Re: Finding only final values in NDSolve

*To*: mathgroup at smc.vnet.net*Subject*: [mg91274] Re: Finding only final values in NDSolve*From*: "Kevin J. McCann" <Kevin.McCann at umbc.edu>*Date*: Wed, 13 Aug 2008 04:38:58 -0400 (EDT)*Organization*: University System of Maryland*References*: <g7lvmq$fdj$1@smc.vnet.net>

Zakseidov, How about something like this: First[{y[3], y'[3]} /. NDSolve[{y''[t] + y[t] == 0, y[0] == 1, y'[0] == -1}, y, {t, 0, 3}]] Kevin zakseidov2 at gmail.com wrote: > Dear Mathematica gurus, > 1. I use NDSolve for integration from some t0 to some tf, but I'm > interested only in FINAL VALUES y(tf),y'(tf). > How to do it (I mean: avoiding InterpolatingFunction and saving all > intermediate values)? > 2. I use WorkingPrecision -> 32(or larger). Final values y(tf),y'(tf) > are of lesser Precision than 32D so i can't use them directly for > further integrations. I do some manupulations to take more artificial > digits... > But what's the best way for doing it automatically not manually? > 3. In other words: I need only values of y(t), y'(t) in fixed t_i with > fixed interval d. > How to do it using NDSolve economically without InterpolatingFunction > (which I guess takes a lot of time if MaxSteps -> 10^8(or larger))? > Thanks a lot, > zakseidov >