Semigroup and prefix computations on improved generalized mesh-connected computers with multiple buses

Various augmenting mechanisms have been proposed to enhance the communication efficiency of mesh-connected computers (MCCs). One major approach is to add nonconfigurable buses for improved broadcasting. A typical example is the mesh-connected computer with multiple buses (MMB). In this paper, we propose a new class of generalized MMBs, the improved generalized MMBs (IMMBs). Each processor in an IMMB is connected to exactly two buses. We show the power of IMMBs by considering semigroup and prefix computations. Specifically, we show that semigroup and prefix computations on N operands, and data broadcasting all take O(log N) time on IMMBs. This is the first O(log N) time algorithm for these problems on arrays with fixed broadcasting buses.