6.4 Define Chunking Parameters for a Variable: NF90_DEF_VAR_CHUNKING
The function NF90_DEF_VAR_CHUNKING sets the chunking parameters for a
variable in a netCDF-4 file.
The total size the chunk must be less than 4 GiB. That is, the product
of all chunksizes and the size of the data (or the size of nc_vlen_t
for VLEN types) must be less than 4 GiB.
This function must be called after the variable is defined, but before
nf_enddef is called.
Usage
function nf90_def_var_chunking(ncid, varid, contiguous, chunksizes)
integer, intent(in) :: ncid
integer, intent(in) :: varid
integer, intent(in) :: contiguous
integer, dimension(:), intent(in) :: chunksizes
integer :: nf90_def_var_chunking
ncid- NetCDF ID, from a previous call to NF90_OPEN or NF90_CREATE.
varid- Variable ID.
contiguous- If non-zero, then contiguous storage is used for this
variable. Variables with one or more unlimited dimensions cannot use
contiguous storage. If contiguous storage is turned on, the chunksizes
parameter is ignored.
chunksizes- An array of chunk sizes. The array must have the one chunksize for
each dimension in the variable. If the contiguous parameter is set,
then the chunksizes parameter is ignored.
Errors
NF90_DEF_VAR_CHUNKING returns the value NF90_NOERR if no errors
occurred. Otherwise, the returned status indicates an error.
Possible return codes include:
NF90_NOERR- No error.
NF90_BADID- Bad ncid.
NF90_ENOTNC4- Not a netCDF-4 file.
NF90_ENOTVAR- Can't find this variable.
NF90_ELATEDEF- This variable has already been the subject of a NC_ENDDEF call. In
netCDF-4 files NC_ENDDEF will be called automatically for any data
read or write. Once enddef has been called, it is impossible to set
the chunking for a variable.
NF90_ENOTINDEFINE- Not in define mode. This is returned for netCDF classic or 64-bit
offset files, or for netCDF-4 files, when they were been created with
NF90_STRICT_NC3 flag. (see NF90_CREATE).
NF90_ESTRICTNC3- Trying to create a var some place other than the root group in a
netCDF file with NF90_STRICT_NC3 turned on.
Example
