Create undirected and directed graphs
These functions are wrappers for creation of graphs as
implemented by graphNEL objects in the graph package.
ug(..., result = "graphNEL") ugList(x, result = "graphNEL") dag(..., result = "graphNEL", forceCheck = FALSE) dagList(x, result = "graphNEL", forceCheck = FALSE)
... |
A generating class for a graph, see examples below |
result |
The format of the graph. The possible choices are "graphNEL" (for a 'graphNEL' object), "igraph" (for an 'igraph' object), "matrix" (for an adjacency matrix), "dgCMatrix" (for a sparse matrix). |
x |
A list or individual components from which a graph can be created. |
forceCheck |
Logical determining if it should be checked if
the graph is acyclical. Yes, one can specify graphs with cycles
using the |
Functions ug(), and dag() can return a
graphNEL object, an 'igraph' object, a sparse or a dense
adjacency matrix.
Søren Højsgaard, sorenh@math.aau.dk
## The following specifications of undirected graphs are equivalent:
uG1 <- ug(~ a:b:c + c:d)
uG2 <- ug(c("a", "b", "c"), c("c", "d"))
uG3 <- ug(c("a", "b"), c("a", "c"), c("b", "c"), c("c", "d"))
graph::edges(uG1)
graph::nodes(uG1)
## The following specifications of directed acyclig graphs are equivalent:
daG1 <- dag(~ a:b:c + b:c + c:d)
daG2 <- dag(c("a", "b", "c"), c("b", "c"), c("c", "d"))
graph::edges(daG1)
graph::nodes(daG2)
## dag() allows to specify directed graphs with cycles:
daG4 <- dag(~ a:b + b:c + c:a) # A directed graph but with cycles
## A check for acyclicity can be done with
## daG5 <- dag(~ a:b + b:c + c:a, forceCheck=TRUE)
## A check for acyclicity is provided by topoSort
topo_sort( daG2 )
topo_sort( daG4 )
## Different representations
uG6 <- ug(~a:b:c + c:d, result="graphNEL") # default
uG7 <- ug(~a:b:c + c:d, result="igraph") # igraph
uG8 <- ug(~a:b:c + c:d, result="matrix") # dense matrix
uG9 <- ug(~a:b:c + c:d, result="dgCMatrix") # sparse matrixPlease choose more modern alternatives, such as Google Chrome or Mozilla Firefox.