# possDe: Find possible descendants of given node(s). In pcalg: Methods for Graphical Models and Causal Inference

## Description

In a DAG, CPDAG, MAG or PAG determine which nodes are (possible) descendants of x on definite status or just any paths potentially avoiding given nodes on the paths.

## Usage

 ```1 2``` ```possDe(m, x, y = NULL, possible = TRUE, ds = TRUE, type = c("cpdag", "pdag", "dag", "mag", "pag")) ```

## Arguments

 `m` Adjacency matrix in coding according to type. `x` Node positions of starting nodes. `y` Node positions of nodes through which a path must not go. `possible` If `TRUE`, possible descendents are returned. `ds` If `TRUE`, only paths of definite status are considered. `type` Type of adjacency matrix in `m`. The coding is according to `amatType`.

## Details

Not all possible combinations of the arguments are currently implemented and will issue an error if called.

## Value

Vector of all node positions found as (possible) descendents of the nodes in `x`.

## Author(s)

Markus Kalisch

`amatType`
 ```1 2 3 4 5 6 7 8``` ```## a -> b -- c amat <- matrix(c(0,1,0, 0,0,1, 0,1,0), 3,3) colnames(amat) <- rownames(amat) <- letters[1:3] plot(as(t(amat), "graphNEL")) possDe(m = amat, x = 1, possible = TRUE, ds = FALSE, type = "pdag") ## all nodes possDe(m = amat, x = 1, possible = FALSE, ds = FALSE, type = "pdag") ## only nodes 1 and 2 possDe(m = amat, x = 1, y = 2, possible = TRUE, ds = FALSE, type = "pdag") ## only node 1 ```