Actual source code: ex5.c


  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. */

 10: int main(int argc,char **args)
 11: {
 12:   PetscMPIInt    rank,size;
 13:   PetscInt       i,m = 10,low,high,ldim,iglobal;
 14:   PetscScalar    v;
 15:   Vec            u;
 16:   PetscViewer    viewer;
 17: #if defined(PETSC_USE_LOG)
 18:   PetscLogEvent  VECTOR_GENERATE,VECTOR_READ;
 19: #endif

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

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

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

 45:   PetscPrintf(PETSC_COMM_WORLD,"writing vector in binary to vector.dat ...\n");
 46:   PetscViewerBinaryOpen(PETSC_COMM_WORLD,"vector.dat",FILE_MODE_WRITE,&viewer);
 47:   VecView(u,viewer);
 48:   PetscViewerDestroy(&viewer);
 49:   VecDestroy(&u);
 50:   PetscOptionsSetValue(NULL,"-viewer_binary_mpiio","");

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

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

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

 67:   /* Free data structures */
 68:   VecDestroy(&u);
 69:   PetscFinalize();
 70:   return 0;
 71: }

 73: /*TEST

 75:      test:
 76:        nsize: 1
 77:        requires: mpiio

 79:      test:
 80:        suffix: 2
 81:        nsize: 2
 82:        requires: mpiio

 84: TEST*/