Unary Operations

Files
file	round.hpp
	Column APIs for round.
file	unary.hpp
	Column APIs for unary ops.

Enumerations
enum class	cudf::rounding_method : int32_t { HALF_UP , HALF_EVEN }
	Different rounding methods for cudf::round More...
enum class	cudf::unary_operator : int32_t {   cudf::SIN , cudf::COS , cudf::TAN , cudf::ARCSIN ,   cudf::ARCCOS , cudf::ARCTAN , cudf::SINH , cudf::COSH ,   cudf::TANH , cudf::ARCSINH , cudf::ARCCOSH , cudf::ARCTANH ,   cudf::EXP , cudf::LOG , cudf::SQRT , cudf::CBRT ,   cudf::CEIL , cudf::FLOOR , cudf::ABS , cudf::RINT ,   cudf::BIT_INVERT , cudf::NOT }
	Types of unary operations that can be performed on data. More...

Functions
std::unique_ptr< column >	cudf::round (column_view const &input, int32_t decimal_places=0, rounding_method method=rounding_method::HALF_UP, rmm::device_async_resource_ref mr=rmm::mr::get_current_device_resource())
	Rounds all the values in a column to the specified number of decimal places. More...
template<typename Fixed , typename Floating , CUDF_ENABLE_IF(cuda::std::is_floating_point_v< Floating > &&is_fixed_point< Fixed >()) >
CUDF_HOST_DEVICE Fixed	cudf::convert_floating_to_fixed (Floating floating, numeric::scale_type scale)
	Convert a floating-point value to fixed point. More...
template<typename Floating , typename Fixed , CUDF_ENABLE_IF(cuda::std::is_floating_point_v< Floating > &&is_fixed_point< Fixed >()) >
CUDF_HOST_DEVICE Floating	cudf::convert_fixed_to_floating (Fixed fixed)
	Convert a fixed-point value to floating point. More...
template<typename Floating , typename Input , CUDF_ENABLE_IF(cuda::std::is_floating_point_v< Floating >) >
CUDF_HOST_DEVICE Floating	cudf::convert_to_floating (Input input)
	Convert a value to floating point. More...
std::unique_ptr< cudf::column >	cudf::unary_operation (cudf::column_view const &input, cudf::unary_operator op, rmm::cuda_stream_view stream=cudf::get_default_stream(), rmm::device_async_resource_ref mr=rmm::mr::get_current_device_resource())
	Performs unary op on all values in column. More...
std::unique_ptr< cudf::column >	cudf::is_null (cudf::column_view const &input, rmm::cuda_stream_view stream=cudf::get_default_stream(), rmm::device_async_resource_ref mr=rmm::mr::get_current_device_resource())
	Creates a column of type_id::BOOL8 elements where for every element in input true indicates the value is null and false indicates the value is valid. More...
std::unique_ptr< cudf::column >	cudf::is_valid (cudf::column_view const &input, rmm::cuda_stream_view stream=cudf::get_default_stream(), rmm::device_async_resource_ref mr=rmm::mr::get_current_device_resource())
	Creates a column of type_id::BOOL8 elements where for every element in input true indicates the value is valid and false indicates the value is null. More...
std::unique_ptr< column >	cudf::cast (column_view const &input, data_type out_type, rmm::cuda_stream_view stream=cudf::get_default_stream(), rmm::device_async_resource_ref mr=rmm::mr::get_current_device_resource())
	Casts data from dtype specified in input to dtype specified in output. More...
bool	cudf::is_supported_cast (data_type from, data_type to) noexcept
	Check if a cast between two datatypes is supported. More...
std::unique_ptr< column >	cudf::is_nan (cudf::column_view const &input, rmm::cuda_stream_view stream=cudf::get_default_stream(), rmm::device_async_resource_ref mr=rmm::mr::get_current_device_resource())
	Creates a column of type_id::BOOL8 elements indicating the presence of NaN values in a column of floating point values. The output element at row i is true if the element in input at row i is NAN, else false More...
std::unique_ptr< column >	cudf::is_not_nan (cudf::column_view const &input, rmm::cuda_stream_view stream=cudf::get_default_stream(), rmm::device_async_resource_ref mr=rmm::mr::get_current_device_resource())
	Creates a column of type_id::BOOL8 elements indicating the absence of NaN values in a column of floating point values. The output element at row i is false if the element in input at row i is NAN, else true More...

