Lecture 16 Gyrfalcon: Force Algorithm with Complexity O(N)



Physics 141/241

Winter 2010




Short article on Gyrfalcon




Long article on Gyrfalcon




Gyrfalcon User Guide

describes gyrfalcON which is the executable code within the NEMO N-body system.




How to run gyrfalCOn from the NEMO system

The Nemo system is installed at /software/physics/nemo on phcomp.ucsd.edu.

If you are in your home directory switch to cshell by typing /bin/csh. The directory paths are set up by executing: source ../public/nemo_start which will set up all the required environment variables. In the case of trouble check whether the user environment variable NEMO is set to /software/physics/nemo (setenv NEMO /software/physics/nemo).

The command gyrfalcON with appropriate parameter inputs will run the code. For instructions, consult the User Guide and the manual page ( gyrfalcON). The file conversion programs are tabtos and snapprint, and the Aarseth to binary snapshot conversion is discussed in the ntmpv manual page.


Log of gyrfalcON test:

5 10:56 mkdir falco-test

6 10:56 cd falco-test/

7 10:56 mv ../galaxy .

8 10:56 ls

9 10:56 nedit galaxy &

10 10:57 ls

11 11:44 ls

12 11:45 ls

13 11:46 cp galaxy x.tab

14 11:47 gyrfalcON

15 11:48 echo $SHELL

16 11:49 source ~/../public/nemo_start

17 11:49 env

18 11:49 gyrfalcON

19 11:53 ls

20 11:53 clear

21 11:53 ls

22 11:58 tabtos in=x.tab out=x.snap header=nbody,time block1=mass,pos,vel

23 11:58 ls

24 12:01 gyrfalcON in=x.snap out=xrun.snap tstop=10 Nlev=1 eps=0.01

25 12:03 ls

26 12:04 tsf xrun.snap

27 12:04 ls

28 12:05 snapprint in=xrun.snap options=m,x,y,z,vx,vy,vz header=t > xrun.tab