Concatenating

Files
file	concatenate.hpp
	Concatenate columns APIs.

Functions
rmm::device_buffer	cudf::concatenate_masks (host_span< column_view const > views, rmm::mr::device_memory_resource *mr=rmm::mr::get_current_device_resource())
	Concatenates views[i]'s bitmask from the bits [views[i].offset(), views[i].offset() + views[i].size()) for all elements views[i] in views into a device_buffer More...
std::unique_ptr< column >	cudf::concatenate (host_span< column_view const > columns_to_concat, rmm::mr::device_memory_resource *mr=rmm::mr::get_current_device_resource())
	Concatenates multiple columns into a single column. More...
std::unique_ptr< table >	cudf::concatenate (host_span< table_view const > tables_to_concat, rmm::mr::device_memory_resource *mr=rmm::mr::get_current_device_resource())
	Columns of tables_to_concat are concatenated vertically to return a single table_view. More...

Detailed Description

Function Documentation

concatenate() [1/2]

std::unique_ptr<column> cudf::concatenate	(	host_span< column_view const >	columns_to_concat,
		rmm::mr::device_memory_resource *	mr = rmm::mr::get_current_device_resource()
	)

Concatenates multiple columns into a single column.

Exceptions

cudf::logic_error

If types of the input columns mismatch

Parameters

columns_to_concat	host_span of column views to be concatenated into a single column
mr	Device memory resource used to allocate the returned column's device memory.

Returns

Unique pointer to a single table having all the rows from the elements of columns_to_concat respectively in the same order.

concatenate() [2/2]

std::unique_ptr<table> cudf::concatenate	(	host_span< table_view const >	tables_to_concat,
		rmm::mr::device_memory_resource *	mr = rmm::mr::get_current_device_resource()
	)

Columns of tables_to_concat are concatenated vertically to return a single table_view.

example:

column_view c0; //Contains {0,1,2,3}
column_view c1; //Contains {4,5,6,7}
table_view t0{{c0, c0}};
table_view t1{{c1, c1}};
...
auto t = concatenate({t0.view(), t1.view()});
column_view tc0 = (t->view()).column(0); //Contains {0,1,2,3,4,5,6,7}
column_view tc1 = (t->view()).column(1); //Contains {0,1,2,3,4,5,6,7}

Exceptions

cudf::logic_error

If number of columns mismatch

Parameters

tables_to_concat	host_span of table views to be concatenated into a single table
mr	Device memory resource used to allocate the returned table's device memory.

Returns

Unique pointer to a single table having all the rows from the elements of tables_to_concat respectively in the same order.

concatenate_masks()

rmm::device_buffer cudf::concatenate_masks	(	host_span< column_view const >	views,
		rmm::mr::device_memory_resource *	mr = rmm::mr::get_current_device_resource()
	)

Concatenates views[i]'s bitmask from the bits [views[i].offset(), views[i].offset() + views[i].size()) for all elements views[i] in views into a device_buffer

Returns empty device_buffer if the column is not nullable

Parameters

views	host_span of column views whose bitmask will to be concatenated
mr	Device memory resource used for allocating the new device_buffer

Returns

rmm::device_buffer A device_buffer containing the bitmasks of all the column views in the views vector