group_data.h File Reference

this file defines utils to group data by integer keys Input: given input sequence (key,value), (k1,v1), (k2,v2) Ouptupt: an array of values data = [v1,v2,v3 .. vn] and a group pointer ptr, data[ptr[k]:ptr[k+1]] contains values that corresponds to key k More...

#include <cstddef>
#include <vector>
#include <algorithm>
#include <utility>
#include "xgboost/base.h"

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Classes
class	xgboost::common::ParallelGroupBuilder< ValueType, SizeType, is_row_major >
	multi-thread version of group builder More...

Namespaces
	xgboost
	namespace of xgboost
	xgboost::common

Detailed Description

this file defines utils to group data by integer keys Input: given input sequence (key,value), (k1,v1), (k2,v2) Ouptupt: an array of values data = [v1,v2,v3 .. vn] and a group pointer ptr, data[ptr[k]:ptr[k+1]] contains values that corresponds to key k

Copyright 2014-2021 by Contributors

This can be used to construct CSR/CSC matrix from un-ordered input The major algorithm is a two pass linear scan algorithm that requires two pass scan over the data

Author

Tianqi Chen