Auxiliary information for a dataset, including mappings to/from strings (or other types) and the datatype of each dimension. More...

#include <dataset_mapper.hpp>

Public Member Functions
	DatasetMapper (const size_t dimensionality=0)
	Create the DatasetMapper object with the given dimensionality. More...

	DatasetMapper (PolicyType &policy, const size_t dimensionality=0)
	Create the DatasetMapper object with the given policy and dimensionality. More...

void	SetDimensionality (const size_t dimensionality)
	Set the dimensionality of an existing DatasetMapper object. More...

template<typename T >
void	MapFirstPass (const InputType &input, const size_t dimension)
	Preprocessing: during a first pass of the data, pass the input on to the MapPolicy if they are needed. More...

template<typename T >
T	MapString (const InputType &input, const size_t dimension)
	Given the input and the dimension to which it belongs, return its numeric mapping. More...

template<typename T >
const InputType &	UnmapString (const T value, const size_t dimension, const size_t unmappingIndex=0) const
	Return the input that corresponds to a given value in a given dimension. More...

template<typename T >
size_t	NumUnmappings (const T value, const size_t dimension) const
	Get the number of possible unmappings for a string in a given dimension.

PolicyType::MappedType	UnmapValue (const InputType &input, const size_t dimension)
	Return the value that corresponds to a given input in a given dimension. More...

Datatype	Type (const size_t dimension) const
	Return the type of a given dimension (numeric or categorical).

Datatype &	Type (const size_t dimension)
	Modify the type of a given dimension (be careful!).

size_t	NumMappings (const size_t dimension) const
	Get the number of mappings for a particular dimension. More...

size_t	Dimensionality () const
	Get the dimensionality of the DatasetMapper object (that is, how many dimensions it has information for). More...

template<typename Archive >
void	serialize (Archive &ar, const uint32_t)
	Serialize the dataset information.

const PolicyType &	Policy () const
	Return the policy of the mapper.

PolicyType &	Policy ()
	Modify the policy of the mapper (be careful!).

void	Policy (PolicyType &&policy)
	Modify (Replace) the policy of the mapper with a new policy.

Detailed Description

template<typename PolicyType, typename InputType = std::string>
class mlpack::data::DatasetMapper< PolicyType, InputType >

Auxiliary information for a dataset, including mappings to/from strings (or other types) and the datatype of each dimension.

DatasetMapper objects are optionally produced by data::Load(), and store the type of each dimension (Datatype::numeric or Datatype::categorical) as well as mappings from strings to unsigned integers and vice versa.

DatasetMapper objects can also map from arbitrary types; the type to map from can be specified with the InputType template parameter. By default, the InputType parameter is std::string.

Template Parameters

PolicyType	Mapping policy used to specify MapString().
InputType	Type of input to be mapped.

Constructor & Destructor Documentation

◆ DatasetMapper() [1/2]

template<typename PolicyType , typename InputType >

mlpack::data::DatasetMapper< PolicyType, InputType >::DatasetMapper ( const size_t dimensionality = 0 )

inlineexplicit

Create the DatasetMapper object with the given dimensionality.

Note that the dimensionality cannot be changed later; you will have to create a new DatasetMapper object.

◆ DatasetMapper() [2/2]

template<typename PolicyType, typename InputType >

mlpack::data::DatasetMapper< PolicyType, InputType >::DatasetMapper	(	PolicyType &	policy,
		const size_t	dimensionality = `0`
	)

inlineexplicit

Create the DatasetMapper object with the given policy and dimensionality.

Note that the dimensionality cannot be changed later; you will have to create a new DatasetMapper object. Policy can be modified by the modifier.

Member Function Documentation

◆ Dimensionality()

template<typename PolicyType , typename InputType >

size_t mlpack::data::DatasetMapper< PolicyType, InputType >::Dimensionality ( ) const

inline

Get the dimensionality of the DatasetMapper object (that is, how many dimensions it has information for).

