Compiling Programs

C Programs 

A2C2 has a number of different C compiliers made by Intel and GCC. There are advantages and drawbacks to each, but, in general, we recommend using the Intel compilers because they are much better optimized for our systems.

To compile a C-program using the Intel compilers:

[saguaro1:~]$ module load intel
[saguaro1:~]$ icc source.c -o output_filename

Where ‘source.c’ contains your source code. For example:

#include <stdio.h>

int main(int argc, char **argv) {

  printf(“Hello, world!”);

  return(0);

}

Fortran Programs

A2C2 has a number of different Fortran compilers made by Intel and Gnu. There are advantages and drawbacks to each, but, in general, we recommend using the Intel compilers because they are much better optimized for our systems.

To compile a Fortran-program using the Intel compilers:

[saguaro1:~]$ module load intel
[saguaro1:~]$ ifort source.f90 -o output_filename

Where ‘source.c’ contains your source code. For example:

protram MyProgram
implicit none

print *, “Hello World!”

end program MyProgram

You can then run your program with:

[saguaro1:~]$ ./output_filename
Hello World!

MPI Programs

MPI (Message Passing Interface) is the de facto standard for writing high speed parallel programs. A simple MPI program in C++ might look something like this:

#include <iostream>

#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);

  int *buffer = new int[1];

  if (rank == 0) {

    buffer[0] = 42;

  }

  std::cout << “hello from “ << rank << “ of “ << size << “ my buffer is: “ << buffer[0] << “ before bcast” << std::endl;

  MPI_Bcast(buffer, 1, MPI_INTEGER, 0, MPI_COMM_WORLD);

  std::cout << “hello from “ << rank << “ of “ << size << “ my buffer is: “ << buffer[0] << “ after bcast” << std::endl;

  delete [] buffer;

  MPI_Finalize();

}