Developer Guide and Reference

  • 2021.4
  • 09/27/2021
  • Public Content
Contents

Tables

Programming interface

All types and functions in this section are declared in the
oneapi::dal
namespace and be available via inclusion of the
oneapi/dal/table/common.hpp
header file.
Table
A base implementation of the table concept. The
table
type and all of its subtypes are reference-counted:
  1. The instance stores a pointer to table implementation that holds all property values and data
  2. The reference count indicating how many table objects refer to the same implementation.
  3. The table increments the reference count for it to be equal to the number of table objects sharing the same implementation.
  4. The table decrements the reference count when the table goes out of the scope. If the reference count is zero, the table frees its implementation.
class
table
Constructors
table
()
An empty table constructor: creates the table instance with zero number of rows and columns.
table
(
const
table&) = default
Creates a new table instance that shares the implementation with another one.
table
(table&&)
Creates a new table instance and moves implementation from another one into it.
Public Methods
table &
operator=
(
const
table&) = default
Replaces the implementation by another one.
table &
operator=
(table&&)
Swaps the implementation of this object and another one.
bool
has_data
()
const
noexcept
Indicates whether a table contains non-zero number of rows and columns.
std::int64_t
get_column_count
()
const
The number of columns in the table.
std::int64_t
get_row_count
()
const
The number of rows in the table.
const
table_metadata &
get_metadata
()
const
The metadata object that holds additional information about the data within the table.
std::int64_t
get_kind
()
const
The runtime id of the table type. Each table sub-type has its unique
kind
. An empty table has a unique
kind
value as well.
data_layout
get_data_layout
()
const
The layout of the data within the table.
Table metadata
An implementation of the table metadata concept. Holds additional information about data within the table. The objects of
table_metadata
are reference-counted.
class
table_metadata
Constructors
table_metadata
()
Creates the metadata instance without information about the features. The
feature_count
should be set to zero. The
data_type
and
feature_type
properties should not be initialized.
table_metadata
(
const
dal::array<data_type> &
dtypes
,
const
dal::array<feature_type> &
ftypes
)
Creates the metadata instance from external information about the data types and the feature types.
Parameters
  • dtypes
    – The data types of the features. Assigned into the
    data_type
    property.
  • ftypes
    – The feature types. Assigned into the
    feature_type
    property.
Preconditions


dtypes.get_count() == ftypes.get_count()

Public Methods
std::int64_t
get_feature_count
()
const
The number of features that metadata contains information about.
const
feature_type &
get_feature_type
(std::int64_t
feature_index
)
const
Feature types in the metadata object. Should be within the range
[0, feature_count)
.
const
data_type &
get_data_type
(std::int64_t
feature_index
)
const
Data types of the features in the metadata object. Should be within the range
[0, feature_count)
.
Data layout
An implementation of the data layout concept.
enum class data_layout { unknown, row_major, column_major };
data_layout::unknown
Represents the data layout that is undefined or unknown at this moment.
data_layout::row_major
The data block elements are stored in raw-major layout.
data_layout::column_major
The data block elements are stored in column_major layout.
Feature type
An implementation of the logical data types.
enum class feature_type { nominal, ordinal, interval, ratio };
feature_type::nominal
Represents the type of Nominal feature.
feature_type::ordinal
Represents the type of Ordinal feature.
feature_type::interval
Represents the type of Interval feature.
feature_type::ratio
Represents the type of Ratio feature.

Product and Performance Information

1

Performance varies by use, configuration and other factors. Learn more at www.Intel.com/PerformanceIndex.