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Received 29 Aug Accepted 08 Nov Published 04 Aug Abstract With problem size and complexity increasing, several parallel and distributed programming models and frameworks have been developed to efficiently handle such problems. Introduction We often happen to meet problems requiring heavy computations or data-intensive processing.
Parallel Computing Models In parallel computing memory architectures, there are shared memory, distributed memory, and hybrid shared-distributed memory [ 12 ]. MPI MPI is a message passing library specification which defines an extended message passing model for parallel, distributed programming on distributed computing environment [ 10 ].
MapReduce MapReduce is a programming paradigm to use Hadoop which is recognized as a representative big data processing framework [ 11 ]. Benchmark Problems The all-pairs-shortest-path problem is to find the shortest path between all pairs of nodes in a graph.
Algorithm 1. Floyd-Warshall algorithm for the all-pairs-shortest-path problem. Figure 1. Algorithm 2. OpenMP pseudocode for the all-pairs-shortest-path problem. Algorithm 3. MPI pseudocode for the all-pairs-shortest-path problem. Algorithm 4. MapReduce pseudocode for the all-pairs-shortest-path problem. Algorithm 5. Algorithm 6. Algorithm 7. Figure 2. Table 1.
Table 2. References D. Culler, J. Singh, and A. Lee and K. View at: Google Scholar H. Lee-Kwang, K. Seong, and K. Lee, J. Kim, H. Wang et al. View at: Google Scholar S. Kim, B. Sohn, K. Jeon, and S. Diaz, C. View at: Google Scholar W. Gropp, S. Huss-Lederman, A. Lumsdaine et al. Dean and S. Coarfa, Y. Dotsenko, J. Mellor-Crummey et al. Alexandrov, S. Ewen, M. Heimel et al. View at: Google Scholar M. Isard, M.
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View at: Google Scholar T. Cormen, C. Leiserson, R. You can think of it as: every bit of code you've written is executed independently by every process. The parallelism occurs because you tell each process exactly which part of the global problem they should be working on based entirely on their process ID.
It is a set of API declarations on message passing such as send, receive, broadcast, etc. The idea of "message passing" is rather abstract. It could mean passing message between local processes or processes distributed across networked hosts, etc. Modern implementations try very hard to be versatile and abstract away the multiple underlying mechanisms shared memory access, network IO, etc. OpenMP is an API which is all about making it presumably easier to write shared-memory multi-processing programs.
There is no notion of passing messages around. Instead, with a set of standard functions and compiler directives, you write programs that execute local threads in parallel, and you control the behavior of those threads what resource they should have access to, how they are synchronized, etc. OpenMP requires the support of the compiler, so you can also look at it as an extension of the supported languages. How are we doing? Please help us improve Stack Overflow. Take our short survey.
Stack Overflow for Teams — Collaborate and share knowledge with a private group. Few projects try to replicate openmp for Java. MPI target both distributed as well shared memory system. OpenMP target only shared memory system. Based on both process and thread based approach. Earlier it was mainly process based parallelism but now with MPI 2 and 3 thread based parallelism is there too.
Usually a process can contain more than 1 thread and call MPI subroutine as desired. Only thread based parallelism. Overhead for creating process is one time. Depending on implementation threads can be created and joined for particular task which add overhead. There are overheads associated with transferring message from one process to another. No such overheads, as thread can share variables. Process in MPI has private variable only, no shared variable. In OpenMP , threads have both private as well shared variable.
Data racing is inherent in OpenMP model. Adding header file : include "mpi. Need to add omp. Running MPI program. User can launch executable openmpExe in normal way. Sample MPI program. This is a simple hello world program. Each processor print its id. Command to run executable with name a.
Hello from 1. Hello from 0. Hello from 2.
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