Discreteness noise versus force errors in N-body simulations

  • Junichiro Makino
3. Computer Simulations and Mappings
Part of the Lecture Notes in Physics book series (LNP, volume 430)


We have investigated the effect of the numerical error of the force calculation on the accuracy of the result of collisionless N-body simulations. Our main result is that force calculation with a low accuracy — a few percent for each particle pair — is sufficient, irrespective of the number of particles. Higher accuracy is useless since the discreteness noise, i.e., the two-body relaxation effect, dominates the error. We have performed numerical experiments for two different cases: a special-purpose machine with low-precision hardware and the tree-code. In both cases, the two-body relaxation effect dominates the error and the effect of the error in the force calculation is practically negligible for all cases we tried.


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Copyright information

© Springer-Verlag 1994

Authors and Affiliations

  • Junichiro Makino
    • 1
  1. 1.Department of Information Science and Graphics, College of Arts and SciencesUniversity of TokyoMeguro-ku, TokyoJapan

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