gum::learning::DBTranslator4IntegerVariable Class Reference

The databases' cell translators for integer variables. More...

#include <agrum/base/database/DBTranslator4IntegerVariable.h>

Inheritance diagram for gum::learning::DBTranslator4IntegerVariable:

Collaboration diagram for gum::learning::DBTranslator4IntegerVariable:

Public Member Functions
Constructors / Destructors
	DBTranslator4IntegerVariable (const IntegerVariable &var, const std::vector< std::string > &missing_symbols, std::size_t max_dico_entries=std::numeric_limits< std::size_t >::max())
	default constructor with an integer variable as translator
	DBTranslator4IntegerVariable (const IntegerVariable &var, std::size_t max_dico_entries=std::numeric_limits< std::size_t >::max())
	default constructor with an integer variable as translator but without missing symbols
	DBTranslator4IntegerVariable (const DBTranslator4IntegerVariable &from)
	copy constructor
	DBTranslator4IntegerVariable (DBTranslator4IntegerVariable &&from)
	move constructor
virtual DBTranslator4IntegerVariable *	clone () const
	virtual copy constructor
virtual	~DBTranslator4IntegerVariable ()
	destructor
Operators
DBTranslator4IntegerVariable &	operator= (const DBTranslator4IntegerVariable &from)
	copy operator
DBTranslator4IntegerVariable &	operator= (DBTranslator4IntegerVariable &&from)
	move operator
Accessors / Modifiers
virtual DBTranslatedValue	translate (const std::string &str) final
	returns the translation of a string
virtual std::string	translateBack (const DBTranslatedValue translated_val) const final
	returns the original value for a given translation
virtual std::size_t	domainSize () const final
	returns the domain size of the variable used for translations
virtual bool	hasEditableDictionary () const final
	indicates that the translator is never in editable dictionary mode
virtual void	setEditableDictionaryMode (bool new_mode) final
	sets/unset the editable dictionary mode
virtual bool	needsReordering () const final
	indicates that the translations should never be reordered
virtual HashTable< std::size_t, std::size_t >	reorder () final
	returns an empty HashTable to indicate that no reordering is needed.
virtual const IntegerVariable *	variable () const final
	returns the variable stored into the translator
virtual DBTranslatedValue	missingValue () const final
	returns the translation of a missing value
Operators
DBTranslatedValue	operator<< (const std::string &str)
	alias for method translate
std::string	operator>> (const DBTranslatedValue translated_val)
	alias for method translateBack
Accessors / Modifiers
virtual const Bijection< std::size_t, std::string > &	getDictionary () const
	returns the translation from database indices to input strings
const Set< std::string > &	missingSymbols () const
	returns the set of missing symbols taken into account by the translator
bool	isMissingSymbol (const std::string &str) const
	indicates whether a string corresponds to a missing symbol
void	setVariableName (const std::string &str) const
	sets the name of the variable stored into the translator
void	setVariableDescription (const std::string &str) const
	sets the name of the variable stored into the translator
DBTranslatedValueType	getValType () const
	returns the type of values handled by the translator
bool	isLossless () const
	returns a Boolean indicating whether the translation is lossless or not
bool	isMissingValue (const DBTranslatedValue &val) const
	indicates whether a translated value corresponds to a missing value

Protected Attributes
bool	is_lossless_
	indicates whether the translation is lossless (e.g., ranges) or not
bool	is_dictionary_dynamic_
	indicates whether the dictionary can be updated or not
std::size_t	max_dico_entries_
	the maximum number of entries that the dictionary is allowed to contain
Set< std::string >	missing_symbols_
	the set of missing symbols
Bijection< std::size_t, std::string >	back_dico_
	the bijection relating back translated values and their original strings.
DBTranslatedValueType	val_type_
	the type of the values translated by the translator

Detailed Description

The databases' cell translators for integer variables.

Translators are used by DatabaseTable instances to transform datasets' strings into DBTranslatedValue instances. The point is that strings are not adequate for fast learning, they need to be preprocessed into a type that can be analyzed quickly (the so-called DBTranslatedValue type).

