Re: Limits on solving large nonlinear system
- To: mathgroup at smc.vnet.net
- Subject: [mg80861] Re: Limits on solving large nonlinear system
- From: Joerg Schaber <schaber at molgen.mpg.de>
- Date: Tue, 4 Sep 2007 03:49:54 -0400 (EDT)
- References: <fbdmq2$pbo$1@smc.twtelecom.net>
For large systems of nonlinear equations you might wnat to use rather global algorityhms rather than local ones, like the ones implemented in FindRoot. FindRoot is problematic because in complex nonlienar landscapes the solution heavily depends on the inital values. If you don't know where your parameters are roughly located you're basically lost. Try NMinimize with SimulatedAnnealing or DifferentialEvolution, for instance. You will not get the best solution but you will get one, even if it takes some times. hope that helps, joerg Tomislav Nad schrieb: > Hi, > > > > I am using Mathematica to solve nonlinear systems of equations, > > without success, because I run out of memory. > > So I try to find out where the limits are for FindRoot: > > size of the system, degree of the equations and so on. > > I actually did not find any information about this. > > > > In all my equations the degree of one variable is always one, > > but I have a lot of expressions where variables are multiplied > > like > > x1*x2*x3*x4 = 0 > > x1*x2*x3+x1*x4 = 0. > > > > Does anyone know more about the limits? > > > > Regards, > > Tomislav > > >