chStat {gRapHD}R Documentation

Internal use

Description

Calculates the deviance associated with the addition of each add-eligible edge. Called from stepw.

Usage

  chStat(model,dataset,previous=NULL,forbEdges=NULL)

Arguments

model a gRapHD object.
dataset matrix (nrow(dataset) observations and ncol(dataset) variables).
previous result of a previous run of chStat.
forbEdges list with edges that should not be considered. Matrix with 2 columns, each row representing an edge, and each column a vertex. Default is NULL.

Details

The deviance and degrees of freedom associated with each add-eligible edge is returned. If previous results are specified these are reused as appropriate, and a concatenated result list is returned. This function is used by stepw.

Value

A list with:

edges.to.test matrix (k by 5), with columns:
1 - first vertex of the tested edge
2 - second vertex (the two values are ordered)
3 - index for the separator in S
4 - deviance statistic associated with adding this edge
5 - degrees of freedom associated with the deviance
S list of separators.

Author(s)

Gabriel Coelho Goncalves de Abreu (Gabriel.Abreu@agrsci.dk)
Rodrigo Labouriau (Rodrigo.Labouriau@agrsci.dk)
David Edwards (David.Edwards@agrsci.dk)

Examples

  data(dsCont)
  m1 <- minForest(dsCont,homog=TRUE,forbEdges=NULL,stat="LR")
  ch <- findEd(m1$edges,m1$p,NULL,m1$varType,0)
  ch <- chStat(m1,dsCont,ch,forbEdges=0)
  #    > str(ch)
  #    List of 2
  #     $ edges.to.test: num [1:53, 1:5] 1 11 19 11 17 2 2 10 10 2 ...
  #     $ S            :List of 53
  #      ..$ : int 11
  #      ..$ : int 21
  #      ..$ : int 21
  #      ..$ : int 21
  #      ..$ : int 27
  #      ..$ : int 17
  #       ...
  #    > head(ch$edges.to.test)
  #         [,1] [,2] [,3]         [,4] [,5]
  #    [1,]    1   21    1  -0.61733689    1
  #    [2,]   11   19    2  -0.24637623    1
  #    [3,]   19   27    3  -0.47194908    1
  #    [4,]   11   27    4  -7.00259895    1
  #    [5,]   17   21    5 -11.09310305    1
  #    [6,]    2   27    6  -0.04690911    1

  # the columns in ch$edges.to.test
  #    1: first vertex in the edge
  #    2: second vertex in the edge
  #    3: index os the separator in ch$S
  #    4: change in the LR for the edge
  #    5: number of parameters for the edge

[Package gRapHD version 0.1.0 Index]