PeleC

A compressible AMR combustion code

PeleC is an adaptive-mesh compressible hydrodynamics code for reacting flows.

A Note on the Current Status of PeleC Development

Please be aware that kernels previously written in Fortran in PeleC have been recently ported to C++ to allow for execution on GPUs. These new kernels are located in directories marked *Cpp. The Fortran kernels are currently preserved in this repo using the original directory organization, as all functionality has not yet been ported to C++ and GPUs. However, development in Fortran will not continue and any future development should be done entirely in C++ and with the ability to execute the code within AMReX's GPU framework. The Fortran kernels will be phased out at a future date. This is done in order to run portably using CPUS, CUDA, HIP, and DPC++ programming model backends in the future.

Getting Started

• To compile and run the Pele suite of codes, one needs a C++ compiler that supports the C++14 standard. A hierarchical strategy for parallelism is supported, based MPI + OpenMP, or MPI + CUDA. The codes work with all major MPI and OpenMP implementations. The codes should build and run with no modifications to the make system if using a Linux system with the GNU compilers, version 4.9.4 and above.

To build PeleC and run a sample 3D flame problem:

1. One can have PeleC use the default submodules for AMReX and PelePhysics in its own repo by simply performing:

   git clone --recursive [email protected]:AMReX-Combustion/PeleC.git
   cd PeleC/ExecCpp/RegTests/PMF
   make
   ./Pele3d.xxx,yyy.ex inputs_ex
   

Alternatively, one can set environment variables to use AMReX and PelePhysics repos from external locations:

1. Set the environment variable, AMREX_HOME, and clone a copy of AMReX there:

   export AMREX_HOME=<location for AMReX>
   git clone [email protected]:AMReX-Codes/amrex.git ${AMREX_HOME}
   

2. Set the environment variable, PELE_PHYSICS_HOME, and clone a copy of PelePhysics there. You should be placed in the development branch:

   export PELE_PHYSICS_HOME=<location for PelePhysics>
   git clone [email protected]:AMReX-Combustion/PelePhysics.git ${PELE_PHYSICS_HOME}
   

3. Set the environment variable, PELEC_HOME, and clone a copy of PeleC there. You should be placed in the development branch:

   export PELEC_HOME=<location for PeleC>
   git clone [email protected]:AMReX-Combustion/PeleC.git ${PELEC_HOME}
   

4. Move to an example build folder, build an executable, run a test case:

   cd ${PELEC_HOME}/ExecCpp/RegTests/PMF
   make
   ./Pele3d.xxx,yyy.ex inputs_ex
   

• Notes

  1. In the exec line above, xxx.yyy is a tag identifying your compiler and various build options, and will vary across pltaform. (Note that GNU compilers must be at least 4.8.4, and MPI should be at least version 3).
  2. The example is 3D premixed flame, flowing vertically upward through the domain with no gravity. The lateral boundaries are periodic. A detailed hydrogen model is used. The solution is initialized with a wrinkled (perturbed) 2D steady flame solution computed using the PREMIX code. Two levels of solution-adaptive refinement are automatically triggered by the presence of the flame intermediate, HO2.
  3. In addition to informative output to the terminal, periodic plotfiles are written in the run folder. These may be viewed with CCSE's Amrvis (<https://ccse.lbl.gov/Downloads/downloadAmrvis.html>) or Vis-It (<http://vis.lbl.gov/NERSC/Software/visit/>):
     1. In Vis-It, direct the File->Open dialogue to select the file named "Header" that is inside each plotfile folder..
     2. With Amrvis, "amrvis3d plt00030", for example.

Dependencies

PeleC was created as a renamed, stripped down version of Maui, and is built on the AMReX library. In the process, the Microphysics folder was extracted, and reorganized into a separate repository, PelePhysics.

Development model

To add a new feature to PeleC, the procedure is:

1. Create a branch for the new feature (locally):

   git checkout -b AmazingNewFeature
   

2. Develop the feature, merging changes often from the development branch into your AmazingNewFeature branch:

   git commit -m "Developed AmazingNewFeature"
   git checkout development
   git pull                     [fix any identified conflicts between local and remote branches of "development"]
   git checkout AmazingNewFeature
   git merge development        [fix any identified conflicts between "development" and "AmazingNewFeature"]
   

3. Push feature branch to PeleC repository:

   git push -u origin AmazingNewFeature [Note: -u option required only for the first push of new branch]
   

4. Submit a merge request through [email protected]:AMReX-Combustion/PeleC.git, and make sure you are requesting a merge against the development branch

5. Check the CI status on Github and make sure the tests passed for merge request

Note

Github CI uses the CMake build system and CTest to test the core source files of PeleC. If you are adding source files, you will need to add them to the list of source files in the CMake directory for the tests to pass. Make sure to add them to the GNU make makefiles as well.

Test Status

Nightly test results for PeleC against multiple compilers and machines can be seen on its CDash page here. Static analysis results for PeleC can be seen in the notes of the newest GCC compiler on CDash. PeleC is also tested using the Clang address sanitizer to detect memory leaks.

Test results for the GNU Make implementation of PeleC can be seen here.

Documentation

The full documentation for Pele exists in the Docs directory; at present this is maintained inline using Doxygen and Sphinx Sphinx. With Sphinx, documentation is written in Restructured Text. reST is a markup language similar to Markdown, but with somewhat greater capabilities (and idiosyncrasies). There are several primers available to get started. One gotcha is that indentation matters. To build the documentation, run Doxygen in the Docs directory then build the sphinx

doxygen Doxyfile
cd sphinx_doc
make html

Acknowledgment

This research was supported by the Exascale Computing Project (ECP), Project Number: 17-SC-20-SC, a collaborative effort of two DOE organizations -- the Office of Science and the National Nuclear Security Administration -- responsible for the planning and preparation of a capable exascale ecosystem -- including software, applications, hardware, advanced system engineering, and early testbed platforms -- to support the nation's exascale computing imperative.