Actual source code: ex6f.F90

  1: program main
  2: #include <petsc/finclude/petscvec.h>
  3:   use petscvec

  5:   implicit none

  7:   PetscErrorCode ierr
  8:   PetscMPIInt ::   mySize
  9:   integer     ::      fd
 10:   PetscInt    ::   i,sz
 11:   PetscInt,parameter   ::   m = 10
 12:   PetscInt,parameter   ::   one = 1
 13:   PetscInt, allocatable,dimension(:) :: t
 14:   PetscScalar, pointer, dimension(:) :: avec
 15:   PetscScalar, pointer, dimension(:) :: array
 16:   Vec            vec
 17:   PetscViewer    view_out,view_in
 18:   character(len=256) :: outstring
 19:   PetscBool :: flg

 21:   call PetscInitialize(PETSC_NULL_CHARACTER,ierr)
 22:    if (ierr /= 0) then
 23:    print*,'PetscInitialize failed'
 24:    stop
 25:   endif

 27:   call MPI_Comm_size(PETSC_COMM_WORLD,mySize,ierr)

 29:   if (mySize /= 1) then
 30:     SETERRA(PETSC_COMM_SELF,PETSC_ERR_WRONG_MPI_SIZE,"This is a uniprocessor example only!")
 31:   endif

 33:   call PetscOptionsGetInt(PETSC_NULL_OPTIONS,PETSC_NULL_CHARACTER,"-m",m,flg,ierr);CHKERRA(ierr)

 35:   ! ----------------------------------------------------------------------
 36:   !          PART 1: Write some data to a file in binary format
 37:   ! ----------------------------------------------------------------------

 39:   ! Allocate array and set values

 41:   allocate(array(0:m-1))
 42:   do i=0,m-1
 43:     array(i) =  real(i)*10.0
 44:   end do

 46:   allocate(t(1))
 47:   t(1) = m
 48:   ! Open viewer for binary output
 49:   call PetscViewerBinaryOpen(PETSC_COMM_SELF,"input.dat",FILE_MODE_WRITE,view_out,ierr);CHKERRA(ierr)
 50:   call PetscViewerBinaryGetDescriptor(view_out,fd,ierr);CHKERRA(ierr)

 52:   ! Write binary output
 53:   call PetscBinaryWrite(fd,t,one,PETSC_INT,ierr);CHKERRA(ierr)
 54:   call PetscBinaryWrite(fd,array,m,PETSC_SCALAR,ierr);CHKERRA(ierr)

 56:   ! Destroy the output viewer and work array
 57:   call PetscViewerDestroy(view_out,ierr);CHKERRA(ierr)
 58:   deallocate(array)

 60:   ! ----------------------------------------------------------------------
 61:   !          PART 2: Read data from file and form a vector
 62:   ! ----------------------------------------------------------------------

 64:   ! Open input binary viewer
 65:   call PetscViewerBinaryOpen(PETSC_COMM_SELF,"input.dat",FILE_MODE_READ,view_in,ierr);CHKERRA(ierr)
 66:   call PetscViewerBinaryGetDescriptor(view_in,fd,ierr);CHKERRA(ierr)

 68:   ! Create vector and get pointer to data space
 69:   call VecCreate(PETSC_COMM_SELF,vec,ierr);CHKERRA(ierr)
 70:   call VecSetSizes(vec,PETSC_DECIDE,m,ierr);CHKERRA(ierr)

 72:   call VecSetFromOptions(vec,ierr);CHKERRA(ierr)

 74:   call VecGetArrayF90(vec,avec,ierr);CHKERRA(ierr)

 76:   ! Read data into vector
 77:   call PetscBinaryRead(fd,t,one,PETSC_NULL_INTEGER,PETSC_INT,ierr);CHKERRA(ierr)
 78:   sz=t(1)

 80:   if (sz <= 0) then
 81:    SETERRA(PETSC_COMM_SELF,PETSC_ERR_USER,"Error: Must have array length > 0")
 82:   endif

 84:   write(outstring,'(a,i2.2,a)') "reading data in binary from input.dat, sz =", sz, " ...\n"
 85:   call PetscPrintf(PETSC_COMM_SELF,trim(outstring),ierr);CHKERRA(ierr)

 87:   call PetscBinaryRead(fd,avec,sz,PETSC_NULL_INTEGER,PETSC_SCALAR,ierr);CHKERRA(ierr)

 89:   ! View vector
 90:   call VecRestoreArrayF90(vec,avec,ierr);CHKERRA(ierr)
 91:   call VecView(vec,PETSC_VIEWER_STDOUT_SELF,ierr);CHKERRA(ierr)

 93:   ! Free data structures
 94:   deallocate(t)
 95:   call VecDestroy(vec,ierr);CHKERRA(ierr)
 96:   call PetscViewerDestroy(view_in,ierr);CHKERRA(ierr)
 97:   call PetscFinalize(ierr);CHKERRA(ierr)

 99:   end program

101: !/*TEST
102: !
103: !     test:
104: !        output_file: output/ex6_1.out
105: !
106: !TEST*/