cudf::tdigest::tdigest_column_view Class Reference

Given a column_view containing tdigest data, an instance of this class provides a wrapper on the compound column for tdigest operations. More...

#include <tdigest_column_view.hpp>

Inheritance diagram for cudf::tdigest::tdigest_column_view:

Public Types
using	offset_iterator = size_type const *
	Iterator over offsets.

Public Member Functions
	tdigest_column_view (column_view const &)
	Construct tdigest_column_view from a column_view.
	tdigest_column_view (tdigest_column_view &&)=default
	Move constructor.
	tdigest_column_view (tdigest_column_view const &)=default
	Copy constructor.
tdigest_column_view &	operator= (tdigest_column_view const &)=default
	Copy assignment operator. More...
tdigest_column_view &	operator= (tdigest_column_view &&)=default
	Move assignment operator. More...
column_view	parent () const
	Returns the parent column. More...
lists_column_view	centroids () const
	Returns the column of centroids. More...
column_view	means () const
	Returns the internal column of mean values. More...
column_view	weights () const
	Returns the internal column of weight values. More...
double const *	min_begin () const
	Returns the first min value for the column. Each row corresponds to the minimum value for the accompanying digest. More...
double const *	max_begin () const
	Returns the first max value for the column. Each row corresponds to the maximum value for the accompanying digest. More...

Static Public Attributes
static constexpr size_type	mean_column_index {0}
	Mean column index.
static constexpr size_type	weight_column_index {1}
	Weight column index.
static constexpr size_type	centroid_column_index {0}
	Centroid column index.
static constexpr size_type	min_column_index {1}
	Min column index.
static constexpr size_type	max_column_index {2}
	Max column index.

Detailed Description

Given a column_view containing tdigest data, an instance of this class provides a wrapper on the compound column for tdigest operations.

A tdigest is a "compressed" set of input scalars represented as a sorted set of centroids (https://arxiv.org/pdf/1902.04023.pdf). This data can be queried for quantile information. Each row in a tdigest column represents an entire tdigest.

The column has the following structure:

struct { // centroids for the digest list { struct { double // mean double // weight } } // these are from the input stream, not the centroids. they are used // during the percentile_approx computation near the beginning or // end of the quantiles double // min double // max }

Definition at line 57 of file tdigest_column_view.hpp.

Member Function Documentation

centroids()

lists_column_view cudf::tdigest::tdigest_column_view::centroids

(

)

const

Returns the column of centroids.

Returns

The list column of centroids

max_begin()

double const* cudf::tdigest::tdigest_column_view::max_begin

(

)

const

Returns the first max value for the column. Each row corresponds to the maximum value for the accompanying digest.

Returns

const pointer to the first max value for the column

means()

column_view cudf::tdigest::tdigest_column_view::means

(

)

const

Returns the internal column of mean values.

Returns

The internal column of mean values

min_begin()

double const* cudf::tdigest::tdigest_column_view::min_begin

(

)

const

Returns the first min value for the column. Each row corresponds to the minimum value for the accompanying digest.

Returns

const pointer to the first min value for the column

operator=() [1/2]

tdigest_column_view& cudf::tdigest::tdigest_column_view::operator= ( tdigest_column_view &&  )

default

Move assignment operator.

Returns

this object after moving the contents of the other object (transfer ownership)

operator=() [2/2]

tdigest_column_view& cudf::tdigest::tdigest_column_view::operator= ( tdigest_column_view const &  )

default

Copy assignment operator.

Returns

this object after copying the contents of the other object (copy)

parent()

column_view cudf::tdigest::tdigest_column_view::parent

(

)

const

Returns the parent column.

Returns

The parent column

weights()

column_view cudf::tdigest::tdigest_column_view::weights

(

)

const

Returns the internal column of weight values.

Returns

The internal column of weight values

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The documentation for this class was generated from the following file:

• tdigest_column_view.hpp