NDSolve Percision

*To*: mathgroup at smc.vnet.net*Subject*: [mg85475] NDSolve Percision*From*: Alex Cloninger <acloninger at wustl.edu>*Date*: Mon, 11 Feb 2008 06:19:10 -0500 (EST)

So I'm running a program that is trying to use NDSolve and parametrically plot the results. The result is periodic, so it should cycle back on itself with a period of 2Pi. It does that, but if I run from {t,0,20Pi} is starts to miss the initial point by more and more. Basically, it's spiraling outward at a slow but unwanted rate. This will be a problem for when I increase the difficulty of the function. How do I increase the precision of NDSolve to make it keep more decimals and make the answer more accurate? The function is solution = NDSolve[{x'[t] == 2p[t], x[0] == 2, p'[t] == -2x[t],p[0] == N[Sqrt[-3], 50]}, {x, p}, {t,0,20Pi}] If you could help me out, I'd really appreciate it. Thanks.