Shifting

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

Functions
std::unique_ptr< column >	cudf::shift (column_view const &input, size_type offset, scalar const &fill_value, rmm::cuda_stream_view stream=cudf::get_default_stream(), rmm::mr::device_memory_resource *mr=rmm::mr::get_current_device_resource())
	Creates a new column by shifting all values by an offset. More...

Detailed Description

Function Documentation

shift()

std::unique_ptr<column> cudf::shift	(	column_view const &	input,
		size_type	offset,
		scalar const &	fill_value,
		rmm::cuda_stream_view	stream = cudf::get_default_stream(),
		rmm::mr::device_memory_resource *	mr = rmm::mr::get_current_device_resource()
	)

Creates a new column by shifting all values by an offset.

Elements will be determined by output[idx] = input[idx - offset]. Some elements in the output may be indeterminable from the input. For those elements, the value will be determined by fill_values.

Examples
-------------------------------------------------
input       = [0, 1, 2, 3, 4]
offset      = 3
fill_values = @
return      = [@, @, @, 0, 1]
-------------------------------------------------
input       = [5, 4, 3, 2, 1]
offset      = -2
fill_values = 7
return      = [3, 2, 1, 7, 7]

Note

if the input is nullable, the output will be nullable.

if the fill value is null, the output will be nullable.

Parameters

input	Column to be shifted
offset	The offset by which to shift the input
fill_value	Fill value for indeterminable outputs
stream	CUDA stream used for device memory operations and kernel launches
mr	Device memory resource used to allocate the returned result's device memory

Exceptions

cudf::logic_error	if input dtype is neither fixed-width nor string type
cudf::logic_error	if fill_value dtype does not match input dtype.

Returns

The shifted column