A method and apparatus for a cellular processing array comprising a plurality of processing cells wherein each cell is capable of detecting intensity changes in a field under observation. The processing cells having one or more outputs connected as inputs to one or more neighboring processing cells and each of the connected inputs is indicative of whether or not its connected neighboring processing cell has detected an intensity change. Means are provided to increment the received inputs if the receiving cell has detected an intensity change from dark to light in consecutive detection cycles and to decrement the received inputs if the receiving cell has detected an intensity change from light to dark in consecutive detection cycles. The inputs as processed are provided as an output to connected neighboring processing cells. No incremental or decremental action on the inputs occurs if the receiving cell has detected light and/or if no intensity change has occurred in consecutive detection cycles, in which case, the inputs as received are provided as outputs to neighboring cells connected to receive output from the receiving output. The incremental or decremental action on received inputs may be a unit value or an amplification factor based upon past detection cycle activity.
An interconnection network for a plurality of process nodes, each illustratively comprised of a processor-memory pair, utilizes an hexagonal mesh arrangement of size n which is wrapped in each of the x, y, and z directions. In accordance with the invention, a unique address value is assigned to each processor node in the network, beginning at a central processor node and continuing along the x direction, and via the wrapping links, until each such processor node has a unique sequential address. Each of the rows, having first and last processor nodes therein, is wrapped by coupling each of the last processor nodes in each row to a respective first processor node in a corresponding row which is n-1 rows away. Point-to-point communication is achieved using the unique addresses of only the source and destination processor nodes, without requiring each intermediate processor node to contain global information about the entire network. An algorithm computes the shortest path between the source and destination processor nodes, in terms of the minimum number of processors which must be encountered by the message as it proceeds along the x, y, and z directions of the network toward the destination processor node. Each intermediate processor node updates the routing information. Point-to-point communication is also used to effect a broadcasting of a message from a source processor node to every other processor node in the network.
