Actual source code: ex5f.F90
petsc-3.13.6 2020-09-29
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      1: program main
      2:  #include <petsc/finclude/petscvec.h>
      3: use petscvec
      4: implicit none

      6:   PetscErrorCode ::ierr
      7:   PetscMPIInt ::   rank,mySize
      8:   PetscInt :: i
      9:   PetscInt, parameter :: one = 1
     10:   PetscInt :: m = 10
     11:   PetscInt :: low,high,ldim,iglobal
     12:   PetscScalar :: v
     13:   Vec ::         u
     14:   PetscViewer :: viewer
     15:   PetscClassId classid
     16:
     17:   PetscBool :: flg
     18: #if defined(PETSC_USE_LOG)
     19:   PetscLogEvent  VECTOR_GENERATE,VECTOR_READ
     20: #endif

     22:   call PetscInitialize(PETSC_NULL_CHARACTER,ierr)
     23:   if (ierr /= 0) then
     24:    print*,'PetscInitialize failed'
     25:    stop
     26:   endif
     27:
     28:   call MPI_Comm_rank(PETSC_COMM_WORLD,rank,ierr)
     29:
     30:   call MPI_Comm_size(PETSC_COMM_WORLD,mySize,ierr);CHKERRA(ierr)  !gives number of processes in the group of comm (integer)
     31:   call PetscOptionsGetInt(PETSC_NULL_OPTIONS,PETSC_NULL_CHARACTER,"-m",m,flg,ierr);CHKERRA(ierr) !gives the integer value for a particular option in the database.

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

     35:   call PetscLogEventRegister("Generate Vector",classid,VECTOR_GENERATE,ierr);CHKERRA(ierr)
     36:   call PetscLogEventBegin(VECTOR_GENERATE,ierr);CHKERRA(ierr)
     37:   ! Generate vector
     38:   call VecCreate(PETSC_COMM_WORLD,u,ierr);CHKERRA(ierr)
     39:   call VecSetSizes(u,PETSC_DECIDE,m,ierr);CHKERRA(ierr)
     40:   call VecSetFromOptions(u,ierr);CHKERRA(ierr)
     41:   call VecGetOwnershipRange(u,low,high,ierr);CHKERRA(ierr)
     42:   call VecGetLocalSize(u,ldim,ierr);CHKERRA(ierr)
     43:   do i=0,ldim-1
     44:    iglobal = i + low
     45:    v       = real(i + 100*rank)
     46:    call VecSetValues(u,one,iglobal,v,INSERT_VALUES,ierr);CHKERRA(ierr)
     47:   end do
     48:   call VecAssemblyBegin(u,ierr);CHKERRA(ierr)
     49:   call VecAssemblyEnd(u,ierr);CHKERRA(ierr)
     50:   call VecView(u,PETSC_VIEWER_STDOUT_WORLD,ierr);CHKERRA(ierr)

     52:   call PetscPrintf(PETSC_COMM_WORLD,"writing vector in binary to vector.dat ...\n",ierr);CHKERRA(ierr)
     53:   call PetscViewerBinaryOpen(PETSC_COMM_WORLD,"vector.dat",FILE_MODE_WRITE,viewer,ierr);CHKERRA(ierr)
     54:   call VecView(u,viewer,ierr);CHKERRA(ierr)
     55:   call PetscViewerDestroy(viewer,ierr);CHKERRA(ierr)
     56:   call VecDestroy(u,ierr);CHKERRA(ierr)
     57:   call PetscOptionsSetValue(PETSC_NULL_OPTIONS,"-viewer_binary_mpiio",PETSC_NULL_CHARACTER,ierr);CHKERRA(ierr)

     59:   call PetscLogEventEnd(VECTOR_GENERATE,ierr);CHKERRA(ierr)

     61:   ! PART 2:  Read in vector in binary format

     63:   ! Read new vector in binary format
     64:   call PetscLogEventRegister("Read Vector",classid,VECTOR_READ,ierr);CHKERRA(ierr)
     65:   call PetscLogEventBegin(VECTOR_READ,ierr);CHKERRA(ierr)
     66:   call PetscPrintf(PETSC_COMM_WORLD,"reading vector in binary from vector.dat ...\n",ierr);CHKERRA(ierr)
     67:   call PetscViewerBinaryOpen(PETSC_COMM_WORLD,"vector.dat",FILE_MODE_READ,viewer,ierr);CHKERRA(ierr)
     68:   call VecCreate(PETSC_COMM_WORLD,u,ierr);CHKERRA(ierr)
     69:   call VecLoad(u,viewer,ierr);CHKERRA(ierr)
     70:   call PetscViewerDestroy(viewer,ierr);CHKERRA(ierr)

     72:   call PetscLogEventEnd(VECTOR_READ,ierr);CHKERRA(ierr)
     73:   call VecView(u,PETSC_VIEWER_STDOUT_WORLD,ierr);CHKERRA(ierr)

     75:   ! Free data structures
     76:   call VecDestroy(u,ierr);CHKERRA(ierr)
     77:   call PetscFinalize(ierr);CHKERRA(ierr)
     78:
     79: end program

     82: !/*TEST
     83: !
     84: !     test:
     85: !       nsize: 1
     86: !       requires: mpiio
     87: !       output_file: output/ex5_1.out
     88: !
     89: !     test:
     90: !       suffix: 2
     91: !       nsize: 2
     92: !       requires: mpiio
     93: !       output_file: output/ex5_2.out
     94: !
     95: !TEST*/