.check_csa_rank: Check rank of augmented CSA matrix
Description
Verifies that the CSA matrix (with lags) is full column rank. Warns but
continues if rank deficient (MG estimates remain consistent per
Chudik & Pesaran 2015, p.398).
Usage
.check_csa_rank(Z, unit_id = "")
Value
Logical: TRUE if full rank, FALSE otherwise.
Arguments
- Z
Numeric matrix: the CSA matrix for a given unit.
- unit_id
Character: unit identifier for warning messages.