Reference system

The example Linux installation described below was done on the following system:
Machine: x86_64-based GNU/Linux cluster
Distribution: Ubuntu 4.4.0-210-generic
Processor: Intel Xeon E5-2670, 2300 MHz, 24 cores
RAM: 128 GB

STEP 1: Download L-Galaxies 2020

OPTION 1: Clone GitHub repository (recommended):
This option requires having a GitHub account and Git. Git is normally already installed on standard Linux systems. If it isn't on yours, download it following the instructions at: https://github.com/git-guides/install-git Once you have Git and a GitHub account, proceed as follows:

  1. Navigate to a directory where you'd like L-Galaxies kept
  2. Decide which branch you wish to download:
    • "master" for the Yates+21a version of L-Galaxies 2020
    • "Yates2023" for the Yates+24 version of L-Galaxies 2020 (recommended - contains latest updates)
  3. Clone the repository:
    • git clone --branch [BRANCH_NAME] --single-branch https://github.com/LGalaxiesPublicRelease/LGalaxies2020_PublicRepository


OPTION 2: Download zip file using browser:

  1. Go to https://github.com/LGalaxiesPublicRelease/LGalaxies2020_PublicRepository
  2. From the drop-down list on the left, select the branch you wish to download:
    • "master" for the Yates+21a version of L-Galaxies 2020
    • "Yates2023" for the Yates+24 version of L-Galaxies 2020 (recommended - contains latest updates)
  3. Click the green "Code" drop-down menu, and select "Download ZIP" [~5-20 MB]
  4. Move the downloaded file ([BRANCH_NAME].zip) to a suitable base directory.
  5. In the terminal (or otherwise), navigate to that base directory, then unzip the file:
    • unzip ./[BRANCH_NAME].zip
    This will create a new directory called /LGalaxies2020_PublicRepository-[BRANCH_NAME], hereafter, the "project root directory".
  6. You can now delete the .zip file, if you wish:
    • rm ./[BRANCH_NAME].zip
  7. Manually add an empty /output folder in the project root directory:
    • cd ./LGalaxies2020_PublicRepository-[BRANCH_NAME]
    • mkdir output


OPTION 3: Download zip file using wget:

  1. Navigate to a directory where you'd like L-Galaxies kept
  2. Decide which branch you wish to download:
    • "master" for the Yates+21a version of L-Galaxies 2020
    • "Yates2023" for the Yates+24 version of L-Galaxies 2020 (recommended - contains latest updates)
  3. Download L-Galaxies 2020:
    • wget -P ./ https://github.com/LGalaxiesPublicRelease/LGalaxies2020_PublicRepository/archive/[BRANCH_NAME].zip
  4. Unzip the file:
    • unzip ./[BRANCH_NAME].zip
    This will create a new directory called/LGalaxies2020_PublicRepository-[BRANCH_NAME], hereafter, the "project root directory".
  5. You can now delete the .zip file, if you wish:
    • rm ./[BRANCH_NAME].zip
  6. Manually add an empty /output folder in the project root directory:
    • cd ./LGalaxies2020_PublicRepository-[BRANCH_NAME]
    • mkdir output


OPTION 4: Download as a local Git repository via the Eclipse IDE:
The L-Galaxies 2020 code can also be obtained from GitHub via the Eclipse IDE, which offers a more intuitive way of editing and debugging code using a Graphical User Interface (GUI). To install L-Galaxies 2020 this way, skip straight to STEP 8 below, where information on how to install Eclipse and synchronise it with L-Galaxies 2020 is provided.

STEP 2: Download spectrophotometric tables and treefiles

  1. Download the standard SpecPhotTables [~1.6 GB] [direct download]
  2. Move the downloaded .tar file (SpecPhotTables.tar) into the project root directory.
  3. In the terminal, navigate to the project root directory.
  4. Untar the file:
    • tar -xf ./SpecPhotTables.tar
    This will create a folder called /SpecPhotTables containing the downloaded spectrophotometic tables
  5. The Millennium-I and Millennium-II treefiles have been pre-packaged into different sets, depending on how much of the simulation volume you want to use. You can choose from:
    6. Millennium-I: Millennium-II:
    • Treefiles 40-79 [~6.0 GB compressed, ~13 GB uncompressed] 40 treefiles (standard test set)
    • Treefiles 0-511 [~76 GB compressed, ~185 GB uncompressed] All treefiles (full volume)
  6. Download your chosen treefile set either by clicking the link above or using wget in the command line, e.g. (for the test sets):
    • wget https://uhhpc.herts.ac.uk/~ry22aas/MR[II]_MergerTrees_[TREEFILE_NUMBERS].tar
  7. Move the downloaded .tar file into the /MergerTrees directory, which is in the project root directory.
  8. In the terminal, navigate to the /MergerTrees.
  9. Untar the treefiles:
    • tar -xzf ./MR[II]_MergerTrees_[TREEFILE_NUMBERS]
    This will create a folder called either /MR/treedata, /MRII/treedata, or /MRII containing the downloaded treefiles.

