Tidy Transition Counts at a Given Lag

Computes the K x K transition count matrix from canonical lag sequential data, optionally returning a tidy long-format edge table alongside the matrix.

Usage

lsa_transitions(x, lag = 1)

Arguments

x

Either an lsa_data object or any input accepted by lsa_data() (which will be coerced).

lag

Integer. The lag at which to count transitions; default 1. A positive lag counts successors (from at t, to at t + lag), a negative lag counts predecessors, and 0 pairs each event with itself (a degenerate diagonal). Must be a single finite whole number.

Value

An object of class c("lsa_transitions", "list") with elements:

obs

The K x K observed transition count matrix with dimnames set to the labels.

row_totals

Length-K vector rowSums(obs).

col_totals

Length-K vector colSums(obs).

n_transitions

Scalar sum(obs).

lag

The lag used.

labels

Character vector of state labels.

edges

Tidy long-format data.frame with one row per (from, to) cell containing columns from, to, lag, count, row_total, col_total, n_transitions.

Details

Transitions are counted within sequences only; no transition spans a sequence boundary. For input that was supplied as a pre-computed transition matrix (source = "transitions" on the lsa_data object), the input matrix is returned at lag 1 and an error is raised for any other lag.

See also

lsa_data(), lsa()

Examples

d <- lsa_data(c("a", "b", "a", "c", "b", "a"))
tx <- lsa_transitions(d, lag = 1)
tx$obs
#>   a b c
#> a 0 1 1
#> b 2 0 0
#> c 0 1 0
head(tx$edges)
#>   from to lag count row_total col_total n_transitions
#> 1    a  a   1     0         2         2             5
#> 2    b  a   1     2         2         2             5
#> 3    c  a   1     0         1         2             5
#> 4    a  b   1     1         2         2             5
#> 5    b  b   1     0         2         2             5
#> 6    c  b   1     1         1         2             5