Installation

Building RAMSES-CPP is designed to be straightforward using modern CMake.

Prerequisites

To build RAMSES-CPP from source, ensure you have the following installed on your system:

• CMake (version 3.15 or higher)
• C++17 compliant compiler (e.g., GCC 9+, Clang 10+, Apple Clang)
• MPI (Message Passing Interface) (Optional, but recommended for parallel execution. e.g., OpenMPI, MPICH)

Building from Source

1. Clone the repository:

   git clone https://github.com/SinsuSquid/RAMSES_CPP.git
   cd RAMSES_CPP
   

2. Create a build directory and configure with CMake:

   mkdir build && cd build
   cmake ..
   

3. Compile the project:

   make -j$(nproc)
   

   This will generate the dimensional executables (e.g., ramses_1d, ramses_3d) and the reference verification tool verify_ref in the build/ directory.

CMake Configuration Options

You can customize the build using the following CMake flags:

• -DRAMSES_NDIM=[1|2|3]: Set the number of dimensions (default is 3).
• -DRAMSES_NENER=N: Set the number of non-thermal energy variables (default is 0).
• -DRAMSES_USE_MHD=[ON|OFF]: Enable or disable the Magnetohydrodynamics module (default is OFF).
• -DRAMSES_USE_MPI=[ON|OFF]: Force enable/disable MPI support (usually auto-detected).

Example: Building for 2D MHD

cmake .. -DRAMSES_NDIM=2 -DRAMSES_USE_MHD=ON
make -j

Parallel Support (MPI)

If an MPI implementation is installed and detected by CMake, the build system will automatically define RAMSES_USE_MPI. This enables the LoadBalancer class for distributed execution and compiles the code to run across multiple MPI ranks. If MPI is not found, the code safely falls back to a sequential build.