1libtorch (C++-only) 2=================== 3 4The core of pytorch does not depend on Python. A 5CMake-based build system compiles the C++ source code into a shared 6object, libtorch.so. 7 8Building libtorch using Python 9------------------------------ 10 11You can use a python script/module located in tools package to build libtorch 12:: 13 cd <pytorch_root> 14 15 # Make a new folder to build in to avoid polluting the source directories 16 mkdir build_libtorch && cd build_libtorch 17 18 # You might need to export some required environment variables here. 19 Normally setup.py sets good default env variables, but you'll have to do 20 that manually. 21 python ../tools/build_libtorch.py 22 23 24Alternatively, you can call setup.py normally and then copy the built cpp libraries. This method may have side effects to your active Python installation. 25:: 26 cd <pytorch_root> 27 python setup.py build 28 29 ls torch/lib/tmp_install # output is produced here 30 ls torch/lib/tmp_install/lib/libtorch.so # of particular interest 31 32To produce libtorch.a rather than libtorch.so, set the environment variable `BUILD_SHARED_LIBS=OFF`. 33 34To use ninja rather than make, set `CMAKE_GENERATOR="-GNinja" CMAKE_INSTALL="ninja install"`. 35 36Note that we are working on eliminating tools/build_pytorch_libs.sh in favor of a unified cmake build. 37 38Building libtorch using CMake 39-------------------------------------- 40 41You can build C++ libtorch.so directly with cmake. For example, to build a Release version from the main branch and install it in the directory specified by CMAKE_INSTALL_PREFIX below, you can use 42:: 43 git clone -b main --recurse-submodule https://github.com/pytorch/pytorch.git 44 mkdir pytorch-build 45 cd pytorch-build 46 cmake -DBUILD_SHARED_LIBS:BOOL=ON -DCMAKE_BUILD_TYPE:STRING=Release -DPYTHON_EXECUTABLE:PATH=`which python3` -DCMAKE_INSTALL_PREFIX:PATH=../pytorch-install ../pytorch 47 cmake --build . --target install 48 49To use release branch v1.6.0, for example, replace ``master`` with ``v1.6.0``. You will get errors if you do not have needed dependencies such as Python3's PyYAML package. 50