Machine issues & portability
On this page we provide links to compiler-specific information.
GNU Fortran compiler
The GNU Fortran compiler is our recommended open-source compiler for GEOS-Chem. Because gfortran is open-source, it can be used on a wide variety of platforms, including the [Amazon Web Services cloud computing platform]. GEOS-Chem is now compatible with gfortran 4.4.7 and higher. As of December 2018, the current version is gfortran 8.2.0.
We are currently experimenting with the use of Linux containers (such as Singularity) in order to provide a consistent computational environment (i.e. with the same libraries and compiler verisons) that can be used across multiple platforms. For more information, please see: this tutorial by Jiawei Zhuang.
A note on performance: When GEOS-Chem is compiled with the GNU Fortran compiler, it runs slower than when compiled with the proprietary Intel Fortran compiler, especially when running on Intel CPUs. This is because GNU Fortran, as an open-source software product, lacks the ability to take advantage of some proprietary Intel CPU optimizations. If performance matters to you, and your institution has an Intel site license, then you might want to consider using the Intel Fortran Compiler instead.
Intel Fortran Compiler
The Intel Fortran compiler is our recommended proprietary compiler for GEOS-Chem. Although Intel Fortran requires the purchase of an expensive site license, you will always obtain the best GEOS-Chem performance when compiling with Intel Fortran and running on a system that has Intel CPUs.
NOTE: If your computer system does not have the Intel Fortran Compiler available, or if you are running on a cloud-computing platform such as Amazon Web Services EC2, then you should use the free and open-source GNU Fortran compiler instead.