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

Endogenous model, Question a) Describe how the endogenous model is an ...

Question a) Describe how the endogenous model is an improvement to the neo-classical model in explaining the long-run effect of investment on economic growth of a country.

Rotations in binary tree, H o w can you r ot a t e a B i n a r y...

H o w can you r ot a t e a B i n a r y Tr e e? E x pl a i n r i g h t a n d l eft r ot a tion s by taking an e x a mpl e.   If after

Prims algorithm, Prim's algorithm employs the concept of sets. Rather than ...

Prim's algorithm employs the concept of sets. Rather than processing the graph by sorted order of edges, this algorithm processes the edges within the graph randomly by building up

Sparse matrices, SPARSE MATRICES Matrices along with good number of zer...

SPARSE MATRICES Matrices along with good number of zero entries are called sparse matrices. Refer the following matrices of Figure (a)

Enumerate about the carrier set members, Enumerate about the carrier set me...

Enumerate about the carrier set members Ruby is written in C, so carrier set members (which is, individual symbols) are implemented as fixed-size arrays of characters (which is

Arrays, Data array A has data series from 1,000,000 to 1 with step size 1, ...

Data array A has data series from 1,000,000 to 1 with step size 1, which is in perfect decreasing order. Data array B has data series from 1 to 1,000,000, which is in random order.

Draws a rectangular grid algorithms, Prepare a GUI called Hotplate GUI that...

Prepare a GUI called Hotplate GUI that holds a central panel that draws a rectangular grid that represents Element objects which should be held in a 2-dimensional array. The applic

Which sorting algorithms not have running time of o (n2), Which sorting al...

Which sorting algorithms does not have a worst case running time of  O (n 2 ) ? Merge sort

What is the best case complexity of quick sort, What is the best case compl...

What is the best case complexity of quick sort In the best case complexity, the pivot is in the middle.

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