Added readme for GPU project

Author: brownbaerchen

docs/source/index.rst

@@ -53,6 +53,7 @@ Projects
    projects/compression.rst
    projects/second_order.rst
    projects/monodomain.rst
+   projects/GPU.rst
 
 
 API documentation

docs/source/projects/GPU.rst

@@ -0,0 +1 @@
+.. include:: /../../pySDC/projects/GPU/README.rst

pySDC/projects/GPU/README.md renamed to pySDC/projects/GPU/README.rst

@@ -1,8 +1,9 @@
 pySDC using GPUs
-===================
+================
+
 Installation
 ------------
-In order to start playing on GPU, install `pySDC` and it's dependencies, ideally in developer mode.
+In order to start playing on GPU, install `pySDC` and its dependencies, ideally in developer mode.
 First start by setting up a virtual environment, e.g. by using [Miniconda](https://docs.conda.io/en/latest/miniconda.html).
 Then also add the CuPy Package (the cuda-toolkit will be installed automatically):
 
@@ -13,28 +14,49 @@ Then also add the CuPy Package (the cuda-toolkit will be installed automatically
 When this is done (and it can take a while), you have your setup to run `pySDC` on the GPU.
 
 Changes in the problem_classes
-------------
+------------------------------
 Now you have to change a little bit in the problem_classes. The first and easy step is to change the datatype.
 To use pySDC on the GPU with CuPy you must use the [cupy-datatype](../../implementations/datatype_classes/cupy_mesh.py).
 The next step is to import cupy in the problem_class. In the following you have to exchange the NumPy/SciPy functions with the CuPy functions.
 A [Comparison Table](https://docs.cupy.dev/en/latest/reference/comparison.html) is given from CuPy to do that.
-For Exmaple: The above steps can be traced using the files 
+For example: The above steps can be traced using the files 
 [HeatEquation_ND_FD_forced_periodic.py](../../implementations/problem_classes/HeatEquation_ND_FD_forced_periodic.py) 
 and [HeatEquation_ND_FD_forced_periodic_gpu.py](../../implementations/problem_classes/HeatEquation_ND_FD_forced_periodic.py)
 Now you are ready to run `pySDC` on the GPU. 
 
 Run pySDC on the GPU
-------------
-You have to configure a Script to run it. You can see at the file [heat.py](heat.py) that the parameters are the 
+--------------------
+You have to configure a script to run it. You can see at the file [heat.py](heat.py) that the parameters are the 
 same for GPU and CPU. Only the import for the problem_class changed.  
 
-
-
 More examples
-----------
+-------------
 Further examples can found with Allen-Cahn:
 * problem: [AllenCahn_2D_FD.py](../../implementations/problem_classes/AllenCahn_2D_FD.py) and [AllenCahn_2D_FD_gpu.py](../../implementations/problem_classes/AllenCahn_2D_FD_gpu.py)
 * problem: [AllenCahn_2D_FFT.py](../../implementations/problem_classes/AllenCahn_2D_FFT.py) and [AllenCahn_2D_FFT_gpu.py](../../implementations/problem_classes/AllenCahn_2D_FFT_gpu.py)
   * Script to run pySDC: [ac-fft.py](ac-fft.py)
 
 
+Running large problems on GPU
+-----------------------------
+This project contains some infrastructure for running and plotting specific problems.
+The main file is `run_experiment` and can be configured using command line arguments.
+For instance, use
+
+.. code-block:: bash
+ 
+    srun -n 4 python work_precision.py --config=GS_USkate --procs=1/1/4 --useGPU=True --mode=run
+    mpirun -np 8 python work_precision.py --config=GS_USkate --procs=1/1/4 --useGPU=True --mode=plot
+    python work_precision.py --config=GS_USkate --procs=1/1/4 --useGPU=True --mode=video
+
+to first run the problem, then make plots and then make a video for Gray-Scott with the U-Skate configuration (see arXiv:1501.01990).
+
+To do a parallel scaling test, you can go to JUWELS Booster and use, for instance,
+
+.. code-block:: bash
+   python analysis_scripts/parallel_scaling.py --mode=run --scaling=strong --space_time=True --XPU=GPU --problem=GS
+   srun python analysis_scripts/parallel_scaling.py --mode=plot --scaling=strong --space_time=True --XPU=GPU --problem=GS
+
+This will generate jobscripts and submit the jobs. Notice that you have to wait for the jobs to complete before you can plot them.
+
+To learn more about the options for the scripts, run them with `--help`.