as_caugi: Convert to a 'caugi'

In caugi: Causal Graph Interface

Convert to a caugi

Description

Convert an object to a caugi. The object can be a graphNEL, matrix, tidygraph, daggity, bn, or igraph.

Usage

as_caugi(
  x,
  class = c("DAG", "UG", "PDAG", "MPDAG", "CPDAG", "ADMG", "AG", "PAG", "UNKNOWN"),
  simple = TRUE,
  collapse = FALSE,
  collapse_to = "---",
  ...
)

Arguments

x	An object to convert to a caugi.
class	Character; one of "DAG", "UG", "PDAG", "MPDAG", "CPDAG", "ADMG", "AG", or "UNKNOWN". "PAG" is only supported for integer coded matrices.
simple	logical. If TRUE (default) the graph will be simple (no multiple edges or self-loops).
collapse	logical. If TRUE collapse mutual directed edges to undirected edges. Default is FALSE.
collapse_to	Character string to use as the edge glyph when collapsing. Should be a registered symmetrical edge glyph. Default is "---".
...	Additional arguments passed to specific methods.

Details

For matrices, as_caugi assumes that the rows are the from nodes and the columns are the to nodes. Thus, for a graph, G: A –> B, we would have that G["A", "B"] == 1 and G["B", "A"] == 0. For PAGs, the integer codes are as follows (as used in pcalg):

• 0: no edge

• 1: circle (e.g., ⁠A o-o B⁠ or ⁠A --o B⁠)

• 2: arrowhead (e.g., ⁠A --> B⁠ or ⁠A o-> B⁠)

• 3: tail (e.g., ⁠A --o B⁠ or A --- B)

Value

A caugi object.

See Also

Other conversions: as_adjacency(), as_bnlearn(), as_dagitty(), as_igraph()

Examples

# igraph
ig <- igraph::graph_from_literal(A - +B, B - +C)
cg_ig <- as_caugi(ig, class = "DAG")

# graphNEL
gn <- graph::graphNEL(nodes = c("A", "B", "C"), edgemode = "directed")
gn <- graph::addEdge("A", "B", gn)
gn <- graph::addEdge("B", "C", gn)
cg_gn <- as_caugi(gn, class = "DAG")

# adjacency matrix
m <- matrix(0L, 3, 3, dimnames = list(LETTERS[1:3], LETTERS[1:3]))
m["A", "B"] <- 1L
m["B", "C"] <- 1L
cg_adj <- as_caugi(m, class = "DAG")

# bnlearn
bn <- bnlearn::model2network("[A][B|A][C|B]")
cg_bn <- as_caugi(bn, class = "DAG")

# dagitty
dg <- dagitty::dagitty("dag {
 A -> B
 B -> C
 }")
cg_dg <- as_caugi(dg, class = "DAG")

cg <- caugi(A %-->% B %-->% C, class = "DAG")

# check that all nodes are equal in all graph objects
for (cg_converted in list(cg_ig, cg_gn, cg_adj, cg_bn, cg_dg)) {
  stopifnot(identical(nodes(cg), nodes(cg_converted)))
  stopifnot(identical(edges(cg), edges(cg_converted)))
}

# collapse mutual edges
ig2 <- igraph::graph_from_literal(A - +B, B - +A, C - +D)
cg2 <- as_caugi(ig2, class = "PDAG", collapse = TRUE, collapse_to = "---")

# coded integer matrix for PAGs (pcalg style)
nm <- c("A", "B", "C", "D")
M <- matrix(0L, 4, 4, dimnames = list(nm, nm))

# A --> B
M["A", "B"] <- 2L # mark at B end
M["B", "A"] <- 3L # mark at A end

# A --- C
M["A", "C"] <- 3L
M["C", "A"] <- 3L

# B o-> C
M["B", "C"] <- 2L
M["C", "B"] <- 1L

# C o-o D
M["C", "D"] <- 1L
M["D", "C"] <- 1L

cg <- as_caugi(M, class = "PAG")

caugi documentation built on Oct. 28, 2026, 1:07 a.m.