CMakeLists.txt

cmake_minimum_required(VERSION 3.15...3.31)
set(PROJECT_NAME FTorch)
set(LIB_NAME ftorch)
set(PACKAGE_VERSION 0.1)

project(
  ${PROJECT_NAME}
  VERSION ${PACKAGE_VERSION}
  LANGUAGES C CXX Fortran)

if(WIN32)
  # if building on windows we need to make sure the symbols are exported
  set(CMAKE_WINDOWS_EXPORT_ALL_SYMBOLS TRUE)
  # required to build the .dll on windows
  set(BUILD_SHARED_LIBS TRUE)
endif()

include(FortranCInterface)
FortranCInterface_VERIFY(CXX QUIET)

set(CMAKE_CXX_STANDARD 17)
set(CMAKE_CXX_STANDARD_REQUIRED ON)
set(CMAKE_CXX_EXTENSIONS OFF)

include(CheckLanguage)
if(ENABLE_CUDA)
  check_language(CUDA)
  if(CMAKE_CUDA_COMPILER)
    enable_language(CUDA)
  else()
    message(WARNING "No CUDA support")
  endif()
endif()

# Set RPATH behaviour
set(CMAKE_SKIP_RPATH FALSE)
set(CMAKE_SKIP_BUILD_RPATH FALSE)
set(CMAKE_BUILD_WITH_INSTALL_RPATH FALSE)
# Embed absolute paths to external libraries that are not part of the project,
# (they are expected to be at the same location on all machines the project will
# be deployed to
set(CMAKE_INSTALL_RPATH_USE_LINK_PATH TRUE)

# Follow GNU conventions for installing directories
include(GNUInstallDirs)

# Define RPATH for executables via a relative expression to enable a fully
# relocatable package
file(RELATIVE_PATH relDir ${CMAKE_CURRENT_BINARY_DIR}/${CMAKE_INSTALL_BINDIR}
     ${CMAKE_CURRENT_BINARY_DIR}/${CMAKE_INSTALL_LIBDIR})
set(CMAKE_INSTALL_RPATH $ORIGIN/${relDir})

# Dependencies
find_package(Torch REQUIRED)

# Library with C and Fortran bindings
add_library(${LIB_NAME} SHARED src/ctorch.cpp src/ftorch.F90
                               src/ftorch_test_utils.f90)

if(UNIX)
  if(NOT APPLE) # only add definition for linux (not apple which is also unix)
    target_compile_definitions(${LIB_NAME} PRIVATE UNIX)
  endif()
endif()

# Add an alias FTorch::ftorch for the library
add_library(${PROJECT_NAME}::${LIB_NAME} ALIAS ${LIB_NAME})
# cmake-format: off
set_target_properties(
  ${LIB_NAME} PROPERTIES PUBLIC_HEADER "src/ctorch.h"
  Fortran_MODULE_DIRECTORY "${CMAKE_BINARY_DIR}/modules")
# cmake-format: on
# Link TorchScript
target_link_libraries(${LIB_NAME} PRIVATE ${TORCH_LIBRARIES})
# Include the Fortran mod files in the library
target_include_directories(
  ${LIB_NAME} PUBLIC $<BUILD_INTERFACE:${CMAKE_BINARY_DIR}/modules>
  # $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>
)

# Install library, create target file
install(
  TARGETS "${LIB_NAME}"
  EXPORT ${PROJECT_NAME}
  LIBRARY DESTINATION "${CMAKE_INSTALL_LIBDIR}"
  PUBLIC_HEADER DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}
  PRIVATE_HEADER DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}
  INCLUDES
  DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/${LIB_NAME})

# Install target file
install(
  EXPORT ${PROJECT_NAME}
  FILE ${PROJECT_NAME}Config.cmake
  NAMESPACE ${PROJECT_NAME}::
  DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake/${PROJECT_NAME})

# Install Fortran module files
install(FILES "${CMAKE_BINARY_DIR}/modules/ftorch.mod"
        DESTINATION "${CMAKE_INSTALL_INCLUDEDIR}/${LIB_NAME}")
install(FILES "${CMAKE_BINARY_DIR}/modules/ftorch_test_utils.mod"
        DESTINATION "${CMAKE_INSTALL_INCLUDEDIR}/${LIB_NAME}")

# Build integration tests
if(CMAKE_BUILD_TESTS)

  set(Python_FIND_VIRTUALENV FIRST) # cmake-lint: disable=C0103
  find_package(
    Python
    COMPONENTS Interpreter
    REQUIRED)

  enable_testing()

  # Unit tests
  # NOTE: We do not currently support unit testing on Windows
  if(UNIX)
    add_subdirectory(test/unit)
  endif()

  # Integration tests
  add_subdirectory(examples)
endif()