STEP 3: Check your compiler and C libraries

L-Galaxies requires a C compiler (e.g. gcc), the make command, and the GNU Scientific Libraries (GSL) to run. Linux distributions typically come with all three of these installed as standard. Likewise, HDF5 is required if you wish to work with L-Galaxies outputs in HDF5 (rather than binary) format. You can check if gcc and make are installed on your system using the following commands, which return the directory in which they are stored (usually /usr/bin/gcc and /usr/bin/make):

GSL is typically installed in /usr/local/include/gsl (for the header files) and /usr/local/lib/ (for the libraries). If you can't find the explicit path yourself, you might be able to simply point L-Galaxies to the relevant environment variables, GSL_INCL = -I$(INCLUDE) and GSL_LIBS = -L$(LD_LIBRARY_PATH) (see STEP 4).

Note that if your Linux system runs with a modular environment, you may need to load the GSL and HDF5 libraries before they can be used:

You can check which packages are available as modules by running:
  • module avail

If your system doesn't have gcc and/or make, the simplest way to install them is probably via the "build-essential" package for either Ubuntu or Debian Linux:

Likewise, if your system doesn't have GSL, it should be installable as follows:
  • sudo apt-get install libgsl-dev libgsl-dbg
And HDF5 (both the standard and high-level HDF5 librarires required) should be installable with something like:
  • sudo apt install libhdf5-dev
If all else fails, you can download the latest version of gcc from here, following the installation instructions provided here. Likewise, the make tool can be downloaded from here. The latest version of GSL can be downloaded from here, with installation instructions provided in the README and INSTALL files and general GSL documentation available here. The latest version of HDF5 can be downloaded from here.

STEP 4: Check the compiler configuration

The L-Galaxies 2020 makefile needs to be told which C compiler to use and where the GSL and HDF5 headers & libraries are stored. This information is provided by the user as a SYSTYPE configuration in the My_Makefile_compilers file, located in the project root directory.

By default, the SYSTYPE is set to "Linux", which should be suitable for most Linux installations. This configuration assumes the gcc compiler is to be used, and that the GSL header files and libraries are stored in their default locations. If your GSL files are not stored in these locations, you will need to change the GSL_INCL and GSL_LIBS paths accordingly. As mentioned above, if you can't find the explicit path to GSL yourself, you might be able to simply point L-Galaxies to the relevant environment variables with something like GSL_INCL = -I$(INCLUDE) and GSL_LIBS = -L$(LD_LIBRARY_PATH).

Likewise, the "Linux" configuration also links to the two main HDF5 libaries required to get the HDF5_OUTPUT option working. Depending on your installation you may need to add additional explicit dependencies, such as: -lsz -laec -lz -ldl -lm

By default, O3 optimization is used. Feel free to add/change the OPTIMIZE flags for your compiler set-up, as you see fit.

If L-Galaxies 2020 compiles without any errors when you run the make command from the terminal in the project root directory, you are probably good to go! If not, here are a few common compiler issues and our (unofficial) fixes for them:


Common compiler issues

  1. Running with an old C standard: If your distribution is quite old, it may not be running with the latest C standard. If so, you may need to inform the compiler of this in My_Makefile_compilers by adding the -std flag to the CC call. (e.g. CC = gcc -std=C99 for systems running with C99). When doing this, you may also need to manually define some extra constants in h_params.h that are not part of the standard math.h library in older C versions. For example: #define M_PI 3.14159265358979323846

  2. Running with old C libraries: Likewise, an old distribution may not have a version of the GNU C libraries (glibc). If so, you may need to install and build new C libraries following the instructions provided here (which is compilcated!). Alternatively, a quick hack (if you do have a recent version of the GSL libraries, see above), is to replace the #include <math.h> statements at the top of each L-Galaxies code .c file with #include <gsl/gsl_math.h>

  3. Multiple tentative definitions: If a compilation crashes with an error stating that "multiple tenative definitions of a global variable in different compilation units" are not allowed, you may need to add the -fcommon flag to the CC call in My_Makefile_compilers. Note that this flag is set by default when running with SYSTYPE = "cygwin".

