P

class pqp.symbols.P(vars, given=None)

Bases: AbstractExpression

Expression representing a probability or conditional probability

Parameters:

• vars (list of Variable) – probability variables

• given (list of Variable) – conditioned variables

Raises:

• ValueError – if a variable is repeated in vars or given

• TypeError – if vars or given are not a list of Variable or Event

Attributes Summary

unassigned

Methods Summary

copy()	Returns a copy of the expression (variables are not copied).
get_conditioned_vars()	Get the set of variables which are conditioned on in this P
get_intervened_vars()	Get the set of variables which are intervened on in this P
get_vars()	Get the set of variables to the left of the conditioning bar in this P
r_adapt_map(func)	Recursive map where the func decides callables used to transform children
r_map(func)	Recursively maps a function over the expression tree
sorted()	Returns a sorted copy of an expression for structural comparison.
syntactic_eq(other)	Test whether two Expressions are syntactically identical (structural compare without sorting first)
to_latex()

Attributes Documentation

unassigned = <object object>

Methods Documentation

copy()

Returns a copy of the expression (variables are not copied).

get_conditioned_vars()

Get the set of variables which are conditioned on in this P

Raises:

TypeError – if self.given contains an element which is not Variable, EqualityEvent or InterventionEvent

Returns:

dict of Variable -> value

get_intervened_vars()

Get the set of variables which are intervened on in this P

Returns:

dict of Variable -> value

Raises:

TypeError – if self.given contains an InterventionEvent which contains neither Variable nor EqualityEvent

get_vars()

Get the set of variables to the left of the conditioning bar in this P

Returns:

set of Variable

Raises:

TypeError – if self.vars contains an element which is neither Variable nor EqualityEvent

r_adapt_map(func)

Recursive map where the func decides callables used to transform children

DO NOT USE! This is a powerful and necessary method but it results in almost unreadable code.

So, func takes an AbstractExpression and needs to return a tuple of two things. First, a function A which maps from AbstractExpression to AbstractExpression. Second, a function B of the same time as func.

At each level of recursion, func will be called on an expression E to get A and B. This method, r_adapt_map will then be called on the children of E with B as input (if B is None, recursion terminates). An expression of the same type as E is then constructed with the results of the recursive calls using B, and A is applied to the result.

Parameters:

func (function) – A function that takes an AbstractExpression and returns two functions (see desc)

r_map(func)

Recursively maps a function over the expression tree

sorted()

Returns a sorted copy of an expression for structural comparison.

syntactic_eq(other)

Test whether two Expressions are syntactically identical (structural compare without sorting first)

to_latex()