[R-sig-ME] Extractor Functions: A request

[Murray Jorgensen]

For the mixed model conventionally written as

y = Xb + Zu + e    [fixed + random + error]

the function model.matrix() extracts X from the fitted model object. The 
matrix Z seems to be available at slot Zt of the fitted model object in 
transposed form. It would be useful to have a function to extract Z from 
the fitted model object. It would be a way of checking that you have got 
the model syntax correct in the formula.

Cheers, Murray
-- 
Dr Murray Jorgensen      http://www.stats.waikato.ac.nz/Staff/maj.html
Department of Statistics, University of Waikato, Hamilton, New Zealand
Email: maj at waikato.ac.nz    majorgensen at ihug.co.nz      Fax 7 838 4155
Phone  +64 7 838 4773 wk    Home +64 7 825 0441   Mobile 021 0200 8350