modify_glist: Modify generating class for a graphical/hierarchical model

In gRim: Graphical Interaction Models

Modify generating class for a graphical/hierarchical model

Description

Modify generating class for a graphical/hierarchical model by 1) adding edges, 2) deleting edges, 3) adding terms and 4) deleting terms.

Usage

modify_glist(glist, items, details = 0)

Arguments

glist	A list of vectors where each vector is a generator of the model.
items	A list with edges / terms to be added and deleted. See section 'details' below.
details	Control the amount of output (for debugging purposes).

Details

The items is a list with named entries as list(add.edge=, drop.edge=, add.term=, drop.term=)

Not all entries need to be in the list. The corresponding actions are carried out in the order in which they appear in the list.

See section 'examples' below for examples.

Notice that the operations do not in general commute: Adding an edge which is already in a generating class and then removing the edge again does not give the original generating class.

Value

A generating class for the modified model. The elements of the list are character vectors.

Author(s)

Søren Højsgaard, [e-mail]

See Also

cmod, dmod, mmod

Examples

glist <- list(c(1, 2, 3), c(2, 3, 4))

## Add edges
modify_glist(glist, items=list(add.edge=c(1, 4)))
modify_glist(glist, items=list(add.edge=~1:4))

## Add terms
modify_glist(glist, items=list(add.term=c(1, 4)))
modify_glist(glist, items=list(add.term=~1:4))

## Notice: Only the first term is added as the second is already 
## in the model.
modify_glist(glist, items=list(add.term=list(c(1, 4), c(1, 3))))
modify_glist(glist, items=list(add.term=~1:4 + 1:3))

## Notice: Operations are carried out in the order given in the
## items list and hence we get different results: 
modify_glist(glist, items=list(drop.edge=c(1, 4), add.edge=c(1, 4)))
modify_glist(glist, items=list(add.edge=c(1, 4), drop.edge=c(1, 4)))

gRim documentation built on Oct. 16, 2024, 1:07 a.m.