Browsing by Author "Hirschberg, Daniel S."
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Item An efficient implementation of Batcher's odd-even merge algorithm and its application in parallel sorting schemes(1981) Kumar, Manoj; Hirschberg, Daniel S.; Sinclair, James B.; Jump, J. RobertAn algorithm is presented to merge two subfiles of size n/2 each, stored in the left and the right halves of a linearly-connected processor array, in 3n/2 route steps and log n compare-exchange steps. This algorithm is extended to merge two horizontally adjacent subfiles of size mXn/2 each, stored in an mXn mesh-connected processor array in row-major order, in m+2n route steps and log mn compare-exchange steps. These algorithms are faster than their counterparts proposed so far. Next, an algorithm is presented to merge two vertically aligned subfiles, stored in a mesh-connected processor array in row-major order. Finally, a sorting scheme is proposed that requires lln route steps and 2 log n compare-exchange steps to sort n elements stored in an nXn mesh-connected processor array. The previous best sorting algorithm requires 14 n route steps ( for practical values of n, 4 < n 512 ).Item Dynamic memory interconnections for rapid access(1981) Iyer, Balakrishna R.; Sinclair, James B.; Hirschberg, Daniel S.; Jump, J. RobertA dynamic memory is a storage facility for fixed-size data items. The memory is comprised of cells, each cell capable of storing one datum. Data paths between cells are provided by a memory interconnection network. Each cell is directly connected to only a small number of cells. At every clock pulse, data items migrate from cell to cell via the data paths. The memory cells may be divided into several groups. A control mechanism provides each group of memory cells with a control signal. This control signal determines the data paths to be taken by data items contained in all cells within the group. Many dynamic memory organizations have been proposed. These exhibit trade-offs between the time to access a datum randomly and the time to access serially a block of logically contiguous data. The access times for these organizations are derived where necessary and compared. A new organization called the deck memory organization is proposed. Access times for the deck are determined and compared with access times derived for other organizations.