Validate a spatial adjacency matrix

Check that a hand-built adjacency matrix is a well-formed spatial graph before passing it to spatial() / spatial_car(): square, symmetric, zero on the diagonal, 0/1 valued, and free of isolated nodes. adjacency() runs the same checks on the graphs it constructs.

Usage

check_adjacency(adjacency, ids = NULL)

Arguments

adjacency

A matrix (dense or sparse Matrix).

ids

Optional cell identifiers; if supplied, their length must match nrow(adjacency) and they must be unique.

Value

Invisibly, a tulpa_adjacency_check list with the per-check results (square, symmetric, zero_diag, binary, isolated-node indices, edge count) and an overall ok flag. Issues are reported via warning() and printed; the function does not stop, so every problem surfaces in one pass.

See also

adjacency() to construct a graph, node_index().

Examples

adj <- matrix(0, 4, 4)
for (i in 1:3) adj[i, i + 1] <- adj[i + 1, i] <- 1
check_adjacency(adj)