gRain (version 0.6.0)

cpt: Create conditional probability tables (CPTs)

Description

Creates conditional probability tables of the form p(v|pa(v)).

Usage

cptable(v, pa = NULL, values = NULL, gmData=NULL, normalize = TRUE, smooth = 0, levels=NULL)
cptspec(x)

Arguments

v

Variable

pa

Possible parents

gmData

Name of gmData object (where to look for v and pa)

values

Probabilities; recycled if necessary

normalize

See 'details' below.

smooth

See 'details' below.

levels

See 'details' below.

x

A list of cpts

Value

• If a gmData object is given, then 'cpt' returns an object of class 'ctab' (which is a general representation of a table). If no gmData object is given, then 'cpt' returns an object of class 'cptTemplate'. 'cptspec' returns an object of class 'cptspec' (which is just a list with a special class attribute).

Details

If normalize=TRUE then for each configuration of the parents, "pa", the probabilities are normalized to sum to one. If smooth is non--zero then zero entries of values are replaced with smooth before normalization takes place. If no gmData object is given, then levels (giving the levels of 'v') must be given. Otherwise levels is ignored.

Examples

g <- newgmData(letters[1:5],nLevels=2)

t1 <- cptable("a",pa="b", gmData=g,values=1:4)

t2 <- cptable("a",pa=c("b","c"), levels=c("y","n"),values=1:4)