Compilers

Compiling MPI Applications

Intel MPI

The following table shows available Intel MPI compiler commands, the underlying Intel and GNU compilers, and ways to override underlying compilers with environment variables or command line options:

Language	Wrapper script	Default compiler	Environment variable	Command line
C	`mpiicc`	`icc`	I_MPI_CC	`-cc`=<compiler>
C	`mpigcc`	`gcc`	I_MPI_CC	`-cc`=<compiler>
C++	`mpiicpc`	`icpc`	I_MPI_CXX	`-cxx`=<compiler>
C++	`mpigxx`	`g++`	I_MPI_CXX	`-cxx`=<compiler>
Fortran	`mpiifort`	`ifort`	I_MPI_FC	`-fc`=<compiler>
Fortran	`mpifc`	`gfortran`	I_MPI_FC	`-fc`=<compiler>

Specify option -show with one of the compiler wrapper scripts to see the underlying compiler together with compiler options, link flags and libraries.

The Intel MPI toolchain is loaded by using module load:

module load intel/2017a

Please see also Running MPI Applications.

Open MPI

The Open MPI compiler wrapper scripts listed in the table below add in all relevant compiler and link flags, and the invoke the underlying compiler, i.e. the compiler the Open MPI installation was built with.

Language	Wrapper script	Environment variable
C	`mpicc`	OMPI_CC
C++	`mpiCC, mpicxx, mpic++`	OMPI_CXX
Fortran	`mpifort`	OMPI_FC

It is possible to change the underlying compiler invoked when calling the compiler wrappers using the environment variables listed in the table. Use the option -showme to see the underlying compiler, the compile and link flags, and the libraries that are linked.