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Name

treecode - fortran version of hackcode

Synopsis

treecode in=snap_in out=snap_out [keyword=value ...]

Description

treecode is the NEMO adaptation of the fortran version (2.2) of Lars Hernquist’s version of the treecode. The fortran dialect is assumed to be recursive.

Computational units are such that the graitational constant G=1.

Parameters

The following parameters are recognized in any order when the keyword is also given
in=in_name
Input file in snapshot format [no default]
out=out_name
Output file in snapshot format [no default]
nsteps=int
Total number of integration steps [100].
nout=int
Steps in between major output [10].
tol=real
Tolerance (opening angle) determining accuracy of force calculation [1.0].
eps=real
Softening length [0.05].
usequad=bool
Include quadrupole corrections to force calculation? [default: f].

Timing

Integrating a Plummer sphere of 128 (?check?) particles with accuracy eta=0.02 for about a crossing time (T=0 to T=2) takes about XX minutes on a SUN 3/60 with a simple f68881 floating point chip.

Limitations

The code has a hardcoded maximum number of particles in the fortran code (nmax.inc), change the PARAMETER statement in the beginning to whatever is required. During NEMO install the makefile macro NMAX can be used to do this automatically and hence easily generate a new version with a different value for NMAX, e.g. make nmax NMAX=10000;make treecode.

Author

Lars Hernquist, Peter Teuben (responsible)

Files

~/src/lars/treecode

See Also

hackcode1(1NEMO) , quadcode(1NEMO) , newton0(1NEMO) , nbody0(1NEMO)

History


xx-xxx-xx    V2 added quadrupole correction              Lars
xx-xxx-xx    V2.1 optimized routines for 2D and 3D       Lars
1-sep-86    V2.2 large tol allowed (avoid self-gravity)    Lars
xx-oct-86    V2.2a SUN version - some ’bug’ removed          PJT
20-jul-86    V2.2b NEMO SUN version - still bugs              PJT


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