usplit-hybrid

The usplit-hybrid utility is now obsolete and no longer being maintained. The cfpart utility is recommended for partitioning an unstructured grid.

usplit-hybrid is used to partition a single-zone unstructured grid into multiple zones for parallel processing. The user is prompted for the name of the input common grid (.cgd) file containing the single-zone unstructured grid, the name to be used for the new .cgd file containing the multi-zone unstructured grid, and the desired number of zones. The file names are limited to a maximum of 32 characters.

In the output multi-zone grid, each zone will have (roughly) the same number of cells. Thus for maximum efficiency, the number of zones should match the number of available processors (except for one processor left free for use as the master), and each processor should be equal in computing power.

Boundary conditions and surfaces defined in the original file are preserved in the partitioned file. Additional "crinkly" surfaces will appear at the boundaries between the newly-created zones, with negative surface ID numbers. The appropriate coupled boundary conditions are automatically set for these zonal boundaries.

Example

The following figure shows the single-zone unstructured grid used for the M2129 s-duct tutorial, available at the NPARC Alliance CFD Verification and Validation web site.

Single-zone grid for M2129 s-duct

The following terminal session shows how usplit-hybrid would be used to split this grid into five zones, suitable for parallel processing on five CPUs. Input data specified by the user is in slanted type.

   % usplit-hybrid
   
                                ***** usplit-hybrid *****
    
             Select the desired version from the following list.
    
   0) END
   1) usplit-hybrid
    
   Single program automatically selected.
    
   Enter single zone unstructured grid common file ....... : M2129_1zone.cgd
   Enter name for partitioned common file (< 32 characters) ....... : M2129_5zone.cgd
   Enter number of partitions ....... : 5
   ***********************************************************************
         usplit-hybrid   - Version 2.6 (Last changed 2007/09/25 13:19:00)
   ***********************************************************************

   ...
   [Many lines describing usplit-hybrid progress and zonal properties]
   ...

    ***********************************************
   successfully wrote preprocessed data in file 5zone.cgd                                                                       
    ***********************************************

   ...

The resulting five-zone grid is shown below.

Five-zone grid for M2129 s-duct