Book contents
- Frontmatter
- Contents
- Preface
- 1 The N-body problem
- 2 Predictor–corrector methods
- 3 Neighbour treatments
- 4 Two-body regularization
- 5 Multiple regularization
- 6 Tree codes
- 7 Program organization
- 8 Initial setup
- 9 Decision-making
- 10 Neighbour schemes
- 11 Two-body algorithms
- 12 Chain procedures
- 13 Accuracy and performance
- 14 Practical aspects
- 15 Star clusters
- 16 Galaxies
- 17 Planetary systems
- 18 Small-N experiments
- Appendix A Global regularization algorithms
- Appendix B Chain algorithms
- Appendix C Higher-order systems
- Appendix D Practical algorithms
- Appendix E KS procedures with GRAPE
- Appendix F Alternative simulation method
- Appendix G Table of symbols
- Appendix H Hermite integration method
- References
- Index
14 - Practical aspects
Published online by Cambridge University Press: 18 August 2009
- Frontmatter
- Contents
- Preface
- 1 The N-body problem
- 2 Predictor–corrector methods
- 3 Neighbour treatments
- 4 Two-body regularization
- 5 Multiple regularization
- 6 Tree codes
- 7 Program organization
- 8 Initial setup
- 9 Decision-making
- 10 Neighbour schemes
- 11 Two-body algorithms
- 12 Chain procedures
- 13 Accuracy and performance
- 14 Practical aspects
- 15 Star clusters
- 16 Galaxies
- 17 Planetary systems
- 18 Small-N experiments
- Appendix A Global regularization algorithms
- Appendix B Chain algorithms
- Appendix C Higher-order systems
- Appendix D Practical algorithms
- Appendix E KS procedures with GRAPE
- Appendix F Alternative simulation method
- Appendix G Table of symbols
- Appendix H Hermite integration method
- References
- Index
Summary
Introduction
In the preceding chapters, we have described a variety of numerical methods and their implementation. Given these tools and algorithms, it should be possible in principle to construct direct N-body codes for dynamical studies. However, the combination of methods introduces considerable complications which have taken many years to master and it is therefore much easier to take over one of the large codes. On the other hand, it would be good programming practice to implement a stand-alone code based on direct summation with softened potential or three-body regularization, where decision-making is considerably simplified.
In the following we provide some hints to facilitate the use of one of the main codes, as well as guidelines for implementing movies. These range from practical comments on getting started to producing a meaningful description of the results. Special counters that record events of interest provide further information. Graphics packages are generally avoided in the codes for reasons of compatibility. However, two versions of stand-alone regularization codes are available with software for movie making which is a good way to study dynamical interactions. We also discuss some diagnostic aspects that may assist in the dissemination of the results and outline various strategies for identifying numerical problems.
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- Chapter
- Information
- Gravitational N-Body SimulationsTools and Algorithms, pp. 252 - 263Publisher: Cambridge University PressPrint publication year: 2003