Detailed Description

Enumeration Type Documentation

rounding_method

enum cudf::rounding_method : int32_t

strong

Different rounding methods for cudf::round

Info on HALF_EVEN rounding: https://en.wikipedia.org/wiki/Rounding#Rounding_half_to_even Info on HALF_UP rounding: https://en.wikipedia.org/wiki/Rounding#Rounding_half_away_from_zero Note: HALF_UP means up in MAGNITUDE: Away from zero! Because of how Java and python define it

Definition at line 41 of file round.hpp.

unary_operator

enum cudf::unary_operator : int32_t

strong

Types of unary operations that can be performed on data.

Enumerator
SIN	Trigonometric sine.
COS	Trigonometric cosine.
TAN	Trigonometric tangent.
ARCSIN	Trigonometric sine inverse.
ARCCOS	Trigonometric cosine inverse.
ARCTAN	Trigonometric tangent inverse.
SINH	Hyperbolic sine.
COSH	Hyperbolic cosine.
TANH	Hyperbolic tangent.
ARCSINH	Hyperbolic sine inverse.
ARCCOSH	Hyperbolic cosine inverse.
ARCTANH	Hyperbolic tangent inverse.
EXP	Exponential (base e, Euler number)
LOG	Natural Logarithm (base e)
SQRT	Square-root (x^0.5)
CBRT	Cube-root (x^(1.0/3))
CEIL	Smallest integer value not less than arg.
FLOOR	largest integer value not greater than arg
ABS	Absolute value.
RINT	Rounds the floating-point argument arg to an integer value.
BIT_INVERT	Bitwise Not (~)
NOT	Logical Not (!)

Definition at line 121 of file unary.hpp.

Function Documentation

cast()

std::unique_ptr<column> cudf::cast	(	column_view const &	input,
		data_type	out_type,
		rmm::cuda_stream_view	stream = cudf::get_default_stream(),
		rmm::device_async_resource_ref	mr = rmm::mr::get_current_device_resource()
	)

Casts data from dtype specified in input to dtype specified in output.

Supports only fixed-width types.

Parameters

input	Input column
out_type	Desired datatype of output column
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

Column of same size as input containing result of the cast operation

Exceptions

cudf::logic_error

if out_type is not a fixed-width type

convert_fixed_to_floating()

template<typename Floating , typename Fixed , CUDF_ENABLE_IF(cuda::std::is_floating_point_v< Floating > &&is_fixed_point< Fixed >()) >

CUDF_HOST_DEVICE Floating cudf::convert_fixed_to_floating

(

Fixed

fixed

)

Convert a fixed-point value to floating point.

Note

This conversion was moved from fixed-point member functions to free functions. This is so that the complex conversion code is not included into many parts of the code base that don't need it, and so that it's more obvious to pinpoint where these conversions are occurring.

Template Parameters

Floating	The floating-point type to convert to
Fixed	The fixed-point type to convert from

Parameters

fixed

The fixed-point value to convert

Returns

The converted floating-point value

Definition at line 86 of file unary.hpp.

convert_floating_to_fixed()

template<typename Fixed , typename Floating , CUDF_ENABLE_IF(cuda::std::is_floating_point_v< Floating > &&is_fixed_point< Fixed >()) >

CUDF_HOST_DEVICE Fixed cudf::convert_floating_to_fixed	(	Floating	floating,
		numeric::scale_type	scale
	)

Convert a floating-point value to fixed point.

Note

This conversion was moved from fixed-point member functions to free functions. This is so that the complex conversion code is not included into many parts of the code base that don't need it, and so that it's more obvious to pinpoint where these conversions are occurring.

Template Parameters

Fixed	The fixed-point type to convert to
Floating	The floating-point type to convert from

Parameters

floating	The floating-point value to convert
scale	The desired scale of the fixed-point value

Returns

The converted fixed-point value

Definition at line 56 of file unary.hpp.

convert_to_floating()

template<typename Floating , typename Input , CUDF_ENABLE_IF(cuda::std::is_floating_point_v< Floating >) >

CUDF_HOST_DEVICE Floating cudf::convert_to_floating

(

Input

input

)

Convert a value to floating point.

