At Thu, 3 Jan 2008 11:41:20 +0100, Jochen Küpper wrote: > Dear Brian, > > have you ever been able to resolve this issue? > > On 26.06.2007, at 20:28, Brian Powell wrote: > > > This email is in reference to what appears to be a notable change in > > performance of the rk4 integrator between older and newer versions > > of gsl. In particular, rk4 from version 1.5 and version 1.8. The > > particular test that I am performing is I am integrating a system of > > ODE's from some initial point to some final point, then reversing > > the integration. Clearly, one expects such evolutions to overlap. > > Surprisingly, they overlap quite well with the older version of rk4, > > but they do not match up well at all with the newer version. I'm > > trying to track down the cause of this, and, so far, can't seem to > > find a system specific reason for this.
I heard back that the explanation in http://lists.gnu.org/archive/html/bug-gsl/2007-07/msg00001.html solved the problem. -- Brian Gough At Tue, 3 Jul 2007 17:48:47 -0400 (EDT), Brian Powell wrote: > > Brian, > > > If you use a stricter tolerance do you still see the same problem of > > the forward and backward evolution not matching up? > > Yes, the solutions match up much better now. Thank you very much for your > quick reply. > > Brian > _______________________________________________ Help-gsl mailing list [email protected] http://lists.gnu.org/mailman/listinfo/help-gsl
