C++ 中 CMakeLists.txt:10 (find_package) 的 Torch CMake 错误

Question

我正在尝试通过调用 torch/torch.h 的 CMake 创建一个 Eclipse C++ 项目。我运行cmake -G "Eclipse CDT4 - Unix Makefiles" ./ 来创建一个Eclipse 项目，但我得到了这个错误：

-- The C compiler identification is GNU 7.3.0
-- The CXX compiler identification is GNU 7.3.0
-- Could not determine Eclipse version, assuming at least 3.6 (Helios). Adjust CMAKE_ECLIPSE_VERSION if this is wrong.
-- Check for working C compiler: /usr/bin/cc
-- Check for working C compiler: /usr/bin/cc -- works
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Detecting C compile features
-- Detecting C compile features - done
-- Check for working CXX compiler: /usr/bin/c++
-- Check for working CXX compiler: /usr/bin/c++ -- works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Detecting CXX compile features
-- Detecting CXX compile features - done
CMake Error at CMakeLists.txt:10 (find_package):
  By not providing "FindTorch.cmake" in CMAKE_MODULE_PATH this project has
  asked CMake to find a package configuration file provided by "Torch", but
  CMake did not find one.

  Could not find a package configuration file provided by "Torch" with any of
  the following names:

    TorchConfig.cmake
    torch-config.cmake

  Add the installation prefix of "Torch" to CMAKE_PREFIX_PATH or set
  "Torch_DIR" to a directory containing one of the above files.  If "Torch"
  provides a separate development package or SDK, be sure it has been
  installed.


-- Configuring incomplete, errors occurred!

其中CMakeLists.txt所在的当前目录有：

cmake_minimum_required(VERSION 3.0 FATAL_ERROR)
project(test)        
find_package(Torch REQUIRED)    
add_executable(test test.cpp)
target_link_libraries(test "${TORCH_LIBRARIES}")
set_property(TARGET test PROPERTY CXX_STANDARD 11)

显然，它找不到TorchConfig.cmake 和torch-config.cmake 文件；不过，我在/home/afshin/libtorch/share/cmake/Torch 中有 TorchConfig.cmake。我通过测试每个将相应的路径添加到CMakeLists.txt文件中：

set(CMAKE_MODULE_PATH "/home/afshin/libtorch/share/cmake/Torch;${CMAKE_MODULE_PATH}")
set(CMAKE_MODULE_PATH "/home/afshin/libtorch/share/cmake;${CMAKE_MODULE_PATH}")
set(CMAKE_MODULE_PATH "/home/afshin/libtorch;${CMAKE_MODULE_PATH}")
set(Torch_DIR "/home/afshin/libtorch;${Torch_DIR}")
set(Torch_DIR "/home/afshin/libtorch/share/cmake/Torch;${Torch_DIR}")
set(Torch_DIR "/home/afshin/libtorch/share/cmake;${Torch_DIR}")
set(DCMAKE_PREFIX_PATH "/home/afshin/libtorch/share/cmake/Torch;${DCMAKE_PREFIX_PATH}")
set(DCMAKE_PREFIX_PATH "/home/afshin/libtorch/share/cmake;${DCMAKE_PREFIX_PATH}")
set(DCMAKE_PREFIX_PATH "/home/afshin/libtorch;${DCMAKE_PREFIX_PATH}")

但是，它没有帮助，我仍然得到同样的错误。 我感谢任何帮助或 cmets。

我也尝试了 cmake-gui，我得到了同样的错误：

谢谢， 阿夫辛

Answer 1

我能够通过将CMakeLists.txt 编辑为：

cmake_minimum_required(VERSION 3.0 FATAL_ERROR)
project(test_cmake)

set(CMAKE_PREFIX_PATH "/home/afshin/libtorch/share/cmake/Torch")
find_package(Torch REQUIRED)

add_executable(test_cmake ./src/test_cmake.cpp)
target_link_libraries(test_cmake "${TORCH_LIBRARIES}")
set_property(TARGET test_cmake PROPERTY CXX_STANDARD 11)

或者，使用cmake-gui 也可以通过以下设置解决问题：

点击configure，然后点击generate。 最后，我通过选择Makefile Project With Existing Code 将这个项目导入Eclipse。此代码已成功编译和构建。

Answer 2

以下修改后的CMakeLists.txt 文件在没有明显缺失的TorchConfig.cmake （在vcpkg 安装here 中也缺失）的情况下工作。我推荐微软的vcpkg 用于跨平台包（c++ 库）管理（用法here）。但是代码是 vcpkg 独立的：可以将TORCH_BASE_PATH（或Torch_INCLUDE_DIR 和Torch_LIBRARIES）设置为正确的路径。

#[[
    tested with:
    - CMake 3.13
    - Visual Studio Community Edition 15.9.4
        (CMake generator: "Visual Studio 15 2017 Win64")
    - torch-th library installed with vcpkg
        generic: vcpkg install torch-th
        for macOS: vcpkg install torch-th:x64-osx-dynamic
            x64-osx-dynamic triplet must be created: x64-osx + "set(VCPKG_LIBRARY_LINKAGE dynamic)"
        for Windows: vcpkg install torch-th:x64-windows

    - easy torch sample: https://apaszke.github.io/torch-internals.html
    ]]
cmake_minimum_required(VERSION 3.0 FATAL_ERROR)
project(test)

# cannot work without a "package configuration file" (TorchConfig.cmake)
#   so we replace it with find_path and find_library
#find_package(Torch REQUIRED)

#[[ 
    the environement variable VCPKG_ROOT used here, contains the path to vcpkg installation folder
        replace the two paths with your paths to TH installation

    usage: #include "TH/TH.h"
    ]]
set(TORCH_BASE_PATH "$ENV{VCPKG_ROOT}/installed/${VCPKG_TARGET_TRIPLET}")
message(STATUS TORCH_BASE_PATH=${TORCH_BASE_PATH})

set(Torch_INCLUDE_DIR "${TORCH_BASE_PATH}/include")
set(Torch_LIBRARIES "${TORCH_BASE_PATH}/lib")
# target_link_libraries is to be preferred
#link_directories(${Torch_LIBRARIES})
find_library(LIBRARY_TORCH TH HINTS ${Torch_LIBRARIES})
#[[ 
    even simpler
    if you use the vcpkg toolchain file "$ENV{VCPKG_ROOT}/scripts/buildsystems/vcpkg.cmake"

        find_path(Torch_INCLUDE_DIR TH/TH.h)
        find_library(LIBRARY_TORCH TH)
    ]]

add_executable(test test.cpp)
target_include_directories(test PRIVATE ${Torch_INCLUDE_DIR})
target_link_libraries(test ${LIBRARY_TORCH})

set(CMAKE_CXX_STANDARD 11)
#set_property(TARGET test PROPERTY CXX_STANDARD 11)