FleCSI is a compile-time configurable framework designed to support multi-physics application development. As such, FleCSI provides a very general set of infrastructure design patterns that can be specialized and extended to suit the needs of a broad variety of solver and data requirements. FleCSI currently supports multi-dimensional mesh topology, geometry, and adjacency information, as well as n-dimensional hashed-tree data structures, graph partitioning interfaces, and dependency closures.

FleCSI introduces a functional programming model with control, execution, and data abstractions that are consistent both with MPI and with state-of-the-art, task-based runtimes such as Legion and Charm++. The abstraction layer insulates developers from the underlying runtime, while allowing support for multiple runtime systems including conventional models like asynchronous MPI.

The intent is to provide developers with a concrete set of user-friendly programming tools that can be used now, while allowing flexibility in choosing runtime implementations and optimizations that can be applied to future architectures and runtimes.

FleCSI's control and execution models provide formal nomenclature for describing poorly understood concepts such as kernels and tasks. FleCSI's data model provides a low-buy-in approach that makes it an attractive option for many application projects, as developers are not locked into particular layouts or data structure representations.

If you are doing development of FleCSI, please take some time to read the developer README.

The primary requirement for building FleCSI is that you have a C++14-capable compiler.

You'll need the following tools in order to build FleCSI:

• Boost >= 1.56
• CMake >= 3.0
• GCC >= 6.1.1

Install tools in the customary manner for your machine, e.g. by using apt-get on a Ubuntu system, or dnf for Fedora.

For documentation, you'll need these as well:

• Doxygen >= 1.8
• cinch-utils >= 1.0
• Pandoc >= 1.19

If you wish to build FleCSI on LANL's Darwin cluster, see the Darwin Cluster section later in this document.

Before installing FleCSI, you should install the FleCSI third-party libraries. We'll assume that you wish to install the FleCSI third-party libraries in your home directory.

Begin by downloading the FleCSI third-party libraries:

$ cd
$ git clone --recursive https://github.com/laristra/flecsi-third-party.git

Next, enter flecsi-third-party and make a build directory:

$ cd flecsi-third-party
$ mkdir build
$ cd build

Then, for example, you can do the following for a debug-mode build:

$ cmake .. \
    -DCMAKE_BUILD_TYPE=Debug \
    -DCMAKE_INSTALL_PREFIX=$HOME/flecsi-third-party-debug/

Alternatively, you can run ccmake in place of cmake, and use ccmake's interface to set the options.

Finally:

$ make

builds and installs the FleCSI third-party libraries in the prefix that you specified.

Now that the FleCSI third-party libraries are installed, you can download and build FleCSI itself. As with the third-party libraries, we'll assume that you wish to install FleCSI in your home directory.

First, download FleCSI from GitHub:

$ cd
$ git clone --recursive https://github.com/laristra/flecsi.git

By default, you'll be on the master branch. Let's say you wish to work in the branchname branch instead. Enter flecsi, switch to the relevant branch, and be sure that you have the latest updates:

$ cd flecsi
$ git checkout branchname   # if you wish to work in this branch
$ git pull
$ git submodule update --recursive

You can now build FleCSI. For example, a Debug build using Legion can be done like this:

$ mkdir build
$ cd build
$ cmake .. \
    -DCMAKE_BUILD_TYPE=Debug \
    -DCMAKE_PREFIX_PATH=$HOME/flecsi-third-party-debug \
    -DENABLE_UNIT_TESTS=ON \
    -DFLECSI_RUNTIME_MODEL=legion
$ make

where cmake's -DCMAKE_PREFIX_PATH should be the path that you used for your FleCSI third-party library installation.

Again, you can run ccmake in place of cmake.

You can build the FleCSI User and Developer Guides, as well as the Doxygen interface documentation by specifying additional arguments to the CMake configuration line:

$ cmake .. \
    -DCMAKE_BUILD_TYPE=Debug \
    -DCMAKE_PREFIX_PATH=$HOME/flecsi-third-party-debug/ \
    -DENABLE_UNIT_TESTS=ON \
    -DFLECSI_RUNTIME_MODEL=legion \
    -DENABLE_DOCUMENTATION=ON \
    -DENABLE_DOXYGEN=ON
$ make

This will build the User and Developer Guides in the doc subdirectory.

In order to build the Doxygen interface documentation, you will need to execute:

$ make doxygen

which will build the interface documentation (also under the doc subdirectory).

From within the build directory, and after running make as described above, you can run

$ make test

to run FleCSI's unit tests.

FleCSI uses the GitHub Flow workflow pattern.

When you check-out FleCSI, you'll be on the master branch. This is the FleCSI development branch, which is protected in order to ensure that it is always deployable.

New work should always be done on a separate feature branch. When you have finished making updates to your branch, you should submit a pull request. Your changes will be tested for compliance, and reviewed by the maintainers of the project. If your changes are accepted, they will be merged into master.

On Darwin, you can simplify some of the build requirements by using the ngc/devel-gnu environment module:

$ module load ngc   # ngc/devel-gnu is the default

which will load up-to-date compiler and documentation tools. You'll also want OpenMPI:

$ module load openmpi

Finally, you may want a later GCC than what the ngc module might provide, and you'll need compatible Boost libraries:

$ module unload gcc
$ module load gcc/6.2.0
$ module load boost/1.59.0_gcc-6.2.0

Note that the Boost module should match the gcc version.

This software has been approved for open source release and has been assigned LA-CC-16-022.

Copyright (c) 2016, Los Alamos National Security, LLC All rights reserved.

Copyright 2016. Los Alamos National Security, LLC. This software was produced under U.S. Government contract DE-AC52-06NA25396 for Los Alamos National Laboratory (LANL), which is operated by Los Alamos National Security, LLC for the U.S. Department of Energy. The U.S. Government has rights to use, reproduce, and distribute this software. NEITHER THE GOVERNMENT NOR LOS ALAMOS NATIONAL SECURITY, LLC MAKES ANY WARRANTY, EXPRESS OR IMPLIED, OR ASSUMES ANY LIABILITY FOR THE USE OF THIS SOFTWARE. If software is modified to produce derivative works, such modified software should be clearly marked, so as not to confuse it with the version available from LANL.

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