CMAKE_CUDA_ARCHITECTURES is not displayed in ccmake

[SimeonEhrig]

If I build alpaka with enabled CUDA backend, the variable CMAKE_CUDA_ARCHITECTURES will be not displayed in the build folder, if I use ccmake.

In a default CUDA CMake project, the variable is visible, if I use ccmake.

cmake_minimum_required(VERSION 3.19)

project(gpu_arch LANGUAGES CXX)

enable_language(CUDA)

add_executable(${CMAKE_PROJECT_NAME})
target_sources(${CMAKE_PROJECT_NAME}
    PRIVATE
    main.cu
)

I think, there is a bug in the alpaka CMake, which hides/deletes the variable.

[SimeonEhrig]

cc @psychocoderHPC

[bernhardmgruber]

When I configure in am empty build directory:

CXX=g++-12 cmake -DCMAKE_CUDA_COMPILER=nvcc -DCMAKE_CUDA_HOST_COMPILER=g++-12 -Dalpaka_ACC_GPU_CUDA_ENABLE=ON ..
ccmake .

I see:

Looks good to me regarding my workflow. I use cmake version 3.28.1 and nvcc 12.3.

[bernhardmgruber]

Also works for your empty project:

bgruber@graviola:~/dev/tet/build$ cat ../main.cu 
bgruber@graviola:~/dev/tet/build$ cat ../CMakeLists.txt 
cmake_minimum_required(VERSION 3.19)

project(gpu_arch LANGUAGES CXX)

enable_language(CUDA)

add_executable(${CMAKE_PROJECT_NAME})
target_sources(${CMAKE_PROJECT_NAME}
    PRIVATE
    main.cu
)
bgruber@graviola:~/dev/tet/build$ rm -rf *
bgruber@graviola:~/dev/tet/build$ CXX=g++-12 cmake -DCMAKE_CUDA_COMPILER=nvcc -DCMAKE_CUDA_HOST_COMPILER=g++-12 ..
-- The CXX compiler identification is GNU 12.3.0
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working CXX compiler: /usr/bin/g++-12 - skipped
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- The CUDA compiler identification is NVIDIA 12.3.107
-- Detecting CUDA compiler ABI info
-- Detecting CUDA compiler ABI info - done
-- Check for working CUDA compiler: /usr/local/cuda/bin/nvcc - skipped
-- Detecting CUDA compile features
-- Detecting CUDA compile features - done
-- Configuring done (1.5s)
-- Generating done (0.0s)
-- Build files have been written to: /home/bgruber/dev/tet/build
bgruber@graviola:~/dev/tet/build$ ccmake .