proportionality constraints

If there are (say) three variance components, v1, v2, and v3, I think
Genstat REML allows me to set a constraint such as v3 = v1 + 0.5 * v2
(using VCOMP[RELATIONSHIP=matrix]). In ASReml, I have to let v2=k*v1,
v3=(1+0.5*k)*v1, and then calculate a profile likelihood for a range of
values of k.

(1) Is there a better way? (2) Is there any reason why ASReml cannot
provide the more general form of constraint?

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I.White
University of Edinburgh
Ashworth Laboratories, West Mains Road
Edinburgh EH9 3JT
Tel: 0131 650 5490 Fax: 0131 650 6564
E-mail: iwhite_at_staffmail.ed.ac.uk
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Received on Wed Apr 21 2005 - 13:00:38 EST