From: bvatul <bvatul@ufl.edu>

Subject: Error message in $COV step

Date: Mon, 09 Jul 2001 17:35:37 -0400

 

Hello All

Could somebody please clarify this?

I was analysing a data set with $COV estimation step. I was encountering

this error and the program took several hours to converge in the final

steps. The code is written below:

$PK

TVCL1=THETA(1)

TVV1=THETA(2)

TVK12=THETA(3)

TVK21=THETA(4)

 

CL1=TVCL1*EXP(ETA(1))

V1=TVV1*EXP(ETA(2))

K12=TVK12*EXP(ETA(3))

K21=TVK21*EXP(ETA(4))

$ERROR

Y=F*(1+ERR(1))+ERR(2)

$EST METHOD=1 INTERACTION MAXEVAL=9999 PRINT=5 NOABORT POSTHOC

 

This is the message which I see in the output. I was wondering was this

means and what could the problem be?

 

0MINIMIZATION SUCCESSFUL

NO. OF FUNCTION EVALUATIONS USED: 673

NO. OF SIG. DIGITS IN FINAL EST.: 3.0

 

ETABAR IS THE ARITHMETIC MEAN OF THE ETA-ESTIMATES,

AND THE P-VALUE IS GIVEN FOR THE NULL HYPOTHESIS THAT THE TRUE MEAN IS

0.

 

ETABAR: -.44E-02 -.57E-02 -.14E-02 .14E-02

 

P VAL.: .78E+00 .74E+00 .70E+00 .81E+00

0R MATRIX ALGORITHMICALLY NON-POSITIVE-SEMIDEFINITE

BUT NONSINGULAR

0COVARIANCE STEP ABORTED

1

 

Thanks in advance

Atul