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Reference Guide
ROOT::Internal::RDF::RRootDS Class Referencefinal

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 FinalizeSlot (unsigned int slot)
 Convenience method called at the end of the data processing associated to a slot. More...
 
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 Initialize ()
 Convenience method called before starting an event-loop. More...
 
void InitSlot (unsigned int slot, ULong64_t firstEntry)
 Convenience method called at the start of the data processing associated to a slot. 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 Finalize ()
 Convenience method called after concluding an event-loop. More...
 
virtual void FinalizeSlot (unsigned int)
 Convenience method called at the end of the data processing associated to a slot. More...
 
virtual const std::vector< std::string > & GetColumnNames () const =0
 Returns a reference to the collection of the dataset's column names. More...
 
template<typename T >
std::vector< T ** > GetColumnReaders (std::string_view columnName)
 Called at most once per column by RDF. More...
 
virtual std::unique_ptr< ROOT::Detail::RDF::RColumnReaderBaseGetColumnReaders (unsigned int, std::string_view, const std::type_info &)
 If the other GetColumnReaders overload returns an empty vector, this overload will be called instead. More...
 
virtual std::vector< std::pair< ULong64_t, ULong64_t > > GetEntryRanges ()=0
 Return ranges of entries to distribute to tasks. More...
 
virtual std::string GetLabel ()
 Return a string representation of the datasource type. More...
 
virtual std::string GetTypeName (std::string_view colName) const =0
 Type of a column as a string, e.g. More...
 
virtual bool HasColumn (std::string_view colName) const =0
 Checks if the dataset has a certain column. More...
 
virtual void Initialize ()
 Convenience method called before starting an event-loop. More...
 
virtual void InitSlot (unsigned int, ULong64_t)
 Convenience method called at the start of the data processing associated to a slot. More...
 
virtual bool SetEntry (unsigned int slot, ULong64_t entry)=0
 Advance the "cursors" returned by GetColumnReaders to the selected entry for a particular slot. More...
 
virtual void SetNSlots (unsigned int nSlots)=0
 Inform RDataSource of the number of processing slots (i.e. More...
 

Protected Member Functions

std::string AsString ()
 
virtual std::string AsString ()
 
virtual Record_t GetColumnReadersImpl (std::string_view name, const std::type_info &)=0
 type-erased vector of pointers to pointers to column values - one per slot More...
 

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 More...
 

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 45 of file RRootDS.cxx.

◆ ~RRootDS()

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

Definition at line 57 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.

◆ FinalizeSlot()

void ROOT::Internal::RDF::RRootDS::FinalizeSlot ( unsigned int  )
virtual

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

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

Reimplemented from ROOT::RDF::RDataSource.

Definition at line 117 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 80 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 23 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 122 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 163 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]colNameThe name of the column

Implements ROOT::RDF::RDataSource.

Definition at line 64 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]colNameThe name of the column

Implements ROOT::RDF::RDataSource.

Definition at line 85 of file RRootDS.cxx.

◆ Initialize()

void ROOT::Internal::RDF::RRootDS::Initialize ( )
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, 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 147 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]slotThe data processing slot wihch needs to be initialized
[in]firstEntryThe 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 92 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]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 128 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 134 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:
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The documentation for this class was generated from the following files: