# SLEEF - Compiling and installing the library

## Table of contents

- Introduction
- Compiling and installing the library

- Preliminaries
- Quick start
- Compiling and installing the library on Linux
- Compiling the library with Microsoft Visual C++
- Compiling and running "Hello SLEEF"
- Importing SLEEF into your project
- Cross compilation for iOS and Android

- Math library reference
- Quad-precision math library reference
- DFT library reference
- Other tools included in the package
- Benchmark results
- Additional notes

## Preliminaries

In order to build SLEEF, you need CMake, which is an open-source and cross-platform building tool. In order to test the library, it is better to have the GNU MPFR Library, Libssl and FFTW.

CMake works by allowing the developer to specify build parameters and rules in a simple text file that cmake then processes to generate project files for the actual native build tools (e.g. UNIX Makefiles, Microsoft Visual Studio, Apple XCode, etc). If you are not already familiar with cmake, please refer to the official documentation or the basic introductions in the wiki.

## Quick start

You will find quick start instructions in the sources or via GitHub in the README.md file.

A more detailed description of CMake usage is provided in the docs/build-with-cmake.md file, along with a list of CMake variables relevant to users.

## Compiling and installing the library on Linux

In order to build the library, you may want to install OpenMP (optional). In order to test the library, you need to install libmpfr, libssl and libfftw3 (optional). Availability of these libraries are checked upon execution of cmake. Please change the directory to sleef-3.X and run the following commands.

    $ sudo apt-get install libmpfr-dev libssl-dev libfftw3-dev
    $ cmake -S . -B build/ ..
    $ cmake --build build/ --clean-first -j
    $ ctest --test-dir build/ -j
    $ sudo cmake --install build/ --prefix /path/to/install/dir

In order to uninstall the libraries and headers, run the following command.

    $ sudo xargs rm -v < build/install_manifest.txt

### Building the library with LTO support

You can build the library with link time opimization(LTO) support with the following commands. Note that you can only build static libraries with LTO support. You also have to use the same compiler with the same version to build the library and other source codes.

    $ CC=gcc cmake -DBUILD_SHARED_LIBS=FALSE -DSLEEF_ENABLE_LTO=TRUE ..

In order to build the library with thinLTO support with clang, you need to specify LLVM AR command that exactly corresponds to the clang compiler.

    $ CC=clang-9 cmake -DBUILD_SHARED_LIBS=FALSE -DSLEEF_ENABLE_LTO=TRUE -DSLEEF_LLVM_AR_COMMAND=llvm-ar-9 ..

### Building the header files for inlining the whole SLEEF functions

Header files for inlining the whole SLEEF functions can be built with the following commands. With these header files, it may be easier to inline the whole SLEEF functions than using LTO. You have to specify "-ffp-contract=off" compiler option when compiling a source code that includes one of these header files.

    $ cmake -DSLEEF_BUILD_INLINE_HEADERS=TRUE ..

## Compiling the library with Microsoft Visual C++

You need Visual Studio 2019. Open developer command prompt for VS2019 and change directory to sleef-3.X. When configuring a build with cmake, you need to use a specific generator: `cmake -G"Visual Studio 16 2019" ..` This generator will create a proper solution `SLEEF.sln` under the build directory. You can still use `cmake --build .` to build the library without opening Visual Studio.

Below is an example of commands for building SLEEF with Visual Studio.

    D:\sleef-3.X> mkdir build
    D:\sleef-3.X> cd build
    D:\sleef-3.X\build> cmake -G"Visual Studio 15 2017 Win64" ..    &:: If you are using VS2017
    D:\sleef-3.X\build> cmake -G"Visual Studio 16 2019" ..          &:: If you are using VS2019
    D:\sleef-3.X\build> cmake --build . --config Release -- /maxcpucount:1

### Compiling the library with Clang on Windows

You need Visual Studio 2019. Install ninja via VS2019 installer. Download and install clang on Windows from llvm.org. Below is an example of commands for building SLEEF with Clang on Windows.

