get.normalization.constant {gRaven}

Get the normalisation constant of a gRaven domain

Description

Get the normalisation constant of a gRaven domain

Usage

get.normalization.constant(domain, log = FALSE)

Arguments

domain

name of a gRaven domain

log

logical, should constant be returned on log scale?

Value

numeric, the value of the normalisation constant (or its logarithm). If no evidence has been entered, the constant is defined as 1.

Author(s)

Peter J. Green, [e-mail]

Examples

yn <- c("yes","no")
chest<-hugin.domain()

add.node(chest,"asia",states=yn)
add.node(chest,"tub",states=yn)
add.node(chest,"smoke",states=yn)
add.node(chest,"lung",states=yn)
add.node(chest,"bronc",states=yn)
add.node(chest,"either",states=yn)
add.node(chest,"xray",states=yn)
add.node(chest,"dysp",states=yn)

add.edge(chest,"tub","asia")
add.edge(chest,"lung","smoke")
add.edge(chest,"bronc","smoke")
add.edge(chest,"either","lung")
add.edge(chest,"either","tub")
add.edge(chest,"xray","either")
add.edge(chest,"dysp","bronc")
add.edge(chest,"dysp","either")

set.table(chest,"asia",c(0.01,0.99))
set.table(chest,"tub",c(0.05,0.95,0.01,0.99))
set.table(chest,"smoke",c(0.5,0.5))
set.table(chest,"lung",c(0.1,0.9,0.01,0.99))
set.table(chest,"bronc",c(0.6,0.4,0.3,0.7))
set.table(chest,"either",c(1,0,1,0,1,0,0,1))
set.table(chest,"xray",c(0.98,0.02,0.05,0.95))
set.table(chest,"dysp",c(0.9,0.1,0.7,0.3,0.8,0.2,0.1,0.9))

compile(chest)
get.normalization.constant(chest)

set.finding(chest,"asia","yes")
set.finding(chest,"dysp","yes")
get.normalization.constant(chest)