samuelkgutierrez/branson

Branson

Introduction

So you've decided to use Branson...

Here are some things to know:

Branson is not an acronym.
The point of Branson is to study different algorithms for parallel Monte Carlo transport. Currently it contains particle passing and mesh passing methods for domain decomposition.
Many of the parameters that impact parallel performance can be set in the input file.
The input file format is ugly right now and I don't have a good list of parameters and what they do. Sorry.
Input files are in XML, which makes them easy to generate and change in python.
Input files are complicated when you want to have multiple spatial regions but are pretty simple otherwise.

How to install

Accessing the sources

Download a tarball from Github, or
Fork and clone the git repository.

# after forking the repository
git clone git@github.com:[github-username]/branson
cd branson
git remote add upstream git@github.com:lanl/branson
git checkout -b develop upstream/develop

Installing Branson:

Build requirements:
- C/C++ compiler(s) with support for C11 and C++14.
- CMake 3.9+
- MPI 3.0+ (OpenMPI 1.10+, mpich, etc.)
- Boost (only headers are required)
- Metis
- Parmetis
Optional dependencies (needed for visualization)
- HDF5
- Silo
- If these tools aren't readily avilable on your target machine, consider using a package manager like spack to help you install these tools.
There is only one CMake user option right now: CMAKE_BUILD_TYPE which can be set on the command line with -DCMAKE_BUILD_TYPE=<Debug|Release> and the default is Release.
If cmake has trouble finding your installed TPLs, you can try
- appending their locations to CMAKE_PREFIX_PATH,
- Setting helper variables like BOOST_ROOT or HDF5_ROOT (refer to the cmake documentation or the FindXXX.cmake scripts in Branson's src/config directory for a list of variables), or
- try running ccmake . from the build directory and changing the values of build system variables related to TPL locations.

EXPORT CXX=`which g++`
cd $build_dir
cmake -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=<install-location> ${branson_source_dir}/src
make -j

Testing the build:

cd $build_dir
ctest -j 32

Special builds

Fake Multigrop Branson:

The clean_mg branch has a new capability that mimics the data flow in real multigroup transport.
This branch sets the number of groups at the configure step in CMake. I know this is messy from a usability standpoint but it makes the data layout very easy to control when the number of groups is known at compile time. Use the N_GROUPS CMake variable to set the number of groups (e.g. cmake -DN_GROUPS=10 ../path/to/CMakeLists.txt).
The code will still produce gray results! The physical value in each group is the same and it's still set via the input deck.
This branch samples a group with a uniform PDF (it does not weight the opacity with a Planckian spectrum).

Authors

Branson was written by Alex R. Long
RNG.h uses code from Draco

Release

Branson is released under the BSD 3-Clause License. For more details see the LICENSE.md file.

LANL code designation: C17048

samuelkgutierrez / branson