  4. Shared and static libraries: Linux will usually use shared versions of C libraries by default. However, if you want to force the use of static libraries instead (i.e. .a files), then add the -static flag for GSL_LIBS in My_Makefile_compilers. Similarly, if you want to force the use of shared libraries (i.e. .dll or .so files), then add the -shared instead.

  5. Shared object errors: Similarly, if you are getting errors like: "Relocation R_X86_64_32 against undefined symbol '[LGALAXIES_PARAMETER]' can not be used when making a shared object", then you may need to add the -fPIC flag to the CC call in My_Makefile_compilers

  6. Ubuntu versions: There have been some reports of issues compiling L-Galaxies on Ubuntu 23.10 (which can return "unsupported symbol" errors). However, this appears to be resolved by running on Ubuntu 22.04 LTS instead.

STEP 5: Compile and run the code

Compiling and running L-Galaxies 2020 is done as follows:

  1. In the terminal, navigate to the project root directory
  2. Compile the code:
    • make
  3. Run the code:
    • ./L-Galaxies ./input/[INPUT FILE]


There are four standard input files to choose from (for info on which to use, see STEP 7):


Straight out of the box, L-Galaxies 2020 will run on treefile 5 of Millennium-I with only redshift 0 data outputted. So the input_MR_W1_PLANCK_LGals2020_MM.par input file is recommended in this case. However, various other standard set-ups are also possible (see STEP 7).

Once L-Galaxies 2020 has finished running, the output file(s) generated will be stored in the /output folder. These can be read in to python for analysis as described in STEP 6.

STEP 6: Reading-in and plotting outputs in python

L-Galaxies 2020 comes with a set of simple python scripts to read-in and plot L-Galaxies 2020 output files. These can be found in /AuxCode/Python. To run these python scripts on your outputs, simply execute the main_lgals.py file. This will generate a galaxy sample (using the selection criteria discussed below) which is saved to an .npy file in the /output/samples folder for quick re-use. It will also produce some plots in the /figures folder. To modify how main_lgals.py works, see below.


Note on HDF5 vs. binary outputs: By default, L-Galaxies 2020 will generate HDF5 output files, and main_lgals.py is set to read them in. This makes things easier than using binary output files, as the structure of the data doesn't need to be known a priori. However, if you prefer to work with binary output files, you can comment-out the HDF5_OUTPUT switch in the My_Makefile_options file before compiling & running L-Galaxies, and set the HDF5_OUTPUT switch in main_lgals.py to 0 when handling the outputs. Using binary files requires a python structure, which is automatically generated by L-Galaxies and saved in /AuxCode/Python as auto_LGalaxy_struct.py. Setting the STRUCT_TYPE option in main_lgals.py to "auto" will use this python structure when reading-in the L-Galaxies binary outputs. Other standard python structures are also stored in /AuxCode/Python, for reference.


Switches
The main_lgals.py file contains a number of switches under "USER DEFINED INPUTS" which can be used to modify how/what data is read-in and how it's handled. For example:


Sample Info
The type of L-Galaxies output to be read, and type of sample you want to generate, can also be set in main_lgals.py via the following variables:


Sample Types
There are four default sample types you can select when generating a sample from the L-Galaxies output file using main_lgals.py:

For more info on the exact selection criteria for these different sample types, see the make_lgals_sample.py file.


Note that the plots generated by these python scripts require LaTeX syntax for some of the axis labels. If your Linux installation does not have (La)TeX capabilities, you may need to install (some) of the following packages:


For more information on how to use/modify these python scripts, feel free to drop me an email (r.yates3 -at- herts.ac.uk).

STEP 7: Changing the model [OPTIONAL]

Default vs. Modified model
Input files (i.e. the .par files) are provided for the Default Model (DM) and Modified Model (MM) versions of L-Galaxies 2020 (see Yates+21a for details). In brief, the Default Model allows the majority of material released by supernovae and stellar winds to mix with the ambient ColdGas before some is blown out as galactic winds. The Modified Model allows the majority of this newly-released material to be directly ejected into the surrounding HotGas, without first mixing with the ColdGas. The Modified Model is recommended, as it more accurately reproduces the chemical evolution of galaxies and their surroundings above redshift 0 (see Yates+21a). You can select the Default Model or Modified Model by using the an input file with a "DM" or "MM" suffix, respectively.



