Random Variables¶

aGrUM/pyAgrum is currently dedicated for discrete probability distributions.

There are 3 types of discrete random variables in aGrUM/pyAgrum: LabelizedVariable, DiscretizedVariable and RangeVariable. The 3 types are mainly provided in order to ease modelization. Derived from DiscreteVariable, they share a common API. They essentially differ by the means to create, name and access to their modalities.

Common API for Random Discrete Variables¶

class pyAgrum.DiscreteVariable(*args, **kwargs)¶

DiscreteVariable is the base class for discrete random variables.

DiscreteVariable(aName, aDesc=’’) -> DiscreteVariable

Parameters:

aName (str) – the name of the variable
aDesc (str) – the (optional) description of the variable

DiscreteVariable(aDRV) -> DiscreteVariable

Parameters:

aDRV (pyAgrum.DiscreteVariable) – the pyAgrum.DiscreteVariable that will be copied

description(self)¶

Returns:	the description of the variable
Return type:	str

domain(self)¶

Returns:	the domain of the variable
Return type:	str

domainSize(self)¶

Returns:	the number of modalities in the variable domain
Return type:	int

empty(self)¶

Returns:	True if the domain size < 2
Return type:	bool

index(self, label)¶

Parameters:	label (str) – a label
Returns:	the indice of the label
Return type:	int

label(self, i)¶

Parameters:	i (int) – the index of the label we wish to return
Returns:	the indice-th label
Return type:	str
Raises:	`gum.OutOfBound` – If the variable does not contain the label

labels(self)¶

Returns:	a tuple containing the labels
Return type:	tuple

name(self)¶

Returns:	the name of the variable
Return type:	str

numerical(self, indice)¶

Parameters:	indice (int) – an index
Returns:	the numerical representation of the indice-th value
Return type:	float

setDescription(self, theValue)¶

set the description of the variable.

Parameters:	theValue (str) – the new description of the variable

setName(self, theValue)¶

sets the name of the variable.

Parameters:	theValue (str) – the new description of the variable

stype(self)¶

toDiscretizedVar(self)¶

Returns:	the discretized variable
Return type:	pyAgrum.DiscretizedVariable
Raises:	`gum.RuntimeError` – If the variable is not a DiscretizedVariable

toIntegerVar(self)¶

toLabelizedVar(self)¶

Returns:	the labelized variable
Return type:	pyAgrum.LabelizedVariable
Raises:	`gum.RuntimeError` – If the variable is not a LabelizedVariable

toRangeVar(self)¶

Returns:	the range variable
Return type:	pyAgrum.RangeVariable
Raises:	`gum.RuntimeError` – If the variable is not a RangeVariable

toStringWithDescription(self)¶

Returns:	a description of the variable
Return type:	str

varType(self)¶

returns the type of variable

Returns:	the type of the variable, 0: DiscretizedVariable, 1: LabelizedVariable, 2: RangeVariable
Return type:	int

Concrete classes for Random Discrete Variables¶

LabelizedVariable¶

class pyAgrum.LabelizedVariable(*args)¶

LabelizedVariable is a discrete random variable with a customizable sequence of labels.

LabelizedVariable(aName, aDesc=’’, nbrLabel=2) -> LabelizedVariable

Parameters:

aName (str) – the name of the variable
aDesc (str) – the (optional) description of the variable
nbrLabel (int) – the number of labels to create (2 by default)

LabelizedVariable(aLDRV) -> LabelizedVariable

Parameters:

aLDRV (pyAgrum.LabelizedVariable) – The pyAgrum.LabelizedVariable that will be copied

Examples

>>> import pyAgrum as gum
>>>
>>> # creating a variable with 3 labels : '0', '1' and '2'
>>> va=gum.LabelizedVariable('a','a labelized variable',3)
>>> print(va)
>>> ## a<0,1,2>
>>>
>>> va.addLabel('foo')
>>> print(va)
>>> ## a<0,1,2,foo>
>>>
>>> va.chgLabel(1,'bar')
>>> print(va)
>>> a<0,bar,2,foo>
>>>
>>> vb=gum.LabelizedVariable('b','b',0).addLabel('A').addLabel('B').addLabel('C')
>>> print(vb)
>>> ## b<A,B,C>
>>>
>>> vb.labels()
>>> ## ('A', 'B', 'C')
>>>
>>> vb.isLabel('E')
>>> ## False
>>>
>>> vb.label(2)
>>> ## 'B'

addLabel(*args)¶

Add a label with a new index (we assume that we will NEVER remove a label).

