dmlc::RowBlock< IndexType, DType > Struct Template Reference

a block of data, containing several rows in sparse matrix This is useful for (streaming-sxtyle) algorithms that scans through rows of data examples include: SGD, GD, L-BFGS, kmeans More...

#include <data.h>

Public Member Functions
Row< IndexType, DType >	operator[] (size_t rowid) const
	get specific rows in the batch
size_t	MemCostBytes (void) const
RowBlock	Slice (size_t begin, size_t end) const
	slice a RowBlock to get rows in [begin, end)

Data Fields
size_t	size
	batch size
const size_t *	offset
	array[size+1], row pointer to beginning of each rows
const DType *	label
	array[size] label of each instance
const real_t *	weight
	With weight: array[size] label of each instance, otherwise nullptr.
const uint64_t *	qid
	With qid: array[size] session id of each instance, otherwise nullptr.
const IndexType *	field
	field id
const IndexType *	index
	feature index
const DType *	value
	feature value, can be NULL, indicating all values are 1

Detailed Description

template<typename IndexType, typename DType = real_t>
struct dmlc::RowBlock< IndexType, DType >

a block of data, containing several rows in sparse matrix This is useful for (streaming-sxtyle) algorithms that scans through rows of data examples include: SGD, GD, L-BFGS, kmeans

The size of batch is usually large enough so that parallelizing over the rows can give significant speedup

Template Parameters

IndexType	type to store the index used in row batch
DType	type to store the label and value used in row batch

Member Function Documentation

MemCostBytes()

template<typename IndexType , typename DType = real_t>

size_t dmlc::RowBlock< IndexType, DType >::MemCostBytes ( void  ) const

inline

Returns

memory cost of the block in bytes

operator[]()

template<typename IndexType , typename DType >

Row< IndexType, DType > dmlc::RowBlock< IndexType, DType >::operator[] ( size_t  rowid ) const

inline

get specific rows in the batch

Parameters

rowid

the rowid in that row

Returns

the instance corresponding to the row

Slice()

template<typename IndexType , typename DType = real_t>

RowBlock dmlc::RowBlock< IndexType, DType >::Slice ( size_t  begin, size_t  end  ) const

inline

slice a RowBlock to get rows in [begin, end)

Parameters

begin	the begin row index
end	the end row index

Returns

the sliced RowBlock

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

• External/xgboost/dmlc-core/include/dmlc/data.h