A flexible c++ code for physical particle simulations. GraSPH2 uses the CUDA API to do most of it's calculations on a GPU, achieving speeds much higher than traditional CPU simulations. Developed for applications in astrophysics, GraSPH2 can be used to perform pure n-body simulations. It's main selling point however is the integration of SPH which allows GraSPH2 to simulate fluids as well as deformable solid body and granular materials.
Simulations can also be run either in "precision mode" or in real time, featuring an interactive openGL visualization.
To use GraSPH you have to compile it yourself from sources.
To compile GraSPH2 yourself you will need:
- CUDA 9
- gcc 6.4
- cmake 3.8 or higher
- mpUtils v0.11.1
If you want to use real time simulation / visualization you will additionally need:
- glm
- glfw3
- glew
- graphics drivers supporting some OpenGL version (preferably 4.5+)
- make sure mpUtils was compiled with graphics features enabled
After installing the third party dependencies, go to the github page of mpUtils and follow the installation instructions there.
If you happen to run on the "Cobra" HPC system at MPCDF, there is a script scripts/loadCobraModules.sh that will load all dependencies
to run and install mpUtils and GraSPH2. Consider adding /path/to/this/scrip/loadCobraModules.sh to your bashrc.
After that, use the following commands to download and install the newest version of GraSPH2.
git clone https://github.com/hschwane/GraSPH2.git
cd GraSPH2
mkdir build
cd bin
cmake ..
make -j 8 #<cahnge 8 to the number of procesors you want to use for compiling>
After this the GraSPH2 executable can be found in th GraSPH2/build folder.
If mpUtils was installed in a non standard path remember to set the
CMAKE_PREFIX_PATH or mpUtills_DIR cmake variable.
The following additional cmake options are available:
OPENGL_FRONTENDthis option will only be availible if openGL was found on your system during theinstallation of mpUtils. Turn this on to have your simulations drawn on screen in real time.FORCE_NEW_VERSIONif enabled a instead of using the version number of the git commit, the version is increased by one. This is mainly used during development and testing.USE_FAST_MATHenable unsafe math optimizations in device code. Better performance, but might impact accuracy.USE_DEBUG_LOGGINGcompile debug logging commands even in release builds.
To start a simulation just launch the executable file. Progress information will be written to the console regularly and the program will terminate once the set time limit is reached.
After launching the executable a window will open showing the initial conditions. You can load also load a tsv or hdf5 file by dragging it onto the window. Press "1" on your keyboard to start the simulation. You can pause it again at any time using the "2" key. The Camera can be moved using "W", "A", "S" and "D", like in a video game. To fly up and down use "Q" and "E". "+" and "-" can be used to change the cameras movement speed. Hold the left mouse button to look around. Use "R" to switch the camera rotation to a "trackball" style mode. In Trackball mode you can Zoom using your mouse wheel and pan by holding the middle mouse button. The console will display some timing information. Press "F" to switch between different color visualization modes. Keys "T" and "G" control the size of the rendered particles. Pressing "V" will show a UI-Window containing display settings for the visualization
GraSPH2 makes heavy use of templates to be as efficient as possible.
Therefore most of the simulation settings need to be done at compile time.
Options can be found in the folder src/settings and are split among several files.
Initial conditions can be load from a file or be generated at the start of the simulation.
See src/settings/settings.h for all options. You can also extend the main() function in
main.cu to generate different initial conditions.
In the file src/settings/outputSettings.h you can name a folder where simulation results are written.
For each step of the simulation a new file is generated.
You can use .tsv or hdf5 files if libhdf5 is availibe on your system.
GraSPH2 is a quite young project and actively developed only by myself and only part time. If you have any issues using the code, find any bugs or are in need of some special feature not availible yet don't hesitate to contact me via mail or create a ticket on github.
You may also try to extend / modify the code yourself if you know any c++. CUDA knowledge is only required if you want to modify the deeper infrastructure of the code, not for extending the physical models.