1. Auburn University http://www.eng.auburn.edu/~xqin
COMP7330/7336 Advanced Parallel and Distributed Computing Odd-Even Sort Implementation
Dr. Xiao Qin
Auburn University
Slides are adopted from Drs. Ananth Grama, Anshul Gupta, George Karypis, and Vipin Kumar

2. Review: Odd-Even Transposition
Sorting n = 8 elements, using the odd-even transposition sort algorithm. During each phase, n = 8 elements are compared.

3. Review: Sequential odd-even transposition sort algorithm

4. Review: Parallel Odd-Even Transposition
Element i is residing on process Pi

5. Parallel Odd-Even Transposition
Consider a block of n/p elements per processor.
The first step is a local sort.
In each subsequent step, the compare exchange operation is replaced by the compare split operation.
The parallel run time of the formulation is

6. Parallel Odd-Even Transposition
The parallel formulation is cost-optimal for p = O(log n).
The isoefficiency function of this parallel formulation is Θ(p2p).

7. Sending and Receiving Messages Simultaneously
To exchange messages, MPI provides the following function:
int MPI_Sendrecv(void *sendbuf, int sendcount,
MPI_Datatype senddatatype, int dest, int sendtag, void *recvbuf, int recvcount, MPI_Datatype recvdatatype, int source, int
recvtag, MPI_Comm comm, MPI_Status *status)
The arguments include arguments to the send and receive
functions. If we wish to use the same buffer for both send and
receive, we can use:
int MPI_Sendrecv_replace(void *buf, int count,
MPI_Datatype datatype, int dest, int sendtag,
int source, int recvtag, MPI_Comm comm,
MPI_Status *status)
Send and receive buffers are disjoint
This problem is solved by using MPI_Sendrecv_replace

8. Parallel Odd-Even - Implementation
P. 248 Show also the prototype of MPI_Sendrecv()

9. Parallel Odd-Even - Implementation

10. Parallel Odd-Even - Implementation

11. Parallel Odd-Even - Implementation

12. Parallel Odd-Even - Implementation

13. Parallel Odd-Even - Implementation