This program calculates the Equations of State for quarks according the SU(2) version of the extended NJL model (eNJL). As references we use (Pais 2016).

1. (Pais 2016) Helena Pais, Débora P. Menezes, and Constança Providência, Neutron stars: From the inner crust to the core with the (extended) Nambu–Jona-Lasinio model, Phys. Rev. C 93, 065805 – Published 8 June 2016, DOI

The latest version of this code is available at github.com/cgraeff/quarks_EOS. A copy can be easily obtained if your system have git installed, just issue the following command in a terminal:

  git clone https://github.com/cgraeff/quarks_EOS.git

To build and run this code make, a C compiler (default is gcc) and the GSL (GNU Scientific Library) must be installed on the system. For plotting graphics, gnuplot is also required.

On Linux the installation varies from distribution to distribution, but generally there are two packages, one for regular use and one for developing. The development version is the one needed for compilation of this code.

On OSX, the location of GSL headers and libraries is assumed to be /usr/local/include and /usr/local/lib. This is the default if GSL is installed from Homebrew. To change, edit the variables at src/Makefile.

Basic build (generate heosexecutable):

• Build with make in the top dir;

Running:

• When executed, heos will calculate the equations of state with the default parameterization;
• The following options are available:
• -p par: uses par parameters set;
• -t val: uses val for temperature value. Must be a double value;
• -y val: uses val for proton fraction. Must be a double value.
• -l: list available parameters set;
• -q: quiet (supress information written to standard out);
• -d: write results using a dir structure;
• -a: run tests. Automatically sets -d;
• -s: run with charge neutrality and beta equilibrium;
• -u: prints usage;
• -h: also prints usage;

For easier running and testing, the following commands are provided:

• Run with make run (implies -d);
• Remove product files with make clean;
• Arguments may be passed with make ARGS="-p Set" run, where -p Set stand for example arguments;
• Run for many parameters sets at once using make multirun or make ARGS="-t 10" multirun, where -t 10 stands for example arguments. The sets must be listed in the MULTIRUN_SETS variable in the Makefile at the root dir;
• Run tests with make tests (it is a shortcut to make ARGS="-a" run with the default parameterization);
• As a shorthand to make ARGS="-s" run or make ARGS="-s" multirun, make srun and make smultirun may be used.

When running on the default tree (that is, on the cloned or downloade dir), the results can be plotted with

• Plot results with make graph
• Plot results for multirun with make mgraph. This also plots the multioutput/gnuplot.gpi which may access files for multiple parameters sets and is useful for making plots comparing results for different sets. As the multirun works by executing for each parameterization and then copying into the multioutput dir, any desired alteration to the plots should be done at output/*/gnuplot.gpi, except for those generated by multioutput/gnuplot.gpi;
• Plot tests with make tgraph;

Two files for each plot will be created, a png file and a tex file. The second is a version created using the tiks terminal for gnuplot and can be used directly into (pdf)latex. The advantage is a much cleaner plot and proper latex equations and text in labels.

Parameters sets must be declared in ParametersSetup() in Parameters.c. Each parameters set is cloned from a reference set with NewCopyOfParametersSetFromTemplate() then the variables which differ from the template are set. Each parameters set must have a unique identifier. Finally, the set must be appendend to the list using AppendParametersSetToList().

To choose a parameters set, the function SetParametersSet() must be used. This is used before the calculation of the main results and if no parameters set is explicitly requested in the command line, the first set declared is used. Each test in Tests() (in Tests.c) should declare a set.

Once set using SetParametersSet(), use parameters.a_parameter to access the parameters values, where a_parameter is one of the parameters declared in the struct in Parameters.h.

The commandline options set in CommandlineOptions.* are globally available using options.an_option.

Tests should be declared in the function RunTests() in Tests.c. This function is executed when the executable is called with -a option.

Paths can be easily set with SetFilePath(). After that, all files created with OpenFile() will be created at that path. After a section of code that uses SetFilePath(), the path should be reset to the working dir with UnsetFilePath(). This is important as other sections of code may expect to write in the working dir while using OpenFile() and this is accomplished with an unset path.