User Account

All Pages

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

Write an algorithm to measure daily temperatures, A geography class decide ...

A geography class decide to measure daily temperatures and hours of sunshine each day over a 12 month period (365 days) Write an algorithm, using a flowchart that inputs tempera

Linked lists, what are grounded header linked lists?

what are grounded header linked lists?

Algorithm, algorithm to search a node in linked list

algorithm to search a node in linked list

Algorithm for the selection sort, Q. Give the algorithm for the selection s...

Q. Give the algorithm for the selection sort. Describe the behaviours of selection sort when the input given is already sorted.

Worst case and average case, Worst Case: For running time, Worst case runn...

Worst Case: For running time, Worst case running time is an upper bound with any input. This guarantees that, irrespective of the type of input, the algorithm will not take any lo

Amortized algorithm analysis, In the amortized analysis, the time needed to...

In the amortized analysis, the time needed to perform a set of operations is the average of all operations performed. Amortized analysis considers as a long sequence of operations

Postfix expression algorithm, Write an algorithm to calculate a postfix exp...

Write an algorithm to calculate a postfix expression.  Execute your algorithm using the given postfix expression as your input : a b + c d +*f ↑ . T o evaluate a postfix expr

Explain all-pair shortest-paths problem, Explain All-pair shortest-paths pr...

Explain All-pair shortest-paths problem Given a weighted linked graph (undirected or directed), the all pairs shortest paths problem asks to find the distances (the lengths of

Signals, How does cpu''s part tming and controls generate and controls sign...

How does cpu''s part tming and controls generate and controls signls in computer?

Pipeling, Asktypes of pipelining question #Minimum 100 words accepted#

Asktypes of pipelining question #Minimum 100 words accepted#

Write Your Message!

Captcha
Order Assignment

Featured Services

Order Now

Popular Subjects

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!

Submit Assignment

Academics

Major Subjects

Majors

Get In Touch

whatsapp: +91-977-207-8620

Phone: +91-977-207-8620

Email: [email protected]

TERMS & POLICIES

HELP & SUPPORT

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