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arc operations {bnlearn} R Documentation

Drop, add or set the direction of an arc

Description

Drop, add or set the direction of an arc.

Usage

set.arc(x, from, to, check.cycles = TRUE, debug = FALSE)
drop.arc(x, from, to, debug = FALSE)
reverse.arc(x, from, to, check.cycles = TRUE, debug = FALSE)

Arguments

x an object of class bn.
from a character string, the label of a node.
to a character string, the label of another node.
check.cycles a boolean value. If TRUE the graph is tested for acyclicity; otherwise the graph is returned anyway.
debug a boolean value. If TRUE a lot of debugging output is printed; otherwise the function is completely silent.

Details

The set.arc function operates in the following way:

  • if there is no arc between from and to, the arc from -> to is added.
  • if there is an undirected arc between from and to, its direction is set to from - to.
  • if the arc to -> from is present, it's reversed.
  • if the arc from -> to is present, no action is taken.

The drop.arc function operates in the following way:

  • if there is no arc between from and to, no action is taken.
  • if there is an undirected arc between from and to, it's dropped.
  • if there is a directed arc between from and to, it's dropped regardless of its direction.

The reverse.arc function operates in the following way:

  • if there is no arc between from and to, it returns an error.
  • if there is an undirected arc between from and to, it returns an error.
  • if the arc to -> from is present, it's reversed.
  • if the arc from -> to is present, it's reversed.

Value

set.arc and drop.arc return invisibly an updated copy of x.

Author(s)

Marco Scutari

Examples

data(learning.test)
res = gs(learning.test)

## use debug = TRUE for more information
## Not run: 
set.arc(res, "A", "B", debug = TRUE)
drop.arc(res, "A", "B", debug = TRUE)
reverse.arc(res, "A", "D", debug = TRUE)
## End(Not run)
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