A DBTranslator4IntegerVariable is a translator that contains and exploits a IntegerVariable for translations. Each time a string needs be translated, we ask the IntegerVariable which index contains the the number represented by the string. The DBTranslatedValue corresponding to the translation of the string contains in its discr_val field this number.

Warning

Translators for integer variables are not editable, that is, you must provide the const variable that will be used for translations. Enabling the editable mode would not make much sense because, during the translation, the DBTranslatedValue of an integer may change after translating another integer.

Here is an example of how to use this class:

// create the translator, with possible missing symbols: "N/A" and "???"
// i.e., each time the translator reads a "N/A" or a "???" string, it
// won't translate it into a number but into a missing value.
std::vector<std::string> missing { "N/A", "???" };
gum::IntegerVariable var ( "X1", "" );
var.addValue( 1 );
var.addValue( 3 );
var.addValue( 10 );
gum::learning::DBTranslator4IntegerVariable<> translator(var, missing);
 
// gets the DBTranslatedValue corresponding to some strings
auto val1 = translator.translate("3");
auto val2 = translator << "1";
// at this point, val1 and val2 are equal to
// gum::learning::DBTranslatedValue { std::size_t(1) } and
// gum::learning::DBTranslatedValue { std::size_t(0) } respectively
 
// if the string contains a number outside the domain of the
// IntegerVariable, then a gum::NotFound exception is raised:
auto val3 = translator << "17"; // NotFound raised
 
// add the numbers assigned to val1, val2
std::size_t sum = val1.discr_val + val2.discr_val;
 
// translate missing values: val4 and val5 will be equal to:
// DBTranslatedValue { std::numeric_limits<std::size_t>::max () }
auto val4 = translator << "N/A";
auto val5 = translator.translate ( "???" );
 
// the following instructions raise TypeError exceptions because the
// strings are not integers
auto val6 = translator << "422.5";
auto val7 = translator.translate ( "xxx" );
 
// given a DBTranslatedValue that is supposed to contain the index of
// an integer, get the string representing this integer.
std::string str;
str = translator.translateBack ( val1 );        // str = "3"
str = translator >> val2;                       // str = "1"
str = translator >> gum::learning::DBTranslatedValue {std::size_t(1)};
                                                // str = "3"
 
// translate back missing values: the string will corresponds to one of
// the missing symbols known to the translator
str = translator >> val4; // str = "N/A" or "???"
str = translator >> val5; // str = "N/A" or "???"
 
// get the variable stored within the translator
const gum::IntegerVariable<float>* var =
  dynamic_cast<const gum::IntegerVariable*>(translator.variable());

Definition at line 142 of file DBTranslator4IntegerVariable.h.

Constructor & Destructor Documentation

DBTranslator4IntegerVariable() [1/4]

gum::learning::DBTranslator4IntegerVariable::DBTranslator4IntegerVariable	(	const IntegerVariable &	var,
		const std::vector< std::string > &	missing_symbols,
		std::size_t	max_dico_entries = std::numeric_limits< std::size_t >::max() )

default constructor with an integer variable as translator

Parameters

var	an integer variable which will be used for translations. The translator keeps a copy of this variable
missing_symbols	the set of symbols in the dataset representing missing values
max_dico_entries	the max number of entries that the dictionary can contain. During the construction, we check that the integer variable passed in argument has fewer values than the admissible dictionary size

Referenced by DBTranslator4IntegerVariable(), DBTranslator4IntegerVariable(), clone(), operator=(), and operator=().

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DBTranslator4IntegerVariable() [2/4]

gum::learning::DBTranslator4IntegerVariable::DBTranslator4IntegerVariable	(	const IntegerVariable &	var,
		std::size_t	max_dico_entries = std::numeric_limits< std::size_t >::max() )

default constructor with an integer variable as translator but without missing symbols

Parameters

var	an integer variable which will be used for translations. The translator keeps a copy of this variable
max_dico_entries	the max number of entries that the dictionary can contain. During the construction, we check that the integer variable passed in argument has a domain size not larger than the admissible dictionary size

DBTranslator4IntegerVariable() [3/4]

gum::learning::DBTranslator4IntegerVariable::DBTranslator4IntegerVariable

(

const DBTranslator4IntegerVariable &

from

)

copy constructor

References DBTranslator4IntegerVariable().

