var-cov matrix issue?

From: Ethan Wu Date: February 24, 2009 technical Source: mail-archive.com
Dear all, I recently encounter this error message (below). My objective was to use nonmem var-cov output for approximation of distribution of parameters for performing a simulation. if such error message occur, 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 limited 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. ETABAR: 0.11E-02 SE: 0.23E-01 P VAL.: 0..96E+00 0S MATRIX ALGORITHMICALLY SINGULAR 0S MATRIX IS OUTPUT 0INVERSE COVARIANCE MATRIX SET TO RS*R, WHERE S* IS A PSEUDO INVERSE OF S 1 "
Feb 24, 2009 Ethan Wu var-cov matrix issue?
Feb 24, 2009 William Bachman RE: var-cov matrix issue?
Feb 24, 2009 Kyunseop Bae RE: var-cov matrix issue?
Feb 24, 2009 Leonid Gibiansky Re: var-cov matrix issue?
Feb 25, 2009 Bob Leary RE: var-cov matrix issue?
Feb 25, 2009 Ethan Wu Re: var-cov matrix issue?
Feb 26, 2009 Ethan Wu Re: var-cov matrix issue?
Feb 27, 2009 Ethan Wu Re: var-cov matrix issue?