# corClasses

##### Correlation Structure Classes

Standard classes of correlation structures (`corStruct`

)
available in the `nlme`

package.

- Keywords
- models

##### Value

Available standard classes:

autoregressive process of order 1.

autoregressive moving average process, with arbitrary orders for the autoregressive and moving average components.

continuous autoregressive process (AR(1) process for a continuous time covariate).

compound symmetry structure corresponding to a constant correlation.

exponential spatial correlation.

Gaussian spatial correlation.

linear spatial correlation.

Rational quadratics spatial correlation.

spherical spatial correlation.

general correlation matrix, with no additional structure.

##### Note

Users may define their own `corStruct`

classes by specifying a
`constructor`

function and, at a minimum, methods for the
functions `corMatrix`

and `coef`

. For
examples of these functions, see the methods for classes `corSymm`

and `corAR1`

.

##### References

Pinheiro, J.C., and Bates, D.M. (2000) "Mixed-Effects Models in S and S-PLUS", Springer.

##### See Also

`corAR1`

, `corARMA`

,
`corCAR1`

, `corCompSymm`

,
`corExp`

, `corGaus`

,
`corLin`

,
`corRatio`

, `corSpher`

,
`corSymm`

,
`summary.corStruct`

*Documentation reproduced from package nlme, version 3.1-145, License: GPL (>= 2) | file LICENCE*