From:"LSEN (Lars Erichsen)"   
Subject:[NMusers] Non-positive definite covariance matrix without warnings from Non  
Date:Wed, February 27, 2002 5:09 am  

Title: Non-positive definite covariance matrix without warnings from NonMem?
Dear nmusers, 

We have a problem with the covariance matrix of population parameter estimates given by nonmem. 
There is no error message but one eigenvalue is negative. 

This may be due to rounding errors in the output file (not enough significant digits)? 
Is it possible to obtain additional digits with nonmem? 

  Thanks in advance 

  Lars