Re: NDSolve precision and velocity problem
- To: mathgroup at smc.vnet.net
- Subject: [mg91315] Re: NDSolve precision and velocity problem
- From: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>
- Date: Fri, 15 Aug 2008 06:53:17 -0400 (EDT)
- References: <g81378$o$1@smc.vnet.net>
Hi, what mean "same methods as the LSODEA" has five methods implemented, as listed in http://www.netlib.org/odepack/opksmain.f and you don't tell us what method you use. And *why* you want to re-invent the wheel if you already *have* a solution with LSODA. Regards Jens Joerg Schaber wrote: > Hi, > > I have an ODE system that takes lots of time to solve with NDSolve > (several minutes), > whereas the same system with the FORTRAN solver LSODA > solves the problem in an second. > When I decrease the precision, e.g. AccuracyGoal->6, NDSolve crashes. It > often crashes, because it finds complex values in a less-than-comparison. > > Maybe it's a method problem. > How do I tell NDSolve, to use the same methods as the LSODEA solver? > > Thanks, > > joerg > >