RE: [NMusers] Estimation method using ITS and IMP iterations

2016-11-10 Thread Jonathan Moss
Dear Nathalie In answer to your question; yes, it is usual to see this "unstability" in the final few iteration OFVs. When using the IMP method, I often include two sequential $EST commands. The first command will perform optimisation of parameter estimates until a global minimum is found.

[NMusers] Splitting the residual error

2016-05-13 Thread Jonathan Moss
Dear all, I would like to share with you and get people's opinions on a recent issue I had. I have a data set of 46 patients, orally dosed, with very dense sampling during absorption (0.25h, 0.5h, 0.75h, 1h, 1.5h, 2h, 3h, 4h, 6h, 8h, 12h, 24h, 36h), Cmax at around 4 hours. During modelling,

[NMusers] DDEs in NONMEM

2016-03-07 Thread Jonathan Moss
Dear all, I have a problem regarding delay differential equations (DDEs) in NONMEM. So far, I have been unable to find a way of successfully using DDEs in NONMEM, due to there being no in-built DDE solver (as far as I know). To me, it seems that the problem is that there is no way of recalling