pcalg (version 1.0-0)

pdag2dag: Extend a PDAG to a DAG

Description

This function extends a PDAG to a DAG, if this is possible.

Usage

pdag2dag(g,keepVstruct=TRUE)

Arguments

g

input PDGA (graph object)

keepVstruct

If TRUE, the v-structures in g are kept. O/w they are ignored and an arbitrary extension is generated.

Value

• List with two entries: "graph" contains consistent DAG extension (graph object) and "success" is TRUE iff the extension was possible.

Details

The PDAG is consistently extended using an algorithm by Dor and Tarsi (see References). If no extension is possible, a DAG corresponding to the skeleton of the PDAG is generated and a warning message is produced.

References

D.Dor, M.Tarsi, A simple algorithm to construct a consistent extension of a partially oriented graph, Technicial Report R-185, Cognitive Systems Laboratory, UCLA, 1992

See Also

udag2pdag,pdag2dag

Examples

p <- 10 # number of random variables
n <- 10000 # number of samples
s <- 0.4 # sparsness of the graph

## generate random data
set.seed(42)
g <- randomDAG(p,s) # generate a random DAG
d <- rmvDAG(n,g) # generate random samples

gSkel <- 
  pcAlgo(d,alpha=0.05) # estimate of the skeleton

gPDAG <- udag2pdag(gSkel)

gDAG <- pdag2dag(gPDAG@graph)