Notes

The DMPOPTION command controls how solution files are written during a distributed-memory parallel (DMP) solution. This command is most useful for controlling how results files (.rst,.rth, etc.) are written.

In a distributed memory parallel solution, a local results file is written by each process (Jobnamen.ext, where N is the process number). By default, the program automatically combines the local results files (for example, Jobnamen.rst) upon leaving the solution processor (for example, upon the FINISH command) into a single global results file (Jobname.rst) which can be used in postprocessing.

Alternatively, the ResCombFreq argument can be used to combine the local results files at certain time points during the distributed solution to create a single combined results file that can be used to postprocess the model while the solution progresses. Doing so increases data communication and I/O between processes, leading to slower performance.

The ResCombFreq option only applies when solving static analyses, and harmonic or transient analyses that use the full method. It does not apply to mode superposition harmonic and mode superposition transient analyses. It does not apply when using the frequency domain decomposition option (DDOPTION,FREQ) in a harmonic analysis.

To reduce communication and I/O, issue DMPOPTION,RST,NO to bypass this step of combining the local results files; the local files remain on the local disks in the current working directory. You can then use RESCOMBINE in the POST1 general postprocessor (/POST1) to read all results into the database for postprocessing.

The RESCOMBINE command macro is intended for use with POST1. If you want to postprocess distributed parallel solution results using the POST26 time-history postprocessor (/POST26), it is recommended that you combine your local results files into one global results file (DMPOPTION,RST,YES or COMBINE).

Local .emat, .esav, .mode, .mlv, .ist, .rfrq, .rdsp, and .full files are also written (when applicable) by each process in a distributed memory parallel solution. If these files are not needed for a downstream solution or operation, you can issue the command DMPOPTION,FileType,NO for each file type to bypass the file combination step and thereby improve performance.

If DMPOPTION,MODE,NO or DMPOPTION,RST,NO is specified in a modal analysis, element results cannot be written to the combined mode file (Jobname.mode). In this case, if distributed-memory parallel processing is used in a downstream harmonic or transient analysis that uses the mode-superposition method, the MSUPkey on the MXPAND command can retain its value. However, if shared-memory parallel processing is used in the downstream harmonic or transient analysis, the MSUPkey is effectively set to NO.

If DMPOPTION,RNNN,YES is specified, all multiframe restart files named Jobname.r001 to Jobname.r999 are automatically combined upon leaving the solution processor (which can be slow and inefficient). To manually combine a single set of .rnnn restart files, use the COMBINE command.

Since local solution files may be required in a downstream analysis, the option to delete them after combination is disabled (DeleOpt = No) by default. However, you can enable this option to reduce disk space usage by removing certain files if you know that they are not needed in any subsequent analysis.

DMPOPTION can be changed between load steps; however, doing so does not affect which set of solution files are combined. The values of Combine and DeleOpt are overwritten if DMPOPTION is issued multiple times for the same FileType. As a result, only the last values of Combine and DeleOpt for each FileType upon leaving the solution processor determine whether the local solution files are combined with or without deletion. For example, in a two-load-step solution, if DMPOPTION, RST, NO is issued in the first load step and DMPOPTION, RST, YES, ,YES is issued in the second load step, all sets on the local results files will be combined, and then the local results files will be deleted. If the opposite is true (DMPOPTION, RST, YES, ,YES is issued in the first load step, and DMPOPTION, RST, NO is issued in the second load step), no results files are combined, and thus no local results files are deleted.

After using DMPOPTION to suppress file combination, you may find it necessary to combine the local files for a specific FileType for use in a subsequent analysis. In this case, use the COMBINE command to combine local solution files into a single, global file.

Menu Paths