Slicing

Files
file	copying.hpp
	Column APIs for gather, scatter, split, slice, etc.

Functions
std::vector< column_view >	cudf::slice (column_view const &input, host_span< size_type const > indices, rmm::cuda_stream_view stream=cudf::get_default_stream())
	Slices a column_view into a set of column_views according to a set of indices. More...
std::vector< column_view >	cudf::slice (column_view const &input, std::initializer_list< size_type > indices, rmm::cuda_stream_view stream=cudf::get_default_stream())
	Slices a column_view into a set of column_views according to a set of indices. More...
std::vector< table_view >	cudf::slice (table_view const &input, host_span< size_type const > indices, rmm::cuda_stream_view stream=cudf::get_default_stream())
	Slices a table_view into a set of table_views according to a set of indices. More...
std::vector< table_view >	cudf::slice (table_view const &input, std::initializer_list< size_type > indices, rmm::cuda_stream_view stream=cudf::get_default_stream())
	Slices a table_view into a set of table_views according to a set of indices. More...

Detailed Description

Function Documentation

slice() [1/4]

std::vector<column_view> cudf::slice	(	column_view const &	input,
		host_span< size_type const >	indices,
		rmm::cuda_stream_view	stream = cudf::get_default_stream()
	)

Slices a column_view into a set of column_views according to a set of indices.

The returned views of input are constructed from an even number indices where the ith returned column_view views the elements in input indicated by the range [indices[2*i], indices[(2*i)+1]).

For all i it is expected indices[i] <= input.size() For all i%2==0, it is expected that indices[i] <= indices[i+1]

Note

It is the caller's responsibility to ensure that the returned views do not outlive the viewed device memory.

input:   {10, 12, 14, 16, 18, 20, 22, 24, 26, 28}
indices: {1, 3, 5, 9, 2, 4, 8, 8}
output:  {{12, 14}, {20, 22, 24, 26}, {14, 16}, {}}

Exceptions

cudf::logic_error	if indices size is not even.
cudf::logic_error	When the values in the pair are strictly decreasing.
cudf::logic_error	When any of the values in the pair don't belong to the range [0, input.size()).

Parameters

input	View of column to slice
indices	Indices used to take slices of input
stream	CUDA stream used for device memory operations and kernel launches

Returns

Vector of views of input indicated by the ranges in indices

slice() [2/4]

std::vector<column_view> cudf::slice	(	column_view const &	input,
		std::initializer_list< size_type >	indices,
		rmm::cuda_stream_view	stream = cudf::get_default_stream()
	)

Slices a column_view into a set of column_views according to a set of indices.

The returned views of input are constructed from an even number indices where the ith returned column_view views the elements in input indicated by the range [indices[2*i], indices[(2*i)+1]).

For all i it is expected indices[i] <= input.size() For all i%2==0, it is expected that indices[i] <= indices[i+1]

Note

It is the caller's responsibility to ensure that the returned views do not outlive the viewed device memory.

input:   {10, 12, 14, 16, 18, 20, 22, 24, 26, 28}
indices: {1, 3, 5, 9, 2, 4, 8, 8}
output:  {{12, 14}, {20, 22, 24, 26}, {14, 16}, {}}

Exceptions

cudf::logic_error	if indices size is not even.
cudf::logic_error	When the values in the pair are strictly decreasing.
cudf::logic_error	When any of the values in the pair don't belong to the range [0, input.size()).

Parameters

input	View of column to slice
indices	Indices used to take slices of input
stream	CUDA stream used for device memory operations and kernel launches

Returns

Vector of views of input indicated by the ranges in indices

slice() [3/4]

std::vector<table_view> cudf::slice	(	table_view const &	input,
		host_span< size_type const >	indices,
		rmm::cuda_stream_view	stream = cudf::get_default_stream()
	)

Slices a table_view into a set of table_views according to a set of indices.

The returned views of input are constructed from an even number indices where the ith returned table_view views the elements in input indicated by the range [indices[2*i], indices[(2*i)+1]).

For all i it is expected indices[i] <= input.size() For all i%2==0, it is expected that indices[i] <= indices[i+1]

Note

It is the caller's responsibility to ensure that the returned views do not outlive the viewed device memory.

input:   [{10, 12, 14, 16, 18, 20, 22, 24, 26, 28},
          {50, 52, 54, 56, 58, 60, 62, 64, 66, 68}]
indices: {1, 3, 5, 9, 2, 4, 8, 8}
output:  [{{12, 14}, {20, 22, 24, 26}, {14, 16}, {}},
          {{52, 54}, {60, 22, 24, 26}, {14, 16}, {}}]

Exceptions

cudf::logic_error	if indices size is not even.
cudf::logic_error	When the values in the pair are strictly decreasing.
cudf::logic_error	When any of the values in the pair don't belong to the range [0, input.size()).

Parameters

input	View of table to slice
indices	Indices used to take slices of input
stream	CUDA stream used for device memory operations and kernel launches

Returns

Vector of views of input indicated by the ranges in indices

slice() [4/4]

std::vector<table_view> cudf::slice	(	table_view const &	input,
		std::initializer_list< size_type >	indices,
		rmm::cuda_stream_view	stream = cudf::get_default_stream()
	)

Slices a table_view into a set of table_views according to a set of indices.

The returned views of input are constructed from an even number indices where the ith returned table_view views the elements in input indicated by the range [indices[2*i], indices[(2*i)+1]).

For all i it is expected indices[i] <= input.size() For all i%2==0, it is expected that indices[i] <= indices[i+1]

Note

It is the caller's responsibility to ensure that the returned views do not outlive the viewed device memory.

input:   [{10, 12, 14, 16, 18, 20, 22, 24, 26, 28},
          {50, 52, 54, 56, 58, 60, 62, 64, 66, 68}]
indices: {1, 3, 5, 9, 2, 4, 8, 8}
output:  [{{12, 14}, {20, 22, 24, 26}, {14, 16}, {}},
          {{52, 54}, {60, 22, 24, 26}, {14, 16}, {}}]

Exceptions

cudf::logic_error	if indices size is not even.
cudf::logic_error	When the values in the pair are strictly decreasing.
cudf::logic_error	When any of the values in the pair don't belong to the range [0, input.size()).

Parameters

input	View of table to slice
indices	Indices used to take slices of input
stream	CUDA stream used for device memory operations and kernel launches

Returns

Vector of views of input indicated by the ranges in indices