GADGET-4

GADGET-4 is a massively parallel code for N-body/hydrodynamical cosmological simulations. It is a flexible code that can be applied to a variety of different types of simulations, offering a number of sophisticated simulation algorithms. An account of the numerical algorithms employed by the code is given in the original code paper, subsequent publications, and this documentation.

GADGET-4 was written mainly by Volker Springel, with important contributions and suggestions being made by numerous people, including Ruediger Pakmor, Oliver Zier, and Martin Reinecke.

Documentation

For documentation of the code as well as the code paper, please refer to the code's web-site.

Instructions for BNL Astro Cluser

This is how I got it to compile since the default modules are outdated.

1. Create your dir in astro workarea /gpf02/astro/workarea/yourusername:

   mkdir /gpfs02/astro/workarea/yourusername
   cd /gpfs02/astro/workarea/yourusername

2. Make a miniconda folder in your workarea to install all prerequisites. Your home folder has very little space.

   mkdir -p miniconda3
   wget https://repo.anaconda.com/miniconda/Miniconda3-latest-Linux-x86_64.sh -O ~/miniconda3/miniconda.sh
   bash miniconda3/miniconda.sh -b -u -p miniconda3
   rm -rf miniconda3/miniconda.sh

   Follow instructions and ensure conda info makes sense. You might need to source ~/.bashrc here.
3. Create a new env for gadget and install dependencies

   conda create -n gadget -c conda-forge python=3.9 mpich-mpicxx gsl fftw hdf5 libhwloc zlib
   conda activate gadget

4. Clone this repo. It has some changes to address an older glibc on BNL astro cluster

   git clone https://github.com/rugvedpund/gadget4.git

5. We can now try compiling. This is just a test compile to check if everything works.

   cd gadget4/
   make DIR=examples/test

   Note that this directory is a copy of the official examples/DM-L50-N128, except the Config.sh file has an extra OLDSTYLE_SHARED_MEMORY_ALLOCATION flag. The Config.sh file should not be modified after compiling. If a different Config.sh is needed, it is recommended to create a new directory with the newConfig.sh and run make in that dir. For more details on the recommended practices, refer to the code's web-site.
6. We can now run the executable with the included params.txt (and outputs.txt, which is called internally for saving snapshots). We will run this directly on the login node for now.

   cd examples/test
   mpiexec -np 8 ./Gadget4 params.txt 0

   Note that the params.txt can be modified and the code can be rerun, just ensure that the output of any previous runs is cleared. The code will save a copy of the params.txt as parameters-usedvalues with every output for later reference.