Fabrizio Luccio – Communications of the ACM

Research and Advances Jan 1 1979

Permutation of data blocks in a bubble memory

A common internal organization of bubble memories consists of a set of (minor) loops, connected through another (major) loop. The problem of obtaining any given permutation of the minor loop contents in minimum time is studied in this paper. A lower bound to the number of steps required by a permutation algorithm is derived, and the class of optimum algorithms is identified.

Author Archives

Research and Advances Nov 1 1978

Power trees

The new class of Pk trees is presented, where height balance is maintained for the nodes lying on particular paths. The number of nodes of a Pk tree asympotically grows as a power of the height, in the worst case. A procedure for node insertion is given, and the class of trees considered is restricted to IPk trees, which are buildable by such a procedure. The average behavior of such trees, studied by an extensive set of simulation runs, is close to that of AVL trees. In particular, the family of IP0 trees whose main advantage is the reduced number of restructurings required after node insertion, is analyzed.

Artificial Intelligence and Machine Learning

Research and Advances Dec 1 1972

Weighted increment linear search for scatter tables

A new linear search for hash tables whose increment step is a function of the key being addressed is presented. Comparisons with known methods are given, in terms of efficiency and computation complexity. In particular, the new method applies to tables of size n = 2r. It allows full table searching, and practically eliminates primary clustering at a very low cost.

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