dreach function

Compute D-SEP(x,y,G)

Let x and y be two distinct vertices in a mixed graph G. This function computes D-SEP(x,y,G), which is defined as follows:

A node v is in D-SEP(x,y,G) iff v is not equal to x and there is a collider path between x and v in G such that every vertex on this path is an ancestor of x or y in G.

See p.136 of Sprirtes et al (2000) or Definition 4.1 of Maathuis and Colombo (2015).

dreach(x, y, amat, verbose = FALSE)

Arguments

• x: First argument of D-SEP, given as the column number of the node in the adjacency matrix.
• y: Second argument of D-SEP, given as the column number of the node in the adjacency matrix (y must be different from x).
• amat: Adjacency matrix of type amat.pag .
• verbose: Logical specifying details should be on output

Returns

Vector of column positions indicating the nodes in D-SEP(x,y,G).

References

P. Spirtes, C. Glymour and R. Scheines (2000) Causation, Prediction, and Search, 2nd edition, The MIT Press.

M.H. Maathuis and D. Colombo (2015). A generalized back-door criterion. Annals of Statistics 43 1060-1088.

Author(s)

Diego Colombo and Markus Kalisch (kalisch@stat.math.ethz.ch )

See Also

backdoor uses this function; pag2magAM.