Algorithms for the parallel alternating direction access machine

We describe a number of algorithms for the model for parallel computation c alled parallel alternating-direction access machine (PADPAM). This model ha s the memory modules of the global memory arranged as a two-dimensional arr ay, with each processor assigned to a row and a column, the processors can switch synchronously between row and column access modes. We study the issu es of inter-processor communication and of efficient use of memory on the P ADAM, and develop: an optimal routing scheme among memory modules, algorith ms enhancing random access of processors to all memory blocks, and general simulations of shared memory machines. Finally, we present optimal algorith ms for the problems of selection, merging, and sorting. (C) 2000 Elsevier S cience B.V. All rights reserved.