README by J. Makino, U. of Tokyo

Version 1.0 July 30, 1994
Version 1.1 April 7, 1997

This is a readme file for the treecode for GRAPE-3AF and GRAPE-4,
developed by J.  Makino. To run this program on GRAPE-3AF/4, you of
course need GRAPE-3AF or GRAPE-4 hardware and software installed. This
kit, however, includes the version which runs on a normal workstation,
without calling GRAPE subroutines. This code might be useful if you
have (a) vector supercomputer or (b) multiprocessor system, since this
version is based on vectrizable treecode developed partly by myself
and partly by Joshua Barnes.

In the following I'll describe how one can use this code with GRAPE-3A.

The part of the code which deals with the tree construction is
reasonably vectorized. The part of the code for force calculation is
based on the algorithm developed by Joshua Barnes and is very well
vectrized. 

Compilation:

Edit the line G3A_LIBS = in the Makefile, so that it tells the
location of the grape3a library. Then, 

make

will create the version which runs on the host only, and

make v_code.g3a 

will create the version that uses GRAPE-3AF.

Execution:

For histrical reasons, the log is written to the file named "vtreelog".
You must remove that file before starting a new run. To run,

v_code(.g3a) < input_parameter_file

Short log also appears on the standard output. For the syntax of the
parameter file, see the content of sampleparm and sampleparm.g3a.
These two files are different only in one place, namely the value of
ncrit. 



Scales:

At present, g3setscale is called in the subroutine gravsumg2start, in
the file treeg3a.F. It sets 1/1024 as xmin, and mass(1)/16 (mass is
the array for mass of particles) as mmin. If these are not appropriate,
one should change them to approproate values.

Modification, Copyright, etc.

You can modify the program as you wish. This program, however, is not
for free distribution. Let me know if you want to give a copy of this
program to someone else. This is mainly to know how many people get
the copy of this code.

Contact address:

makino@grape.c.u-tokyo.ac.jp