extract_design function

Extracting covariance matrices from lme

This function extracts the full covariance matrices from a mixed/hierarchical linear model fit using lme.

extract_design(b)

Arguments

• b: a fitted model object of class lme.

Returns

A list of matrices is returned.

• D contains the covariance matrix of the random effects.
• V contains the covariance matrix of the response.
• X contains the fixed-effect model matrix.
• Z contains the random-effect model matrix.

References

This method has been adapted from the method mgcv::extract.lme.cov in the mgcv package, written by Simon N. Wood simon.wood@r-project.org .

Author(s)

Adam Loy loyad01@gmail.com