Last figure Figure 4. Each PE has a fixed 32MB portion of the file while the global file size increases accordingly as number of PEs increases. File is striped over 39 disk partitions. Synchronization of all PEs with the master PE is not always possible or advisable. 1D array oriented, all the aboved mentioned approach can be used for 1D array.
Writing follows the reversed order.
1D distribution can be easily handled easily and efficiently. An example is a 2D matrix distributed on a 2D processor array by dividing both i and j dimensions. The 2D distribution are more complicated due to the fact that data in matrix subblock are not contiguous in the original global matrix data array and can not be extracted using a single memory copy. But more often, applications with high dimensional data arrays use lower dimension domain decomposition, for a variety of practical reasons. This is dictated by how the 3D data is mapped into linear storage in memory in the language.