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Each process defines a hyperslab in the file as described below and writes data to it. The C and Fortran 90 examples below result in the same data layout in the file.
Figure a C Example
|
Figure b FORTRAN 90 Example |
The C and Fortran 90 examples use four processes to write the pattern shown above. Each process defines a hyperslab by:
- Specifying a stride of 2 for each dimension, which indicates
that you wish to write to every other position along a dimension.
- Specifying a different offset for each process:
C: Process 0 Process 1 Process 2 Process 3 --------- --------- --------- --------- offset[0] = 0 offset[0] = 1 offset[0] = 0 offset[0] = 1 offset[1] = 0 offset[1] = 0 offset[1] = 1 offset[1] = 1 FORTRAN 90: offset(1) = 0 offset(1) = 0 offset(1) = 1 offset(1) = 1 offset(2) = 0 offset(2) = 1 offset(2) = 0 offset(2) = 1
- Specifying the size of the slab to write. The count is the number of positions along a dimension to
write to. If writing a 4 x 2 slab, then the count would be:
C: FORTRAN 90: count[0] = 4 count(1) = 2 count[1] = 2 count(2) = 4
Figure a C Example
|
Figure b FORTRAN 90 Example |
Below are example programs for writing hyperslabs by pattern in Parallel HDF5:
-
[ C Example ]
--
Hyperslab_by_pattern.c
[ F90 Example ] --
hyperslab_by_pattern.f90
HDF5 "SDS_pat.h5" { GROUP "/" { DATASET "IntArray" { DATATYPE H5T_STD_I32BE DATASPACE SIMPLE { ( 8, 4 ) / ( 8, 4 ) } DATA { 1, 3, 1, 3, 2, 4, 2, 4, 1, 3, 1, 3, 2, 4, 2, 4, 1, 3, 1, 3, 2, 4, 2, 4, 1, 3, 1, 3, 2, 4, 2, 4 } } } }The h5dump utility is written in C so the output is in C order.
- - Last modified: 05 July 2016