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ROOT::RDF::RLazyDS< ColumnTypes > Class Template Referencefinal

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 initialised 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 53 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
 Returns a reference to the collection of the dataset's column names. More...
 
std::vector< std::pair< ULong64_t, ULong64_t > > GetEntryRanges ()
 Return ranges of entries to distribute to tasks. More...
 
std::string GetLabel ()
 Return a string representation of the datasource type. More...
 
std::string GetTypeName (std::string_view colName) const
 Type of a column as a string, e.g. More...
 
bool HasColumn (std::string_view colName) const
 Checks if the dataset has a certain column. More...
 
void Initialise ()
 Convenience method called before starting an event-loop. More...
 
bool SetEntry (unsigned int slot, ULong64_t entry)
 Advance the "cursors" returned by GetColumnReaders to the selected entry for a particular slot. More...
 
void SetNSlots (unsigned int nSlots)
 Inform RDataSource of the number of processing slots (i.e. More...
 
- Public Member Functions inherited from ROOT::RDF::RDataSource
virtual ~RDataSource ()=default
 
virtual void Finalise ()
 Convenience method called after concluding an event-loop. More...
 
virtual void FinaliseSlot (unsigned int)
 Convenience method called at the end of the data processing associated to a slot. More...
 
template<typename T >
std::vector< T ** > GetColumnReaders (std::string_view columnName)
 Called at most once per column by RDF. More...
 
virtual void InitSlot (unsigned int, ULong64_t)
 Convenience method called at the start of the data processing associated to a slot. More...
 

Protected Member Functions

std::string AsString ()
 

Private Types

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

Private Member Functions

template<std::size_t... S>
void ColLenghtChecker (std::index_sequence< S... >)
 
Record_t GetColumnReadersImpl (std::string_view colName, const std::type_info &id)
 type-erased vector of pointers to pointers to column values - one per slot More...
 
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_tfPointerHolders
 
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 >:
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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 60 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 138 of file RLazyDSImpl.hxx.

◆ ~RLazyDS()

template<typename... ColumnTypes>
ROOT::RDF::RLazyDS< ColumnTypes >::~RLazyDS ( )
inline

Definition at line 146 of file RLazyDSImpl.hxx.

Member Function Documentation

◆ AsString()

template<typename... ColumnTypes>
std::string ROOT::RDF::RLazyDS< ColumnTypes >::AsString ( )
inlineprotectedvirtual

Reimplemented from ROOT::RDF::RDataSource.

Definition at line 135 of file RLazyDSImpl.hxx.

◆ ColLenghtChecker()

template<typename... ColumnTypes>
template<std::size_t... S>
void ROOT::RDF::RLazyDS< ColumnTypes >::ColLenghtChecker ( std::index_sequence< S... >  )
inlineprivate

Definition at line 114 of file RLazyDSImpl.hxx.

◆ GetColumnNames()

template<typename... ColumnTypes>
const std::vector<std::string>& ROOT::RDF::RLazyDS< ColumnTypes >::GetColumnNames ( ) const
inlinevirtual

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

Implements ROOT::RDF::RDataSource.

Definition at line 155 of file RLazyDSImpl.hxx.

◆ GetColumnReadersImpl()

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

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

Implements ROOT::RDF::RDataSource.

Definition at line 74 of file RLazyDSImpl.hxx.

◆ GetEntriesNumber()

template<typename... ColumnTypes>
size_t ROOT::RDF::RLazyDS< ColumnTypes >::GetEntriesNumber ( )
inlineprivate

Definition at line 104 of file RLazyDSImpl.hxx.

◆ GetEntryRanges()

template<typename... ColumnTypes>
std::vector<std::pair<ULong64_t, ULong64_t> > ROOT::RDF::RLazyDS< ColumnTypes >::GetEntryRanges ( )
inlinevirtual

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 157 of file RLazyDSImpl.hxx.

◆ GetLabel()

template<typename... ColumnTypes>
std::string ROOT::RDF::RLazyDS< ColumnTypes >::GetLabel ( )
inlinevirtual

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 221 of file RLazyDSImpl.hxx.

◆ GetTypeName()

template<typename... ColumnTypes>
std::string ROOT::RDF::RLazyDS< ColumnTypes >::GetTypeName ( std::string_view  ) const
inlinevirtual

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

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

Parameters
[in]columnNameThe name of the column

Implements ROOT::RDF::RDataSource.

Definition at line 163 of file RLazyDSImpl.hxx.

◆ HasColumn()

template<typename... ColumnTypes>
bool ROOT::RDF::RLazyDS< ColumnTypes >::HasColumn ( std::string_view  ) const
inlinevirtual

Checks if the dataset has a certain column.

Parameters
[in]columnNameThe name of the column

Implements ROOT::RDF::RDataSource.

Definition at line 169 of file RLazyDSImpl.hxx.

◆ Initialise()

template<typename... ColumnTypes>
void ROOT::RDF::RLazyDS< ColumnTypes >::Initialise ( )
inlinevirtual

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 200 of file RLazyDSImpl.hxx.

◆ SetEntry()

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

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

Parameters
[in]slotThe data processing slot that needs to be considered
[in]entryThe 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 176 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 106 of file RLazyDSImpl.hxx.

◆ SetNSlots()

template<typename... ColumnTypes>
void ROOT::RDF::RLazyDS< ColumnTypes >::SetNSlots ( unsigned int  nSlots)
inlinevirtual

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 182 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 63 of file RLazyDSImpl.hxx.

◆ fColTypesMap

template<typename... ColumnTypes>
const std::map<std::string, std::string> ROOT::RDF::RLazyDS< ColumnTypes >::fColTypesMap
private

Definition at line 64 of file RLazyDSImpl.hxx.

◆ fColumns

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

Definition at line 62 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 71 of file RLazyDSImpl.hxx.

◆ fNSlots

template<typename... ColumnTypes>
unsigned int ROOT::RDF::RLazyDS< ColumnTypes >::fNSlots {0}
private

Definition at line 72 of file RLazyDSImpl.hxx.

◆ fPointerHolders

template<typename... ColumnTypes>
std::vector<PointerHolderPtrs_t> ROOT::RDF::RLazyDS< ColumnTypes >::fPointerHolders
private

Definition at line 70 of file RLazyDSImpl.hxx.

◆ fPointerHoldersModels

template<typename... ColumnTypes>
const PointerHolderPtrs_t ROOT::RDF::RLazyDS< ColumnTypes >::fPointerHoldersModels
private

Definition at line 69 of file RLazyDSImpl.hxx.


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