Avinash Shukla, Anil Kishore Saxena / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 2, Issue 5, September- October 2012, pp.555-560 ‘Review of Radix Sort & Proposed Modified Radix Sort for Heterogeneous Data Set in Distributed Computing Environment’ Avinash Shukla, Anil Kishore Saxena ABSTRACT We have proposed a Modified Pure Radix keys at all. The approach is generally known as Sort for Large Heterogeneous Data Set. In this "bucket sorting", "radix sorting," or "digital sorting," research paper we discuss the problems of radix because it is based on the digits on the keys. sort, brief study of previous works of radix sort & There are two approaches of radix sorting. present new modified pure radix sort algorithm 1.1 MSD (most-significant-digit) Radix Sort for large heterogeneous data set. We try to Examine the digits in the keys in a left-to-right order, optimize all related problems of radix sort working with the most significant digits first, MSD through this algorithm. This algorithm works on radix sorts partition the file according to the leading the Technology of Distributed Computing which is digits of the keys, and then recursively apply the implemented on the principal of divide & conquer same method to the sub files method. 1.2 LSD (least-significant-digit) Radix Sort 1. INTRODUCTION The second class of radix-sorting methods Sorting is a computational building block of examine the digits in the keys in a right-to-left order, fundamental importance and is the most widely working with the least significant digits first. Radix studied algorithmic problem. The importance of sort is work on the radix of elements then the sorting has lead to the design of efficient sorting Number of passes depends on the maximum length of algorithms for a variety of architectures. Many elements following are observed. applications rely on the availability of efficient For the data set with uniform length, Radix sorting routines as a basis for their own efficiency, Sort work highly efficiently. while some algorithms can be conveniently phrased For data set with unequal length elements, in terms of sorting. Database systems make extensive number of passes increases because use of sorting operations. The construction of spatial depending on the maximum length of data structures that are essential in computer graphics elements in list, thus increasing Space & and geographic information systems is fundamentally Time Complexity. a sorting process. Efficient sort routines are also a In the case of string, strings are sorted but it useful building block in implementing algorithms is corrupted data. like sparse matrix multiplication and parallel programming patterns like Map Reduce. It is 2. REVIEW OF LITERATURE therefore important to provide efficient sorting Nilsson [2] Re-evaluated the method for routines on practically any programming platform, managing buckets held at leaves & shows better and with the evolution of new computer architectures choice of data structures further improves the there is a need to explore efficient sorting techniques efficiency, at a small additional cost in memory. For on them. Acceleration of existing techniques as well sets of around 30,000,000 strings, the improved burst as developing new sorting approaches is crucial for sort is nearly twice as fast as the previous best sorting many real-time graphics scenarios, database systems, algorithm. Jon l. Bentley [3] suggested a detailed and numerical simulations. While optimal sorting implementation combining the most effective models for serial execution on a single processor improvements to Quick sort, along with a discussion exists; efficient parallel sorting remains a challenge. of how to implement it in assembly language. It is Radix sort is classified by Knuth as "sorting by wide applicability as an internal sorting method distribution". It is the most efficient sorting method which requires minimal memory. Arne Anderson [4] for alphanumeric keys on modern computers had presented and evaluated several optimized and provided that the keys are not too long. Floating implemented techniques for string sorting. Forward number sorting is also possible, with same radix sort has a good worst-case behavior. modifications. Radix sort is stable, very fast and is an Experimental results indicate that radix sorting is excellent algorithm on computers having large considerably faster (often more than twice as fast) memory. The idea of radix soft is similar to the idea than comparison-based sorting. It is possible to of hashing algorithms. The final position of the implement a radix sort with good worst-case running record is computed for each key. If there is already a time without sacrificing average-case performance. record(s) with this key, it is placed after them The implementations are competitive with the best (overflow area). The key is not compared with other previously published string sorting programs. Naila 555 | P a g e Avinash Shukla, Anil Kishore Saxena / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 2, Issue 5, September- October 2012, pp.555-560 Rahman [5] Discuss the problem of large applications Radix sort (SCS-Radix sort). The three important data set which were too massive to fit completely features of the SCS-Radix are the dynamic detection inside the computer’s internal memory. The resulted of data skew, the exploitation of the memory input/output communication between fast internal hierarchy and the execution time stability when memory and slower external memory was a major sorting data sets with different characteristics. They performance bottleneck. [5] Also discussed the claim the algorithm to be 1:2 to 45 times faster distribution and merging techniques for using the compare to Radix sort or quick sort. Navarro & disks independently. These are useful techniques for Josep [10] focused on the improvement of data batched EM problems involving matrices (such as locality. CC-Radix improved the data locality by matrix multiplication and transposition), geometric dynamically partitioning the data set into subsets that data (such as finding intersections and constructing fit in cache level L2. Once in that cache level, each convex hulls), and graphs (such as list ranking, subset is sorted with Radix sort. The proposed connected components, topological sorting, and algorithm is about 2 and1:4 times faster than Quick shortest paths) were proposed. In the online domain, sort and Explicit Block Transfer Radix sort. Ranjan canonical EM applications include dictionary lookup Sinha [11] suggested that the Algorithms for sorting and range searching. They also re-examined some of large data sets can be made more efficient with the EM problems in slightly different settings, such careful use of memory hierarchies and reduction in as when the data items are moving, or when the data the number of costly memory accesses. Burst sort items are variable-length (e.g., text strings), or when dynamically builds a small tree that is used to rapidly the allocated amount of internal memory can change allocate each string to a bucket. Sinha & Zobel dynamically. Rajeev Raman [6] illustrated the introduced new variants of algorithm: SR-burst sort, importance of reducing misses in the standard DR-burst sort, and DRL-burst sort. These algorithms implementation of least-significant bit first in (LSB) a-priori construct a tree from random samples. radix sort, these techniques simultaneously reduce Experimental results with sets of over 30 million cache and TLB misses for LSB radix sort, all the strings show that the new variants reduce, by up to techniques proposed yield algorithms whose 37percent cache misses than the original burst sort, implementations of LSB Radix sort & comparison- and simultaneously reducing instruction counts by up based sorting algorithms. Danial [7] explained the to 24 percent. Jian- Jun Han [12] proposed two Communication and Cache Conscious Radix sort contention-aware scheduling algorithms viz. OIHSA Algorithm (C3-Radix sort). C3-Radix sort uses the (Optimal Insertion Hybrid Scheduling Algorithm) distributed shared memory parallel programming and BBSA (Bandwidth Based Scheduling Models. Exploiting the memory hierarchy locality Algorithm). Both the algorithms start from the and reduce the amount of communication for inherent characteristic of the edge scheduling distributed Memory computers. C3-Radix sort problem, and select route paths with relatively low implements & analyses on the SGI Origin 2000 network workload to transfer communication data by NUMA Multiprocessor & provides results for up to modified routing algorithm. OISHA optimizes the 16 processors and 64M 32bit keys. The results show start time of communication data transferred on links. that for small data sets compared to the number of BBSA exploits bandwidth of network links processors, the MPI implementation is the faster optimally. Moreover, the proposed algorithms adapt while for large data sets, the shared memory not only to homogeneous systems but also implementation is faster. Shin-Jae Lee [8] solved the heterogeneous systems. Sinha, R. and Zobel [13 & 14] load imbalance problem present in parallel radix sort. examined that the Burst sort is a cache-oriented Redistributing the keys in each round of radix, each sorting technique using dynamic tree to efficiently processor has exactly the same number of keys, divide large sets of string keys into related subsets