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DBTranslator4IntegerVariable() [4/4]

gum::learning::DBTranslator4IntegerVariable::DBTranslator4IntegerVariable

(

DBTranslator4IntegerVariable &&

from

)

move constructor

References DBTranslator4IntegerVariable().

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~DBTranslator4IntegerVariable()

virtual gum::learning::DBTranslator4IntegerVariable::~DBTranslator4IntegerVariable ( )

virtual

destructor

Member Function Documentation

clone()

virtual DBTranslator4IntegerVariable * gum::learning::DBTranslator4IntegerVariable::clone ( ) const

virtual

virtual copy constructor

Implements gum::learning::DBTranslator.

References DBTranslator4IntegerVariable().

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domainSize()

virtual std::size_t gum::learning::DBTranslator4IntegerVariable::domainSize ( ) const

finalvirtual

returns the domain size of the variable used for translations

Warning

Note that missing values are encoded as std::numeric_limits<>::max () and are not taken into account in the domain sizes.

Implements gum::learning::DBTranslator.

getDictionary()

virtual const Bijection< std::size_t, std::string > & gum::learning::DBTranslator::getDictionary ( ) const

virtualinherited

returns the translation from database indices to input strings

getValType()

DBTranslatedValueType gum::learning::DBTranslator::getValType ( ) const

inherited

returns the type of values handled by the translator

Returns

either DBTranslatedValueType::DISCRETE if the translator includes a discrete variable or DBTranslatedValueType::CONTINUOUS if it contains a continuous variable. This is convenient to know how to interpret the DBTranslatedValue instances produced by the DBTranslator: either using their discr_val field or their cont_val field.

Referenced by gum::learning::BNDatabaseGenerator< GUM_SCALAR >::toDatabaseTable().

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hasEditableDictionary()

virtual bool gum::learning::DBTranslator4IntegerVariable::hasEditableDictionary ( ) const

finalvirtual

indicates that the translator is never in editable dictionary mode

Reimplemented from gum::learning::DBTranslator.

References hasEditableDictionary().

Referenced by hasEditableDictionary().

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isLossless()

bool gum::learning::DBTranslator::isLossless ( ) const

inherited

returns a Boolean indicating whether the translation is lossless or not

Some translations can lose some information. For instance, a translator for a discretized variable will translate all the values of a discretization interval as the same value (the index of the interval). As such it looses some information because, knowing this index, it is impossible to get back to the original value that was translated. Method isLossless() indicates whether the translation never loses any information or not.

isMissingSymbol()

bool gum::learning::DBTranslator::isMissingSymbol ( const std::string & str ) const

inherited

indicates whether a string corresponds to a missing symbol

isMissingValue()

bool gum::learning::DBTranslator::isMissingValue ( const DBTranslatedValue & val ) const

inherited

indicates whether a translated value corresponds to a missing value

missingSymbols()

const Set< std::string > & gum::learning::DBTranslator::missingSymbols ( ) const

inherited

returns the set of missing symbols taken into account by the translator

missingValue()

virtual DBTranslatedValue gum::learning::DBTranslator4IntegerVariable::missingValue ( ) const

finalvirtual

returns the translation of a missing value

Implements gum::learning::DBTranslator.

References missingValue().

Referenced by missingValue().

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needsReordering()

virtual bool gum::learning::DBTranslator4IntegerVariable::needsReordering ( ) const

finalvirtual

indicates that the translations should never be reordered

Implements gum::learning::DBTranslator.

References needsReordering().

Referenced by needsReordering().

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operator<<()

DBTranslatedValue gum::learning::DBTranslator::operator<< ( const std::string & str )

inherited

alias for method translate

operator=() [1/2]

DBTranslator4IntegerVariable & gum::learning::DBTranslator4IntegerVariable::operator=

(

const DBTranslator4IntegerVariable &

from

)

copy operator

References DBTranslator4IntegerVariable().

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operator=() [2/2]

DBTranslator4IntegerVariable & gum::learning::DBTranslator4IntegerVariable::operator=

(

DBTranslator4IntegerVariable &&

from

)

move operator

References DBTranslator4IntegerVariable().