Parameters:	aLabel (str) – the label to be added to the labelized variable
Returns:	the labelized variable
Return type:	pyAgrum.LabelizedVariable
Raises:	`gum.DuplicateElement` – If the variable already contains the label

changeLabel(self, pos, aLabel)¶

Change the label at the specified index

Parameters:	pos (int) – the index of the label to be changed aLabel (str) – the label to be added to the labelized variable
Raises:	`gum.DuplicatedElement` – If the variable already contains the new label `gum.OutOfBounds` – If the index is greater than the size of the variable

description(self)¶

Returns:	the description of the variable
Return type:	str

domain(self)¶

Returns:	the domain of the variable as a string
Return type:	str

domainSize(self)¶

Returns:	the number of modalities in the variable domain
Return type:	int

empty(self)¶

Returns:	True if the domain size < 2
Return type:	bool

eraseLabels(self)¶: Erase all the labels from the variable.

index(self, label)¶

Parameters:	label (str) – a label
Returns:	the indice of the label
Return type:	int

isLabel(self, aLabel)¶

Indicates whether the variable already has the label passed in argument

Parameters:	aLabel (str) – the label to be tested
Returns:	True if the label already exists
Return type:	bool

label(self, i)¶

Parameters:	i (int) – the index of the label we wish to return
Returns:	the indice-th label
Return type:	str
Raises:	`gum.OutOfBound` – If the variable does not contain the label

labels(self)¶

Returns:	a tuple containing the labels
Return type:	tuple

name(self)¶

Returns:	the name of the variable
Return type:	str

numerical(self, index)¶

Parameters:	indice (int) – an index
Returns:	the numerical representation of the indice-th value
Return type:	float

posLabel(self, label)¶

setDescription(self, theValue)¶

set the description of the variable.

Parameters:	theValue (str) – the new description of the variable

setName(self, theValue)¶

sets the name of the variable.

Parameters:	theValue (str) – the new description of the variable

stype(self)¶

toDiscretizedVar(self)¶

Returns:	the discretized variable
Return type:	pyAgrum.DiscretizedVariable
Raises:	`gum.RuntimeError` – If the variable is not a DiscretizedVariable

toIntegerVar(self)¶

toLabelizedVar(self)¶

Returns:	the labelized variable
Return type:	pyAgrum.LabelizedVariable
Raises:	`gum.RuntimeError` – If the variable is not a LabelizedVariable

toRangeVar(self)¶

Returns:	the range variable
Return type:	pyAgrum.RangeVariable
Raises:	`gum.RuntimeError` – If the variable is not a RangeVariable

toStringWithDescription(self)¶

Returns:	a description of the variable
Return type:	str

varType(self)¶

returns the type of variable

Returns:	the type of the variable, 0: DiscretizedVariable, 1: LabelizedVariable, 2: RangeVariable
Return type:	int

DiscretizedVariable¶

class pyAgrum.DiscretizedVariable(*args)¶

DiscretizedVariable is a discrete random variable with a set of ticks defining intervalls.

DiscretizedVariable(aName, aDesc=’’) -> DiscretizedVariable`

Parameters:

aName (str) – the name of the variable
aDesc (str) – the (optional) description of the variable

DiscretizedVariable(aDDRV) -> DiscretizedVariable

Parameters:

aDDRV (pyAgrum.DiscretizedVariable) – the pyAgrum.DiscretizedVariable that will be copied

Examples

>>> import pyAgrum as gum
>>>
>>> vX=gum.DiscretizedVariable('X','X has been discretized')
>>> vX.addTick(1).addTick(2).addTick(3).addTick(3.1415) #doctest: +ELLIPSIS
>>> ## <pyAgrum.DiscretizedVariable;...>
>>> print(vX)
>>> ## X<[1;2[,[2;3[,[3;3.1415]>
>>>
>>> vX.isTick(4)
>>> ## False
>>>
>>> vX.labels()
>>> ## ('[1;2[', '[2;3[', '[3;3.1415]')
>>>
>>> # where is the real value 2.5 ?
>>> vX.index('2.5')
>>> ## 1

addTick(*args)¶

Parameters:	aTick (double) – the Tick to be added
Returns:	the discretized variable
Return type:	pyAgrum.DiscretizedVariable
Raises:	`gum.DefaultInLabel` – If the tick is already defined

description(self)¶

Returns:	the description of the variable
Return type:	str

domain(self)¶

Returns:	the domain of the variable as a string
Return type:	str

domainSize(self)¶

Returns:	the number of modalities in the variable domain
Return type:	int

empty(self)¶

Returns:	True if the domain size < 2
Return type:	bool

eraseTicks(self)¶: erase all the Ticks

index(self, label)¶

Parameters:	label (str) – a label
Returns:	the indice of the label
Return type:	int

isTick(self, aTick)¶

Parameters:	aTick (double) – the Tick to be tested
Returns:	True if the Tick already exists
Return type:	bool

label(self, i)¶

Parameters:	i (int) – the index of the label we wish to return
Returns:	the indice-th label
Return type:	str
Raises:	`gum.OutOfBound` – If the variable does not contain the label

labels(self)¶

Returns:	a tuple containing the labels
Return type:	tuple

name(self)¶

Returns:	the name of the variable
Return type:	str

numerical(self, indice)¶

Parameters:	indice (int) – an index
Returns:	the numerical representation of the indice-th value
Return type:	float

setDescription(self, theValue)¶

set the description of the variable.

Parameters:	theValue (str) – the new description of the variable

setName(self, theValue)¶

sets the name of the variable.

