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

Double linked list, In a doubly linked list, also called as 2 way list, eac...

In a doubly linked list, also called as 2 way list, each node is divided into 3 parts. The first part is called previous pointer field. It contains the address of the preceding

Assignment, How do I submit a three page assignment

How do I submit a three page assignment

Algorithm, write an algorithm for the gpa of six students

write an algorithm for the gpa of six students

Define tree ?, A tree is a non-empty set one component of which is designat...

A tree is a non-empty set one component of which is designated the root of the tree while the remaining components are partitioned into non-empty groups each of which is a subtree

A tree having ''m'' nodes has (m-1) branches. prove., Q. Prove the hypothes...

Q. Prove the hypothesis that "A tree having 'm' nodes has exactly (m-1) branches".      Ans: A tree having m number of nodes has exactly (m-1) branches Proof: A root

Explain class p problems, Explain class P problems Class  P  is  a  cla...

Explain class P problems Class  P  is  a  class  of  decision  problems  that  can  be  solved  in  polynomial time  by(deterministic) algorithms. This class of problems is kno

Depth first search and breadth first search, Q. Illustrate the result of ru...

Q. Illustrate the result of running BFS and DFS on the directed graph given below using vertex 3 as source.  Show the status of the data structure used at each and every stage.

Kruskal algorithm for minimum spanning, Implementations of Kruskal's algori...

Implementations of Kruskal's algorithm for Minimum Spanning Tree. You are implementing Kruskal's algorithm here. Please implement the array-based Union-Find data structure.

Avl trees, An AVL tree is a binary search tree that has the given propertie...

An AVL tree is a binary search tree that has the given properties: The sub-tree of each of the node differs in height through at most one. Each sub tree will be an AVL tre

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