Algorithms for the parallel alternating direction access machine

We describe a number of algorithms for the model for parallel computation called parallel alternating-direction access machine (PADAM). This model has the memory modules of the global memory arranged as a two-dimensional array, with each processor assigned to a row and a column, the processors can switch synchronously between row and column access modes. We study the issues of inter-processor communication and of efficient use of memory on the PADAM, and develop: an optimal routing scheme among memory modules, algorithms enhancing random access of processors to all memory blocks, and general simulations of shared memory machines. Finally, we present optimal algorithms for the problems of selection, merging, and sorting.