Reconfigurable Cellular Computers

When a collection of processors c=(p/sub 1/, ..., p/sub n/) operates in parallel, it is desirable that at any given stage of the computation, each p/sub i/ should have a task of about the same size to perform, and each p/sub i/ should require about the same amount of information from the other ps in order to perform its task. To the extent that these conditions are violated, parallelism is impaired, in the sense that the ps are not all used with equal efficiency. In cellular computers, e.g. as they might be used for parallel image processing, these conditions are maintained by having the ps all perform similar computations on different parts of the input data, and by allowing each p/sub i/ to receive information from a fixed set of the others (its neighbours), where these sets are all of bounded size. This paper discusses, on an abstract level, the concept of a reconfigurable cellular computer, in which each p/sub i/ can receive information from a set s/sub i/ of the other ps, and the s/sub i/s are all of bounded size, but they need not remain fixed throughout a computation. Requiring the s/sub i/s to have bounded size impliesmore » that most ps cannot communicate directly; the expected time required for two arbitrary ps to communicate depends on the graph structure defined by the sets s/sub i/. The question of how to change the s/sub i/s in parallel during the course of a computation is also discussed. 15 references.« less