Filling

Files
file	filling.hpp
	Column APIs for fill, repeat, and sequence.

Functions
void	cudf::fill_in_place (mutable_column_view &destination, size_type begin, size_type end, scalar const &value, rmm::cuda_stream_view stream=cudf::get_default_stream())
	Fills a range of elements in-place in a column with a scalar value. More...
std::unique_ptr< column >	cudf::fill (column_view const &input, size_type begin, size_type end, scalar const &value, rmm::cuda_stream_view stream=cudf::get_default_stream(), rmm::mr::device_memory_resource *mr=rmm::mr::get_current_device_resource())
	Fills a range of elements in a column out-of-place with a scalar value. More...
std::unique_ptr< table >	cudf::repeat (table_view const &input_table, column_view const &count, rmm::cuda_stream_view stream=cudf::get_default_stream(), rmm::mr::device_memory_resource *mr=rmm::mr::get_current_device_resource())
	Repeat rows of a Table. More...
std::unique_ptr< table >	cudf::repeat (table_view const &input_table, size_type count, rmm::cuda_stream_view stream=cudf::get_default_stream(), rmm::mr::device_memory_resource *mr=rmm::mr::get_current_device_resource())
	Repeat rows of a Table. More...
std::unique_ptr< column >	cudf::sequence (size_type size, scalar const &init, scalar const &step, rmm::cuda_stream_view stream=cudf::get_default_stream(), rmm::mr::device_memory_resource *mr=rmm::mr::get_current_device_resource())
	Fills a column with a sequence of value specified by an initial value and a step. More...
std::unique_ptr< column >	cudf::sequence (size_type size, scalar const &init, rmm::cuda_stream_view stream=cudf::get_default_stream(), rmm::mr::device_memory_resource *mr=rmm::mr::get_current_device_resource())
	Fills a column with a sequence of value specified by an initial value and a step of 1. More...
std::unique_ptr< cudf::column >	cudf::calendrical_month_sequence (size_type size, scalar const &init, size_type months, rmm::cuda_stream_view stream=cudf::get_default_stream(), rmm::mr::device_memory_resource *mr=rmm::mr::get_current_device_resource())
	Generate a sequence of timestamps beginning at init and incrementing by months for each successive element, i.e., output[i] = init + i * months for i in [0, size). More...

Detailed Description

Function Documentation

calendrical_month_sequence()

std::unique_ptr<cudf::column> cudf::calendrical_month_sequence	(	size_type	size,
		scalar const &	init,
		size_type	months,
		rmm::cuda_stream_view	stream = cudf::get_default_stream(),
		rmm::mr::device_memory_resource *	mr = rmm::mr::get_current_device_resource()
	)

Generate a sequence of timestamps beginning at init and incrementing by months for each successive element, i.e., output[i] = init + i * months for i in [0, size).

If a given date is invalid, the date is scaled back to the last available day of that month.

Example:

size = 3
init = 2020-01-31 08:00:00
months = 1
return = [2020-01-31 08:00:00, 2020-02-29 08:00:00, 2020-03-31 08:00:00]

Exceptions

cudf::logic_error

if input datatype is not a TIMESTAMP

Parameters

size	Number of timestamps to generate
init	The initial timestamp
months	Months to increment
stream	CUDA stream used for device memory operations and kernel launches
mr	Device memory resource used to allocate the returned column's device memory

Returns

Timestamps column with sequences of months

fill()

std::unique_ptr<column> cudf::fill	(	column_view const &	input,
		size_type	begin,
		size_type	end,
		scalar const &	value,
		rmm::cuda_stream_view	stream = cudf::get_default_stream(),
		rmm::mr::device_memory_resource *	mr = rmm::mr::get_current_device_resource()
	)

Fills a range of elements in a column out-of-place with a scalar value.

Creates a new column as-if an in-place fill was performed into input; i.e. it is as if a copy of input was created first and then the elements indicated by the indices [begin, end) were overwritten by value.

Exceptions

cudf::logic_error	for invalid range (if begin < 0, begin > end, or end > destination.size()).
cudf::logic_error	if destination and value have different types.

Parameters

input	The input column used to create a new column. The new column is created by replacing the values of input in the specified range with value.
begin	The starting index of the fill range (inclusive)
end	The index of the last element in the fill range (exclusive)
value	The scalar value to fill
stream	CUDA stream used for device memory operations and kernel launches
mr	Device memory resource used to allocate the returned column's device memory

Returns

The result output column

fill_in_place()

void cudf::fill_in_place	(	mutable_column_view &	destination,
		size_type	begin,
		size_type	end,
		scalar const &	value,
		rmm::cuda_stream_view	stream = cudf::get_default_stream()
	)

Fills a range of elements in-place in a column with a scalar value.

