Circular Shift of Loop Body - Programme Transformation, Promoting Parallelism

Abstract

The article deals with the programme transformation executing the circular shift of loop body statements. It can be used for vectorizing or parallelizing. This becomes possible due to the fact that when the order of loop body statements is changed, some of the bottom-up arcs become top-down arcs. Besides, sometimes loop carried dependence arcs are substituted by loop independent ones. It should be pointed out that in executing the circular shift the number of loop iterations is reduced by one. The transformation can be used both independently and in conjunction with other transformations promoting parallelism. These could be "forward substitution", "scalar expansion", "privatization", "array expansion", etc. The transformation under consideration in this article can be used both in hand parallelization and added to a paralleling (optimizing) compiler. Moreover, the application of the transformation results in the equivalent code only for the loops where loop unrolling is the equivalent transformation. Thus, they can contain nested loops, if statements and other programming language statements.

Numerical Modelling of the Dynamics of the Galactic Halos in the Colliding Galaxies

“…A detailed description of the numerical algorithms SPH and N-body is given in papers [28,29]. In the papers [30,31] it was also noted that the result of the parallel software implementation and its efficiency depends on the details of the code and on the sequence of the numerical operations. Fig.…”

New Features of Parallel Implementation of N-Body Problems on GPU

“…In computational astrophysics, the problem of the software transfer to new hardware platforms becomes relevant due to the wide distribution of powerful computer systems on graphics processors. The result of the parallel software implementation and its efficiency depend a lot on the features of the code and the sequence of numerical operations [13,14].…”