Which of the following is not valid with reference to Message Passing…
2015
Which of the following is not valid with reference to Message Passing Interface(MPI) ?
Answer: C. All parallelism is implicit — Correct answer: 'All parallelism is implicit' is not valid with respect to MPI. Why this statement is incorrect: MPI uses an explicit parallel programming…
- A.
MPI can run on any hardware platform
- B.
The programming model is a distributed memory model
- C.
All parallelism is implicit
- D.
MPI- Comm - Size returns the total number of MPI processes in specified communication
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Correct answer: C
Correct answer: 'All parallelism is implicit' is not valid with respect to MPI.
Why this statement is incorrect:
MPI uses an explicit parallel programming model. The programmer must explicitly start multiple processes and write message-passing calls to coordinate them.
Typical MPI routines that show this explicitness include MPI_Init, MPI_Comm_size, MPI_Comm_rank, MPI_Send, and MPI_Recv.
Because the programmer controls process creation and communication, parallelism in MPI is explicit rather than implicit or automatic.
Brief notes on the other statements to justify they are valid:
MPI can run on many hardware platforms as long as an MPI implementation exists for the target platform (examples: clusters, multicore nodes, supercomputers).
The MPI programming model is a distributed-memory model: each process has its own address space and communicates via message passing.
MPI_Comm_size returns the number of processes in the given communicator (for example, calling it with MPI_COMM_WORLD returns the total number of processes in MPI_COMM_WORLD).