A data area may consist of a region that conforms to one type, followed by a region that conforms to another. Example might include a strided region where one wants to begin and/or end in the middle of a group, rather than have a integral number of whole groups, or may be two unrelated segments of data. For this, a sequence of PINT_Request structures is specified using the stype field to determine the sequence. The offset is specified relative to the beginning of the data area.
In this example we have a strided region shown in D. We want to start 8 bytes into the first group (yellow), then have 15 whole groups (blue), and finally end 4 bytes into the last group (green). Each group is 6 elements, and each element is a float (4 bytes). The stride between groups is 48 bytes (12 floats).
FIRST-PTYPE:
offset = OFFSET
num_ereqs = 4
stride = 1
num_blocks = 1
ub = 764
lb = 0
aggregate_size = 380
depth = 1
num_contig_chunks = 17
etype = PVFS_Request_float
stype = NEXT-PTYPE
NEXT-PTYPE:
offset = OFFSET + 40
num_ereqs = 6
stride = 48
num_blocks = 15
ub = 764
lb = 40
aggregate_size = 364
depth = 1
num_contig_chunks = 16
etype = PVFS_Request_float
stype = LAST-PTYPE
LAST-PTYPE:
offset = OFFSET + 760
num_ereqs = 1
stride = 1
num_blocks = 1
ub = 764
lb = 760
aggregate_size = 4
depth = 1
num_contig_chunks = 1
etype = PVFS_Request_float
stype = NULL
Note that ub, lb, aggregate_size, depth, and num_contig_chunks always refers to the region represented down stream of the current PINT_Request record, and not the whole region, however ub and lb are still expressed in terms of the entire data area.