第05章 MPI并行程序设计

1、MPI并行程序设计教师：彭四伟教师：彭四伟MPICH2的下载和安装n官方下载地址：官方下载地址：n/research/projects/mpich2/downloads/index.php?s=downloadsn安装条件安装条件n.Net Frame 1.1/2.0nVisual C+ 2005 SP1 Redistributable Package (x86)n管理员权限管理员权限MPICH2服务（守护进程）nMPICH2的守护进程的守护进程smpdn服务的安装服务的安装nSmpd -installn服务的卸载服务的卸载nSmpd -removen

2、服务的开启服务的开启nSmpd -startn服务的停止服务的停止nSmpd -stopMPICH2的配置n设设置置工工作作账账号号MPICH2的配置n设设置置环环境境参参数数MPICH2编程环境设置n在编译器选项下设置在编译器选项下设置include路径路径n加入加入includen在编译器选项下设置在编译器选项下设置lib路径路径n加入加入libn在编译器选项下加入链接库在编译器选项下加入链接库nmpi.libMPICH2程序的布置和运行n程序的布署程序的布署n程序要求分布在各结点的相同路径中。程序要求分布在各结点的相同路径中。n通过通过mpiexec运行运行nmpiexec n 4 he

3、llonmpiexec hosts 4 pc1 pc2 pc3 pc4 hellonmpiexec hosts 2 pc1 2 pc2 3 hellonmpiexec localonly 4 helloMPI并行程序设计nMPI程序的一般模式程序的一般模式#include int main(int argc, char *argv) int size, rank; MPI_Init(&argc, &argv); /* initialize MPI */ MPI_Comm_size(MPI_COMM_WORLD, &size); MPI_Comm_rank(MPI_COM

4、M_WORLD, &rank); if (rank = 0) master(); else slave(); MPI_Finalize(); /* cleanup MPI */ return 0;#include int main(int argc, char *argv) int size, rank; MPI_Init(&argc, &argv); /* initialize MPI */ MPI_Comm_size(MPI_COMM_WORLD, &size); MPI_Comm_rank(MPI_COMM_WORLD, &rank); switc

5、h (rank) case 0: . case 1: . . default: . MPI_Finalize(); /* cleanup MPI */ return 0;#include “mpi.h”int foo(int i) . int main( int argc, char *argv )int i, tmp, sum=0, group_size, my_rank, N; MPI_Status status;MPI_Init( &argc, &argv );MPI_Comm_size( MPI_COMM_WORLD, &group_size );MPI_Com

6、m_rank( MPI_COMM_WORLD, &my_rank );if (my_rank=0)printf( “N=“ ); scanf( “%d”, &N );for (i=1; igroup_size; i+)S1:MPI_Send( &N, 1, MPI_INT, i, i, MPI_COMM_WORLD; );for (i=my_rank; iN; i+=group_size)sum += foo(i);for (i=1; igroup_size; i+)S2:MPI_Recv( &tmp, 1, MPI_INT, i, i, MPI_COMM_WO

7、RLD, &status );sum += tmp;printf (“nThe result=%dn”, sum );elseS3:MPI_Recv( &N, 1, MPI_INT, 0, my_rank, MPI_COMM_WORLD, &status );for (i=my_rank; iN; i+=group_size)sum += foo(i);S4:MPI_Send( &sum, 1, MPI_INT, 0, i, MPI_COMM_WORLD );MPI_Finalize();return 0;10)(niifoo#include #include

8、#define N 1000000main()double sum=0, local, mypi, pi, dx;long i, taskid, numtask;A:dx = 1.0/N;MPI_Init( &argc, &argv );MPI_Comm_rank( MPI_COMM_WORLD, &taskid );MPI_COMM_size( MPI_COMM_WORLD, &numtask );B:for (i=taskid; iN; i+=numtask)P:local = (i+0.5)*dx;Q:sum += 4.0/(1.0+local*local

9、);mypi = sum*dx;C:MPI_Reduce( &mypi, &pi, 1, MPI_DOUBLE, MPI_SUM, 0, MPI_COMM_WORLD );D:if (taskid=0) printf( “pi is %lfn”, pi );MPI_Finalize();4)(1110102xarctgdxx#include #include using namespace std;int main(int argc, char *argv)int size, rank, x=-1;MPI_Status status;MPI_Init(&argc, &a

10、mp;argv);MPI_Comm_size(MPI_COMM_WORLD, &size);MPI_Comm_rank(MPI_COMM_WORLD, &rank);while (x!=0)if (rank=0)cout x;cout Read x from rank rank endl;elseMPI_Recv(&x, 1, MPI_INT, rank-1, 0, MPI_COMM_WORLD, &status);cout Recevied x from rank rank-1 endl;if (ranksize-1)MPI_Send(&x, 1, M

