Randomization function

In computer science, a randomization function or randomizing function is an algorithm or procedure that implements a randomly chosen function between two specific sets, suitable for use in a randomized algorithm. In computer science, a randomization function or randomizing function is an algorithm or procedure that implements a randomly chosen function between two specific sets, suitable for use in a randomized algorithm. Randomizing functions are related to random number generators and hash functions, but have somewhat different requirements and uses, and often need specific algorithms. Randomizing functions are used to turn algorithms that have good expected performance for random inputs, into algorithms that have the same performance for any input. For example, consider a sorting algorithm like quicksort, which has small expected running time when the input items are presented in random order, but is very slow when they are presented in certain unfavorable orders. A randomizing function from the integers 1 to n to the integers 1 to n can be used to rearrange the n input items in 'random' order, before calling that algorithm. This modified (randomized) algorithm will have small expected running time, whatever the input order.