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Дата изменения: Sat Oct 17 01:50:30 2015
Дата индексирования: Sat Apr 9 23:31:34 2016
Кодировка:

2015 2016 . . : .., . . .

2 6 2015 .

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. MPI. .

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MPI: A Message-Passing Interface Standard

http://www.mpi-forum.org/docs/

(http://parallel.ru/docs/Parallel/mpi1.1/mpi-report.html) .. MPI: . -.: - , 2004.-71 . .., .. .- , : https://computing.llnl.gov/tutorials/mpi, www.parallel.ru, intuit.ru, www.mpi-forum.org, www.open-mpi.org, www.openmp.org http://www.mcs.anl.gov/research/projects/mpi/www/www3

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, (OpenMP, ...)

- "Message Passing" - Message Passing : MPI ("Message Passing Interface") PVM ("Parallel Virtual Machine") Shmem, MPT ( Cray)
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#include #define N 1024 int main(int argc, char *argv[]) { double sum; double a[N], b[N]; int status, i, n =N; for (i=0; i " ", 2

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MPI
#include #include #define N 1024 int main(int argc, char *argv[]) { double sum; double dot_prod; double a[N], b[N]; int i, n =N; int size, myrank; n= n/ size; for (i=myrank*n; i
MPI_Init(&argc, &argv); MPI_Comm_rank(MPI_COMM_WORLD, If ( !myrank) &myrank); printf ("Dot product =%f\n", dot_prod); MPI_Comm_size(MPI_COMM_WORLD, MPI_Finalize(); &size);

MPI_Reduce(& sum,& all_sum, 1, MPI_DOUBLE, MPI_SUM, 0, MPI_COMM_WORL

return 0; }

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MPI

MPI 1.1 Standard 92-94 MPI 2.0 - 95-97 MPI 2.1 - 2008 MPI 3.0 2012

http://www.mcs.anl.gov/mpi http://www.mpi-forum.org/docs/docs.html

http://www-unix.mcs.anl.gov/mpi/www/
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MPI

:

:

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MPI

MPICH LAM/MPI Mvapich OpenMPI Intel,IBM .
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MPI

, . MPI . :
.

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Message passing = +

Process 0

Data

?

Process 1

Data Data Data Data Data Data Data Data

Time

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MPI-
· SPMD Single Program Multiple Data · · .

:

Processor 0
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Processor
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2.12

MPI-

: mpirun np : : mpirun np 3 prog np ()
- , .

0

1

2

MPI- :

np rank [0 ... np-1]

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MPI

MPI . .
.
Process 0 Send(data) Receive(data) Process 1

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MPI

Process 0
Send(data) Receive(data)

Process 1

:

? ? ? ?
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. . . , .

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MPI

MPI , . MPI_COMM_WORLD: - MPI_Init : - MPI_COMM_SELF ()
-

MPI_COMM_NULL
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MPI

: (address, count, datatype), datatype :

, (, MPI_INT, MPI_DOUBLE_PRECISION) MPI

MPI , , , (int, float).
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MPI-
MPI datatype
MPI_CHAR MPI_SHORT MPI_INT MPI_LONG MPI_UNSIGNED_CHAR MPI_UNSIGNED_SHORT MPI_UNSIGNED MPI_UNSIGNED_LONG MPI_FLOAT MPI_DOUBLE

C datatype
signed char signed short int signed int signed long int unsigned char unsigned short int unsigned int unsigned long int float double

MPI_LONG_DOUBLE

long double
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MPI

MPI_Comm MPI_Status MPI_datatype

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. MPI_ANY_TAG. -MPI . MPI , MPI.

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C:

MPI helloworld.c

#include #include int main(int argc, char **argv){ MPI_Init(&argc, &argv); printf("Hello, MPI world\n"); MPI_Finalize(); return 0; }

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MPI-
C ( ): error = MPI_Xxxxx(parameter,...);
MPI_Xxxxx(paramet
er,...);

C++ (case sensitive):
error = MPI::Xxxxx(parameter,...); MPI::Xxxxx(parameter,...); . :

MPI_COMM_WORLD

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int MPI_Init(int *argc, char ***argv) , int MPI_Comm_size(MPI_Comm comm, int *size) int MPI_Comm_rank(MPI_Comm comm, int *rank) ( 0) int MPI_Finalize() int MPI_Abort (MPI_Comm_size(MPI_Comm comm, int*errorcode)

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MPI

MPI_Init , C: int MPI_Init(int *argc, char ***argv)

http://www.mcs.anl.gov/research/projects/mpi/www/www3/MPI_Init.html

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MPI-
MPI_SUCCESS

I int error; ...... error = MPI_Init(&argc, &argv)); If (error != MPI_SUCCESS) { fprintf (stderr, " MPI_Init error \n"); return 1; }

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MPI_Comm_size

int MPI_Comm_size(MPI_Comm comm, int *size)

http://www-unix.mcs.anl.gov/mpi/www/www3/MPI_Comm_size.html

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MPI_Comm_rank (process rank)

Process ID 0 (n-1), n int MPI_Comm_rank(MPI_Comm comm, int *rank)

