RE: permissible band matrix

Sam, I think you should have gotten the error: INITIAL ESTIMATE OF OMEGA HAS A NONZERO BLOCK WHICH IS NUMERICALLY NOT POSITIVE DEFINITE which is the case. (you can check this in Excel, using the MDETERM function, the determinant is -2945). When you get this message, try reducing the off-diagonal elements, I think you'll find that $OMEGA BLOCK(4) 9 5 9 0 5 9 0 0 5 9 will work Mark Mark Sale MD Next Level Solutions, LLC www.NextLevelSolns.com 919-846-9185 > -------- Original Message -------- From: Sam Liao <[EMAIL PROTECTED]> Date: Fri, October 12, 2007 10:43 am To: nmusers < > > [email protected] > > > Dear NONMEM users: Can someone please help me to solve this problem with a band matrix? $OMEGA BLOCK(4) 0.09 ;BSV_V1C 0.07 0.09 ;BSV_CLC 0 0.07 0.09 ;BSV_CLN 0 0 0.07 0.09 ;BSV_V1N Why this one above is getting an error in NONMEM? $OMEGA BLOCK(4) 0.09 ;BSV_V1C 0.07 0.09 ;BSV_CLC 0 0 0.09 ;BSV_CLN 0 0 0.07 0.09 ;BSV_V1N This one above is fine, but I need to run a simulation in which there are some correlation between CLC and CLN. There were some very helpful discussion on band matrix few years ago. But I still couldn't figure out why this band matrix not permissible. Sam Liao < > > http://www.cognigencorp.com/nonmem/nm/96mar232001.html > > >