Study of the efficiency of some deterministic preprocessing methods for sorting algorithms

Abstract

To verify the hypothesis about decrease in time of sorting by algorithms of different computational complexity experiments have been conducted. Several ideas on deterministic preprocessing of data arrays for sorting algorithms have been tested. The following algorithms are proposed: quick preprocessing – prediction of the index of an element in a sorted array and permutation, preprocessing with memory - prediction and permutation with memorization of previously set elements, preprocessing with reordering – reverting sequences of elements sorted in reverse order. Also proposed block variations of quick and preprocessing with memory, which are performed for parts of the array of a given length. It has been defined that the higher efficiency of preprocessing is achieved by using with sorting algorithms, which are significantly accelerated on sorted (or almost sorted) arrays of data. Block preprocessing methods can be performed faster due to the possibility of avoiding cache misses, but show a lower percentage of array sorting. Experiments were conducted to evaluate the effectiveness of various sorting algorithms after and together with the proposed preprocessing methods.