S3L Array Handles

When an S3L array is declared, it is associated with a unique array handle. This is an S3L internal structure that fully describes the array. An S3L array handle contains all the information needed to define both the global and local characteristics of an S3L array. For example, an array handle includes

• global features, such as the array's rank and information about how the array is distributed

• local features, such as its extents and its location in memory on the process

By describing both local and global features of an array, an array handle makes it possible for any process to easily access data in array sections that are on other processes, not just data in its local section. That is, no matter how an array has been distributed, the associated S3L array handle ensures that its layout is understood by all participating processes.

In C programs, S3L array handles are declared as type S3L_array_t and in Fortran programs as type integer*8.