Find the children nodes of a node in a context tree

This function returns a list (possibly empty) of ctx_node objects. Each object represents one of the children of the node represented by the node parameter.

Usage

children(node)

# S3 method for ctx_node
children(node)

# S3 method for ctx_node_cpp
children(node)

Arguments

node

a ctx_node object as returned by find_sequence()

Value

a list of ctx_node objects, see details.

Details

Each node of a context tree represents a sequence. When find_sequence() is called with success, the returned object represents the corresponding node in the context tree. If this node has no child, the present function returns an empty list. When the node has at least one child, the function returns a list with one value for each element in the state space (see states()). The value is NULL if the corresponding child is empty, while it is a ctx_node object when the child is present. Each ctx_node object is associated to the sequence obtained by adding to the past of the sequence represented by node an observation of the associated state (this corresponds to an extension to the left of the sequence in temporal order).

Examples

dts <- c(0, 1, 1, 1, 0, 0, 1, 0, 1, 0)
dts_ctree <- ctx_tree(dts, min_size = 1, max_depth = 3)
ctx_00 <- find_sequence(dts_ctree, c(0, 0))
## this context can only be extended in the past by 1:
children(ctx_00)
#> $`0`
#> NULL
#> 
#> $`1`
#> Context [T]: 1, 0, 0 
#>  followed by 0 (0), 1 (1)
#> 
ctx_10 <- find_sequence(dts_ctree, c(1, 0))
## this context can be extended by both states
children(ctx_10)
#> $`0`
#> Context [T]: 0, 1, 0 
#>  followed by 0 (0), 1 (1)
#> 
#> $`1`
#> Context [T]: 1, 1, 0 
#>  followed by 0 (1), 1 (0)
#> 
## C++ backend
dts <- c(0, 1, 1, 1, 0, 0, 1, 0, 1, 0)
dts_ctree <- ctx_tree(dts, min_size = 1, max_depth = 3, backend = "C++")
ctx_00 <- find_sequence(dts_ctree, c(0, 0))
## this context can only be extended in the past by 1:
children(ctx_00)
#> $`0`
#> NULL
#> 
#> $`1`
#> Context [T]: 1, 0, 0 
#>  followed by 0 (0), 1 (1)
#> 
ctx_10 <- find_sequence(dts_ctree, c(1, 0))
## this context can be extended by both states
children(ctx_10)
#> $`0`
#> Context [T]: 0, 1, 0 
#>  followed by 0 (0), 1 (1)
#> 
#> $`1`
#> Context [T]: 1, 1, 0 
#>  followed by 0 (1), 1 (0)
#>