More Examples of Collective Communication/Computation
Four Processors where each has a send buffer of size 2
- 0 1 2 3 Processors
- (2,4) (5,7) (0,3) (6,2) Initial Send Buffers
- MPI_SENDRECV with 0,1 and 2,3 paired
- (5,7) (2,4) (6,2) (0,3) Resultant Buffers
- MPI_GATHER with root=0
- (2,4,5,7,0,3,6,2) (_,_) (_,_) (_,_) Resultant Buffers
- Now take four Processors where only rank=0 has send buffer
- (2,4,5,7,0,3,6,2) (_,_) (_,_) (_,_) Initial send Buffers
- MPI_SCATTER with root=0
- (2,4) (5,7) (0,3) (6,2) Resultant Buffers