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MPI-
MPI C:

int MPI_Finalize() int MPI_Abort (MPI_Comm_size(MPI_Comm comm, int*errorcode)

- MPI_Finalize, .
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Hello, MPI world! (2)
#include #include "mpi.h" int main(int argc, char **argv){ int rank, size; MPI_Init(&argc, &argv); MPI_Comm_rank(MPI_COMM_WORLD, &rank); MPI_Comm_size(MPI_COMM_WORLD, &size); printf("Hello, MPI world! I am %d of %d\n",rank,size); MPI_Finalize(); return 0; }
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MPI-

mpicc o <_> <>.c <> : mpicc o hw helloworld.c mpirun np 128 hw

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MPI-

mpicc o hw helloworld.c mpisubmit n 128 hw mpisubmit -help

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mpisubmit -help

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hello_world

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«-»

,
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«-»

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MPI «-»

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«»
1 4

communicator 5 2 destination 3 0 source

-(Source process) - (Destination process ) - -
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"" , , , , .. Send: , , Receive: , ,

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MPI () Send
: MPI_SEND (buf, count, datatype, dest, tag, comm)

(start, count, datatype).

(dest) (rank) (comm) . .
MPI_Send(buf, count, datatype, dest, tag, comm)
Address of Datatype of Message tag send buffer each item Number of items Rank of destination Communicator to send process
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MPI () Receive
MPI_RECV(buf, count, datatype, source, tag, comm, status)

, source tag source MPI_ANY_SOURCE. comm

status

MPI_Recv(buf, count, datatype, src, tag, comm, status)
Address of Datatype of receive buffer each item Maximum number Rank of source Communicator of items to receive process
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Status Message tag after operation

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MPI_Send
int MPI_Send(void *buf,int count, MPI_Datatype datatype,int dest, int tag, MPI_Comm comm)
buf count Datatype dest tag comm MPI datatype rank - , MPI-

: MPI_Send(data,500,MPI_FLOAT,6,33,MPI_COMM_WORLD)

http://www-unix.mcs.anl.gov/mpi/www/www3/MPI_Send.html

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MPI_Recv
int MPI_Recv(void *buf,int count, MPI_Datatype datatype,int source, int tag, MPI_Comm comm, MPI_Status *status )
buf count Datatype source tag comm status MPI datatype rank - , MPI-,

: MPI_Recv(data,500,MPI_FLOAT,6,33,MPI_COMM_WORLD,&stat)

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: MPI Send/Receive (1)
#include #include int main(int argc, char *argv[]){ int numtasks, rank, dest, source, rc, tag=1; char inmsg, outmsg='X'; MPI_Status Stat; MPI_Init (&argc,&argv); MPI_Comm_size (MPI_COMM_WORLD, &numtasks); MPI_Comm_rank (MPI_COMM_WORLD, &rank); if (rank == 0) { dest = 1; rc = MPI_Send (&outmsg, 1, MPI_CHAR, dest, tag, MPI_COMM_WORLD); printf("Rank0 sent: %c\n", outmsg); source = 1; rc = MPI_Recv (&inmsg, 1, MPI_CHAR, source, tag, MPI_COMM_WORLD, &Stat); }

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: MPI Send/Receive (2)
else if (rank == 1) { source = 0; rc = MPI_Recv (&inmsg, 1, MPI_CHAR, source, tag, MPI_COMM_WORLD, &Stat); printf("Rank1 received: %c\n", inmsg); dest = 0; rc = MPI_Send (&outmsg, 1, MPI_CHAR, dest, tag, MPI_COMM_WORLD); } MPI_Finalize(); }

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Wildcarding ()

MPI_ANY_SOURCE MPI_ANY_TAG
- status

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MPI_Recv status
: Source: status.MPI_SOURCE Tag: status.MPI_TAG Count: MPI_Get_count

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, MPI_Recv count

C:
int MPI_Get_count (MPI_Status *status, MPI_Datatype datatype, int *count)

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int recvd_tag, recvd_from, recvd_count; MPI_Status status; MPI_Recv (..., MPI_ANY_SOURCE, MPI_ANY_TAG, ..., &status ) recvd_tag = status.MPI_TAG; recvd_from = status.MPI_SOURCE; MPI_Get_count( &status, datatype, &recvd_count );

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«-»

rank rank -

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MPI_Probe
int MPI_Probe(int source, int tag, MPI_Comm comm, MPI_Status* status)
. MPI_Recv

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if (rank == 0) { // Send size of integers to process 1 MPI_Send(buf, size, MPI_INT, 1, 0, MPI_COMM_WORLD); printf("0 sent %d numbers to 1\n", size); } else if (rank == 1) { MPI_Status status; // Probe for an incoming message from process MPI_Probe (0, 0, MPI_COMM_WORLD, &status); MPI_Get_count (&status, MPI_INT, &size); int* number_buf = (int*)malloc(sizeof(int) * size); // Now receive the message with the allocated buffer MPI_Recv (number_buf, size, MPI_INT, 0, 0, MPI_COMM_WORLD, MPI_STATUS_IGNORE); printf("1 dynamically received %d numbers from 0.\n", number_amount); free(number_buf); }

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