Braid: the canonical detector of trajectories (central + absorbed)

Decomposes the cumulative-clustering DAG into trajectories via trunk edges (mutual dominance: v -> u where u is v's heaviest successor and v is u's heaviest predecessor). Trunk edges form disjoint chains. A chain ending at a final-year group node is a central trajectory (tr::<group>, one per final group, reaches the final year); every other chain is absorbed (tr1 … trN), merging into an absorber (central or another absorbed) where its head flows out via a non-trunk edge. Absorption is transitive, forming a confluence forest.

Usage

sniff_trajectory_braid(x, min_group_size = 10, jaccard_min = 0.05, k_out = 2)

Arguments

x

A sniff_trajectory_dag() object, a sniff_groups_lineage() object, or a docs_per_group tibble (the DAG is built internally).

min_group_size, jaccard_min, k_out

Passed to sniff_trajectory_dag() when x is not already a DAG object.

Value

A birddog_flow object: a classed list with trajectories (tibble: traj_id, type ("central"/"absorbed"), group (destination group; NA if extinct), start, end, size (distinct papers), depth (0 = central), absorbed_into (absorber traj_id, NA for central), absorption_year (NA for central), nodes list-col), tree (edges child, parent, absorption_year), graph, docs_per_group, last_year.

See also

sniff_trajectory_channel(), sniff_trajectory_dag(), sniff_trajectory_dynamics()

Other trajectory detection: is_flow(), sniff_trajectory_channel(), sniff_trajectory_dag(), subset.birddog_flow(), validate_flow()