71 строка
3.0 KiB
C
71 строка
3.0 KiB
C
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#include "nbc.h"
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/* an allgatherv schedule can not be cached easily because the contents
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* ot the recvcounts array may change, so a comparison of the address
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* would not be sufficient ... we simply do not cache it */
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/* simple linear MPI_Iallgatherv
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* the algorithm uses p-1 rounds
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* first round:
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* each node sends to it's left node (rank+1)%p sendcount elements
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* each node begins with it's right node (rank-11)%p and receives from it recvcounts[(rank+1)%p] elements
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* second round:
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* each node sends to node (rank+2)%p sendcount elements
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* each node receives from node (rank-2)%p recvcounts[(rank+2)%p] elements */
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int NBC_Iallgatherv(void* sendbuf, int sendcount, MPI_Datatype sendtype, void* recvbuf, int *recvcounts, int *displs, MPI_Datatype recvtype, MPI_Comm comm, NBC_Handle *handle) {
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int rank, p, res, r, speer, rpeer;
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MPI_Aint rcvext, sndext;
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NBC_Schedule *schedule;
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char *rbuf, *sbuf, inplace;
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NBC_IN_PLACE(sendbuf, recvbuf, inplace);
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res = NBC_Init_handle(handle, comm);
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if(res != NBC_OK) { printf("Error in NBC_Init_handle(%i)\n", res); return res; }
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res = MPI_Comm_rank(comm, &rank);
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if (MPI_SUCCESS != res) { printf("MPI Error in MPI_Comm_rank() (%i)\n", res); return res; }
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res = MPI_Comm_size(comm, &p);
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if (MPI_SUCCESS != res) { printf("MPI Error in MPI_Comm_size() (%i)\n", res); return res; }
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res = MPI_Type_extent(sendtype, &sndext);
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if (MPI_SUCCESS != res) { printf("MPI Error in MPI_Type_extent() (%i)\n", res); return res; }
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res = MPI_Type_extent(recvtype, &rcvext);
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if (MPI_SUCCESS != res) { printf("MPI Error in MPI_Type_extent() (%i)\n", res); return res; }
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schedule = malloc(sizeof(NBC_Schedule));
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if (NULL == schedule) { printf("Error in malloc() (%i)\n", res); return res; }
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handle->tmpbuf=NULL;
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res = NBC_Sched_create(schedule);
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if(res != NBC_OK) { printf("Error in NBC_Sched_create, (%i)\n", res); return res; }
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if(!((rank == 0) && inplace)) {
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/* copy my data to receive buffer */
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rbuf = ((char *)recvbuf) + (displs[rank]*rcvext);
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NBC_Copy(sendbuf, sendcount, sendtype, rbuf, recvcounts[rank], recvtype, comm);
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if (NBC_OK != res) { printf("Error in NBC_Copy() (%i)\n", res); return res; }
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}
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sbuf = ((char *)recvbuf) + (displs[rank]*rcvext);
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/* do p-1 rounds */
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for(r=1;r<p;r++) {
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speer = (rank+r)%p;
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rpeer = (rank-r+p)%p;
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rbuf = ((char *)recvbuf) + (displs[rpeer]*rcvext);
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res = NBC_Sched_recv(rbuf, false, recvcounts[rpeer], recvtype, rpeer, schedule);
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if (NBC_OK != res) { printf("Error in NBC_Sched_recv() (%i)\n", res); return res; }
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/* send to rank r - not from the sendbuf to optimize MPI_IN_PLACE */
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res = NBC_Sched_send(sbuf, false, recvcounts[0], recvtype, speer, schedule);
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if (NBC_OK != res) { printf("Error in NBC_Sched_send() (%i)\n", res); return res; }
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}
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res = NBC_Sched_commit(schedule);
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if (NBC_OK != res) { printf("Error in NBC_Sched_commit() (%i)\n", res); return res; }
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res = NBC_Start(handle, schedule);
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if (NBC_OK != res) { printf("Error in NBC_Start() (%i)\n", res); return res; }
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return NBC_OK;
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}
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