| choose.direction {bnlearn} |
R Documentation |
Try to infer the direction of an undirected arc
Description
Check both possible directed arcs for existence, and choose the one with the lowest p-value, the highest
score or the highest bootstrap probability.
Usage
choose.direction(x, arc, data, criterion = NULL, ...,
debug = FALSE)
Arguments
x |
an object of class bn. |
arc |
a character string vector of length 2, the labels of two nodes of the graph. |
data |
a data frame containing the data the Bayesian network was learned from. |
criterion |
a character string, the label of a score function, the label of an independence test or
bootstrap. See bnlearn-package for details on
the first two possibilities. |
... |
additional tuning parameters for the network score. See score for
details. |
debug |
a boolean value. If TRUE a lot of debugging output is printed; otherwise the function is
completely silent. |
Value
choose.direction returns invisibly an updated copy of x.
Author(s)
Marco Scutari
See Also
score, arc.strength.
Examples
data(learning.test)
res = gs(learning.test)
## the arc A - B has no direction.
choose.direction(res, learning.test, arc = c("A", "B"), debug = TRUE)
# * testing A - B for direction.
# > testing A -> B with conditioning set ' '.
# > p-value is 0 .
# > testing B -> A with conditioning set ' '.
# > p-value is 0 .
# @ nothing to do, same p-value.
## let's see score equivalence in action.
choose.direction(res, learning.test, criterion = "aic",
arc = c("A", "B"), debug = TRUE)
# * testing A - B for direction.
# > initial score for node A is -5495.051 .
# > initial score for node B is -4834.284 .
# > score delta for arc A -> B is 1166.914 .
# > score delta for arc B -> A is 1166.914 .
# @ nothing to do, same score delta.
## arcs which introduce cycles are handled correctly.
res = set.arc(res, "A", "B")
# now A -> B -> E -> A is a cycle.
choose.direction(res, learning.test, arc = c("E", "A"), debug = TRUE)
# * testing E - A for direction.
# > testing E -> A with conditioning set ' '.
# > p-value is 1.426725e-99 .
# > testing A -> E with conditioning set ' B F '.
# > p-value is 0.9818423 .
# > adding E -> A creates cycles!.
# > arc A -> E isn't good, either.