Template Parameters

Floating	The floating-point type to convert to
Input	The input type to convert from

Parameters

input

The input value to convert

Returns

The converted floating-point value

Definition at line 109 of file unary.hpp.

is_nan()

std::unique_ptr<column> cudf::is_nan	(	cudf::column_view const &	input,
		rmm::cuda_stream_view	stream = cudf::get_default_stream(),
		rmm::device_async_resource_ref	mr = rmm::mr::get_current_device_resource()
	)

Creates a column of type_id::BOOL8 elements indicating the presence of NaN values in a column of floating point values. The output element at row i is true if the element in input at row i is NAN, else false

Exceptions

cudf::logic_error

if input is a non-floating point type

Parameters

input	A column of floating-point elements
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

A non-nullable column of type_id::BOOL8 elements with true representing NAN values

is_not_nan()

std::unique_ptr<column> cudf::is_not_nan	(	cudf::column_view const &	input,
		rmm::cuda_stream_view	stream = cudf::get_default_stream(),
		rmm::device_async_resource_ref	mr = rmm::mr::get_current_device_resource()
	)

Creates a column of type_id::BOOL8 elements indicating the absence of NaN values in a column of floating point values. The output element at row i is false if the element in input at row i is NAN, else true

Exceptions

cudf::logic_error

if input is a non-floating point type

Parameters

input	A column of floating-point elements
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

A non-nullable column of type_id::BOOL8 elements with false representing NAN values

is_null()

std::unique_ptr<cudf::column> cudf::is_null	(	cudf::column_view const &	input,
		rmm::cuda_stream_view	stream = cudf::get_default_stream(),
		rmm::device_async_resource_ref	mr = rmm::mr::get_current_device_resource()
	)

Creates a column of type_id::BOOL8 elements where for every element in input true indicates the value is null and false indicates the value is valid.

Parameters

input	A column_view as input
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

A non-nullable column of type_id::BOOL8 elements with true representing null values.

is_supported_cast()

bool cudf::is_supported_cast ( data_type  from, data_type  to  )

noexcept

Check if a cast between two datatypes is supported.

Parameters

from	source type
to	target type

Returns

true if the cast is supported.

is_valid()

std::unique_ptr<cudf::column> cudf::is_valid	(	cudf::column_view const &	input,
		rmm::cuda_stream_view	stream = cudf::get_default_stream(),
		rmm::device_async_resource_ref	mr = rmm::mr::get_current_device_resource()
	)

Creates a column of type_id::BOOL8 elements where for every element in input true indicates the value is valid and false indicates the value is null.

Parameters

input	A column_view as input
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

A non-nullable column of type_id::BOOL8 elements with false representing null values.

round()

std::unique_ptr<column> cudf::round	(	column_view const &	input,
		int32_t	decimal_places = 0,
		rounding_method	method = rounding_method::HALF_UP,
		rmm::device_async_resource_ref	mr = rmm::mr::get_current_device_resource()
	)

Rounds all the values in a column to the specified number of decimal places.

cudf::round currently supports HALF_UP and HALF_EVEN rounding for integer, floating point and decimal32 and decimal64 numbers. For decimal32 and decimal64 numbers, negated numeric::scale is equivalent to decimal_places.

Example:

using namespace cudf;
 
column_view a; // contains { 1.729, 17.29, 172.9, 1729 };
 
auto result1 = round(a);     // { 2,   17,   173,   1729 }
auto result2 = round(a, 1);  // { 1.7, 17.3, 172.9, 1729 }
auto result3 = round(a, -1); // { 0,   20,   170,   1730 }
 
column_view b; // contains { 1.5, 2.5, 1.35, 1.45, 15, 25 };
 
auto result4 = round(b,  0, rounding_method::HALF_EVEN); // { 2,   2,   1,   1,   15, 25};
auto result5 = round(b,  1, rounding_method::HALF_EVEN); // { 1.5, 2.5, 1.4, 1.4, 15, 25};
auto result6 = round(b, -1, rounding_method::HALF_EVEN); // { 0,   0,   0,   0,   20, 20};

Parameters

input	Column of values to be rounded
decimal_places	Number of decimal places to round to (default 0). If negative, this specifies the number of positions to the left of the decimal point.
method	Rounding method
mr	Device memory resource used to allocate the returned column's device memory

Returns

Column with each of the values rounded

unary_operation()

std::unique_ptr<cudf::column> cudf::unary_operation	(	cudf::column_view const &	input,
		cudf::unary_operator	op,
		rmm::cuda_stream_view	stream = cudf::get_default_stream(),
		rmm::device_async_resource_ref	mr = rmm::mr::get_current_device_resource()
	)

Performs unary op on all values in column.

Note: For decimal32 and decimal64, only ABS, CEIL and FLOOR are supported.

Parameters

input	A column_view as input
op	operation to perform
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

Column of same size as input containing result of the operation