the package-wide default tolerance for deciding that two scores are tied
Source:R/match.R
reid_tie_tolerance.Rd`sqrt(.Machine$double.eps)`, about 1.5e-8, used as a **relative** tolerance: two scores count as tied when they agree to roughly the first 8 significant digits. That is `all.equal()`'s default and it deliberately spends half of a double's 16 digits, because the last 8 are where representation noise lives.