- Created by Barbara Jones, last modified on Jul 21, 2020
H5S_SELECT_HYPERSLAB
Selects a hyperslab region to add to the current selected region
Procedure:
H5S_SELECT_HYPERSLAB ( space_id, op, start, stride, count, block )
Signature:
herr_t H5Sselect_hyperslab(hid_t space_id,
H5S_seloper_t op,
const hsize_t *start,
const hsize_t *stride,
const hsize_t *count,
const hsize_t *block
)
Fortran90 Interface: h5sselect_hyperslab_f
SUBROUTINE h5sselect_hyperslab_f(space_id, op, start, count,
hdferr, stride, block)
IMPLICIT NONE
INTEGER(HID_T), INTENT(IN) :: space_id ! Dataspace identifier
INTEGER, INTENT(IN) :: op ! Flag, valid values are:
! H5S_SELECT_SET_F
! H5S_SELECT_OR_F
INTEGER(HSIZE_T), DIMENSION(*), INTENT(IN) :: start
! Offset of start of hyperslab
INTEGER(HSIZE_T), DIMENSION(*), INTENT(IN) :: count
! Number of blocks to select
! from dataspace
INTEGER, INTENT(OUT) :: hdferr ! Error code
! 0 on success and -1 on failure
INTEGER(HSIZE_T), DIMENSION(*), OPTIONAL, INTENT(IN) :: stride
! Array of how many elements to
! move in each direction
INTEGER(HSIZE_T), DIMENSION(*), OPTIONAL, INTENT(IN) :: block
! Size of the element block
END SUBROUTINE h5sselect_hyperslab_f
Parameters:
hid_t space_id | IN: Identifier of dataspace selection to modify |
H5S_seloper_t op | IN: Operation to perform on current selection |
const hsize_t *start | IN: Offset of start of hyperslab |
const hsize_t *stride | IN: Hyperslab stride |
const hsize_t *count | IN: Number of blocks included in hyperslab |
const hsize_t *block | IN: Size of block in hyperslab |
Description:
H5S_SELECT_HYPERSLAB selects a hyperslab region to add to the current selected region for the dataspace specified by space_id.
The start, stride, count, and block arrays must be the same size as the rank of the dataspace. For example, if the dataspace is 4-dimensional, each of these parameters must be a 1-dimensional array of size 4.
The selection operator op determines how the new selection is to be combined with the already existing selection for the dataspace. The following operators are supported:
H5S_SELECT_SET | Replaces the existing selection with the parameters from this call. Overlapping blocks are not supported with this operator. |
H5S_SELECT_OR | Adds the new selection to the existing selection. (Binary OR) |
H5S_SELECT_AND | Retains only the overlapping portions of the new selection and the existing selection. (Binary AND) |
H5S_SELECT_XOR | Retains only the elements that are members of the new selection or the existing selection, excluding elements that are members of both selections. (Binary exclusive-OR, XOR) |
H5S_SELECT_NOTB | Retains only elements of the existing selection that are not in the new selection. |
H5S_SELECT_NOTA | Retains only elements of the new selection that are not in the existing selection. |
The start array specifies the offset of the starting element of the specified hyperslab.
The stride array chooses array locations from the dataspace with each value in the stride array determining how many elements to move in each dimension. Setting a value in the stride array to 1 moves to each element in that dimension of the dataspace; setting a value of 2 in allocation in the stride array moves to every other element in that dimension of the dataspace. In other words, the stride determines the number of elements to move from the start location in each dimension. Stride values of 0 are not allowed. If the stride parameter is NULL, a contiguous hyperslab is selected (as if each value in the stride array were set to 1).
The count array determines how many blocks to select from the dataspace, in each dimension.
The block array determines the size of the element block selected from the dataspace. If the block parameter is set to NULL, the block size defaults to a single element in each dimension (as if each value in the block array were set to 1).
For example, consider a 2-dimensional dataspace with hyperslab selection settings as follows: the start offset is specified as [1,1], stride is [4,4], count is [3,7], and block is [2,2]. In C, these settings will specify a hyperslab consisting of 21 2x2 blocks of array elements starting with location (1,1) with the selected blocks at locations (1,1), (5,1), (9,1), (1,5), (5,5), etc.; in Fortran, they will specify a hyperslab consisting of 21 2x2 blocks of array elements starting with location (2,2) with the selected blocks at locations (2,2), (6,2), (10,2), (2,6), (6,6), etc.
Regions selected with this function call default to C order iteration when I/O is performed.
Returns:
Returns a non-negative value if successful; otherwise returns a negative value.
Example:
Coming Soon!
History:
| Release | Change |
|---|---|
| 1.6.4 | C: Fortran90: |
--- Last Modified: July 21, 2020 | 11:33 AM