Public Types | Public Member Functions | Static Public Attributes | List of all members
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...

Inheritance diagram for cudf::tdigest::tdigest_column_view:
cudf::column_view

Public Types

using offset_iterator = offset_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 (const tdigest_column_view &)=default
 Copy constructor.
 
tdigest_column_viewoperator= (tdigest_column_view const &)=default
 Copy assignment operator. More...
 
tdigest_column_viewoperator= (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...
 
auto size_begin () const
 Returns an iterator that returns the size of each tdigest in the column (each row is 1 digest) 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 69 of file tdigest_column_view.cuh.

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

◆ size_begin()

auto cudf::tdigest::tdigest_column_view::size_begin ( ) const
inline

Returns an iterator that returns the size of each tdigest in the column (each row is 1 digest)

Returns
An iterator that returns the size of each tdigest in the column

Definition at line 136 of file tdigest_column_view.cuh.

◆ weights()

column_view cudf::tdigest::tdigest_column_view::weights ( ) const

Returns the internal column of weight values.

Returns
The internal column of weight values

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