GNUmake Build System (Legacy)

CMake is our primary build system. In this section, we describe our legacy build scripts - do not use them unless you used them before.

WarpX is built on AMReX, which also provides support for a Linux-centric set of build scripts implemented in GNUmake. Since we sometimes need to move fast and test highly experimental compilers and Unix derivates on core components of WarpX, this set of build scripts is used by some of our experienced developers.

Warning

On the long-term, these scripts do not scale to the full feature set of WarpX and its dependencies. Please see the CMake-based developer section instead.

This page describes the most basic build with GNUmake files and points to instructions for more advanced builds.

Downloading the source code

Clone the source codes of WarpX, and its dependencies AMReX and PICSAR into one single directory (e.g. warpx_directory):

mkdir warpx_directory
cd warpx_directory
git clone https://github.com/ECP-WarpX/WarpX.git
git clone https://github.com/ECP-WarpX/picsar.git
git clone https://github.com/ECP-WarpX/warpx-data.git
git clone https://github.com/AMReX-Codes/amrex.git

Note

The warpx-data repository is currently only needed for MCC cross-sections.

Basic compilation

WarpX requires a C/C++ compiler (e.g., GNU, LLVM or Intel) and an MPI implementation (e.g., OpenMPI or MPICH). Start a GNUmake build by cd-ing into the directory WarpX and type

make -j 4

This will generate an executable file in the Bin directory.

Compile-time vs. run-time options

WarpX has multiple compile-time and run-time options. The compilation options are set in the file GNUmakefile. The default options correspond to an optimized code for 3D geometry. The main compile-time options are:

  • DIM=3 or 2: Geometry of the simulation (note that running an executable compiled for 3D with a 2D input file will crash).

  • DEBUG=FALSE or TRUE: Compiling in DEBUG mode can help tremendously during code development.

  • USE_PSATD=FALSE or TRUE: Compile the Pseudo-Spectral Analytical Time Domain Maxwell solver. Requires an FFT library.

  • USE_RZ=FALSE or TRUE: Compile for 2D axisymmetric geometry.

  • COMP=gcc or intel: Compiler.

  • USE_MPI=TRUE or FALSE: Whether to compile with MPI support.

  • USE_OMP=TRUE or FALSE: Whether to compile with OpenMP support.

  • USE_GPU=TRUE or FALSE: Whether to compile for Nvidia GPUs (requires CUDA).

  • USE_OPENPMD=TRUE or FALSE: Whether to support openPMD for I/O (requires openPMD-api).

  • USE_LLG=TRUE or FALSE: Whether to compile with Landau-Lifshitz-Gilbert (LLG) model to compute magnetization.

  • MPI_THREAD_MULTIPLE=TRUE or FALSE: Whether to initialize MPI with thread multiple support. Required to use asynchronous IO with more than amrex.async_out_nfiles (by default, 64) MPI tasks. Please see ../visualization/visualization for more information.

  • MPI_THREAD_MULTIPLE=TRUE or FALSE: Whether to initialize MPI with thread multiple support. Required to use asynchronous IO with more than amrex.async_out_nfiles (by default, 64) MPI tasks. Please see data formats for more information.

  • PRECISION=FLOAT USE_SINGLE_PRECISION_PARTICLES=TRUE: Switch from default double precision to single precision (experimental).

For a description of these different options, see the corresponding page in the AMReX documentation.

Alternatively, instead of modifying the file GNUmakefile, you can directly pass the options in command line ; for instance:

make -j 4 USE_OMP=FALSE

In order to clean a previously compiled version (typically useful for troubleshooting, if you encounter unexpected compilation errors):

make realclean

before re-attempting compilation.