LoadPartial.cpp

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    1 /** @example LoadPartial.cpp \n
    2  * \brief Load a part of a file  \n
    3  * <b>To run</b>: LoadPartial [file] [tag_name] [val1] [val2] ...\n
    4  *
    5  * In this example, it is shown how to load only a part of one file; the file must be organized in
    6  * sets. (cherry-picking only the sets we want) The sets to load are identified by a tag name and
    7  * the tag values for the sets of interest. This procedure is used  when reading in parallel, as
    8  * each processor will load only its part of the file, identified either by partition or by
    9  * material/block sets by default, this example will load parallel partition sets with values 1, 2,
   10  * and 5 from ../MeshFiles/unittest/64bricks_1khex.h5m The example will always write the output to a
   11  * file name part.h5m
   12  */
   13  
   14 #include <iostream>
   15 #include <vector>
   16  
   17 // Include header for MOAB instance and tag conventions for
   18 #include "moab/Core.hpp"
   19 #include "MBTagConventions.hpp"
   20  
   21 #define NTAGVALS 3
   22  
   23 using namespace moab;
   24 using namespace std;
   25  
   26 // Function to parse input parameters
   27 ErrorCode get_file_options( int argc, char** argv, string& filename, string& tagName, vector< int >& tagValues )
   28 {
   29     // Get mesh filename
   30     if( argc > 1 )
   31         filename = string( argv[1] );
   32     else
   33         filename = string( MESH_DIR ) + string( "/64bricks_512hex_256part.h5m" );
   34  
   35     // Get tag selection options
   36     if( argc > 2 )
   37         tagName = string( argv[2] );
   38     else
   39         tagName = "USERTAG";
   40  
   41     if( argc > 3 )
   42     {
   43         tagValues.resize( argc - 3, 0 );
   44         for( int i = 3; i < argc; ++i )
   45             tagValues[i - 3] = atoi( argv[i] );
   46     }
   47     else
   48     {
   49         for( unsigned i = 0; i < tagValues.size(); ++i )
   50             tagValues[i] = 2 * i + 1;
   51     }
   52  
   53     if( argc > 1 && argc < 4 )  // print usage
   54         cout << " usage is " << argv[0] << " <file> <tag_name> <value1> <value2> .. \n";
   55     return MB_SUCCESS;
   56 }
   57  
   58 int main( int argc, char** argv )
   59 {
   60     // Get MOAB instance
   61     Interface* mb = new( std::nothrow ) Core;
   62     if( NULL == mb ) return 1;
   63  
   64     std::string filename, tagname;
   65     vector< int > tagvals( NTAGVALS );  // Allocate for a maximum of 5 tag values
   66     ErrorCode rval = get_file_options( argc, argv, filename, tagname, tagvals );MB_CHK_ERR( rval );
   67  
   68 #ifdef MOAB_HAVE_HDF5
   69     // This file is in the mesh files directory
   70     rval = mb->load_file( filename.c_str(), 0, 0, PARALLEL_PARTITION_TAG_NAME, tagvals.data(), (int)tagvals.size() );MB_CHK_SET_ERR( rval, "Failed to read" );
   71  
   72     // If HANDLEID tag present, convert to long, and see what we read from file
   73     Tag handleid_tag;
   74     rval = mb->tag_get_handle( "HANDLEID", handleid_tag );
   75     if( MB_SUCCESS == rval )
   76     {
   77         // Convert a few values for a few vertices
   78         Range verts;
   79         rval = mb->get_entities_by_type( 0, MBVERTEX, verts );MB_CHK_SET_ERR( rval, "Failed to get vertices" );
   80         vector< long > valsTag( verts.size() );
   81         rval = mb->tag_get_data( handleid_tag, verts, &valsTag[0] );
   82         if( MB_SUCCESS == rval ) cout << "First 2 long values recovered: " << valsTag[0] << " " << valsTag[1] << "\n";
   83     }
   84  
   85     rval = mb->write_file( "part.h5m" );MB_CHK_SET_ERR( rval, "Failed to write partial file" );
   86     cout << "Wrote successfully part.h5m.\n";
   87  
   88 #else
   89     std::cout << "Configure MOAB with HDF5 to build and use this example correctly.\n";
   90 #endif
   91     delete mb;
   92     return 0;
   93 }