11、PI_INT, rank+1, 0, MPI_COMM_WORLD);cout Send x to rank rank+1 endl;MPI_Barrier(MPI_COMM_WORLD);MPI_Finalize();return 0;MPI的通信模式分类分类发送发送接收接收阻塞通信MPI_SendMPI_RecvMPI_IrecvMPI_BsendMPI_RsendMPI_Ssend非阻塞通信MPI_IsendMPI_IbsendMPI_IrsendMPI_IssendB:Buffer R:Ready S:SynchonousI:Immediately#include #include u

12、sing namespace std;int main(int argc, char *argv) int rank; MPI_Init(&argc, &argv); MPI_Comm_rank(MPI_COMM_WORLD, &rank); char msg17, msg317; double msg22; int s1, s2, s3; MPI_Status status; MPI_Pack_size(7, MPI_CHAR, MPI_COMM_WORLD, &s1); MPI_Pack_size(2, MPI_DOUBLE, MPI_COMM_WORLD,

13、 &s2); MPI_Pack_size(17, MPI_CHAR, MPI_COMM_WORLD, &s3); int bufsize = 3*MPI_BSEND_OVERHEAD + s1 + s2 + s3; char *buf = new charbufsize; MPI_Buffer_attach(buf, bufsize); if (rank = 0) MPI_Bsend(msg1, 7, MPI_CHAR, 1, 0, MPI_COMM_WORLD); MPI_Bsend(msg2, 2, MPI_DOUBLE, 1, 0, MPI_COMM_WORLD); MP

14、I_Bsend(msg3, 17, MPI_CHAR, 1, 0, MPI_COMM_WORLD); else if (rank = 1) MPI_Recv(msg1, 7, MPI_CHAR, 0, 0, MPI_COMM_WORLD, &status); MPI_Recv(msg2, 2, MPI_DOUBLE, 0, 0, MPI_COMM_WORLD, &status); MPI_Recv(msg3, 17, MPI_CHAR, 0, 0, MPI_COMM_WORLD, &status); MPI_Buffer_detach(&buf, &bu

15、fsize); delete buf; MPI_Finalize(); return 0;缓冲模式if (rank = 0) MPI_Recv(buffer, n, MPI_INT, 1, 1, MPI_COMM_WORLD, &status); MPI_Barrier(MPI_COMM_WORLD);else if (rank = 1) MPI_Barrier(MPI_COMM_WORLD); MPI_Rsend(buffer, n, MPI_INT, 0, 1, MPI_COMM_WORLD);就绪模式MPI中的通信安全问题n例程：例程：rank传递传递01230123#inclu

16、de main(int argc, char *argv ) int rank, size, x; MPI_Status status; MPI_Init( &argc, &argv ); MPI_Comm_rank( MPI_COMM_WORLD, &rank ); MPI_Comm_size( MPI_COMM_WORLD, &size ); MPI_Send(&rank,1,MPI_INT, (rank+1)%size, 1,MPI_COMM_WORLD); MPI_Recv(&x, 1, MPI_INT, (rank+size-1)%si

17、ze, 1, MPI_COMM_WORLD, &status); MPI_Finalize(); return 0;MPI中的通信安全问题MPI中的通信安全问题MPI中的通信安全问题MPI中的通信安全问题n例程：避免死锁的例程：避免死锁的rank传递传递#include main(int argc, char *argv ) . if (rank%2=0) MPI_Send(&rank,1,MPI_INT, (rank+1)%size, 1,MPI_COMM_WORLD); MPI_Recv(&x, 1, MPI_INT, (rank+size-1)%size, 1,

18、MPI_COMM_WORLD, &status); else MPI_Recv(&x, 1, MPI_INT, (rank+size-1)%size, 1, MPI_COMM_WORLD, &status); MPI_Send(&rank,1,MPI_INT, (rank+1)%size, 1,MPI_COMM_WORLD); MPI_Finalize(); return 0;MPI中的通信安全问题n捆绑接收发送：捆绑接收发送：MPI_Sendrecvnint MPI_Sendrecv(void *sendbuf, int sendcount, MPI_Data

19、type sendtype, int dest, int sendtag, void *recvbuf, int recvcount, MPI_Datatype recvtype, int source, int recvtag, MPI_Comm comm, MPI_Status *status)MPI的数据类型nMPI的数据类型是用于保障消息传递过程中的数据类型是用于保障消息传递过程中的数据能够被正确的解释，而不是为了用的数据能够被正确的解释，而不是为了用于计算。于计算。n消息传递中的类型匹配消息传递中的类型匹配n有类型数据的通信，发送方和接收方均使用相同的数据类型有类型数据的通信，发送方和接收方均使用相同的