If this object was created by a call to mlpack::data::Load(), then the dimensionality will be the same as the number of rows (dimensions) in the dataset.

◆ MapFirstPass()

template<typename PolicyType , typename InputType>

template<typename T >

void mlpack::data::DatasetMapper< PolicyType, InputType >::MapFirstPass	(	const InputType &	input,
		const size_t	dimension
	)

Preprocessing: during a first pass of the data, pass the input on to the MapPolicy if they are needed.

Parameters

input	Input to map.
dimension	Dimension to map for.

◆ MapString()

template<typename PolicyType , typename InputType>

template<typename T >

T mlpack::data::DatasetMapper< PolicyType, InputType >::MapString	(	const InputType &	input,
		const size_t	dimension
	)

inline

Given the input and the dimension to which it belongs, return its numeric mapping.

If no mapping yet exists, the input is added to the list of mappings for the given dimension. The dimension parameter refers to the index of the dimension of the string (i.e. the row in the dataset).

Template Parameters

T	Numeric type to map to (int/double/float/etc.).

Parameters

input	Input to find/create mapping for.
dimension	Index of the dimension of the string.

◆ NumMappings()

template<typename PolicyType , typename InputType >

size_t mlpack::data::DatasetMapper< PolicyType, InputType >::NumMappings ( const size_t dimension ) const

inline

Get the number of mappings for a particular dimension.

If the dimension is numeric, then this will return 0.

◆ SetDimensionality()

template<typename PolicyType , typename InputType >

void mlpack::data::DatasetMapper< PolicyType, InputType >::SetDimensionality ( const size_t dimensionality )

inline

Set the dimensionality of an existing DatasetMapper object.

This resets all mappings (but not the PolicyType).

Parameters

dimensionality New dimensionality.

◆ UnmapString()

template<typename PolicyType , typename InputType >

template<typename T >

const InputType & mlpack::data::DatasetMapper< PolicyType, InputType >::UnmapString	(	const T	value,
		const size_t	dimension,
		const size_t	unmappingIndex = `0`
	)		const

inline

Return the input that corresponds to a given value in a given dimension.

If the value is not a valid mapping in the given dimension, a std::invalid_argument is thrown. Note that this does not remove the mapping.

If the mapping is non-unique (i.e. many strings can map to the same value), then you can pass a different value for unmappingIndex to get a different string that maps to the given value. unmappingIndex should be in the range from 0 to (NumUnmappings(value, dimension) - 1).

If the mapping is unique (which it is for DatasetInfo), then the unmappingIndex parameter can be left as the default.

Parameters

value	Mapped value for input.
dimension	Dimension to unmap string from.
unmappingIndex	Index of non-unique unmapping (optional).

◆ UnmapValue()

template<typename PolicyType , typename InputType>

PolicyType::MappedType mlpack::data::DatasetMapper< PolicyType, InputType >::UnmapValue	(	const InputType &	input,
		const size_t	dimension
	)

inline

Return the value that corresponds to a given input in a given dimension.

If the value is not a valid mapping in the given dimension, a std::invalid_argument is thrown. Note that this does not remove the mapping.

Parameters

input	Mapped input for value.
dimension	Dimension to unmap input from.

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

src/mlpack/core/data/dataset_mapper.hpp
src/mlpack/core/data/dataset_mapper_impl.hpp

Public Member Functions

Detailed Description

template<typename PolicyType, typename InputType = std::string> class mlpack::data::DatasetMapper< PolicyType, InputType >

Constructor & Destructor Documentation

◆ DatasetMapper() [1/2]

◆ DatasetMapper() [2/2]

Member Function Documentation

◆ Dimensionality()

◆ MapFirstPass()

◆ MapString()

◆ NumMappings()

◆ SetDimensionality()

◆ UnmapString()

◆ UnmapValue()

template<typename PolicyType, typename InputType = std::string>
class mlpack::data::DatasetMapper< PolicyType, InputType >