Fills N elements of destination starting at begin with value, where N = (end - begin).

Overwrites the range of elements in destination indicated by the indices [begin, end) with value. Use the out-of-place fill function returning std::unique_ptr<column> for use cases requiring memory reallocation.

Exceptions

cudf::logic_error	if memory reallocation is required (e.g. for variable width types).
cudf::logic_error	for invalid range (if begin < 0, begin > end, or end > destination.size()).
cudf::logic_error	if destination and value have different types.
cudf::logic_error	if value is invalid but destination is not nullable.

Parameters

destination	The preallocated column to fill into
begin	The starting index of the fill range (inclusive)
end	The index of the last element in the fill range (exclusive)
value	The scalar value to fill
stream	CUDA stream used for device memory operations and kernel launches

repeat() [1/2]

std::unique_ptr<table> cudf::repeat	(	table_view const &	input_table,
		column_view const &	count,
		rmm::cuda_stream_view	stream = cudf::get_default_stream(),
		rmm::mr::device_memory_resource *	mr = rmm::mr::get_current_device_resource()
	)

Repeat rows of a Table.

Creates a new table by repeating the rows of input_table. The number of repetitions of each element is defined by the value at the corresponding index of count Example:

in = [4,5,6]
count = [1,2,3]
return = [4,5,5,6,6,6]

count should not have null values; should not contain negative values; and the sum of count elements should not overflow the size_type's limit. The behavior of this function is undefined if count has negative values or the sum overflows.

Exceptions

cudf::logic_error	if the data type of count is not size_type.
cudf::logic_error	if input_table and count have different number of rows.
cudf::logic_error	if count has null values.

Parameters

input_table	Input table
count	Non-nullable column of an integral type
stream	CUDA stream used for device memory operations and kernel launches
mr	Device memory resource used to allocate the returned table's device memory

Returns

The result table containing the repetitions

repeat() [2/2]

std::unique_ptr<table> cudf::repeat	(	table_view const &	input_table,
		size_type	count,
		rmm::cuda_stream_view	stream = cudf::get_default_stream(),
		rmm::mr::device_memory_resource *	mr = rmm::mr::get_current_device_resource()
	)

Repeat rows of a Table.

Creates a new table by repeating count times the rows of input_table. Example:

in = [4,5,6]
count = 2
return = [4,4,5,5,6,6]

Exceptions

cudf::logic_error	if count is negative.
std::overflow_error	if input_table.num_rows() * count overflows size_type.

Parameters

input_table	Input table
count	Number of repetitions
stream	CUDA stream used for device memory operations and kernel launches
mr	Device memory resource used to allocate the returned table's device memory

Returns

The result table containing the repetitions

sequence() [1/2]

std::unique_ptr<column> cudf::sequence	(	size_type	size,
		scalar const &	init,
		rmm::cuda_stream_view	stream = cudf::get_default_stream(),
		rmm::mr::device_memory_resource *	mr = rmm::mr::get_current_device_resource()
	)

Fills a column with a sequence of value specified by an initial value and a step of 1.

Creates a new column and fills with size values starting at init and incrementing by 1, generating the sequence [ init, init+1, init+2, ... init + (size - 1)]

size = 3
init = 0
return = [0, 1, 2]

Exceptions

cudf::logic_error	if init is not numeric.
cudf::logic_error	if size is < 0.

Parameters

size	Size of the output column
init	First value in the sequence
stream	CUDA stream used for device memory operations and kernel launches
mr	Device memory resource used to allocate the returned column's device memory

Returns

The result column containing the generated sequence

sequence() [2/2]

std::unique_ptr<column> cudf::sequence	(	size_type	size,
		scalar const &	init,
		scalar const &	step,
		rmm::cuda_stream_view	stream = cudf::get_default_stream(),
		rmm::mr::device_memory_resource *	mr = rmm::mr::get_current_device_resource()
	)

Fills a column with a sequence of value specified by an initial value and a step.

Creates a new column and fills with size values starting at init and incrementing by step, generating the sequence [ init, init+step, init+2*step, ... init + (size - 1)*step]

size = 3
init = 0
step = 2
return = [0, 2, 4]

Exceptions

cudf::logic_error	if init and step are not the same type.
cudf::logic_error	if scalar types are not numeric.
cudf::logic_error	if size is < 0.

Parameters

size	Size of the output column
init	First value in the sequence
step	Increment value
stream	CUDA stream used for device memory operations and kernel launches
mr	Device memory resource used to allocate the returned column's device memory

Returns

The result column containing the generated sequence