Purdue University

Compiling OpenMP Programs

All compilers installed on Anvil include OpenMP functionality for C, C++, and Fortran. An OpenMP program is a single process that takes advantage of a multi-core processor and its shared memory to achieve a form of parallel computing called multithreading. It distributes the work of a process over processor cores in a single compute node without the need for MPI communications.

INCLUDE 'omp_lib.h'

use omp_lib

use omp_lib

#include <omp.h>

#include <omp.h>

Sample programs illustrate task parallelism of OpenMP:

• omp_hello.f
• omp_hello.f90
• omp_hello.f95
• omp_hello.c
• omp_hello.cpp

A sample program illustrates loop-level (data) parallelism of OpenMP:

• omp_loop.c

To load a compiler, enter one of the following:

$ module load intel
$ module load gcc
$ module load aocc

$ ifort -qopenmp myprogram.f -o myprogram

$ gfortran -fopenmp myprogram.f -o myprogram

$ flang -fopenmp program.f -o program

$ ifort -qopenmp myprogram.f90 -o myprogram

$ gfortran -fopenmp myprogram.f90 -o myprogram

$ flang -fopenmp program.f90 -o program

$ ifort -qopenmp myprogram.f90 -o myprogram

$ gfortran -fopenmp myprogram.f90 -o myprogram

$ flang -fopenmp program.f90 -o program

$ icc -qopenmp myprogram.c -o myprogram

$ gcc -fopenmp myprogram.c -o myprogram

$ clang -fopenmp program.c -o program

$ icc -qopenmp myprogram.cpp -o myprogram

$ g++ -fopenmp myprogram.cpp -o myprogram

$ clang++ -fopenmp program.cpp -o program

The Intel, GNU and AOCC compilers will not output anything for a successful compilation. Also, the Intel compiler does not recognize the suffix ".f95". You may use ".f90" to stand for any Fortran code regardless of version as it is a free-formatted form.

Here is some more documentation from other sources on OpenMP:

• OpenMP Home
• Community of OpenMP Users
• Intel OpenMP
• GCC OpenMP