|Controls printed output (
VMODEL is one of a suite of procedures designed to simplify the assessment of alternative models for a
REML analysis. The first step is to form a model-definition structure for each candidate model, using the
VFSTRUCTURE procedures (these define the model settings controlled by the
VSTRUCTURE directives, respectively). The model-definition structures can then be used as input to procedures like
VARANDOM, which assesses possible random models.
VMODEL to specify each model, in turn, so that it can fit it using
REML. The relevant results from each fit are saved by the
VRACCUMULATE procedure, so that a decision about the recommended random model can be made once they have all been tried.
Printed output is controlled by the
||shows the contents of the model-definition structure (to help check for any errors in the definition).|
The model-definition structure is supplied by the
Commands for: REML analysis of linear mixed models.
CAPTION 'VMODEL example',\ 'Slate Hall Farm data (Guide to REML in Genstat, Section 1.8).';\ STYLE=meta,plain SPLOAD '%gendir%/data/slatehall.gsh' " analyse as a Lattice square design " VFMODEL [MODELSTRUCTURE=Latticesq; DESCRIPTION='Lattice square';\ FIXED=variety] replicates/(rows*columns) VMODEL Latticesq REML yield " analyse with an Ar1 (x) Ar1 model " VFMODEL [MODELSTRUCTURE=AR1xAR1; DESCRIPTION='Ar1 (x) AR1';\ FIXED=variety] fieldrow.fieldcolumn VFSTRUCTURE [MODELSTRUCTURE=AR1xAR1; TERMS=fieldrow.fieldcolumn]\ 2('AR'); ORDER=1; FACTOR=fieldrow,fieldcolumn VMODEL AR1xAR1 REML [PRINT=model,components,wald] yield