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Installation

Building XAD

Prerequisites

  • CMake, version 3.15 or newer
  • Compiler/IDE options:
    • Visual Studio 2015 or newer (for Microsoft compilers)
    • Visual Studio 2019 or newer with Clang toolset (for Clang)
  • Git client

For Windows, we recommend the latest Visual Studio 2022 IDE with its integrated CMake support.

  • CMake, version 3.15 or newer
  • Compiler Options:
    • GCC 5.4 or newer
    • Clang 11 or newer
  • Git client
  • MacOS 10.9.5 or newer
  • CMake, version 3.15 or newer
  • Apple Clang 11 or newer
  • Git client

For the full list of platforms and compilers covered by continuous integration, see tested platforms.

Cloning the Repository

git clone https://github.com/auto-differentiation/XAD.git

Building

  1. Use "Open Folder" to open the cloned directory
  2. Select the desired configuration from the top toolbar (e.g. Release x64), or add a new one using Manage Configurations...
  3. Select Project > Build (or press F7)

See the documentation for Visual Studio's built-in CMake support for more information.

Note: The compiler toolset should be in the path. In Windows, start a Visual Studio Developer command prompt with the desired toolset first.

  1. Create a directory for the build artefacts
    cd XAD
    mkdir build
    cd build
    
  2. Run cmake to generate the build files
    cmake ..
    
  3. Build using the native build system or with the generic cmake build command
    cmake --build .
    
  1. Open the CMake GUI and select the source and build folders
  2. Click the Configure button, selecting the desired compiler toolset
  3. Click Generate, which creates the native build files provided.
  4. If the Visual Studio generator was chosen, click Open Project to start Visual Studio, where the solution can be built

More information about how to use the CMake GUI is available from the official CMake documentation.

Running the Tests

The tests are managed by CMake's CTest tool. The can be executed as:

Open the Test > Test Explorer to run / debug individual tests or the full suite conveniently. Visual Studio discovers the CTest tests after each build automatically. Refer to the documentation for the test explorer for more information how to use this convenient tool.

Run the ctest tool inside the build folder:

ctest

Note that the flag -j<num_proc> can be given to run <num_proc> parallel processes, and there are more convenient ctest flags for example for controlling output, ordering, or selecting specific tests.

Most tests are combined into a single Google Test executable called xad_test, which can be found in the test directory in the build tree. This can also be executed directly:

cd test
./xad_test

It also provides parameters, e.g. for selecting specific tests, control outputs, which can be seen when running ./xad_test --help

Installing

Run the install build target to place the header files, library files, docs, and samples into the CMAKE_INSTALL_PREFIX (configurable with CMake).

Select Build > Install from the menu.

Run the following from the build folder:

cmake --install .

Integration Approaches

In order to use XAD as part of other code, we recommend one of the following approaches.

1: Submodule + CMake

If your codebase is using CMake, XAD can be integrated easily into your project by adding it as a git submodule.

To add the submodule in a subdirectory extern/XAD:

git submodule add https://github.com/auto-differentiation/XAD.git extern/XAD

Users then need to clone recursively (git clone --recursive ...) or initialise and update the submodules (git submodule init && git submodule update). More information about submodules can be found in the Git documentation.

To add XAD to the project, all that is needed in one of the CMakeLists.txt files is to add the xad directory, and then link the relevant libraries or executables to XAD::xad:

add_subdirectory(extern/XAD)

add_executable(some_executable ...)
target_link_libraries(some_executable PRIVATE XAD::xad)

2: FetchContent + CMake

The CMake FetchContent module allows to clone the git repository at configure-time into the build folder and add it to your project after:

include(FetchContent)

FetchContent_Declare(XAD
    GIT_REPOSITORY https://github.com/auto-differentiation/XAD.git
    GIT_TAG 1.2.0    # pick a tag, hash, or branch here
)
FetchContent_MakeAvailable(XAD)

The relevant libraries or executables can then be linked to XAD::xad in the usual way:

add_executable(some_executable ...)
target_link_libraries(some_executable PRIVATE XAD::xad)

Another approach is to install XAD into a convenient prefix (e.g. /usr/local/) first (instructions above, setting CMAKE_INSTALL_PREFIX appropriately). Note that the package can also be zipped on one machine and downloaded/extracted on another.

