Doc: how to compile and run on Juwels (ECP-WarpX#1133)

* Doc how to compile and run on Juwels

* add a bunch of AMReX-specific options

* Update juwels.rst

* Update Docs/source/building/juwels.rst

Co-authored-by: MaxThevenet <mthevenet@lbl.gov>

* Juwels: Filesystem Note

* Jewels Docs: Missing newline

Co-authored-by: Axel Huebl <axel.huebl@plasma.ninja>

Docs/source/building/building.rst

@@ -102,3 +102,4 @@ Building for specific platforms
 
    cori
    summit
+   juwels

Docs/source/building/cori.rst

@@ -1,7 +1,7 @@
 .. _building-cori:
 
-Building WarpX for Cori (NERSC)
-===============================
+Cori (NERSC)
+============
 
 Standard build
 --------------

Docs/source/building/juwels.rst

@@ -0,0 +1,74 @@
+.. _building-juwels:
+
+Juwels (JSC)
+============
+
+The `Juwels supercomputer <https://www.fz-juelich.de/ias/jsc/EN/Expertise/Supercomputers/JUWELS/JUWELS_node.html>`_ is located at JSC.
+
+See `this page <https://apps.fz-juelich.de/jsc/hps/juwels/quickintro.html>`_ for a quick introduction.
+
+* Batch system: `Slurm <https://apps.fz-juelich.de/jsc/hps/juwels/quickintro.html#batch-system-on-system-name>`_
+* `Production directories <https://apps.fz-juelich.de/jsc/hps/juwels/environment.html?highlight=scratch#available-filesystems>`_:
+
+  * ``$SCRATCH``: Scratch filesystem for temporary data (90 day purge)
+  * ``$FASTDATA/``: Storage location for large data (backuped)
+  * Note that the ``$HOME`` directory is not designed for simulation runs and producing output there will impact performance.
+
+Installation
+------------
+
+Use the following commands to download the WarpX source code and switch to the correct branch:
+
+.. code-block:: bash
+
+   mkdir ~/src
+   cd ~/src
+
+   git clone https://github.com/ECP-WarpX/WarpX.git warpx
+   git clone --branch QED https://github.com/ECP-WarpX/picsar.git
+   git clone --branch development https://github.com/AMReX-Codes/amrex.git
+
+We use the following modules and environments on the system.
+
+.. code-block:: bash
+
+   # please set your project account
+   export proj=<yourProject>
+
+   # required dependencies
+   module load GCC
+   module load OpenMPI
+   module load CUDA
+
+   # JEWELS' job scheduler may not map ranks to GPUs,
+   # so we give a hint to AMReX about the node layout.
+   # This is usually done in Make.<supercomputing center> files in AMReX
+   # but there is no such file for JSC yet.
+   export GPUS_PER_SOCKET=2
+   export GPUS_PER_NODE=4
+
+Note that for now WarpX must rely on OpenMPI instead of the recommended MPI implementation on this platform MVAPICH2.
+
+We recommend to store the above lines in a file, such as ``$HOME/warpx.profile``, and load it into your shell after a login:
+
+.. code-block:: bash
+
+   source $HOME/warpx.profile
+
+Then, ``cd`` into the directory ``$HOME/src/warpx`` and use the following commands to compile:
+
+.. code-block:: bash
+
+   make -j 16 COMP=gcc USE_GPU=TRUE
+
+The other :ref:`general compile-time options <building-source>` apply as usual.
+
+Running
+-------
+
+An example submission script reads
+
+.. literalinclude:: ../../../Tools/BatchScripts/batch_juwels.sh
+   :language: bash
+
+See :doc:`../visualization/yt` for more information on how to visualize the simulation results.

Docs/source/building/summit.rst

@@ -1,7 +1,7 @@
 .. _building-summit:
 
-Building WarpX on Summit (OLCF)
-===============================
+Summit (OLCF)
+=============
 
 The `Summit cluster <https://www.olcf.ornl.gov/summit/>`_ is located at OLCF.
 

Tools/BatchScripts/batch_juwels.sh

@@ -0,0 +1,20 @@
+#!/bin/bash -l
+
+#SBATCH -A $proj
+#SBATCH --partition=gpus
+#SBATCH --nodes=2
+#SBATCH --ntasks=8
+#SBATCH --ntasks-per-node=4
+#SBATCH --gres=gpu:4
+#SBATCH --time=00:05:00
+#SBATCH --job-name=warpx
+#SBATCH --output=warpx-%j-%N.txt
+#SBATCH --error=warpx-%j-%N.err
+
+export OMP_NUM_THREADS=1
+
+module load GCC
+module load OpenMPI
+module load CUDA
+
+srun -n 8 --cpu_bind=sockets $HOME/src/warpx/Bin/main3d.gnu.TPROF.MPI.CUDA.ex inputs