Millennium-I vs. Millennium-II
By default, L-Galaxies 2020 will try to run on Millennium-I merger trees. To switch to Millennium-II, make sure you've downloaded some Millennium-II treefiles (see STEP 2), and then do the following:

  1. Open the My_Makefile_options file in the project root directory
  2. Uncomment the MRII switch
  3. Save and close My_Makefile_options
  4. Use the default model (DM) or modified model (MM) Millennium-II input files as the argument when running the code (see STEP 5 above):
    • input_MRII_W1_PLANCK_LGals2020_DM.par
    • input_MRII_W1_PLANCK_LGals2020_MM.par



Snapshot vs. Galaxytree mode
Snapshot mode (the default for L-Galaxies 2020) will only output data for a user-defined set of redshifts (i.e. snapshots). Galaxytree mode will instead output data from all snapshots, along with the IDs needed to link a given galaxy to its progenitors and descendents (note that this generates much larger output files).

To use/modify snapshot mode:

  1. Open desired_output_redshifts.txt in the /inputs folder
  2. Add the redshifts you wish to be outputted to the top of this file, one on each line, with an empty line at the end of your list (L-Galaxies will match these to their nearest snapshots automatically)
  3. Open the My_Makefile_options file in the project root directory
  4. Set the NOUT parameter to equal the number of redshifts you set to be outputted in desired_output_redshifts.txt
  5. Make sure that the GALAXYTREE switch is commented-out
  6. Save and close My_Makefile_options
  7. Compile and run L-Galaxies 2020 as described in STEP 5

To use galaxytree mode:
  1. Open the My_Makefile_options file in the project root directory
  2. Uncomment the GALAXYTREE switch
  3. Save and close My_Makefile_options
  4. Compile and run L-Galaxies 2020 as described in STEP 5



MCMC mode
For detailed instructions on how to run L-Galaxies in MCMC mode, in order to retune model parameters, see the MCMC instructions kindly provided by Marcel van Daalen.



Changing the output file name

  1. Open the input file you wish to use (see above) in the /inputs folder
  2. Change FileNameGalaxies to an appropriate name. This will be the prefix in the name of the output file(s) that L-Galaxies generates.
  3. Save and close the input file
  4. Compile and run L-Galaxies 2020 as described in STEP 5
  5. Remember to modify the variables used to read-in L-Galaxies outputs in main_lgals.py too (e.g. the VERSION variable).



Changing the treefiles used

  1. Open the input file you wish to use (see above) in the /inputs folder
  2. Set FirstFile to the first treefile you wish to use
  3. Set LastFile to the last treefile you wish to use
  4. Save and close the input file
  5. Compile and run L-Galaxies 2020 as described in STEP 5
  6. Remember to modify the variables used to read-in L-Galaxies outputs in main_lgals.py too (i.e. FirstFile and LastFile).

To run L-Galaxies 2020 on the full set of Millennium-I or II trees, set FirstFile to 0 and LastFile to 511. For testing purposes on Millennium-I, treefile 5 alone is normally sufficient. For quick but statistically-significant runs on Millennium-I, treefiles 0-9 are normally sufficient. For quick but statistically-significant runs on Millennium-II, treefiles 40-79 are normally sufficient.



Model switches
L-Galaxies 2020 comes with a series of pre-defined model options (or "switches") that change the physics models used, the treefiles used, which properties are tracked/outputted, etc. These switches are defined in the My_Makefile_options file in the project root directory. There meanings should be quite self explanatory, but if you are unsure, feel free to ask! You are also able to add your own switches to your version of the code. These should be defined in My_Makefile_options and then utilised in the necessary code files via "ifdef statements" (or equivalent). For example, to create a switch which prevents the property BulgeMassRings from being outputted:

  1. Open My_Makefile_options in the project root directory
  2. Add the following line:
    • OPT += -DNO_BULGEMASSRINGS_OUTPUT
  3. Save and close My_Makefile_options
  4. Put the following ifdef statement around the instances of BulgeMassRings in h_galaxy_output.h and save.c (see below for more details):
    • #ifndef NO_BULGEMASSRINGS_OUTPUT
    • ...
    • #endif //NO_BULGEMASSRINGS_OUTPUT
  5. Save and close the code files
If working with binary output files, this modification will be automatically updated in the python structure saved in /AuxCode/Python/ as auto_LGalaxy_struct.py during compilation.



