RE: NONMEM ODE solver

Hi Juergen The LSODA solver is also implemented in the odesolve package in R and used together with nlme for mixed-effects modeling in nlmeODE. I don't think you will find many PKPD programs with more well-tuned ODE solvers for mixed-effects modeling compared to NONMEM. You might also want to take a look at programs in other scientific areas besides PKPD since I've heard there has been quite a bit of improvements in the ODE solver field especially tuned for estimation problems. Best Chris ________________________________ Fra: [EMAIL PROTECTED] på vegne af Jurgen Bulitta Sendt: sø 27-05-2007 18:19 Til: [email protected] Emne: Re: [NMusers] NONMEM ODE solver Dear Dr Sale, ADAPT (including Adapt II (Rel. 4), Adapt V, and S-Adapt) uses the LSODA (Livermore Solver for Ordinary Differential equations with Automatic method switching for stiff and nonstiff problems). According to the Adapt user guide: "The ability of LSODA to detect stiffness and switch between Adam's and Gear's methods, together with its capability to control the step size and order of the selected method, makes this program [ADAPT] the most robust we know of for this application." I have not yet run a head to head comparison of the stability of the ODE solver in Adapt and NONMEM on the same project myself. However, some of my colleagues told me that they found the LSODA in Adapt very robust. I would be happy, if someone could share his/her opinion on the robustness of ODE solvers e.g. implemented in PKPD programs. Best regards Juergen ----------------------------------------------- Juergen Bulitta, PhD, Post-doctoral Fellow Pharmacometrics, University at Buffalo, NY, USA Phone: +1 716 645 2855 ext. 281, [EMAIL PROTECTED]