Writing MPI programs I

First program with MPI (hello.c). Write the following code and study the response.

$\includegraphics[scale=1]{figures/1-1}$

```
#include "mpi.h"
```
provides basic MPI definitions and types.
```
MPI_Init
```
starts MPI.
```
MPI_Finalize
```
exits MPI.
Note that all non-MPI routines are local; thus the
```
printf
```
run on each process.

mpicc -o hello hello.c
mpirun -np 2 hello

mpirun is not part of the standard, but some version of it is common with several MPI implementations. The version shown here is for the MPICH implementation of MPI.

Cem Ozdogan 2010-12-27