DIRECT

Abstract

Direct is a tool designed to test more complicated gravity codes such as Barnes-Hut, Fast Multipole and error-controlling tree-codes as well as FFT codes in the future (once support for periodic boundary conditions has been added). It is also the method of choice when dealing with less than about 10000 particles. The primary application remains the testing and error analysis of more sophisticated codes. Typical things looked at in analysis of errors are the distribution of relative and absolute errors in the acceleration as well as the maximum and rms values. Another application when a well understood mass distribution is calculated (such as a king model), is the analysis of the discreteness noise as a function of N. Direct uses no approximations in its calculation of the gravitational interaction, it simply sums over all pairwise interactions. This causes direct to scale as O(N^2) in CPU time.

DateOfInformation

Thr Sep 25 15:49:41 1997

Domain

Scientific and Engineering Applications

Name

DIRECT

TargetEnvironment

UNIX

Webpage

http://www-hpcc.astro.washington.edu/tools/

ContactIs

hpccsoft@astro.washington.edu