 of file RNTupleDS.hxx.

◆ fColumnNames

std::vector<std::string> ROOT::Experimental::RNTupleDS::fColumnNames

private

Definition at line 54 of file RNTupleDS.hxx.

◆ fColumnReaderPrototypes

std::vector<std::unique_ptr<ROOT::Experimental::Internal::RNTupleColumnReader> > ROOT::Experimental::RNTupleDS::fColumnReaderPrototypes

private

We prepare a column reader prototype for every column.

If a column reader is actually requested in GetColumnReaders(), we move a clone of the prototype into the hands of RDataFrame. Only the clone connects to the backing page store and acquires I/O resources.

Definition at line 53 of file RNTupleDS.hxx.

◆ fColumnTypes

std::vector<std::string> ROOT::Experimental::RNTupleDS::fColumnTypes

private

Definition at line 55 of file RNTupleDS.hxx.

◆ fHasSeenAllRanges

bool ROOT::Experimental::RNTupleDS::fHasSeenAllRanges = false

private

Definition at line 59 of file RNTupleDS.hxx.

◆ fNSlots

unsigned ROOT::Experimental::RNTupleDS::fNSlots = 0

private

Definition at line 58 of file RNTupleDS.hxx.

◆ fSources

std::vector<std::unique_ptr<ROOT::Experimental::Detail::RPageSource> > ROOT::Experimental::RNTupleDS::fSources

private

Clones of the first source, one for each slot.

Definition at line 48 of file RNTupleDS.hxx.

Libraries for ROOT::Experimental::RNTupleDS:

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

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

Public Member Functions

Protected Member Functions

Private Member Functions

Private Attributes

Additional Inherited Members

Constructor & Destructor Documentation

◆ RNTupleDS()

◆ ~RNTupleDS()

Member Function Documentation

◆ AddField()

◆ Finalize()

◆ GetColumnNames()

◆ GetColumnReaders()

◆ GetColumnReadersImpl()

◆ GetEntryRanges()

◆ GetLabel()

◆ GetTypeName()

◆ HasColumn()

◆ Initialize()

◆ SetEntry()

◆ SetNSlots()

Member Data Documentation

◆ fActiveColumns

◆ fColumnNames

◆ fColumnReaderPrototypes

◆ fColumnTypes

◆ fHasSeenAllRanges

◆ fNSlots

◆ fSources