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::mr::device_memory_resource *mr=rmm::mr::get_current_device_resource())
	Rounds all the values in a column to the specified number of decimal places. 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::mr::device_memory_resource *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::mr::device_memory_resource *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::mr::device_memory_resource *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::mr::device_memory_resource *mr=rmm::mr::get_current_device_resource())
	Casts data from dtype specified in input to dtype specified in output. More...
std::unique_ptr< column >	cudf::is_nan (cudf::column_view const &input, rmm::cuda_stream_view stream=cudf::get_default_stream(), rmm::mr::device_memory_resource *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::mr::device_memory_resource *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 39 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 37 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::mr::device_memory_resource *	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

is_nan()

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

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