Date: 2013-07-02T14:40:18+00:00

Actual source code: ex5.c
petsc-3.4.2 2013-07-02

      2: static char help[] = "Tests binary I/O of vectors and illustrates the use of user-defined event logging.\n\n";

      4: #include <petscvec.h>

      6: /* Note:  Most applications would not read and write a vector within
      7:   the same program.  This example is intended only to demonstrate
      8:   both input and output. */

     12: int main(int argc,char **args)
     13: {
     15:   PetscMPIInt    rank,size;
     16:   PetscInt       i,m = 10,low,high,ldim,iglobal;
     17:   PetscScalar    v;
     18:   Vec            u;
     19:   PetscViewer    viewer;
     20: #if defined(PETSC_USE_LOG)
     21:   PetscLogEvent  VECTOR_GENERATE,VECTOR_READ;
     22: #endif

     24:   PetscInitialize(&argc,&args,(char*)0,help);
     25:   MPI_Comm_rank(PETSC_COMM_WORLD,&rank);
     26:   MPI_Comm_size(PETSC_COMM_WORLD,&size);
     27:   PetscOptionsGetInt(NULL,"-m",&m,NULL);

     29:   /* PART 1:  Generate vector, then write it in binary format */

     31:   PetscLogEventRegister("Generate Vector",VEC_CLASSID,&VECTOR_GENERATE);
     32:   PetscLogEventBegin(VECTOR_GENERATE,0,0,0,0);
     33:   /* Generate vector */
     34:   VecCreate(PETSC_COMM_WORLD,&u);
     35:   VecSetSizes(u,PETSC_DECIDE,m);
     36:   VecSetFromOptions(u);
     37:   VecGetOwnershipRange(u,&low,&high);
     38:   VecGetLocalSize(u,&ldim);
     39:   for (i=0; i<ldim; i++) {
     40:     iglobal = i + low;
     41:     v       = (PetscScalar)(i + 100*rank);
     42:     VecSetValues(u,1,&iglobal,&v,INSERT_VALUES);
     43:   }
     44:   VecAssemblyBegin(u);
     45:   VecAssemblyEnd(u);
     46:   VecView(u,PETSC_VIEWER_STDOUT_WORLD);

     48:   PetscPrintf(PETSC_COMM_WORLD,"writing vector in binary to vector.dat ...\n");
     49:   PetscViewerBinaryOpen(PETSC_COMM_WORLD,"vector.dat",FILE_MODE_WRITE,&viewer);
     50:   VecView(u,viewer);
     51:   PetscViewerDestroy(&viewer);
     52:   VecDestroy(&u);
     53:   /*  PetscOptionsClear();*/
     54:   PetscOptionsSetValue("-viewer_binary_mpiio","");

     56:   PetscLogEventEnd(VECTOR_GENERATE,0,0,0,0);

     58:   /* PART 2:  Read in vector in binary format */

     60:   /* Read new vector in binary format */
     61:   PetscLogEventRegister("Read Vector",VEC_CLASSID,&VECTOR_READ);
     62:   PetscLogEventBegin(VECTOR_READ,0,0,0,0);
     63:   PetscPrintf(PETSC_COMM_WORLD,"reading vector in binary from vector.dat ...\n");
     64:   PetscViewerBinaryOpen(PETSC_COMM_WORLD,"vector.dat",FILE_MODE_READ,&viewer);
     65:   VecCreate(PETSC_COMM_WORLD,&u);
     66:   VecLoad(u,viewer);
     67:   PetscViewerDestroy(&viewer);
     68:   PetscLogEventEnd(VECTOR_READ,0,0,0,0);
     69:   VecView(u,PETSC_VIEWER_STDOUT_WORLD);

     71:   /* Free data structures */
     72:   VecDestroy(&u);
     73:   PetscFinalize();
     74:   return 0;
     75: }