Reducing reverse-mode memory requirements by using profile-driven checkpointing

In this paper, we describe a particular instance of this checkpointing problem: we were using reverse-mode code generated by Adifor 3.0 to compute derivatives of a large computational fluid dynamics code. Our effort labored under the additional constraint that development time was minimal (as always, it was needed yesterday). Our solution was to use profiling to narrowly focus our checkpoint analysis. This profiling approach worked well for our problem. Furthermore, the profiling idea is sufficiently general that it should work well for other problems. This paper details both our results on our specific problem and guidelines for applying the profiling technique to other checkpoint-based reverse-mode development problems.