Changing which properties are outputted

You are free to customise which properties are actually outputted by L-Galaxies 2020. This is done as follows:

  1. Open h_galaxy_output.h in the /code folder
  2. In the GALAXY_OUTPUT structure, add/comment-out the property you wish to be outputted/not outputted
    3. For example, to remove BulgeMassRings, either put it in a newly-defined #ifndef (see above) or directly comment it out:
    • // float BulgeMassRings[RNUM];
  3. Save and close h_galaxy_output.h
  4. Open save.c in the /code folder
  5. In the prepare_galaxy_for_output() function, add/comment-out the property you wish to be outputted/not outputted
    6. For example, to remove BulgeMassRings, either put it in a newly-defined #ifndef (see above) or directly comment it out:
    • // o->BulgeMassRings[ll] = g->BulgeMassRings[ll];
  6. Save and close save.c
If running with the HDF5_OUTPUT switch on, all your modifications will automatically be known by main_lgals.py when reading-in your newly-generated output files. If running with binary output files, as mentioned above, the python structure required is automatically saved in /AuxCode/Python/ as auto_LGalaxy_struct.py during compilation. However, if you are working with a manually-edited python structure of your own, make sure to modify it to reflect the new set of properties you are outputting.

Note: The majority of errors occurring when trying to read-in L-Galaxies output binaries come from a mis-match between the actual output contents and the python structure! Therefore, make sure you keep your output structure up-to-date with your code!



Processing binary_c data [Yates2023 branch only]
The Yates23 version of L-Galaxies allows the inclusion of chemical yields and supernova rates from stellar populations containing binary stars, by utilising the binary stellar evolution (BSE) calculations made by the binary_c code. To do this, "ensemble" outputs from binary_c are loaded and converted into yield tables that can be read by L-Galaxies.

Standard versions of these tables are already generated and stored in the /YieldTables/binary_c_yields/default folder. However, if a different set of chemical elements is required (N.B. only 'H','He','C','N','O','Ne','Mg','Si','S','Ca', and 'Fe' are loaded by default), or if you want to use a new set of binary_c ensembles, then new yield tables can be easily generated by executing the process_binaryc_outputs.py script found in the /AuxCode/Python folder.

To change the chemical elements/isotoptes considered, simply modify the elements list under "INPUT VARIABLES" in process_binaryc_outputs.py. A new h_metals.h header file will automatically be written in the /code folder, which allows the new list of elements/isotopes chosen to be tracked in L-Galaxies.

To generate yield tables for a new set of binary_c ensembles, simply place the new ensemble .json files into the /YieldTables/binary_c_yields/new/ensembles folder and turn on the USE_NEW_ENSEMBLES switch in process_binaryc_outputs.py before running this script.

For more information on how to handle binary_c data with L-Galaxies, feel free to drop me an email (r.yates3 -at- herts.ac.uk).

STEP 8: Running L-Galaxies in the Eclipse IDE [OPTIONAL]

Although L-Galaxies 2020 can be used with any basic word processor and the command line, using an Interactive Development Environment (IDE) can make modifying, compiling, running, and debugging code significantly easier and more efficient. This can save a lot of time and energy in the long run. Therefore, we recommend using an IDE (that is compatible with C makefile projects) when working with L-Galaxies. Below, we outline how to download, install, and synchronise the Java-based Eclipse IDE for L-Galaxies, which has already been extensively tried and tested with the code.


Check C compiler and libraries:

  1. If you haven't already, complete STEP 3 above to install the gcc compiler, make, and GSL.


Install jdk:
Eclipse is a java-based IDE, so it needs the Java Development Kit (JDK) to run. You can check if JDK is already installed on your system by running java -version in the command line. If this command returns information on a Java "Runtime Environment", you probably have a working version of JDK installed. If you don't have JDK, you can install the latest version as a private user as follows:

  1. Go to: https://www.oracle.com/java/technologies/downloads/#jdk19-linux
  2. Click the download link for the "x64 Compressed Archive" (if running on Debian/Ubuntu) or the "Arm 64 Compressed Archive" (if running on ARM CPU architecture)
  3. In the terminal, navigate to the directory where you want to install JDK, then move the downloaded .tar.gz file to that directory
  4. Unpack the tarball and install JDK:
    • tar zxvf jdk-19_linux-x64_bin.tar.gz
      • or
    • tar zxvf jdk-19_linux-aarch64_bin.tar.gz
    The JDK files will be installed to a directory called /jdk-19.
  5. Delete the .tar.gz file if you want to save disk space.


