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Modules

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Files

file  reshape.hpp
 Column APIs for interleave and tile.
 

Enumerations

enum  cudf::flip_endianness : bool { NO, YES }
 Configures whether byte casting flips endianness.
 

Functions

std::unique_ptr< columncudf::interleave_columns (table_view const &input, rmm::mr::device_memory_resource *mr=rmm::mr::get_current_device_resource())
 Interleave columns of a table into a single column. More...
 
std::unique_ptr< tablecudf::tile (table_view const &input, size_type count, rmm::mr::device_memory_resource *mr=rmm::mr::get_current_device_resource())
 Repeats the rows from input table count times to form a new table. More...
 
std::unique_ptr< columncudf::byte_cast (column_view const &input_column, flip_endianness endian_configuration, rmm::mr::device_memory_resource *mr=rmm::mr::get_current_device_resource())
 Converts a column's elements to lists of bytes. More...
 
std::unique_ptr< tablecudf::explode (table_view const &input_table, size_type explode_column_idx, rmm::mr::device_memory_resource *mr=rmm::mr::get_current_device_resource())
 Explodes a list column's elements. More...
 

Detailed Description

Function Documentation

◆ byte_cast()

std::unique_ptr<column> cudf::byte_cast ( column_view const &  input_column,
flip_endianness  endian_configuration,
rmm::mr::device_memory_resource mr = rmm::mr::get_current_device_resource() 
)

Converts a column's elements to lists of bytes.

input<int32> = [8675, 309]
configuration = flip_endianness::YES
return = [[0x00, 0x00, 0x21, 0xe3], [0x00, 0x00, 0x01, 0x35]]
Parameters
input_columnColumn to be converted to lists of bytes.
endian_configurationWhether to retain or flip the endianness of the elements.
mrDevice memory resource used to allocate the returned column's device memory.
Returns
The column containing the lists of bytes.

◆ explode()

std::unique_ptr<table> cudf::explode ( table_view const &  input_table,
size_type  explode_column_idx,
rmm::mr::device_memory_resource mr = rmm::mr::get_current_device_resource() 
)

Explodes a list column's elements.

Any list is exploded, which means the elements of the list in each row are expanded into new rows in the output. The corresponding rows for other columns in the input are duplicated. Example:

[[5,10,15], 100],
[[20,25], 200],
[[30], 300],
returns
[5, 100],
[10, 100],
[15, 100],
[20, 200],
[25, 200],
[30, 300],

Nulls and empty lists propagate in different ways depending on what is null or empty.

[[5,null,15], 100],
[null, 200],
[[], 300],
returns
[5, 100],
[null, 100],
[15, 100],

Note that null lists are completely removed from the output and nulls and empty lists inside lists are pulled out and remain.

Parameters
input_tableTable to explode.
explode_column_idxColumn index to explode inside the table.
mrDevice memory resource used to allocate the returned column's device memory.
Returns
A new table with explode_col exploded.

◆ interleave_columns()

std::unique_ptr<column> cudf::interleave_columns ( table_view const &  input,
rmm::mr::device_memory_resource mr = rmm::mr::get_current_device_resource() 
)

Interleave columns of a table into a single column.

Converts the column major table input into a row major column. Example:

in = [[A1, A2, A3], [B1, B2, B3]]
return = [A1, B1, A2, B2, A3, B3]
Exceptions
cudf::logic_errorif input contains no columns.
cudf::logic_errorif input columns dtypes are not identical.
Parameters
[in]inputTable containing columns to interleave.
Returns
The interleaved columns as a single column

◆ tile()

std::unique_ptr<table> cudf::tile ( table_view const &  input,
size_type  count,
rmm::mr::device_memory_resource mr = rmm::mr::get_current_device_resource() 
)

Repeats the rows from input table count times to form a new table.

output.num_columns() == input.num_columns() output.num_rows() == input.num_rows() * count

input = [[8, 4, 7], [5, 2, 3]]
count = 2
return = [[8, 4, 7, 8, 4, 7], [5, 2, 3, 5, 2, 3]]
Parameters
[in]inputTable containing rows to be repeated.
[in]countNumber of times to tile "rows". Must be non-negative.
Returns
The table containing the tiled "rows".