This page is not a comprehensive listing of the group's
computing resources, but contains some useful starting points and links
to other references.
UNIX services are currently provided through the Department
and the University via the glue network.
General access to these resources are available through the University machine
glue.umd.edu and through the Department
Large computational jobs should be run on the group's machine wheeler.physics.umd.edu, which
is a DEC Alpha workstation purchased through Prof. Misner's numerical relativity
grant. Although Prof. Misner and his students have priority use of this
machine, it is generally available to all members of the group.
There are two paths for obtaining accounts. Members of
the department (faculty, postdocs, and students) apply differently than visitors.
The domain name for email sent to accounts created by either process is physics.umd.edu.
Members of the Physics Department are eligible for glue
accounts. Please see the Department's
registration instruction page for details on obtaining your glue account.
Members of the GRT group who want access to wheeler and who already
have glue accounts should email their request to David Fiske at email@example.com.
Members of the GRT group are also eligible for additional storage space
in group space. The allocation of group space is
currently managed by David Fiske. Contact him for concerns about your quota.
Applying as a visitor
Visitors to the group may request a sponsored account on the glue system.
To do so,
- Telnet to register.physics.umd.edu.
Use the login
register. Leave the password field blank.
- If you have a University ID (unlikely if you are a visitor), enter it
when prompted. If you do not have an ID, you will have to invent one which
is unique to the system and 9 digits in length.
- After completing the online registration, send an email to Ted Jacobson
with your chosen user name and your ID number.
Visitor accounts have a fairly small home directory quota, but visitors
will be given additional storage space in the GRT group
If you are running long calculations on wheeler (or any
machine for that matter), please be kind and
renice your job.
This tells the machine that it will be a long job and properly allocates
the CPU time so that short jobs continue to be short.
In order to renice, you will need the process id number
assigned to your job by the operating system. Typing
at the command line will generate a listing of all of the
processes that you are running on the machine together with each processes's
id number. Once you have the process id number, type
at the command line.
When should you renice? For long jobs (a day or more)
you should always renice.
Via our connection to the campus-wide glue network, we have
access to a large number of standard computational tools. The Department's computing page
lists many of these resources. Please refer to it first for questions. Do
note, however, that some programs must be "tapped" before they can be accessed.
In particular, this affects LaTeX, Maple, and Mathematica. They are made
available, respectively, by the commands:
For those interested in software development, there are two C/C++ compilers
available. The machine native compiler on wheeler is
at the command line.
People doing a small amount of work on the UNIX system
will probably be fine using their home directories for storing their files.
(Except for visitors, who have very small home directories.) Your home
directory is where you start each time that you log into the system and where
you go if you type
c++ for C++. The GNU C/C++ compilers are available through
gcc. For Fortran, use
The GNU debugger
gdb is available and working, while, as of
ddd is technically available but not functional.
To enable core dumps, you may need to type
cd ~ at the command line.
People doing more work on the system will run out
of space in the their home directories. They should then utilize the GRT
group space. Each GRT user has group space in the directory
or can get such space by contacting David Fiske (firstname.lastname@example.org).
At the moment there is one Linux box in the group
dedicated to computational tasks (i.e. not someone's PC). The machine (LBTNL
-- linux box to be named later) does not have a name at the moment, but can
be accessed by
ssh via its IP number. This machine is primarily
being used by Bei-Lok Hu and his collaborators, but accounts on it are available
to members of the group. Contact Chad Galley to setup an account.
MathTensor for Mathematica has been installed on this
machine. In order to use the package, you must add the following lines to
your Mathematica init file
init.m file is located in your home
directory. (If you don't have such a file, created it with the above lines.)
Once you've appropriately modified your init file,
you can start MathTensor from within a Mathematica session with the line
If you have additional questions, contact Nicholas Phillips.
For a general description of renicing as a concept
and when to renice, see the UNIX renicing section
of this document. The syntax on Red Hat linux machines is different than
on the UNIX machines that we use here. To renice on Linux, issue the command
at the command line where <procid> is the process id number,
which you can find by typing
at the command line.
Everyone in the group should have a personal research
interest page linked off of the group personnel
page. In addition to this group webpage, which is standard to the group,
you may also have a webpage through the
glue system. The two
To create a new research interest page if you don't have one, contact
David Fiske for help. To edit the information on your page, log onto a "glued" UNIX machine, and change to the
directory. There you will find a page with your name, which you can edit
with any text editor (e.g.
vi). If you
find that you do not have the necessary permission to edit your page, contact
David Fiske, who will correct the problem.
If you cannot find what you need in this document, try these
- PNCE (Physics Network
- The Department's general information page
- Project GLUE
- The University-wide page for the GLUE system
- AFS help at AEI-Potsdam
- Help on the Andrew File System (AFS) from an external site
help at DESY
- Help on the Andrew File System from an external site
Last modified 16 November 2004 by T. Jacobson.