Install Eclipse IDE:

  1. Go to: https://www.eclipse.org/downloads/packages/installer
  2. Click the download link for the Eclipse 2022-09 R x86_64 Installer for Linux (probably the x86_64 version, unless you have AArch64 system architecture)
  3. Execute the installer (called eclipse-inst-jre-linux64.tar.gz)
  4. Once downloaded, in the terminal, navigate to the directory where you want to install the Eclipse IDE, then move the downloaded .tar.gz file to that directory
  5. Unpack the tarball:
    • tar zxvf eclipse-inst-jre-linux64.tar.gz
      • or
    • tar zxvf eclipse-inst-jre-linux-aarch64.tar.gz
  6. From the eclipse-installer sub-directory, install eclipse:
    • ./eclipse-inst
  7. When prompted, select: Eclipse IDE for C/C++ Developers
  8. Confirm that "Java 17+ VM:" is pointing to where JDK is installed, and confirm the default Installation Folder
  9. Click "install"
  10. Accept the user agreement
  11. Once it's installed, click "launch"
  12. Confirm the default Workspace and click "launch" again.


Clone L-Galaxies 2020 repository:

  1. In the Eclipse IDE, "Hide" the welcome screen (if still visible)
  2. Click the "Open Perspective" button in the top right corner (symbol of a GUI interface with a plus sign)
  3. Select "Git"
  4. Click "Clone a Git Repository" (left)
  5. Enter the L-Galaxies 2020 repository URI: https://github.com/LGalaxiesPublicRelease/LGalaxies2020_PublicRepository
  6. Click "Next"
  7. Select which branch(es) you wish to clone and click "Next"
  8. Confirm the destination directory (this will become your git-synchronised project root directory).
  9. Click "Finish"
    10. Eclipse will now clone a local version of the L-Galaxies 2020 repository (progress bar in the bottom right corner)
  10. Once cloned, right click / two-finger click the name of the project in the left-hand panel (LGalaxies2020_PublicRepository)
  11. Click "Import projects..."
  12. In the new window, click "Finish"
    13. The L-Galaxies 2020 code is now ready to be used in the standard "C/C++ Perspective" in Eclipse


Define as a makefile project:

  1. Click the "C/C++ Perspective" button in the top right corner (symbol of a GUI interface with a letter "C")
  2. Click on the project name in the left-hand panel (LGalaxies2020_PublicRepository), so that it's highlighted
  3. Press Ctrl+n on the keyboard
  4. Select: "Convert to C/C++ project (Adds C/C++ Nature)" and click "Next"
  5. Under "Convert to C or C++", select "C project"
  6. Under "Project Options", select "Makefile project" and the "Linux GCC" toolchain
  7. Click "Finish"


Set-up a run configuration:

  1. In the "C/C++ perspective", click the project name in the left-hand panel (LGalaxies2020_PublicRepository), so that it's highlighted
  2. From the top menu bar, select "Run" > "Run configurations..."
  3. In the new window (left-hand panel), click "C/C++ Allpication"
  4. Click the "New Launch configuration" button (symbol of a blank page with a plus sign)
  5. In the right-hand panel, set "Name" to: "LGalaxies2020_PublicRepository" (i.e. delete " Default")
  6. Set "C/C++ Application" to: "L-Galaxies"
  7. Click the "Arguments" tab (right-hand panel)
  8. Under "Program arguments", add the local path to your preferred input file (e.g. ./input/input_MR_W1_PLANCK_LGals2020_DM.par)
  9. Click "Apply", then click "Close"


Add an output folder:

  1. In the "C/C++ perspective", two-finger click the project name in the left-hand panel (LGalaxies2020_PublicRepository)
  2. Select "New" > "Folder"
  3. In the new window, set Folder name as "output"
  4. Click "Finish"


Download treefiles and specphot tables:

  1. If you haven't already, complete STEP 2 above for this cloned L-Galaxies 2020 repository


Check compiler configuration:

  1. Complete STEP 4 above to check the gcc compiler is configured correctly for L-Galaxies 2020 on your system
    2. For example, set the SYSTYPE to "Linux" in My_Makefile_compilers


Compile and run in Eclipse:

  1. In the "C/C++ perspective", click the project name in the left-hand panel (LGalaxies2020_PublicRepository), so that it's highlighted
  2. To compile: Click the "Build" button in the top left corner (symbol of a hammer)
  3. To run: Click the "Run" button in the top left corner (symbol of a green "play" sign)