H5Sselect_elements
(
hid_t space_id
,
H5S_seloper_t op
,
size_t num_elements
,
const hsize_t *coord
)
H5Sselect_elements
selects array elements to be
included in the selection for the space_id
dataspace.
This is referred to as a point selection.
The number of elements selected is set in the
num_elements
parameter.
The coord
parameter is a pointer to a buffer
containing a serialized 2-dimensional array of size
num_elements
by the rank of the dataspace.
The array lists dataset elements in the point selection;
that is, it’s a list of of zero-based values specifying the
coordinates in the dataset of the selected elements.
The order of the element coordinates in the
coord
array specifies the order in which
the array elements are iterated through when I/O is performed.
Duplicate coordinate locations are not checked for.
See below for examples of the mapping between
the serialized contents of the buffer and
the point selection array that it represents.
The selection operator op
determines how the
new selection is to be combined with the previously 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. Adds the new selection to the existing selection. |
H5S_SELECT_APPEND
| Adds the new selection following the last element of the existing selection. |
H5S_SELECT_PREPEND
| Adds the new selection preceding the first element of the existing selection. |
Mapping the serialized coord
buffer
to a 2-dimensional point selection array:
To illustrate the construction of the contents of the
coord
buffer, consider two simple examples:
a selection of 5 points in a 1-dimensional array and
a selection of 3 points in a 4-dimensional array.
In the 1D case, we will be selecting five points and a 1D dataspace has rank 1, so the selection will be described in a 5-by-1 array. To select the 1st, 14th, 17th, 23rd, 8th elements of the dataset, the selection array would be as follows (remembering that point coordinates are zero-based):
0 13 16 22 7This point selection array will be serialized in the
coord
buffer as:
0 13 16 22 7
In the 4D case, we will be selecting three points and a 4D dataspace has rank 4, so the selection will be described in a 3-by-4 array. To select the points (1,1,1,1), (14,6,12,18), and (8,22,30,22), the point selection array would be as follows:
0 0 0 0 13 5 11 17 7 21 29 21This point selection array will be serialized in the
coord
buffer as:
0 0 0 0 13 5 11 17 7 21 29 21
hid_t space_id |
IN: Identifier of the dataspace. |
H5S_seloper_t op |
IN: Operator specifying how the new selection is to be combined with the existing selection for the dataspace. |
size_t num_elements |
IN: Number of elements to be selected. |
const hsize_t *coord |
IN: A pointer to a buffer containing a serialized copy of a 2-dimensional array of zero-based values specifying the coordinates of the elements in the point selection. |
SUBROUTINE h5sselect_elements_f(space_id, operator, rank, num_elements, coord, hdferr) IMPLICIT NONE INTEGER(HID_T), INTENT(IN) :: space_id ! Dataspace identifier INTEGER, INTENT(IN) :: operator ! Flag, valid values are: ! H5S_SELECT_SET_F ! H5S_SELECT_APPEND_F ! H5S_SELECT_PREPEND_F INTEGER, INTENT(IN) :: rank ! Number of dataspace ! dimensions INTEGER(SIZE_T), INTENT(IN) :: num_elements ! Number of elements to be ! selected INTEGER(HSIZE_T), DIMENSION(rank,num_elements), INTENT(IN) :: coord ! A 1-based array containing the ! coordinates of the selected ! elements ! NOTE: Reversed dimension declaration ! compared to the C specification ! of coord(num_elements, rank) INTEGER, INTENT(OUT) :: hdferr ! Error code ! 0 on success and -1 on failure END SUBROUTINE h5sselect_elements_f
Release | Change |
1.6.4 |
C coord parameter type changed to
const hsize_t.
Fortran coord parameter type changed to
INTEGER(HSIZE_T) . |