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

Design and implement a software system, In this assignment, you are invited...

In this assignment, you are invited to design and implement a software system for catalogue sale. A catalogue is organised in a tree structure. Each node of the catalogue tree repr

ALGORITHM AND TRACING, WRITE AN ALGORITHM TO CONVERT PARENTHIZED INFIX TO P...

WRITE AN ALGORITHM TO CONVERT PARENTHIZED INFIX TO POSTFIX FORM ALSO TRACE ALG ON ((A+B)*C-(D-E)$F+G)

Write an algorithm for binary search., Write an algorithm for binary search...

Write an algorithm for binary search. Algorithm for Binary Search 1.  if (low> high) 2.  return (-1) 3.  Mid = (low + high)/2 4.  if ( X = = a[mid]) 5.  return (mid); 6.

B-tree of degree 3, Q. Explain the result of inserting the keys given. ...

Q. Explain the result of inserting the keys given. F, S, Q, K, C, L, H, T, V, W, M, R, N, P, A, B, X, Y, D, Z, E  in an order to an empty B-tree of degree-3.

Perform inorder, QUESTION (a) Construct a binary tree for the following...

QUESTION (a) Construct a binary tree for the following numbers assuming that a number greater than the node (starting from the root) goes to the left else it goes to the right.

2 way merge sort, merge sort process for an example array {38, 27, 43, 3, 9...

merge sort process for an example array {38, 27, 43, 3, 9, 82, 10}. If we take a closer look at the diagram, we can see that the array is recursively divided in two halves till the

Explain about the string abstract data type operations, Explain about the S...

Explain about the String Abstract data type operations Symbol ADT has no concatenation operations, but presuming we have a full-featured String ADT, symbols can be concatenated

Multidimensional array, Q. The system allocates the memory for any of the m...

Q. The system allocates the memory for any of the multidimensional array from a big single dimensional array. Describe two mapping schemes that help us to store the two dimensi

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