template<typename... ColumnTypes>
class ROOT::RDF::RLazyDS< ColumnTypes >

A RDataSource implementation which is built on top of result proxies.

This component allows to create a data source on a set of columns coming from one or multiple data frames. The processing of the parent data frames starts only when the event loop is triggered in the data frame initialized with a RLazyDS.

The implementation takes care of matching compile time information with runtime information, e.g. expanding in a smart way the template parameters packs.

Definition at line 41 of file RLazyDSImpl.hxx.

Public Member Functions
	RLazyDS (std::pair< std::string, RResultPtr< std::vector< ColumnTypes > > >... colsNameVals)

	~RLazyDS ()

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

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

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 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.

virtual std::size_t	GetNFiles () const
	Returns the number of files from which the dataset is constructed.

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

Protected Member Functions
std::string	AsString () final

Private Types
using	PointerHolderPtrs_t = std::vector< ROOT::Internal::TDS::TPointerHolder * >

Private Member Functions
template<std::size_t... S>
void	ColLengthChecker (std::index_sequence< S... >)

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

size_t	GetEntriesNumber ()

template<std::size_t... S>
void	SetEntryHelper (unsigned int slot, ULong64_t entry, std::index_sequence< S... >)

Private Attributes
const std::vector< std::string >	fColNames

const std::map< std::string, std::string >	fColTypesMap

std::tuple< RResultPtr< std::vector< ColumnTypes > >... >	fColumns

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

unsigned int	fNSlots {0}

std::vector< PointerHolderPtrs_t >	fPointerHolders

const PointerHolderPtrs_t	fPointerHoldersModels

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

#include <ROOT/RDF/RLazyDSImpl.hxx>

Inheritance diagram for ROOT::RDF::RLazyDS< ColumnTypes >:

[legend]

Member Typedef Documentation

◆ PointerHolderPtrs_t

template<typename... ColumnTypes>

using ROOT::RDF::RLazyDS< ColumnTypes >::PointerHolderPtrs_t = std::vector<ROOT::Internal::TDS::TPointerHolder *>

private

Definition at line 42 of file RLazyDSImpl.hxx.

Constructor & Destructor Documentation

◆ RLazyDS()

template<typename... ColumnTypes>

ROOT::RDF::RLazyDS< ColumnTypes >::RLazyDS ( std::pair< std::string, RResultPtr< std::vector< ColumnTypes > > >... colsNameVals )

inline

Definition at line 120 of file RLazyDSImpl.hxx.

◆ ~RLazyDS()

template<typename... ColumnTypes>

ROOT::RDF::RLazyDS< ColumnTypes >::~RLazyDS ( )

inline

Definition at line 128 of file RLazyDSImpl.hxx.

Member Function Documentation

◆ AsString()

template<typename... ColumnTypes>

std::string ROOT::RDF::RLazyDS< ColumnTypes >::AsString ( )

inlinefinalprotectedvirtual

Reimplemented from ROOT::RDF::RDataSource.

Definition at line 117 of file RLazyDSImpl.hxx.

◆ ColLengthChecker()

template<typename... ColumnTypes>

template<std::size_t... S>

void ROOT::RDF::RLazyDS< ColumnTypes >::ColLengthChecker ( std::index_sequence< S... > )

inlineprivate

Definition at line 96 of file RLazyDSImpl.hxx.

◆ GetColumnNames()

template<typename... ColumnTypes>

const std::vector< std::string > & ROOT::RDF::RLazyDS< ColumnTypes >::GetColumnNames ( ) const

inlinefinalvirtual

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

Implements ROOT::RDF::RDataSource.

Definition at line 137 of file RLazyDSImpl.hxx.

◆ GetColumnReadersImpl()

template<typename... ColumnTypes>

Record_t ROOT::RDF::RLazyDS< ColumnTypes >::GetColumnReadersImpl	(	std::string_view	name,
		const std::type_info &
	)

inlinefinalprivatevirtual

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

Implements ROOT::RDF::RDataSource.

Definition at line 56 of file RLazyDSImpl.hxx.

◆ GetEntriesNumber()

template<typename... ColumnTypes>

size_t ROOT::RDF::RLazyDS< ColumnTypes >::GetEntriesNumber ( )

inlineprivate

Definition at line 86 of file RLazyDSImpl.hxx.

◆ GetEntryRanges()

template<typename... ColumnTypes>

std::vector< std::pair< ULong64_t, ULong64_t > > ROOT::RDF::RLazyDS< ColumnTypes >::GetEntryRanges ( )

inlinefinalvirtual

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 139 of file RLazyDSImpl.hxx.

