Re: NDSolve limits

*To*: mathgroup at smc.vnet.net*Subject*: [mg89097] Re: NDSolve limits*From*: Szabolcs <szhorvat at gmail.com>*Date*: Sun, 25 May 2008 06:27:13 -0400 (EDT)*References*: <g1avpe$fdh$1@smc.vnet.net>

On May 25, 9:08 am, alrobnett <alrobn... at alumni.princeton.edu> wrote: > I am working on a three body orbit problem. My equations have resulted > in a beautiful 3D graph of the orbits, but only in one direction from > t=0. (I have boundary conditions only for t=0). I can get the orbits > for negative time by reversing all of the velocities, and I could > combine the results to get a graph from negative time to positive > time. Alternatively, I could use the results from the negative time > calculations to become initial conditions for a new calculation, but > these both seem like "klutsy" bandaids for the problem. Any > suggestions? > I'm not sure I understand your question. Maybe the following example will be helpful: NDSolve[{f''[x] + f[x] == 0, f[0] == 0, f'[0] == 1}, f, {x, -10,= 10}] Note that the boundary of the solution domain does not need to be the same as the point where the initial condition is given.