@FILE { ftp://ftp-hpcc.astro.washington.edu/pub/hpcc/tipsy.tar.gz
title{43}: TIPSY - Theoretical Image Processing System
contact{29}: hpccsoft@astro.washington.edu
abstract{746}: The developement of TIPSY was motivated by the need to quickly
display and analyze the results of cosmological N-body simulations. Most data
visualization packages are designed for the display of gridded data,
and hence are unsuitable for use with particle data. Therefore, a
special package was built that could easily perform the following
functions:
- Display particle positions (as points), and velocities (as line
segments) from an arbitrary viewpoint.
- Zoom in to a chosen position.
- Color particles to display scalar fields.
- Select a subset of the particles for display and
analysis.
- Follow selected particles from one timestep to another.
- Find cumulative properties of a collection of particles.
keywords{55}: particle data visualization; cosmology; N-body problems
category{11}: application
description{100}: http://www-hpcc.astro.washington.edu/tools/
}
@FILE { ftp://ftp-hpcc.astro.washington.edu/pub/hpcc/smooth.2.01.tar.Z.
title{77}: SMOOTH - calculates mean-field quantities in cosmological N-body
simulations
contact{29}: hpccsoft@astro.washington.edu
version{4}: 2.01
abstract{743}: Smooth can calculate several mean quantities for all particles in an
cosmological N-Body simulation output file. The program produces a file for each
type of output specified by the user. Example outputs are calculation
of the density, mean velocity, mean speed, velocity dispersion, mach
number, and phase density. These output files contain one
"smoothed" quantity per particle. The output files produced by
smooth are in the tipsy array format.
Smooth takes input files in the tipsy binary format.
By default the program uses a symmetric spline
smoothing kernel similar to that used in SPH calculations.
A new features for release 2.01 is support for mark arrays to allow
quick calculation of mean quantities on a subset of the particles.
keywords{41}: data analysis; cosmology; N-body problems
description{100}: http://www-hpcc.astro.washington.edu/tools/
}
@FILE { ftp://ftp-hpcc.astro.washington.edu/pub/hpcc/denmax-1.1.tar.gz
title{79}: DENMAX - finds gravitationally bound groups in cosmological N-body
simulations
contact{29}: hpccsoft@astro.washington.edu
version{3}: 1.1
abstract{576}: Denmax finds gravitationally bound groups in cosmological
N-body simulations. Denmax takes input files in the tipsy binary format.
Denmax groups different types of particles depending on the type of
input binary file. The type may be dark matter particles, gas particles,
star particles, or gas and star particles.
Once groups with at least a certain minimum number of members
have been determined, denmax will remove particles which are not
bound to the group, using a procedure called unbinding. Denmax
produces output files in tipsy array, vector, and binary formats.
keywords{41}: data analysis; cosmology; N-body problems
description{100}: http://www-hpcc.astro.washington.edu/tools/
}
@FILE { ftp://ftp-hpcc.astro.washington.edu/pub/hpcc/fof-1.1.tar.gz
title{76}: FOF - A friends-of-friends group finder for cosmological N-body
simulations
contact{29}: hpccsoft@astro.washington.edu
version{3}: 1.1
abstract{845}: Fof is a simple group finder, which uses the friends-of-friends
method to find groups. A particle belongs to a friends-of-friends
group if it is within some linking length of any other particle in the
group. After all such groups are found, those with less than a
specified minimum number of group members are rejected. The
program takes input files in the tipsy binary format and produces a
single ASCII output file called fof.grp. This output file is in the tipsy
array format and contains the group number to which each particle
belongs.
The fof.grp file can be read in by tipsy and used to
visualize the groups that are found by fof. Simulations with periodic
boundary conditions can also be handled by fof by specifying the
period in each dimension on the command line.
For a more sophisticated group finding code, see the denmax
program.
keywords{41}: data analysis; cosmology; N-body problems
description{100}: http://www-hpcc.astro.washington.edu/tools/
}
@FILE { ftp://ftp-hpcc.astro.washington.edu/pub/hpcc/afof.0.9.tar.gz
title{90}: AFOF - An approximate friends-of-friends group finder for
cosmological N-body simulations
contact{29}: hpccsoft@astro.washington.edu
version{3}: 0.9
abstract{849}: Afof is an approximate group finder, which uses the
friends-of-friends method to find groups. A particle belongs to a
friends-of-friends group if it is within some linking length tau of
some other particle in the group. The algorithm is approximate. It
takes an additional parameter epsilon which indicates how much
error can be tolerated. The error will take the form of over-linking.
After all such groups are
found, those with less than a specified minimum number of group
members are rejected. The program takes input files in the tipsy
binary format and produces a single ASCII output file called afof.grp.
The afof.grp file
can be read in by tipsy and used to visualize the groups that
are found by afof. Simulations with periodic boundary conditions can
also be handled by afof by specifying the period in each dimension on
the command line.
keywords{41}: data analysis; cosmology; N-body problems
description{100}: http://www-hpcc.astro.washington.edu/tools/
}
@FILE { ftp://ftp-hpcc.astro.washington.edu/pub/hpcc/direct.1.1.tar.Z
title{42}: DIRECT - An O(N^2) direct sum gravity tool
contact{29}: hpccsoft@astro.washington.edu
version{3}: 1.1
abstract{908}: 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.
keywords{52}: error analysis; cosmology; gravitational interaction
description{100}: http://www-hpcc.astro.washington.edu/tools/
}