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Installation

We've tried to make Skywalker as easy as possible to use with your current software. To build it, you need

  • CMake v3.10+
  • GNU Make
  • Reliable C and C++ compilers (like GCC and Clang)
  • A decent Fortran compiler (like GFortran or Intel's ifort)

You can also build Skywalker on Windows. It has been tested with Visual Studio 2022 Community Edition with the Intel oneAPI Fortran Classіc (ifort) compiler. Your mileage may vary if you use different versions of Visual Studio or a different Fortran compiler.

Clone the Repository

First, go get the source code at GitHub:

git clone git@github.com:eagles-project/skywalker.git

git clone https://github.com/eagles-project/skywalker.git

This places a skywalker folder into your current path. If you're using Visual Studio, just use your Git workflow to clone the repository.

Configure Skywalker

Skywalker uses CMake as its build system. CMake accepts a few options that specify how Skywalker should be built. Here are the most important options for you to consider.

  • CMAKE_INSTALL_PREFIX sets the path to which the Skywalker C, C++, and Fortran headers/module and libraries are installed. This is often something like /usr/local by default.
  • CMAKE_BUILD_TYPE controls whether optimization is on (Release) or whether the build is instrumented for a debugger (Debug).
  • SKYWALKER_PRECISION can be set to single or double (default) to control the precision of floating point numbers.
  • CMAKE_C_COMPILER sets the C compiler that is used to build Skywalker. Usually, the default compiler is fine, but if you want to use an MPI-capable compiler or a specific vendor compiler, you can specify it with this option.
  • ENABLE_FORTRAN, when set to ON (its default value), builds Fortran support for Skywalker. You can set this to OFF if you don't need Fortran.
  • CMAKE_Fortran_COMPILER sets the Fortran compiler that is used to build Skywalker's Fortran interface.

From the top-level skywalker directory, create a "build" directory (e.g. build). This is where you'll configure and build Skywalker. For example, to configure a debuggable build of Skywalker that uses double precision, do the following:

mkdir build
cd build
cmake -DCMAKE_INSTALL_PREFIX=/path/to/install \
      -DCMAKE_BUILD_TYPE=Debug \
      -DSKYWALKER_PRECISION=double \
      ..

This creates a set of Makefiles in your build directory. Now you're ready to build.

Visual Studio gets its settings from CMakeSettings.json in the top-level source directory.

Build, Test, and Install Skywalker

To build skywalker, make sure you're in your build directory and type

make -j

If this process succeeds, you can run the tests and examples included with Skywalker by typing

make test

If you're using Linux, you can also run Skywalker's tests through Valgrind to check for memory corruptions and leaks with

make memcheck

(but be prepared to wait a while for the tests to finish).

You should see several tests run (and hopefully pass!). Now, to install Skywalker to the path you specified with CMAKE_INSTALL_PREFIX, type

make install

You should be able to use the Build and Test workflows in Visual Studio to build, test, and install Skywalker.

The installation process produces the following artifacts, which you can use to build your own Skywalker programs:

  • PREFIX/lib/libskywalker_<precision>.a, a library you can use with a C or C++ Skywalker program.
  • PREFIX/include/skywalker.h, a C header file that provides Skywalker's C interface.
  • PREFIX/include/skywalker.hpp, a C++ header file that provides Skywalker's C++ interface.
  • PREFIX/share/skywalker.cmake, a CMake file that includes installation information for Skywalker, plus a function called add_skywalker_driver you can use to build your own driver programs.

When ENABLE_FORTRAN is set to ON, you get additional Fortran artifacts: * PREFIX/lib/libskywalker_f90_<precision>.a, a library you can use with a Fortran Skywalker program. * PREFIX/include/skywalker.mod, a Fortran 90 module header file that provides Skywalker's Fortran interface.

On Windows, the library files have a .lib suffix instead of .a.

Here, PREFIX stands for the path you passed to CMAKE_INSTALL_PREFIX. These files are all you need to build Skywalker programs.

Try It Out!

At this point, you're ready to start using Skywalker. Look at the Quick Start section to get started.