R: General structure variance models

general_vs {asreml} | R Documentation

## General structure variance models

### Description

General correlation and variance structures. The class of general variance models includes the simple, banded and general correlation models (`cor`, `corb`, `corg`), the diagonal, unstructured, Cholesky and antedependence variance models (`diag`, `us`, `chol`, `cholc`, `ante`) and the factor analytic structures (`sfa`, `facv`, `fa`).

### Usage

    cor(obj, init = NA)

    corv(obj, init = NA)

    corh(obj, init = NA)

    corb(obj, b = 1, init = NA)

    corbv(obj, init = NA)

    corbh(obj, init = NA)

    corg(obj, init = NA)

    corgv(obj, init = NA)

    corgh(obj, init = NA)

    diag(obj, init = NA)

    us(obj, init = NA)

    chol(obj, k = 1, init = NA)

    cholc(obj, k = 1, init = NA)

    ante(obj, k = 1, init = NA)

    sfa(obj, k = 1, init = NA)

    facv(obj, k = 1, init = NA)

    fa(obj, k = 1, init = NA)

    rr(obj, k = 1, init = NA)

### Arguments

`obj` | A factor in `data`.
`init` | A vector of initial values (correlation parameters followed by variance parameters) with an optional `names` attribute from the set {`P`, `U`, `F`} specifying the boundary constraint as positive, unconstrained or fixed, respectively.
`b` | Number of (sub-diagonal) bands in banded correlation models (default = `1`).
`k` | Order of the model (for `chol, ante`) or number of factors (for `sfa, facv, fa, rr`) (default = `1`).

### Functions

- `asr_cor()`: Simple correlation model; correlation form.

- `asr_corv()`: Simple correlation model; homogeneous variance form.

- `asr_corh()`: Simple correlation model; heterogeneous variance form.

- `asr_corb()`: Banded correlation model with `b` bands; correlation form.

- `asr_corbv()`: Banded correlation model with `b` bands; homogeneous variance form.

- `asr_corbh()`: Banded correlation model with `b` bands, heterogeneous variance form.

- `asr_corg()`: General correlation model; correlation form.

- `asr_corgv()`: General correlation model; homogeneous variance form.

- `asr_corgh()`: General correlation model; heterogeneous variance form.

- `asr_diag()`: Diagonal variance model.

- `asr_us()`: Unstructured variance model.

- `asr_chol()`: Cholesky variance model of order `k`.

- `asr_cholc()`: Cholesky C variance model of order `k`.

- `asr_ante()`: Antedependence variance model of order `k`.

- `asr_sfa()`: Factor analytic model with `k` factors; the variance-covariance matrix is modelled on the correlation scale.

- `asr_facv()`: Factor analytic model with `k` factors; the variance-covariance matrix is modelled on the covariance scale.

- `asr_fa()`: Factor analytic model with `k` factors; sparse formulation where `k` “extra” levels are inserted in the mixed model equations.

- `asr_rr()`: Factor analytic model with `k` factors; reduced rank formulation of `fa()` where the default boundary constraints for the specific variances are set to `F` (fixed).

[Package asreml version 4.2.0.480 Index]