Syntax
>>> PVM: nhosts (SLEEP: isleep) (FILE: node-file) ((AGGRESSIVE) LEVENBERG (ALL PROCESSORS / PROCESSORS: nprocslm))
HOST1PVM hostname_1
HOST2PVM hostname_2
... ...
HOSTnhostsPVM hostname_nhosts
Parent Command
>> OPTION
Subcommand
-
Description
The number of hosts nhosts is provided on the command line, followed by nhosts lines containing the keyword *HOSTihostPVM* (ihost = 1,…, nhosts) and the name of the host. The wild card * must be a unique identifier if more than one iTOUGH2-PVM applications are run simultaneously. The name of the host must be identical to that appended to the file name of the iTOUGH2 executable on that specific machine. A host (especially a multiprocessor machine) may be named several times in the list of hosts. The parent process must not be included in the list.
The nodes can also be provided on an external file (keyword FILE: node-file). This latter option is useful if iTOUGH2-PVM is started using a scheduler on a Linux cluster, i.e., when the nodes are determined dynamically. The names of the available nodes can be written to a file node-file and read in by iTOUGH2. No list of hosts is required in this case; however, nhosts lines with incrementing HOSTihostPVM still need to be provided.
If the Levenberg-Marquardt algorithm is used, trial parameter sets obtained with different Levenberg parameters can be evaluated in parallel on nrocslm processors using keyword LEVENBERG. By default, each trial parameter set is calculated using an increased Levenberg parameter, resulting in smaller, more robust update steps in the parameter space. Keyword AGGRESSIVE instructs iTOUGH2 to evaluate parameter sets with both increased and decreased values of the Levenberg parameter. The parent process can be suspended for isleep seconds each time it checks for incoming residuals (default: isleep = 1).
Example
Example 1: Heterogeneous cluster of Unix workstations:
> COMPUTATION
>> OPTION
>>> use LEVENBERG-MARQUARDT minimization algorithm
>>> PVM: 5 processors (parallelize JACOBIAN only, SLEEP for : 1 sec)
HOST1PVM presto.lbl.gov
HOST2PVM hydra.lbl.gov
HOST3PVM hydra.lbl.gov
HOST4PVM aqua.eth.edu
HOST5PVM telos
<<<
<<
Example 2: Linux cluster; run through scheduler:
> COMPUTATION
>> OPTION
>>> use LEVENBERG-MARQUARDT minimization algorithm
>>> PVM: 5 nodes provided on FILE: PBS-NODES
HOST1PVMbatch
HOST2PVMbatch
HOST3PVMbatch
HOST4PVMbatch
HOST5PVMbatch
<<<
<<
See Also
Report Parallelization of iTOUGH2 Using PVM