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5.2.3.2 simple_xy_nc4_rd.f90
     ! This is part of the netCDF package.
     ! Copyright 2006 University Corporation for Atmospheric Research/Unidata.
     ! See COPYRIGHT file for conditions of use.
     
     ! This is a simple example which reads a small dummy array, from a
     ! netCDF data file created by the companion program simple_xy_wr.f90.
     
     ! This is intended to illustrate the use of the netCDF fortran 77
     ! API. This example program is part of the netCDF tutorial, which can
     ! be found at:
     ! http://www.unidata.ucar.edu/software/netcdf/docs/netcdf-tutorial
     
     ! Full documentation of the netCDF Fortran 90 API can be found at:
     ! http://www.unidata.ucar.edu/software/netcdf/docs/netcdf-f90
     
     ! $Id: simple_xy_nc4_rd.f90,v 1.3 2009/02/25 12:23:45 ed Exp $
     
     program simple_xy_rd
       use netcdf
       implicit none
     
       ! This is the name of the data file and variable.
       character (len = *), parameter :: FILE_NAME = "simple_xy_nc4.nc"
       character (len = *), parameter :: VAR_NAME = "data"
     
       ! We are reading 2D data, a 12 x 6 grid.
       integer, parameter :: NX = 6, NY = 12, MAX_DIMS = 2
       integer :: data_in(NY, NX)
     
       ! This will be the netCDF ID for the file and data variable.
       integer :: ncid, varid
     
       ! Information we will read about the variable.
       character (len = nf90_max_name) :: name
       integer :: xtype, ndims, dimids(MAX_DIMS), natts
       integer :: chunksizes(MAX_DIMS), deflate_level, endianness
       logical :: contiguous, shuffle, fletcher32
     
       ! Loop indexes, and error handling.
       integer :: x, y
     
       ! Open the file. NF90_NOWRITE tells netCDF we want read-only access
       ! to the file.
       call check( nf90_open(FILE_NAME, NF90_NOWRITE, ncid) )
     
       ! Get the varid of the data variable, based on its name.
       call check( nf90_inq_varid(ncid, VAR_NAME, varid) )
     
       ! Learn about the variable. This uses all optional parameters.
       call check( nf90_inquire_variable(ncid, varid, name, xtype, ndims, &
            dimids, natts, contiguous = contiguous, chunksizes = chunksizes, &
            deflate_level = deflate_level, shuffle = shuffle, &
            fletcher32 = fletcher32, endianness = endianness) )
     
       ! Make sure we got the correct answers. These depend on what was set
       ! when creating the file in simple_xy_nc4_wr.f90. Endianness will be
       ! whatever is native for the machine that's building this example.
       if (name .ne. VAR_NAME .or. xtype .ne. NF90_INT .or. ndims .ne. 2 .or. &
            natts .ne. 0 .or. contiguous .or. .not. shuffle .or. &
            deflate_level .ne. 1 .or. fletcher32) stop 3
     
       ! Read the data.
       call check( nf90_get_var(ncid, varid, data_in) )
     
       ! Check the data.
       do x = 1, NX
          do y = 1, NY
             if (data_in(y, x) /= (x - 1) * NY + (y - 1)) then
                print *, "data_in(", y, ", ", x, ") = ", data_in(y, x)
                stop "Stopped"
             end if
          end do
       end do
     
       ! Close the file, freeing all resources.
       call check( nf90_close(ncid) )
     
       print *,"*** SUCCESS reading example file ", FILE_NAME, "! "
     
     contains
       subroutine check(status)
         integer, intent ( in) :: status
     
         if(status /= nf90_noerr) then
           print *, trim(nf90_strerror(status))
           stop 2
         end if
       end subroutine check
     end program simple_xy_rd