What is Polyphase Sort, Data Structure & Algorithms

Assignment Help:
One of the best known methods for external sorting on tapes is the polyphase sort.

Principle: The basic strategy of this sort is to distribute ordered initial runs of predetermined size on the available tapes and then to repeatedly merge these runs in multiple phases in which each phase has a predetermined number of merges before a new target tape is selected.

To distribute the initial runs a Fibonacci distribution is adopted. After the distribution of the runs according to Fibonacci distribution, the merging procedure is continued until the tape with the least number of run lists is empty. When this occurs the remaining working tapes are logically rotated such that the newly emptied tape becomes the new target tape and the old target tape then becomes one of the working tapes to be merged. The sort ends when all runs are merged into one.

Let the number of tapes be T and p = T - 1. The Fibonacci distribution for p = 3 is given.

Level

s
Tape
Total number of runs
1
2
3
1
0
0
1
1
2
1
1
1
3
3
1
2
2
5
4
2
3
4
9
5
4
6
7
17
6
7
11
13
31
7
13
20
24
57
8
24
37
44
105
9
44
68
81
193
Algorithm:

1. Let A be the list of N unsorted elements and R be the number of runs.

2. Let T1, T2, T3 and T4 be the tapes on which sorting is done.

3. Split the list A into R=N runs so that each run has only one element.

4. If R is not equal to perfect Fibonacci distribution then add dummy records to bring up perfect Fibonacci distribution.

5. Distribute the records in the remaining tapes according to the Fibonacci distribution.

6. Merge 3 runs, one from each tape and put into next empty tape.

7. Repeat step 6 till a single run is generated.

Related Discussions:- What is Polyphase Sort

EM13845162, Do you have a library solution for this problem?

Do you have a library solution for this problem?

General, whats the definition of ADT and data type?

whats the definition of ADT and data type?

Total impedent of the circuit, an electrical student designed a circuit in...

an electrical student designed a circuit in which the impedence in one part of a series circuit is 2+j8 ohms and the impedent is another part of the circuit is 4-j60 ohm mm program

Dynamic memory management, How memory is freed using Boundary tag method in...

How memory is freed using Boundary tag method in the context of Dynamic memory management? Boundary Tag Method to free Memory To delete an arbitrary block from the free li

Searching, Searching is the procedure of looking for something: Finding one...

Searching is the procedure of looking for something: Finding one piece of data that has been stored inside a whole group of data. It is frequently the most time-consuming part of m

State the ways to construct container taxonomy, State the ways to construct...

State the ways to construct container taxonomy There are several ways that we could construct our container taxonomy from here; one way that works well is to make a fundamental

Pseudocodes, how to write a pseudo code using Kramer''s rule

how to write a pseudo code using Kramer''s rule

Splaying algorithm, Insertion & deletion of target key requires splaying of...

Insertion & deletion of target key requires splaying of the tree. In case of insertion, the tree is splayed to find the target. If, target key is found out, then we have a duplicat

Deletion of any element from the circular queue, Algorithm for deletion of ...

Algorithm for deletion of any element from the circular queue: Step-1: If queue is empty then say "queue is empty" & quit; else continue Step-2: Delete the "front" element

Algorithams example, any simple algoritham questions with answers

any simple algoritham questions with answers

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd