Trait-specific unique variance: unique(0 + trait | g)

Arguments

formula

0 + trait | g style formula.

common

FALSE (default) for trait-specific variances; TRUE for one shared variance across traits at this tier. For new standalone marginal code, prefer indep(..., common = TRUE); for new paired ordinary intercept-only decompositions, prefer latent(..., common = TRUE).

Value

A formula marker; never evaluated.

Details

unique() is soft-deprecated as compatibility syntax in gllvmTMB 0.2.0. Use indep() for standalone marginal diagonal tiers, including indep(..., common = TRUE) for the scalar standalone marginal case. Ordinary latent() now carries \(\boldsymbol\Psi\) by default, so paired latent() + unique() remains accepted compatibility syntax. Removal is a later API-change decision while the parser and source-specific exports remain live. The paired legacy unique(..., common = TRUE) parsimony knob remains accepted, but new ordinary intercept-only code should use latent(..., common = TRUE).

Canonical name for the trait-specific unique-variance covstruct inside a gllvmTMB() formula. Formerly diag(0 + trait | g) – same engine, new name. The new name avoids the clash with base::diag(). The diag() keyword still works for backward compat but emits a one-shot deprecation warning per session.

Compatibility spelling inside a gllvmTMB() formula:

value ~ 0 + trait + latent(0 + trait | unit, d = 2) +
                    unique(0 + trait | unit)

New code can write the ordinary decomposition as latent() alone; the explicit unique() companion is retained for compatibility.

This is a formula keyword – it's recognised by the parser inside a gllvmTMB() formula's RHS but is never evaluated as a function call. unique is not exported as an R function (because that would shadow base::unique()); the parser handles the symbol directly.

common = TRUE parsimony mode

For new standalone marginal fits where the trait-specific \(\sigma_S\) estimates are weakly identified, write indep(..., common = TRUE) to fit a single shared \(\sigma_S\) across all traits at this tier (one parameter instead of T). Legacy standalone unique(..., common = TRUE) remains accepted and objective-equivalent as compatibility syntax. Paired latent() + unique(..., common = TRUE) also remains compatibility syntax; new ordinary intercept-only decompositions can write latent(..., common = TRUE) instead.

See also

latent(), diag_re, extract_Sigma().