MPI学习小结

MPI环境配置函数

MPI_Init(&argc, &argv)
MPI_Finalize()
MPI_Comm_size(comm, &size)
MPI_Comm_rank(comm, &rank)

MPI::Init(&argc, &argv);
MPI::COMM_WORLD.Get_rank();
MPI::COMM_WORLD.Get_size();
MPI::Finalize();

点对点通信

MPI_Send(buffer, count, type, dest, tag, comm)
描述数据内容(buffer, count, type)
接受进程dest
消息标签tag

MPI_Recv(buffer, count, type, source, tag, comm, status)
匹配的信息(匹配source和tag）
接受少于count的type
status包含更多信息

通配符
source:
MPI_ANY_SOURCE
tag:
MPI_ANY_TAG

点对点通信（非阻塞）

MPI_Isend(buffer, count, type, dest, tag, comm, request)
request为返回的非阻塞通信对象（句柄），用以查询非阻塞发送是否完成

MPI_Irecv(buffer, count, type, source, tag, comm, request)
request为返回的非阻塞通信对象（句柄），用以查询非阻塞接收是否完成

MPI_Wait(request, status)
MPI_Waitall(count, array_of_requests, array_of_statuses)

MPI数据类型

MPI集合通信

广播

MPI_Bcast(&buffer, count, datatype, root, comm)

归约

MPI_Reduce(&sendbuf, &recvbuf, count, datatype, op, dest, comm)

分散

MPI_Scatter(&sendbuf, sendcnt, sendtype, &recvbuf, recvcnt, recvtype, root, comm)

收集

MPI_Gather(&sendbuf, sendcnt, sendtype, &recvbuf, recvcnt, recvtype, root, comm)

其他MPI集合通信

MPI_Allgather(&sendbuf, sendcount, sendtype, &recvbuf, recvcount, recvtype, comm)
MPI_Allreduce(&sendbuf, &recvbuf, count, datatype, op, comm)
MPI_Alltoall(&sendbuf, sendcount, sendtype, &recvbuf, recvcount, recvtype, comm)
MPI_Barrier(comm)

MPI通信域和组

MPI_Comm_group(Comm, &Group)
MPI_Group_incl(Group, size, ranks[], &NewGroup)
MPI_Comm_create(Comm, NewGroup, &NewComm)

MPI-IO

MPI_File_open(MPI_Comm comm, char *filename, int amode, MPI_Info info, MPI_File *fh)
MPI_File_close(MPI_File *fh)
MPI_File_read(MPI_File fh, void *buf, int count, MPI_Datatype datatype, MPI_Status *status)
MPI_File_write(MPI_File fh, void *buf, int count, MPI_Datatype datatype, MPI_Status *status)
MPI_File_read_all(MPI_File fh, void *buf, int count, MPI_Datatype datatype, MPI_Status *status)
MPI_File_write_all(MPI_File fh, void *buf, int count, MPI_Datatype datatype, MPI_Status *status)
MPI_File_sync(MPI_File fh)
MPI_File_seek(MPI_File fh, MPI_Offset offset, int whence)
MPI_File_read_at(MPI_File fh, MPI_Offset offset, void *buf, int count, MPI_Datatype datatype, MPI_Status *status)

编译运行

如果是C程序，使用如下命令进行编译：

mpicc helloworld.c -o helloworld
如果是C++程序，使用如下命令进行编译：

mpicxx hellowprld.cpp -o helloworld
编译完成后，使用如下命令运行

mpirun -np 4 ./helloworld    
其中"-np"用来指定进程数