NONMEM Users Network Archive

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var-cov matrix issue?

From: Ethan Wu <ethan.wu75>
Date: Tue, 24 Feb 2009 09:01:08 -0800 (PST)

Dear all,  I recently encounter this error message (below). My objecti=
ve was to use nonmem var-cov output  for approximation of distribution =
of parameters for performing a simulation.  if such error message occ=
ur, is the var-cov matrix  still OK to use? -- I know that better way =
to figure out distribution of parameters is to do bootstrap, but given limi=
ted time I have.... thanks "0MINIMIZATION SUCCESSFUL  NO. OF =
FUNCTION EVALUATIONS USED:  331  NO. OF SIG. DIGITS IN FINAL EST.: =
 3.3  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.  ETAB=
AR:   0.11E-02  SE:       0.23E-01  P VAL.:   0=
..96E+00 0S MATRIX ALGORITHMICALLY SINGULAR 0S MATRIX IS OUTPUT 0INVER=
SE COVARIANCE MATRIX SET TO RS*R, WHERE S* IS A PSEUDO INVERSE OF S 1 "=
Received on Tue Feb 24 2009 - 12:01:08 EST

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