Overview

In Sun S3L, arrays are distributed in blocks across multiple processes, allowing S3L operations to be performed in parallel on different sections of the array. These arrays are referred to in this manual as S3L arrays and, more generically, as parallel arrays.

Arrays passed to Sun S3L routines by C or F77 message-passing programs can have block, cyclic, or block-cyclic distributions. Regardless of the type of distribution specified by the calling program, Sun S3L will automatically select the distribution scheme that is most efficient for the routine being called. If that means Sun S3L changes the distribution method internally, it will restore the original distribution scheme on the resultant array before passing it back to the calling program.

Arrays from C and F77 message-passing programs can also be undistributed. That is, all the elements of the array can be located on the same process--a serial array in the conventional sense.

The balance of this chapter describes S3L arrays in more detail.