CCAKE

CCAKE is a relativistic viscous hydrodynamic code with 3 conserved charges (baryon number, strangeness, and electric charge) that uses Smoothed Particle Hydrodynamics. CCAKE can make state-of-the-art predictions for heavy-ion collisions. It uses the 4D lattice QCD equation of state with T, baryon, strangeness, and electric charge that is coupled to the PDG16+ particle list.

If you use this code in your research, please remember to cite us: arXiv:2405.09648.

1. Apptainer (Singularity) usage

It is recommended to use the apptainer (former singularity) to execute the code. You can find out instructions in here.

2. Compiling from source instructions

2.1. Dependencies

To compile ccake, you need to have the following dependencies installed:

• C++ compiler with support for C++17 (g++ > 7.2.0)
• CMake (>= 3.4)
• HDF5
• GSL

Dealing with missing dependencies: The easiest way is to install the missing dependencies using your package manager. For example, on Ubuntu, you can run sudo apt install cmake libhdf5-dev libgsl-dev cmake. If for some reason you you can`t or don't want to install the dependencies (e.g., you are on a cluster and don't have root access), you can use either compile the dependencies from source or use a virtual environment (recommended). HPC clusters may also offer them as loadable modules.

2.2. Compiling

The recommended way to compile is by sourcing the bootstrap.sh script. You can manually compile the project by following the steps below.

1. Create a build directory and enter it: mkdir build && cd build
2. Configure the build with cmake ..
3. Build with make -jN where N is the number of cores you want to use. For a personal computer, N=4 is a good choice.
4. Download the EoS with:

mkdir -p EoS/Houston && \
wget -O EoS/Houston/thermo.dat https://zenodo.org/record/6829115/files/thermo.dat?download=1 && \
wget -O EoS/Houston/thermo.h5 https://zenodo.org/record/6829115/files/thermo.h5?download=1

3. Usage

Make sure that in your working directory, a copy or a symlink of the folder EoS is present. Create an output directory and then run ccake as ccake path/to/input-file path/to/output-directory. For example, if you are in the project root directory and wants to run a Gubser test, you can use the command mkdir -p output && ./ccake input/Input_Parameters_Gubser_checks.inp output.

4. Reporting bugs and getting help

If you are facing some problem or found some bug, feel free to open an issue or create a pull request.

5. Debugging

If you are developing ccake, you might want to debug it. To do so, you need to compile it with debug symbols. Steps to do so are as follows:

1. Create a build directory and enter it: mkdir build && cd build as above
2. At the configure step, add the flag -DCMAKE_BUILD_TYPE=Debug to the cmake command. For example, cmake -DCMAKE_BUILD_TYPE=Debug ..
3. Build with make -jN as above

To debug, you can use gdb or lldb. For example, run gdb --args build/bin/ccake path/to/input-file. If it is your first time debugging, you might want to read the gdb tutorial.

VSCode users: You can use the C/C++ extension to debug ccake. Install it from the extensions tab. A launch configuration is already provided in the .vscode directory. You can set breakpoints by clicking on the left of the line number (a red dot will appear). Then, run the debugger by pressing F5. You may inspect the variables by hovering over them or in the left panel.

6. Generating doxygen documentation

To generate the doxygen documentation, you need to have doxygen installed. Then, in the project root directory, run doxygen Doxyfile. The documentation will be generated in the docs directory. Two formats for the documentation will be generated: html and latex. To view the html documentation, open the file docs/html/index.html in your browser. To view the latex documentation, you need to compile the latex files. To do so, run make in the docs/latex. The generated pdf will be in docs/latex/refman.pdf.