Re:Over 150 new families of Newtonian periodic planar three-...
by strainer on Monday May 08, 2017 @09:12AM
(#14291155)
>64 bit double precision is millimeter accurate to the orbit of Neptune.
It's a good point of order though, I got this mixed up last time I looked at issues in that system. I got fed up trying to explain, that the integration scheme used there is "symplectic" - it doesn't require gross adjustments, so the many bugs that have and will spring up shouldnt be patched with gross adjustments. If the model is gaining or loosing energy, i cant blame it on the integrator or on missing physics.
So regardless of that, thanks for the correction, i had got it in my head 53bit mantissa was somewhat less than mm resolution at Neptune. Im still wary that the resolution could easily cause problems, but accept there is a fair chance these could be avoided with careful calculations.
It's a good point of order though, I got this mixed up last time I looked at issues in that system. I got fed up trying to explain, that the integration scheme used there is "symplectic" - it doesn't require gross adjustments, so the many bugs that have and will spring up shouldnt be patched with gross adjustments. If the model is gaining or loosing energy, i cant blame it on the integrator or on missing physics.
So regardless of that, thanks for the correction, i had got it in my head 53bit mantissa was somewhat less than mm resolution at Neptune. Im still wary that the resolution could easily cause problems, but accept there is a fair chance these could be avoided with careful calculations.