Parameters:	theValue (str) – the new description of the variable

stype(self)¶

tick(self, i)¶

Indicate the index of the Tick

Parameters:	i (int) – the index of the Tick
Returns:	aTick – the index-th Tick
Return type:	double
Raises:	`gum.NotFound` – If the index is greater than the number of Ticks

ticks(self)¶

Returns:	a tuple containing all the Ticks
Return type:	tuple

toDiscretizedVar(self)¶

Returns:	the discretized variable
Return type:	pyAgrum.DiscretizedVariable
Raises:	`gum.RuntimeError` – If the variable is not a DiscretizedVariable

toIntegerVar(self)¶

toLabelizedVar(self)¶

Returns:	the labelized variable
Return type:	pyAgrum.LabelizedVariable
Raises:	`gum.RuntimeError` – If the variable is not a LabelizedVariable

toRangeVar(self)¶

Returns:	the range variable
Return type:	pyAgrum.RangeVariable
Raises:	`gum.RuntimeError` – If the variable is not a RangeVariable

toStringWithDescription(self)¶

Returns:	a description of the variable
Return type:	str

varType(self)¶

returns the type of variable

Returns:	the type of the variable, 0: DiscretizedVariable, 1: LabelizedVariable, 2: RangeVariable
Return type:	int

RangeVariable¶

class pyAgrum.RangeVariable(*args)¶

RangeVariable represents a variable with a range of integers as domain.

RangeVariable(aName, aDesc,minVal, maxVal) -> RangeVariable

Parameters:

aName (str) – the name of the variable
aDesc (str) – the description of the variable
minVal (int) – the minimal integer of the interval
maxVal (int) – the maximal integer of the interval

RangeVariable(aName, aDesc=’’) -> RangeVariable

Parameters:

aName (str) – the name of the variable
aDesc (str) – the description of the variable

By default minVal=0 and maxVal=1

RangeVariable(aRV) -> RangeVariable

Parameters:

aDV (RangeVariable) – the pyAgrum.RangeVariable that will be copied

Examples

>>> import pyAgrum as gum
>>>
>>> vI=gum.gum.RangeVariable('I','I in [4,10]',4,10)
>>> print(vI)
>>> ## I[4-10]
>>>
>>> vX.maxVal()
>>> ## 10
>>>
>>> vX.belongs(1)
>>> ## False
>>>
>>> # where is the value 5 ?
>>> vX.index('5')
>>> ## 1
>>>
>>> vi.labels()
>>> ## ('4', '5', '6', '7', '8', '9', '10')

belongs(self, val)¶

Parameters:	val (long) – the value to be tested
Returns:	True if the value in parameters belongs to the variable’s interval.
Return type:	bool

description(self)¶

Returns:	the description of the variable
Return type:	str

domain(self)¶

Returns:	the domain of the variable
Return type:	str

domainSize(self)¶

Returns:	the number of modalities in the variable domain
Return type:	int

empty(self)¶

Returns:	True if the domain size < 2
Return type:	bool

index(self, arg2)¶

Parameters:	arg2 (str) – a label
Returns:	the indice of the label
Return type:	int

label(self, index)¶

Parameters:	indice (int) – the index of the label we wish to return
Returns:	the indice-th label
Return type:	str
Raises:	`gum.OutOfBound` – If the variable does not contain the label

labels(self)¶

Returns:	a tuple containing the labels
Return type:	tuple

maxVal(self)¶

Returns:	the upper bound of the variable.
Return type:	long

minVal(self)¶

Returns:	the lower bound of the variable
Return type:	long

name(self)¶

Returns:	the name of the variable
Return type:	str

numerical(self, index)¶

Parameters:	indice (int) – an index
Returns:	the numerical representation of the indice-th value
Return type:	float

setDescription(self, theValue)¶

set the description of the variable.

Parameters:	theValue (str) – the new description of the variable

setMaxVal(self, maxVal)¶

Set a new value of the upper bound

Parameters:	maxVal (long) – The new value of the upper bound

Warning

An error should be raised if the value is lower than the lower bound.

setMinVal(self, minVal)¶

Set a new value of the lower bound

Parameters:	minVal (long) – The new value of the lower bound

Warning

An error should be raised if the value is higher than the upper bound.

setName(self, theValue)¶

sets the name of the variable.

Parameters:	theValue (str) – the new description of the variable

stype(self)¶

toDiscretizedVar(self)¶

Returns:	the discretized variable
Return type:	pyAgrum.DiscretizedVariable
Raises:	`gum.RuntimeError` – If the variable is not a DiscretizedVariable

toIntegerVar(self)¶

toLabelizedVar(self)¶

Returns:	the labelized variable
Return type:	pyAgrum.LabelizedVariable
Raises:	`gum.RuntimeError` – If the variable is not a LabelizedVariable

toRangeVar(self)¶

Returns:	the range variable
Return type:	pyAgrum.RangeVariable
Raises:	`gum.RuntimeError` – If the variable is not a RangeVariable

toStringWithDescription(self)¶

Returns:	a description of the variable
Return type:	str

varType(self)¶

returns the type of variable

Returns:	the type of the variable, 0: DiscretizedVariable, 1: LabelizedVariable, 2: RangeVariable
Return type:	int