More Comparisons of Numerical Integrations in the Gravitational NBodyProblem
Abstract
The evolution of two groups of gravitational 25body systems have been computed by numerical techniques. In each group the initial conditions are either identical or very close to each other. The calculations have been performed on different computers with the same integration method and the same program. The initial conditions of the first group are those of the I.A.U. "Standard problem". Those of the second group are such that the virial coefficient is equal to 1. In both cases the reproducibility of these numerical experiments is liniited to the beginning of the evolution. For that period very few close encounters occur and the motion of the bodies is governed mainly by the mean field. The reproducibility is all the better for the individual coordinates of these bodies which move far from the central region of the system. The instability of the solutions of the Nbody gravitational problem as well as the integration method and the finite number of bits used by computers  this number is not the same for different computers  are responsible of the defect of reproducibility.
 Publication:

Astronomy and Astrophysics
 Pub Date:
 August 1970
 Bibcode:
 1970A&A.....7..249H