Warning

Since XAD is built as a static library, be careful to use the same compiler and flags for your project and XAD itself. Otherwise the binaries may not be compatible. We therefore recommend the subproject approach, building from source within your project. The library builds very fast.

CMake

Then, when you use CMake, you can setup your project to find the XAD dependency in a CMakeLists.txt file as:

find_package(XAD REQUIRED)

If XAD is installed in a standard location, CMake automatically looks for it there and finds it. Otherwise, the CMAKE_PREFIX_PATH variable can be set at configure-time to add a different directory to its search path:

cmake /path/to/src -DCMAKE_PREFIX_PATH=/path/to/XAD/installprefix

Other Build Tools

If your project does not use CMake, an installed package can also be linked by adding the following settings:

  • Add /path/to/XAD/include to the compiler's include search path
  • Enable at least C++ 11 support (-std=c++11 in GCC)
  • Enable threading in Linux (requires -pthread in GCC for compile and link)
  • Add the library path /path/to/XAD/lib to the linker search paths
  • Link on of the following depending on the configuration:
  • Linux or Mac, Release: libxad.a
  • Linux or Mac, Debug: libxad_d.a
  • Windows 64bit, Release, toolset 14.3 (VS 2022): xad64_vc143_md.lib
  • Windows 64bit, Debug, toolset 14.3 (VS 2022): xad64_vc143_mdd.lib
  • Windows 64bit, Release, toolset 14.2 (VS 2019): xad64_vc142_md.lib
  • Windows 64bit, Debug, toolset 14.2 (VS 2019): xad64_vc142_mdd.lib
  • Windows 64bit, Release, toolset 14.1 (VS 2017): xad64_vc141_md.lib
  • Windows 64bit, Debug, toolset 14.1 (VS 2017): xad64_vc141_mdd.lib

Tuning Behaviour and Performance

A number of options are available via CMake configuration variables to control the build and tune the performance. They can be configured as:

From the Configurations dropdown in the top toolbar, select Manage Configurations... to see the available configuration and adjust the CMake variables.

Within the build directory, variables can be set either with the initial cmake command or at a later point as:

cmake . -DVARIABLE=value

The variables with there default settings are listed in the main part of the GUI can can be changed directly.

Influential variables controlling the build are:

Variable Description Default
XAD_ENABLE_TESTS Enable building tests and samples. ON if main project
OFF if sub project
XAD_WARNINGS_PARANOID Enable a high warning level and flag warnings as errors. ON
XAD_STATIC_MSVC_RUNTIME Use the static multi-threaded runtime in Visual C++ (default is dynamic)
XAD_POSITION_INDEPENDENT_CODE Generate position-indepent code, i.e. allow linking into a shared library. ON
XAD_ENABLE_ADDRESS_SANITIZER Enable address sanitizer (leak detector) - GCC/Clang only. OFF

Options with an impact on the performance of the tape in adjoint mode (application-specific). These should not be changed in client code after the tape has been compiled:

Variable Description Default
XAD_SIMD_OPTION Select between SSE2, AVX, AVX2, and AVX512 instruction sets. Only enable what the target CPU supports. AVX
XAD_TAPE_REUSE_SLOTS Keep track of unused slots in tape and re-use them (less memory, more compute) OFF
XAD_NO_THREADLOCAL Disable thread-local tapes (use with single-threaded code only OFF

Options that can be set by client code as well, adjusting settings after the XAD library has already been compiled and installed (in Config.hpp or client code pre-processor definitions):

Variable Description Default
XAD_USE_STRONG_INLINE Force inlining expression templates, rather than letting the compiler decide. (faster, slow compilation, possible compiler crashes) OFF
XAD_ALLOW_INT_CONVERSION Add real -> integer conversion operator, similar to double. This may result missing some variable dependency tracking for AAD. ON

Building the Documentation

The user documentation uses the popular MkDocs Material tool. It is entirely generated from the markdown files located in the docs folder. It can be edited with one of the following approaches.