    D:\sleef-3.X> "c:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Auxiliary\Build\vcvars64.bat"
    D:\sleef-3.X> cmake -S . -B build -GNinja -DCMAKE_C_COMPILER:PATH="C:\Program Files\LLVM\bin\clang.exe" ..
    D:\sleef-3.X> cmake --build build --clean-first

## Compiling and running "Hello SLEEF"

Now, let's try compiling the source code shown in Fig. 2.1.

    #include <stdio.h>
    #include <x86intrin.h>
    #include <sleef.h>

    int main(int argc, char **argv) {
      double a[] = {2, 10};
      double b[] = {3, 20};

      __m128d va, vb, vc;

      va = _mm_loadu_pd(a);
      vb = _mm_loadu_pd(b);

      vc = Sleef_powd2_u10(va, vb);

      double c[2];

      _mm_storeu_pd(c, vc);

      printf("pow(%g, %g) = %g\n", a[0], b[0], c[0]);
      printf("pow(%g, %g) = %g\n", a[1], b[1], c[1]);
    }

Fig. 2.1: Source code for testing

Fig.2.2 shows typical commands for compiling and executing the hello code on Linux computers.

    $ gcc hellox86.c -o hellox86 -lsleef
    $ ./hellox86
    pow(2, 3) = 8
    pow(10, 20) = 1e+20
    $ █

Fig. 2.2: Commands for compiling and executing hellox86.c

You may need to set LD_LIBRARY_PATH environment variable appropriately. If you are trying to execute the program on Mac OSX or Windows, try copying the DLLs to the current directory.

## Importing SLEEF into your project

Below is an example CMakeLists.txt for compiling the above hellox86.c. CMake will automatically download SLEEF from GitHub repository, and thus there is no need to include SLEEF in your software package. If you prefer importing SLEEF as a submodule in git, you can use SOURCE_DIR option instead of GIT_REPOSITORY option for ExternalProject_Add.

    cmake_minimum_required(VERSION 3.5.1)
    include(ExternalProject)
    find_package(Git REQUIRED)

    ExternalProject_Add(libsleef
      GIT_REPOSITORY https://github.com/shibatch/sleef
      CMAKE_ARGS -DCMAKE_INSTALL_PREFIX=${CMAKE_BINARY_DIR}/contrib
    )

    include_directories(${CMAKE_BINARY_DIR}/contrib/include)
    link_directories(${CMAKE_BINARY_DIR}/contrib/lib)

    add_executable(hellox86 hellox86.c)
    add_dependencies(hellox86 libsleef)
    target_link_libraries(hellox86 sleef)

Fig. 2.3: Example CMakeLists.txt

## Cross compilation for iOS and Android

SLEEF has preliminary support for iOS and Android. Here, "preliminary" means that the library is only tested to be built, but not tested to work correctly on the real devices. In order to cross compile the library, you need a cmake tool chain file for the corresponding OS. The tool chain file for iOS can be downloaded from https://github.com/leetal/ios-cmake. The tool chain file for Android is included in the SDK. You first need to build the library for the host computer, then for the target OS. Below is an example sequence of commands for cross compiling the library for iOS.

    $ mkdir build-native
    $ cd build-native
    $ cmake -GNinja ..
    $ ninja
    $ cd ..
    $ mkdir build-cross
    $ cd build-cross
    $ cmake -GNinja -DCMAKE_TOOLCHAIN_FILE=../ios.toolchain.cmake -DNATIVE_BUILD_DIR=`pwd`/../build-native -DSLEEF_DISABLE_MPFR=TRUE -DSLEEF_DISABLE_SSL=TRUE ..
    $ ninja

Below is an example sequence of commands for cross compiling the library for Android.

    $ mkdir build-native
    $ cd build-native
    $ cmake -GNinja ..
    $ ninja
    $ cd ..
    $ mkdir build-cross
    $ cd build-cross
    $ cmake -GNinja -DCMAKE_TOOLCHAIN_FILE=/opt/android-ndk-r21d/build/cmake/android.toolchain.cmake -DNATIVE_BUILD_DIR=`pwd`/../build-native -DANDROID_ABI=arm64-v8a ..
    $ ninja