Construct an item-pool adjacency matrix.

For an item pool with N items, this returns an N x N matrix. The diagonal elements contain the number of times each item has been administered. The off-diagonal element \((i, j)\) contains the number of respondents who have been administered both item \(i\) and item \(j\). In general this function is not called directly, but is instead called within meow(). It is exposed to aid users who are testing item selection functions they have written.

Usage

construct_adj_mat(admin)

Arguments

admin

An administration matrix with one row per respondent and one column per item. Non-zero entries indicate that an item has been administered to a respondent (see meow() for details of the matrix-based simulation state). A logical matrix is also accepted.

Value

An item-item adjacency matrix of type matrix.

Examples

admin <- matrix(c(1, 1, 0,
                  1, 0, 1), nrow = 2, byrow = TRUE)
construct_adj_mat(admin)
#>        item_1 item_2 item_3
#> item_1      2      1      1
#> item_2      1      1      0
#> item_3      1      0      1