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operator>>()

std::string gum::learning::DBTranslator::operator>> ( const DBTranslatedValue translated_val )

inherited

alias for method translateBack

reorder()

virtual HashTable< std::size_t, std::size_t > gum::learning::DBTranslator4IntegerVariable::reorder ( )

finalvirtual

returns an empty HashTable to indicate that no reordering is needed.

Implements gum::learning::DBTranslator.

References reorder().

Referenced by reorder().

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setEditableDictionaryMode()

virtual void gum::learning::DBTranslator4IntegerVariable::setEditableDictionaryMode ( bool new_mode )

finalvirtual

sets/unset the editable dictionary mode

Reimplemented from gum::learning::DBTranslator.

References setEditableDictionaryMode().

Referenced by setEditableDictionaryMode().

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setVariableDescription()

void gum::learning::DBTranslator::setVariableDescription ( const std::string & str ) const

inherited

sets the name of the variable stored into the translator

setVariableName()

void gum::learning::DBTranslator::setVariableName ( const std::string & str ) const

inherited

sets the name of the variable stored into the translator

translate()

virtual DBTranslatedValue gum::learning::DBTranslator4IntegerVariable::translate ( const std::string & str )

finalvirtual

returns the translation of a string

This method tries to translate a given string into the DBTranslatedValue that should be stored into a databaseTable. If the translator cannot find the translation in its current dictionary, then the translator raises either a TypeError if the string is not a number or an UnknownLabelInDatabase exception.

Warning

Note that missing values (i.e., string encoded as missing symbols) are translated as std::numeric_limits<std::size_t>::max ().

If the variable contained into the translator has an integer that corresponds to a missing value symbol, the integer will be taken into account in the translation, not the missing symbol.

Returns

the translated value of the string to be stored into a DatabaseTable

Exceptions

UnknownLabelInDatabase	is raised if the translation cannot be found.
TypeError	is raised if the translation cannot be found in the translator and the string does not correspond to a number.

Implements gum::learning::DBTranslator.

translateBack()

virtual std::string gum::learning::DBTranslator4IntegerVariable::translateBack ( const DBTranslatedValue translated_val ) const

finalvirtual

returns the original value for a given translation

Returns

the string that was translated into a given DBTranslatedValue.

Exceptions

UnknownLabelInDatabase

is raised if this original value cannot be found

Implements gum::learning::DBTranslator.

variable()

virtual const IntegerVariable * gum::learning::DBTranslator4IntegerVariable::variable ( ) const

finalvirtual

returns the variable stored into the translator

Implements gum::learning::DBTranslator.

References variable().

Referenced by variable().

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Member Data Documentation

back_dico_

Bijection< std::size_t, std::string > gum::learning::DBTranslator::back_dico_

mutableprotectedinherited

the bijection relating back translated values and their original strings.

Note that the translated values considered here are of type std::size_t because only the values for discrete variables need be stored, those for continuous variables are actually identity mappings.

Warning

only the values of the random variable are stored into this bijection. Missing values are not considered here.

Definition at line 399 of file DBTranslator.h.

is_dictionary_dynamic_

bool gum::learning::DBTranslator::is_dictionary_dynamic_

protectedinherited

indicates whether the dictionary can be updated or not

Definition at line 385 of file DBTranslator.h.

is_lossless_

bool gum::learning::DBTranslator::is_lossless_

protectedinherited

indicates whether the translation is lossless (e.g., ranges) or not

Definition at line 382 of file DBTranslator.h.

max_dico_entries_

std::size_t gum::learning::DBTranslator::max_dico_entries_

protectedinherited

the maximum number of entries that the dictionary is allowed to contain

Definition at line 388 of file DBTranslator.h.

missing_symbols_

Set< std::string > gum::learning::DBTranslator::missing_symbols_

protectedinherited

the set of missing symbols

Definition at line 391 of file DBTranslator.h.

val_type_

DBTranslatedValueType gum::learning::DBTranslator::val_type_

protectedinherited

the type of the values translated by the translator

Definition at line 402 of file DBTranslator.h.

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

• agrum/base/database/DBTranslator4IntegerVariable.h