getCovariate.corStruct function

Extract corStruct Object Covariate

This method function extracts the covariate(s) associated with object.

## S3 method for class 'corStruct'
getCovariate(object, form, data)

Arguments

• object: an object inheriting from class corStruct

  representing a correlation structure.

• form: this argument is included to make the method function compatible with the generic. It will be assigned the value of formula(object) and should not be modified.

• data: an optional data frame in which to evaluate the variables defined in form, in case object is not initialized and the covariate needs to be evaluated.

Returns

when the correlation structure does not include a grouping factor, the returned value will be a vector or a matrix with the covariate(s) associated with object. If a grouping factor is present, the returned value will be a list of vectors or matrices with the covariate(s) corresponding to each grouping level. For spatial correlation structures, this extracts the distances

implied by the covariates, and excludes 1-observation groups.

References

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

Author(s)

José Pinheiro and Douglas Bates bates@stat.wisc.edu

See Also

getCovariate

Examples

cs1 <- corAR1(form = ~ 1 | Subject)
getCovariate(cs1, data = Orthodont)