NONMEM Users Network Archive

Hosted by Cognigen

Change of NSIG or R matrix

From: Xinting Wang <wxinting1986>
Date: Tue, 8 Oct 2013 15:57:49 +0800

Dear all,

I have a naive question regarding the modeling building process in NONMEM.
With more and more covariates added in the model, I often come across an
error message saying that "ERROR 134", or R MATRIX SINGULAR.

After searching from the internet, I learned that changing NSIG in
$ESTIMATION and MATRIX=S in $COV would be helpful for both problems
respectively. And from my own experience, it dose help with the modeling

However, my concern is, I used different NSIG and MATRIX in the previous
steps. Is it proper to use different NSIGs and MATRICE in a single model
building? If not, could you please explain this a little bit?

Thank you in advance!

Best Regards

Received on Tue Oct 08 2013 - 03:57:49 EDT

The NONMEM Users Network is maintained by ICON plc. Requests to subscribe to the network should be sent to:

Once subscribed, you may contribute to the discussion by emailing: