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

The space - time trade off, The Space - Time Trade Off The best algorit...

The Space - Time Trade Off The best algorithm to solve a given problem is one that needs less space in memory and takes less time to complete its implementation. But in practic

Define a tree and list its properties, QUESTION (a) Define a tree and l...

QUESTION (a) Define a tree and list its properties. (b) By showing all your workings, draw the spanning tree for the following graph based on the Breadth-First-Search algori

Splaying procedure, For splaying, three trees are maintained, the central, ...

For splaying, three trees are maintained, the central, left & right sub trees. At first, the central subtree is the complete tree and left and right subtrees are empty. The target

Insertion in list, In the array implementation of lists, elements are store...

In the array implementation of lists, elements are stored into continuous locations. In order to add an element into the list at the end, we can insert it without any problem. But,

What is Oscillating Sort?, For the Oscillating sort to be applied, it is ne...

For the Oscillating sort to be applied, it is necessary for the tapes to be readable in both directions and able to be quickly reversed. The oscillating sort is superior to the po

Explain insertion sort, Q. Explain the insertion sort with a proper algorit...

Q. Explain the insertion sort with a proper algorithm. What is the complication of insertion sort in the worst case?

Array and two-dimensional array, Q. Describe the term array.  How do we rep...

Q. Describe the term array.  How do we represent two-dimensional arrays in memory?  Explain how we calculate the address of an element in a two dimensional array.

Lilz, I need to know about data structure and algorithms. can you help me?

I need to know about data structure and algorithms. can you help me?

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