Manual

UltraScan Beowulf Control Panel:

Performing Monte Carlo analysis on nonlinear least squares fitting sessions is a CPU-intensive proposition, and such as a task is well suited for parallel execution. A Linux Beowulf Supercomputer is a cluster of Linux workstations, generally connected through a switched 100baseT ethernet or gigabit network, which allows you to perform calculations in parallel, by distributing the calculation load over many processors.

UltraScan is designed to take advantage of Beowulf-type supercomputers to assist in the speedup of Monte Carlo analysis. You can start the Beowulf module from the Monte Carlo control window, by clicking on "Beowulf Control".

Explanation of Buttons and Fields:

• Add Host:
  Use this button to add a new host, which should be listed in the field to the right of the button, to the list of computing nodes used for the calculation of the Monte Carlo analysis. Not all available nodes have to be used, this way you can control the load on the Beowulf system by only specifying a subset of the available computing nodes. For multiprocessor nodes, you can specify multiple copies of the same hostname, which will cause UltraScan to issue the job multiple times on the host. You can double-click on any entry in the listbox to copy the name into the edit field.

• Delete Host:
  Delete the host in the edit field from the list of valid nodes.

• Save Setup:
  Save the currently defined list of Beowulf nodes in the file $ULTRASCAN/etc/hosts.beowulf

• Start Run:
  Start a Beowulf Monte Carlo Run using the currently defined Beowulf hosts.

• Merge Output Files
  This function will merge all individual output files into a single file that can be read by the Monte Carlo analysis program. Each process operating on a remote or local node will receive an individual seed (an integer value) that assures that each process will randomize differently, so that individual processes do not replicate the same calculations. UltraScan will save the output of each individual process with the file name of the Monte Carlo output, plus the integer value of the seed, so they can be differentiated. The "Merge Output Files" function will merge all of these files into a single file.

• Stop all MC Processes
  This function will stop all currently running Monte Carlo processes on local or remote nodes to free up resources, if they become needed before the application terminates by itself based on the iteration setting in the Monte Carlo module.

• Help:
  Show this Help File.

• Close:
  Close the Beowulf Control Panel and exit.

• Use ssh:
  If checked, UltraScan will use the ssh remote shell program to start the job. Check the ssh manpage for detailed instructions on how to set up ssh/sshd. This is the preferred method if executing over an untrusted network, since all communication will be encrypted. ssh/ssd need to be configured to allow password-less connections for the user executing this program.

• Use rsh:
  If checked, UltraScan will use rsh/rlogin to start the job. This method doesn't require the installation of ssh/sshd, but should only be used on closed networks or networks properly secured by a firewall. Check your systems manual for configuration options of rsh. rsh needs to be configured to allow password-less connections for the user executing this program.

• Use X-Display:
  UltraScan will export the X-display to the host and display specified on this line as an environment variable for the program. Please note that the X-transport will not be encrypted, even if ssh is selected, but this is not a problem since no X-output will be generated anyway.