Date: Mon, 12 Jul 1999 09:44:14 -0400 (EDT)
From: SRIRAM KRISHNASWAMI <Sriram.Krishnaswami@dupontpharma.com>
Subject: Error message

Dear All

Could anybody help me with the following error message

0PROGRAM TERMINATED BY OBJ
ERROR IN NCONTR WITH INDIVIDUAL 1 ID=0.10000000E+01
NUMERICAL HESSIAN OF OBJ. FUNC. FOR COMPUTING CONDITIONAL ESTIMATE
IS NON POSITIVE DEFINITE
MESSAGE ISSUED FROM ESTIMATION STEP
AT 0TH ITERATION, UPON EVALUATION OF GRADIENT WITH RESPECT TO OMEGA
0TRY SUBSTANTIALLY INCREASING "INITIAL ESTIMATE OF SIGMA"
Stop - Program terminated

I am trying to use the FOCE method to analyze the data when this error message appears.

FO method works very well for the same initial sigma and omega estimates


And no matter how much the omegas and sigmas are , this error message appears with the FOCE method.

Thanks in advance
Sriram

 

 

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Date: Tue, 13 Jul 1999 10:52:26 -0700 (PDT)
From: ABoeckmann <alison@c255.ucsf.edu>
Subject: Re: Error message

A question was asked about the message

NUMERICAL HESSIAN OF OBJ. FUNC. FOR COMPUTING CONDITIONAL ESTIMATE IS NON POSITIVE DEFINITE

In general, this message indicates that an estimate of the individual's eta could not be obtained at the specified theta value. There is probably something rather wrong with the intraindividual model for the individual's data.

Since this message appears with the first individual and the initial estimate of theta, the modeling difficulty may apply to the data from other individuals as well.

-- Alison Boeckmann