1: Docker

The docs can be generated easily using docker by running in the project root:

docker run --rm -it -p 8000:8000 -v "%cd%":/docs squidfunk/mkdocs-material
docker run --rm -it -p 8000:8000 -v ${PWD}:/docs squidfunk/mkdocs-material

This will serve the documentation on http://localhost:8000 and watch for changes in the docs folder automatically. The files can now be modified and conveniently viewed in the browser.

2: Local Python

Alternatively, MkDocs can be installed locally into a Python environment and executed as follows (we recommend a virtual environment as shown below).

Setup the environment and dependencies (first time):

python -m venv .venv
.venv\Scripts\activate.bat
pip install mkdocs-material mkdocs-minify-plugin mkdocs-redirects "pillow<10" "cairosvg>=2.5"
python -m venv .venv
.venv\Scripts\activate.ps1
pip install mkdocs-material mkdocs-minify-plugin mkdocs-redirects "pillow<10" "cairosvg>=2.5"
python -m venv .venv
source .venv/bin/activate
pip install mkdocs-material mkdocs-minify-plugin mkdocs-redirects "pillow<10" "cairosvg>=2.5"

Run mkdocs (in the activated environment):

mkdocs serve

This will serve the documentation on http://localhost:8000 and watch for changes in the docs folder automatically. The files can now be modified and conveniently viewed in the browser.

Getting Help

If you have found an issue, want to report a bug, or have a feature request, please raise a GitHub issue.

For general questions about XAD, sharing ideas, engaging with community members, etc, please use GitHub Discussions.

Tested Platforms

The following platforms are part of the continuous integration workflow, i.e. they are tested on each commit. You can use other configurations at your own risk, or submit a PR to include it in the CI workflow.

Operating System Compiler Configurations Test Coverage Recorded
Windows Server 2019 Visual Studio 2015 (Toolset 14.0) Debug, Release no
Windows Server 2022 Visual Studio 2017 (Toolset 14.1) Debug, Release no
Windows Server 2022 Visual Studio 2019 (Toolset 14.2) Debug, Release no
Windows Server 2022 Visual Studio 2022 (Toolset 14.3) Debug, Release no
Windows Server 2022 Clang 16.0 (Toolset 14.3) Debug, Release no
Ubuntu 16.04 GCC 5.4.0 Debug, Release, Release with XAD_TAPE_REUSE_SLOTS no
Ubuntu 17.10 GCC 6.4.0 Debug, Release, Release with XAD_TAPE_REUSE_SLOTS no
Ubuntu 17.10 GCC 7.2.0 Debug, Release, Release with XAD_TAPE_REUSE_SLOTS no
Ubuntu 18.04 GCC 8.4.0 Debug, Release, Release with XAD_TAPE_REUSE_SLOTS no
Ubuntu 19.10 GCC 9.2.0 Debug, Release, Release with XAD_TAPE_REUSE_SLOTS no
Ubuntu 20.04 GCC 10.3.0 Debug, Release, Release with XAD_TAPE_REUSE_SLOTS no
Ubuntu 20.04 GCC 11.1.0 Debug, Release, + both with XAD_TAPE_REUSE_SLOTS yes
Ubuntu 20.04 Clang 11.0.0 Debug, Release, Release with XAD_TAPE_REUSE_SLOTS no
Ubuntu 22.04 Clang 12.0.1 Debug, Release, Release with XAD_TAPE_REUSE_SLOTS no
Ubuntu 22.04 Clang 13.0.1 Debug, Release, Release with XAD_TAPE_REUSE_SLOTS no
Ubuntu 22.04 Clang 14.0.0 Debug, Release, Release with XAD_TAPE_REUSE_SLOTS no
Ubuntu 22.04 Clang 15.0.7 Debug, Release, Release with XAD_TAPE_REUSE_SLOTS no
MacOS 12.6.5 AppleClang 14.0.0 Debug, Release yes