◆ GetLabel()

template<typename... ColumnTypes>

std::string ROOT::RDF::RLazyDS< ColumnTypes >::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 203 of file RLazyDSImpl.hxx.

◆ GetTypeName()

template<typename... ColumnTypes>

std::string ROOT::RDF::RLazyDS< ColumnTypes >::GetTypeName ( std::string_view colName ) const

inlinefinalvirtual

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 145 of file RLazyDSImpl.hxx.

◆ HasColumn()

template<typename... ColumnTypes>

bool ROOT::RDF::RLazyDS< ColumnTypes >::HasColumn ( std::string_view colName ) const

inlinefinalvirtual

Checks if the dataset has a certain column.

Parameters

[in] colName The name of the column

Implements ROOT::RDF::RDataSource.

Definition at line 151 of file RLazyDSImpl.hxx.

◆ Initialize()

template<typename... ColumnTypes>

void ROOT::RDF::RLazyDS< ColumnTypes >::Initialize ( )

inlinefinalvirtual

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 182 of file RLazyDSImpl.hxx.

◆ SetEntry()

template<typename... ColumnTypes>

bool ROOT::RDF::RLazyDS< ColumnTypes >::SetEntry	(	unsigned int	slot,
		ULong64_t	entry
	)

inlinefinalvirtual

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 158 of file RLazyDSImpl.hxx.

◆ SetEntryHelper()

template<typename... ColumnTypes>

template<std::size_t... S>

void ROOT::RDF::RLazyDS< ColumnTypes >::SetEntryHelper	(	unsigned int	slot,
		ULong64_t	entry,
		std::index_sequence< S... >
	)

inlineprivate

Definition at line 88 of file RLazyDSImpl.hxx.

◆ SetNSlots()

template<typename... ColumnTypes>

void ROOT::RDF::RLazyDS< ColumnTypes >::SetNSlots ( unsigned int nSlots )

inlinefinalvirtual

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 164 of file RLazyDSImpl.hxx.

Member Data Documentation

◆ fColNames

template<typename... ColumnTypes>

const std::vector<std::string> ROOT::RDF::RLazyDS< ColumnTypes >::fColNames

private

Definition at line 45 of file RLazyDSImpl.hxx.

◆ fColTypesMap

template<typename... ColumnTypes>

const std::map<std::string, std::string> ROOT::RDF::RLazyDS< ColumnTypes >::fColTypesMap

private

Definition at line 46 of file RLazyDSImpl.hxx.

◆ fColumns

template<typename... ColumnTypes>

std::tuple<RResultPtr<std::vector<ColumnTypes> >...> ROOT::RDF::RLazyDS< ColumnTypes >::fColumns

private

Definition at line 44 of file RLazyDSImpl.hxx.

◆ fEntryRanges

template<typename... ColumnTypes>

std::vector<std::pair<ULong64_t, ULong64_t> > ROOT::RDF::RLazyDS< ColumnTypes >::fEntryRanges {}

private

Definition at line 53 of file RLazyDSImpl.hxx.

◆ fNSlots

template<typename... ColumnTypes>

unsigned int ROOT::RDF::RLazyDS< ColumnTypes >::fNSlots {0}

private

Definition at line 54 of file RLazyDSImpl.hxx.

◆ fPointerHolders

template<typename... ColumnTypes>

std::vector<PointerHolderPtrs_t> ROOT::RDF::RLazyDS< ColumnTypes >::fPointerHolders

private

Definition at line 52 of file RLazyDSImpl.hxx.

◆ fPointerHoldersModels

template<typename... ColumnTypes>

const PointerHolderPtrs_t ROOT::RDF::RLazyDS< ColumnTypes >::fPointerHoldersModels

private

Definition at line 51 of file RLazyDSImpl.hxx.

tree/dataframe/inc/ROOT/RDF/RLazyDSImpl.hxx

Public Member Functions

Protected Member Functions

Private Types

Private Member Functions

Private Attributes

Additional Inherited Members

Member Typedef Documentation

◆ PointerHolderPtrs_t

Constructor & Destructor Documentation

◆ RLazyDS()

◆ ~RLazyDS()

Member Function Documentation

◆ AsString()

◆ ColLengthChecker()

◆ GetColumnNames()

◆ GetColumnReadersImpl()

◆ GetEntriesNumber()

◆ GetEntryRanges()

◆ GetLabel()

◆ GetTypeName()

◆ HasColumn()

◆ Initialize()

◆ SetEntry()

◆ SetEntryHelper()

◆ SetNSlots()

Member Data Documentation

◆ fColNames

◆ fColTypesMap

◆ fColumns

◆ fEntryRanges

◆ fNSlots

◆ fPointerHolders

◆ fPointerHoldersModels