MPI-Hello World. Timothy H. Kaiser, PH.D.

Transcription

1 MPI-Hello World Timothy H. Kaiser, PH.D. 1

2 Calls we will Use MPI_INIT( ierr ) MPI_Get_Processor_name(myname,resultlen,ierr) MPI_FINALIZE(ierr) MPI_COMM_RANK( MPI_COMM_WORLD, myid, ierr ) MPI_COMM_SIZE( MPI_COMM_WORLD, numprocs, ierr ) 2

3 Starting Point program hello! use mpi!! include mpif.h! character (len=mpi_max_processor_name):: name! call MPI_INIT( ierr )! call MPI_COMM_RANK( MPI_COMM_WORLD, myid, ierr )! call MPI_COMM_SIZE( MPI_COMM_WORLD, numprocs, ierr )! call MPI_Get_processor_name(name,nlen,ierr)! write(*,'("fort says Hello from",i4," on ",a)')myid,trim(name)!! write (*,*) "Numprocs is ",numprocs! call MPI_FINALIZE(ierr)! stop! end 3

4 Add MPI include files program hello! use mpi!! include mpif.h! character (len=mpi_max_processor_name):: name! call MPI_INIT( ierr )! call MPI_COMM_RANK( MPI_COMM_WORLD, myid, ierr )! call MPI_COMM_SIZE( MPI_COMM_WORLD, numprocs, ierr )! call MPI_Get_processor_name(name,nlen,ierr)! write(*,'("fort says Hello from",i4," on ",a)')myid,trim(name)!! write (*,*) "Numprocs is ",numprocs! call MPI_FINALIZE(ierr)! stop! end 4

5 Define Variables program hello! use mpi!! include mpif.h! character (len=mpi_max_processor_name):: name! integer ierr,myid,numprocs,nlen! call MPI_INIT( ierr )! call MPI_COMM_RANK( MPI_COMM_WORLD, myid, ierr )! call MPI_COMM_SIZE( MPI_COMM_WORLD, numprocs, ierr )! call MPI_Get_processor_name(name,nlen,ierr)! write(*,'("fort says Hello from",i4," on ",a)')myid,trim(name)!! write (*,*) "Numprocs is ",numprocs! call MPI_FINALIZE(ierr)! stop! end 5

6 Start/Terminate MPI program hello! use mpi!! include mpif.h! character (len=mpi_max_processor_name):: name! integer ierr,myid,numprocs,nlen! call MPI_INIT( ierr )! call MPI_COMM_RANK( MPI_COMM_WORLD, myid, ierr )! call MPI_COMM_SIZE( MPI_COMM_WORLD, numprocs, ierr )! call MPI_Get_processor_name(name,nlen,ierr)! write(*,'("fort says Hello from",i4," on ",a)')myid,trim(name)!! write (*,*) "Numprocs is ",numprocs! call MPI_FINALIZE(ierr)! stop! end 6

7 Get MPI task Information program hello! use mpi!! include mpif.h! character (len=mpi_max_processor_name):: name! integer ierr,myid,numprocs,nlen! call MPI_INIT( ierr )! call MPI_COMM_RANK( MPI_COMM_WORLD, myid, ierr )! call MPI_COMM_SIZE( MPI_COMM_WORLD, numprocs, ierr )! call MPI_Get_processor_name(name,nlen,ierr)! write(*,'("fort says Hello from",i4," on ",a)')myid,trim(name)! write (*,*) "Numprocs is ",numprocs! call MPI_FINALIZE(ierr)! stop! end 7

8 Write out Hello numprocs times) program hello! use mpi!! include mpif.h! character (len=mpi_max_processor_name):: name! integer ierr,myid,numprocs,nlen! call MPI_INIT( ierr )! call MPI_COMM_RANK( MPI_COMM_WORLD, myid, ierr )! call MPI_COMM_SIZE( MPI_COMM_WORLD, numprocs, ierr )! call MPI_Get_processor_name(name,nlen,ierr)! write(*,'("fort says Hello from",i4," on ",a)')myid,trim(name)! write (*,*) "Numprocs is ",numprocs! call MPI_FINALIZE(ierr)! stop! end 8

9 C version #include <stdio.h>! #include <stdlib.h>! #include <mpi.h>! #include <math.h>!! /************************************************************! This is a simple hello world program. Each processor prints out! it's rank and the size of the current MPI run (Total number of! processors).! ************************************************************/! int main(int argc,char **argv)! {! int myid, numprocs;! int resultlen;! char myname[mpi_max_processor_name];! MPI_Init(&argc,&argv);! MPI_Comm_size(MPI_COMM_WORLD,&numprocs);! MPI_Comm_rank(MPI_COMM_WORLD,&myid);! MPI_Get_processor_name(myname,&resultlen);! printf("c says Hello from %4d on %s\n",myid,myname);! printf("numprocs is %d\n",numprocs);! MPI_Finalize();!! } 9

10 Compile Lines Blue Gene mpixlc_r hello.c -o hello.x mpixlf90_r hello.f90 -o hello.x Most other platforms mpicc hello.c -o hello.x mpif90 hello.f90 -o hello.x 10

11 Slurm Run Script #!/bin/bash -x #SBATCH --job-name="hybrid" #comment = glorified hello world" #SBATCH --nodes=2 #SBATCH --ntasks-per-node=8 #SBATCH --ntasks=16 #SBATCH --exclusive #SBATCH --time=10:00:00!! # Go to the directoy from which our job was launched cd $SLURM_SUBMIT_DIR! # run an application srun $SLURM_SUBMIT_DIR/hello.x To run it: sbatch myscript 11

12 Output ~]$ cat slurm-6644.out C says Hello from 5 on Task 5 of 16 (0,0,0,0,0,5) R00-M0-N00-J28 C says Hello from 11 on Task 11 of 16 (0,0,0,0,1,3) R00-M0-N00-J27 C says Hello from 7 on Task 7 of 16 (0,0,0,0,0,7) R00-M0-N00-J28 C says Hello from 13 on Task 13 of 16 (0,0,0,0,1,5) R00-M0-N00-J27 C says Hello from 6 on Task 6 of 16 (0,0,0,0,0,6) R00-M0-N00-J28 C says Hello from 10 on Task 10 of 16 (0,0,0,0,1,2) R00-M0-N00-J27 C says Hello from 2 on Task 2 of 16 (0,0,0,0,0,2) R00-M0-N00-J28 C says Hello from 15 on Task 15 of 16 (0,0,0,0,1,7) R00-M0-N00-J27 C says Hello from 1 on Task 1 of 16 (0,0,0,0,0,1) R00-M0-N00-J28 C says Hello from 8 on Task 8 of 16 (0,0,0,0,1,0) R00-M0-N00-J27 C says Hello from 12 on Task 12 of 16 (0,0,0,0,1,4) R00-M0-N00-J27 C says Hello from 0 on Task 0 of 16 (0,0,0,0,0,0) R00-M0-N00-J28 C says Hello from 9 on Task 9 of 16 (0,0,0,0,1,1) R00-M0-N00-J27 C says Hello from 4 on Task 4 of 16 (0,0,0,0,0,4) R00-M0-N00-J28 C says Hello from 3 on Task 3 of 16 (0,0,0,0,0,3) R00-M0-N00-J28 C says Hello from 14 on Task 14 of 16 (0,0,0,0,1,6) R00-M0-N00-J27 12

13 Every Site Should have A Cut/Paste guide for building and running applications Source code (hello world) Makefile script 13