###### Description

unstructured: General correlation and covariance models.

###### 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) 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. |

`k` |
Order of the model (`chol, ante` ) or number of factors (`sfa, facv, fa, rr` ). |

###### Details

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`

).

###### Functions

`asr_corv:` |
Simple correlation model, homogeneous variance form. |

`asr_corh:` |
Simple correlation model, heterogeneous variance form. |

`asr_corb:` |
Banded correlation model with `b` bands. |

`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. |

`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_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 Fixed. |