MUSIC is a 3+1D relativistic second-order viscous hydrodynamics for heavy ion collisions written in C++. A user manual for MUSIC is available here: https://webhome.phy.duke.edu/~jp401/old_music_manual/

New results computed with MUSIC may necessitate modifying certain parts of the code (the routines compute hadronic observables, transport coefficients, initial conditions, ...). To avoid any confusion about the physics behind MUSIC, we ask that publications containing results computed with MUSIC specify the initial conditions, equation of state, transport coefficients (first and second order), freeze-out criteria and other information necessary to reproduce the results.

The following papers should be cited when referring to MUSIC:

1. Schenke, S. Jeon, C. Gale. "3+1D hydrodynamic simulation of relativistic heavy-ion collisions" Phys.Rev.C 82, 014903 (2010) [arXiv:1004.1408]
2. Schenke, S. Jeon, C. Gale. "Elliptic and triangular flow in event-by-event (3+1)D viscous hydrodynamics” Phys.Rev.Lett. 106, 042301 (2011) [arXiv:1009.3244]
3. J.-F. Paquet, C. Shen, G. S. Denicol, M. Luzum, B. Schenke, S. Jeon, and C. Gale. "Production of photons in relativistic heavy-ion collisions” Phys. Rev. C 93, 044906 (2016) [arXiv:1509.06738]

If simulations include net baryon diffusion, please cite in addition,

• G. S. Denicol, C. Gale, S. Jeon, A. Monnai, B. Schenke, and C. Shen, "Net baryon diffusion in fluid dynamic simulations of relativistic heavy-ion collisions," Phys. Rev. C98, 034916 (2018) arXiv:1804.10557 [nucl-th]

The freeze-out surface at constant temperature or energy density is generated by Cornelius. When using this feature, please cite

• P. Huovinen and H. Petersen, "Particlization in hybrid models," Eur. Phys. J. A48, 171 (2012), arXiv:1206.3371 [nucl-th]

MUSIC users may need to modify various parts of the code. The GPL license allows for such modifications to be made and distributed (subject to restrictions that can be found in the license). Nevertheless, we ask and require that you state clearly any scientifically relevant modifications made to the code when you share this modified version of MUSIC. This is to avoid any misunderstanding about the physics behind the code.

Should you make changes to MUSIC that you believe would benefit from being shared with the wider community, please get in touch with the code's maintainers through the MUSIC website. Contributions will be considered whenever possible. While no promises can be made regarding the inclusion of these modifications in the main version of the code, they could be made available separately on the MUSIC website for other users' convenience. Bug fixes will be considered separately and will be applied promptly.

The MUSIC code can be compiled using standard cmake.

Alternatively, you can compile the MUSIC code using a makefile. In this way, please make sure the information about the openMP and the directory of the GSL library is correct in the src/GNUmakefile. Then one can compile the code by typing make.

An input file is required that contains the line EndOfData, preceded by a list of parameter names and values, one per line, with parameter names and values separated by a space or tab. If omitted, each parameter will be assigned a default value. Example input files can be found under the folder example_inputfiles/.

The list of possible parameters and default values, along with a brief description, can be found in utilities/music_parameters_dict.py.

To run hydro simulation, one can start by running the python script generate_music_inputfile.py (can be found in utilites folder) to generate input files and job running script. The job script can run under bash and qsub systems. For some help information about generate_music_inputfile.py, one can simply type:

generate_music_inputfile.py -h

MUSIC uses openMP for parallelization. For example, to run on two processors and use the sample input file, type:

export OMP_NUM_THREADS=2
./MUSIChydro input_example

Once the prerequisites are installed, you can build the package using:

make -j 10 #Adjust 10 to the number of cores available.

The result will be an executable named MUSIChydro.