RE: Help: Non-positive semi-definite message
From: "Piotrovskij, Vladimir [JanBe]" <VPIOTROV@janbe.jnj.com>
Subject: RE: Help: Non-positive semi-definite message
Date: Thu, 16 Aug 2001 09:59:45 +0200
Alan,
Don't you think your model is a bit over-parameterized? Often $COV fails
when you have too many random effects not supported by the data. Did you try
dropping one of your ETAs? Note: using MATRIX = S may be misleading.
Best regards,
Vladimir
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Vladimir Piotrovsky, Ph.D.
Research Fellow
Global Clinical Pharmacokinetics and Clinical Pharmacology
Janssen Research Foundation
B-2340 Beerse
Belgium