BuildingCMake.rst

Building MFiX-Exa with CMake

CMake build is a two-step process. First cmake is invoked to create configuration files and makefiles in a chosen directory (builddir). Next, the actual build is performed by invoking make from within builddir. The CMake build process is summarized as follows:

mkdir /path/to/builddir
cd    /path/to/builddir
cmake [options] -DCMAKE_BUILD_TYPE=[Debug|Release|RelWithDebInfo|MinSizeRel] /path/to/mfix
make

In the above snippet, [options] indicates one or more options for the customization of the build, as described later in this section. If the option CMAKE_BUILD_TYPE is omitted, CMAKE_BUILD_TYPE=Release is assumed.

There are two modes to build MFiX-Exa with cmake:

o STANDALONE: MFiX-Exa source code is built separately and linked to an existing AMReX installation. This is ideal for continuous integration severs (CI) and regression testing applications. AMReX library version and configuration options must meet MFiX-Exa requirements.

o SUPERBUILD (recommended): AMReX is downloaded and built as part of the MFiX-Exa build process. This method is strongly encouraged as it ensures that the configuration options for MFiX-Exa and AMReX are consistent.

STANDALONE instructions

Build AMReX Library

Clone AMReX from the official Git repository and checkout the development branch:

> git clone https://github.com/AMReX-Codes/amrex.git
> cd amrex
> git checkout development

Next, configure, build and install AMReX as follows:

> mkdir build
> cd build
> cmake -DCMAKE_BUILD_TYPE=[Debug|Release|RelWithDebInfo|MinSizeRel] -DENABLE_PARTICLES=yes -DENABLE_AMRDATA=yes -DENABLE_EB=yes [other amrex options] -DCMAKE_INSTALL_PREFIX:PATH=/absolute/path/to/installdir ..
> make install

The options ENABLE_PARTICLES=yes, ENABLE_AMRDATA=yes, and ENABLE_EB=yes are required by MFiX-Exa. [other amrex options] in the snippet above refers to any other AMReX configuration option in addition to the required ones. Please refer to the AMReX user guide for more details on building AMReX with CMake.

Building MFiX-Exa

Clone and build MFiX-Exa:

> git clone http://mfix.netl.doe.gov/gitlab/exa/mfix.git
> mkdir build
> cd build
> cmake -DCMAKE_BUILD_TYPE=[Debug|Release|RelWithDebInfo|MinSizeRel] [mfix options] -DAMReX_ROOT=/absolute/path/to/amrex/installdir ..
> make -j

Passing -DAMReX_ROOT=/absolute/path/to/amrex/installdir instructs CMake to search /absolute/path/to/amrex/installdir before searching system paths for an available AMReX installation. AMReX_ROOT can also be set as an environmental variable instead of passing it as a command line option.

[mfix options] indicates any of the configuration option listed in the table below.

Option name	Description	Possible values	Default value
CMAKE_Fortran_FLAGS	User-defined Fortran flags	valid Fortran compiler flags	None
CMAKE_CXX_FLAGS	User-defined C++ flags	valid C++ compiler flags	None
CMAKE_CUDA_FLAGS	User-defined CUDA flags	valid CUDA compiler flags	None
ENABLE_MPI	Enable build with MPI	no/yes	yes
ENABLE_OMP	Enable build with OpenMP	no/yes	no
ENABLE_CUDA	Enable build with CUDA	no/yes	no
ENABLE_HYPRE	Enable HYPRE support	no/yes	no
ENABLE_FPE	Build with Floating-Point Exceptions checks	no/yes	no

SUPERBUILD Instructions (recommended)

If no AMReX installation is found on the system, or if one is found but does not meet MFiX-Exa requirements, MFiX-Exa CMake falls back to SUPERBUILD mode. When building in SUPERBUILD mode, the AMReX git repo is checked out via a git submodule before AMReX CMake build system is included into MFiX-Exa CMake infrastructure. Consequently, MFiX-Exa CMake inherents AMReX's CMake targets and configuration options, that is, MFiX-Exa and AMReX are configured and built as a single entity.

Assuming no valid AMReX installation is present on the target system, and AMReX_ROOT is not set in the environment, the following code will build MFiX-Exa in SUPERBUILD mode:

> git clone http://mfix.netl.doe.gov/gitlab/exa/mfix.git
> cd mfix
> mkdir build
> cd build
> cmake [amrex options] -DCMAKE_BUILD_TYPE=[Debug|Release|RelWithDebInfo|MinSizeRel] ..
> make -j

[amrex options] is a list of any of the AMReX configuration options listed in the AMReX user guide

Few more notes on building MFiX-Exa

The system defaults compilers can be overwritten as follows:

> cmake -DCMAKE_CXX_COMPILER=<c++-compiler> -DCMAKE_Fortran_COMPILER=<f90-compiler> [options]  ..

When building on a platform that uses the module utility, use either the above command (with full path to the compilers) or the following:

> cmake -DCMAKE_CXX_COMPILER=CC -DCMAKE_Fortran_COMPILER=ftn [options] ..

MFiX-Exa uses the same compiler flags used to build AMReX, unless CMAKE_Fortran_FLAGS/CMAKE_CXX_FLAGS is explicitly provided, or the environmental variables FFLAGS/CXXFLAGS are set.