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cfpart is used to partition a single-zone unstructured grid into multiple zones for parallel processing. 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.

Mapping data is written into the partitioned .cgd file, that maps the split grid to the original single-zone grid. This data is used by the cfspart utility when re-partitioning multi-zone common flow (.cfl) and boundary data (.tda) files into a different number of zones.

Input to cfpart is specified in a keyword input file, with the three-letter extension .inp. Lines in the input file starting with a "/" are comments. The following keywords and values may be specified.

    CHECK   Checks the input file for errors without performing any operations.

FILE file_in.cgd The input common grid (.cgd) file (80 characters max), containing the unstructured grid to be partitioned.

OUTPUT file_out.cgd The output .cgd file (80 characters max), containing the partitioned grid.

NCPUS value The number of zones into which the grid is to be partitioned. Each zone will have (roughly) the same number of cells. Thus for maximum efficiency, the number of zones should match the number of available worker CPUs.

CREATELINES Turns on the global line calculation, required for the line Gauss-Seidel implicit solver (i.e., the LINE option in the Wind-US IMPLICIT keyword). This is especially important for viscous calculations.

MINLINE nmin The minimum length of a line. The default value is 20.

MAXLINE nmax The maximum length of a line. The default value is 1000. This value is not currently used.

ANGLELIMIT angle The maximum turning angle allowed when creating lines, in degrees. The default value is 85.

ASPECTRATIOMIN ar The minimum aspect ratio allowed for cells to be eligible for inclusion in lines. The default value is 1.6.

MINFACESPERCELLINLINE nfaces This keyword controls which cell types are included when creating lines. Set nfaces = 4 to include all cell types, 5 to only include non-tetrahedral cells, and 6 to only include hexahedral cells. The default value is 4.

LINEMODE mode This specifies the approach used to determine lines. Setting mode = 0 corresponds to the basic way of evaluating the transformation matrix to a canonical element; set mode = 1 to use projected face areas to determine an aspect ratio. The default value is 0.

WRITELINES If this keyword is specified, the lines will be written to a file named lines.fvp. Fieldview can read and display these lines as particle paths.

LOWMEM If this keyword is specified, data required by cfpart will be written to disk instead of being kept in memory. This will increase the CPU time required, and should only be used on systems with insufficient memory.

GROUPFILENAME filename \ [MODE {APPEND|REPLACE}] Read surface group definitions from a text file and include these group definitions in the output grid (.cgd) file. Mode APPEND will append to the list of existing groups read from the input grid (.cgd) file and give an error if the specified groupname already exists. Mode REPLACE will ignore any existing groups from the input grid file. The format of the group definition file is as follows:
   BEGIN [GROUP] groupname
      { [SURFACE U surfID [ZONE zone]] | \

        [GROUP groupname] }
      ...(repeat as necessary for additional surfaces)
   ...(repeat as necessary for additional groups)


The following example shows how cfpart may be used to partition a single-zone grid into five zones, suitable for parallel processing on five CPUs. The keyword input file, named M2129_cfpart.inp is:

   / Input single-zone grid
   FILE M2129_1zone.cgd
   / Output grid
   OUTPUT M2129_5zone.cgd
   / Split for 5 CPUs
   NCPUS 5
   / Create lines for line Gauss-Seidel solver

The terminal session is shown below. Lines in a slanted font are typed by the user.

   % cfpart
                                ***** cfpart *****
             Select the desired version from the following list.
   0) END
   1) cfpart
   Single program automatically selected.
   Omit the .inp extension!
   Enter cfpart INPUT FILE ............. (<CR>=cfpart.inp) : M2129_cfpart
    CFPART - Version 1.2 (last changed 2008/09/05 19:58:42)
    * Warning: This software contains technical data whose export is           *
    * restricted by the Arms Export Control Act (Title 22, U.S.C., Sec 2751,   *
    * et seq.) or Executive Order 12470. Violation of these export-control     *
    * laws is subject to severe criminal penalties. Dissemination of this      *
    * software is controlled under DoD Directive 5230.25 and AFI 61-204.       *
    beginning of us_main
    Step Read grid
    Time=  0.2639600      0.2639600    
    Step Face Connectivity
    Time=  0.8398730       1.103833    
    Step Partitoning
     *** Line statistics report ***
     num lines           =        16695
     zero length lines   =            0
     minimum line length =           20
     maximum line length =          149
     average line length =    26.3946091644205     
    Time=   1.734736       2.838569    
    Step Global-Local cell function
    Time=  3.9999485E-03   2.842569    
    Step Surface and face pointers           1
    Time=  2.6996136E-02   2.869565    
    Step Volume data           1
    Time=  2.3995876E-02   2.893561    
    Step CGD write           1
    Time=  3.6993980E-02   2.930555    
    Step Surface and face pointers           2
    Time=  2.0997047E-02   2.951552    
    Step Volume data           2
    Time=  2.5995970E-02   2.977548    
    Step CGD write           2
    Time=  3.8993120E-02   3.016541    
    Step Surface and face pointers           3
    Time=  2.1996975E-02   3.038538    
    Step Volume data           3
    Time=  2.7996063E-02   3.066534    
    Step CGD write           3
    Time=  3.8993835E-02   3.105528    
    Step Surface and face pointers           4
    Time=  2.1996975E-02   3.127525    
    Step Volume data           4
    Time=  2.4996042E-02   3.152521    
    Step CGD write           4
    Time=  3.8994074E-02   3.191515    
    Step Surface and face pointers           5
    Time=  1.8996954E-02   3.210512    
    Step Volume data           5
    Time=  2.4996996E-02   3.235509    
    Step CGD write           5
    Time=  3.6995173E-02   3.273503    
    Total time   3.278502    
    end of us_main
    in Linelet- Remapping cells
    Total time   3.326493    
    end of cfpart_main

Last updated 15 Nov 2011