Rebase on KokkosFFT

.github/workflows/tests.yml

@@ -159,6 +159,7 @@ jobs:
           export benchmark_ROOT=$PWD/opt/benchmark
           export GTest_ROOT=$PWD/opt/gtest
           export Kokkos_ROOT=$PWD/opt/kokkos
+          export KokkosFFT_ROOT=$PWD/opt/kokkos-fft
           export KokkosKernels_ROOT=$PWD/opt/kokkos-kernels
           export mdspan_ROOT=$PWD/opt/mdspan
 
@@ -197,6 +198,16 @@ jobs:
           cmake --install build --prefix $Kokkos_ROOT
           rm -rf build
 
+          cmake \
+            -DCMAKE_BUILD_TYPE=${{matrix.cmake_build_type}} \
+            -DCMAKE_CXX_STANDARD=${{matrix.cxx_version}} \
+            -DKokkosFFT_ENABLE_HOST_AND_DEVICE=ON \
+            -B build \
+            -S /src/vendor/kokkos-fft
+          cmake --build build --parallel 2
+          cmake --install build --prefix $KokkosFFT_ROOT
+          rm -rf build
+
           cmake \
             -DCMAKE_BUILD_TYPE=${{matrix.cmake_build_type}} \
             -DCMAKE_CXX_STANDARD=${{matrix.cxx_version}} \
@@ -234,6 +245,7 @@ jobs:
             -DDDC_benchmark_DEPENDENCY_POLICY=INSTALLED \
             -DDDC_GTest_DEPENDENCY_POLICY=INSTALLED \
             -DDDC_Kokkos_DEPENDENCY_POLICY=INSTALLED \
+            -DDDC_KokkosFFT_DEPENDENCY_POLICY=INSTALLED \
             -DDDC_mdspan_DEPENDENCY_POLICY=INSTALLED \
             -B build \
             -S /src

.gitmodules

@@ -21,3 +21,6 @@
 [submodule "vendor/doxygen-awesome-css"]
 	path = vendor/doxygen-awesome-css
 	url = https://github.com/jothepro/doxygen-awesome-css.git
+[submodule "vendor/kokkos-fft"]
+	path = vendor/kokkos-fft
+	url = https://github.com/kokkos/kokkos-fft.git

CMakeLists.txt

@@ -78,19 +78,6 @@ endif()
 # Custom cmake modules
 list( APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/cmake" )
 
-# FFTW
-if("${DDC_BUILD_KERNELS_FFT}" AND NOT FFTW_FOUND)
-	find_package( FFTW MODULE REQUIRED )
-endif()
-
-## CUDA + CUDAToolkit
-if("${DDC_BUILD_KERNELS_FFT}" AND "${Kokkos_ENABLE_CUDA}")
-	find_package( CUDAToolkit MODULE REQUIRED )
-	if( NOT(CUDAToolkit_FOUND) )
-	  message(FATAL_ERROR "CUDAToolkit not found." )
-	endif()
-endif()
-
 
 ## PDI
 
@@ -196,30 +183,26 @@ install(
 
 # Link library to DDC
 
-if( FFTW_FOUND )
-	target_link_libraries( DDC INTERFACE FFTW::Float )
-	target_link_libraries( DDC INTERFACE FFTW::Double )
-endif()
-
-if( FFTW_FOUND AND "${Kokkos_ENABLE_SERIAL}")
-	target_compile_definitions(DDC INTERFACE fftw_serial_AVAIL)
-endif()
-
-if( FFTW_FOUND AND "${Kokkos_ENABLE_OPENMP}")
-	target_link_libraries( DDC INTERFACE FFTW::FloatOpenMP )
-	target_link_libraries( DDC INTERFACE FFTW::DoubleOpenMP )
-	target_compile_definitions(DDC INTERFACE fftw_omp_AVAIL)
-endif()
-
-if( CUDAToolkit_FOUND AND "${Kokkos_ENABLE_CUDA}")
-	target_link_libraries( DDC INTERFACE CUDA::cufft )
-	target_compile_definitions(DDC INTERFACE cufft_AVAIL)
-endif()
+if("${DDC_BUILD_KERNELS_FFT}")
+  # Kokkos-fft
+  set(DDC_KokkosFFT_DEPENDENCY_POLICY "AUTO" CACHE STRING "Policy to find the `Kokkos-fft` package. Options: ${DDC_DEPENDENCY_POLICIES}")
+  set_property(CACHE DDC_KokkosFFT_DEPENDENCY_POLICY PROPERTY STRINGS "${DDC_DEPENDENCY_POLICIES}")
+  if("${DDC_KokkosFFT_DEPENDENCY_POLICY}" STREQUAL "AUTO")
+    if(NOT TARGET KokkosFFT::fft)
+      find_package(KokkosFFT CONFIG QUIET)
+      if(NOT KokkosFFT_FOUND)
+        set(KokkosFFT_ENABLE_HOST_AND_DEVICE ON)
+        add_subdirectory(vendor/kokkos-fft)
+      endif()
+    endif()
+  elseif("${DDC_KokkosFFT_DEPENDENCY_POLICY}" STREQUAL "EMBEDDED")
+    set(KokkosFFT_ENABLE_HOST_AND_DEVICE ON)
+    add_subdirectory(vendor/kokkos-fft)
+  elseif("${DDC_KokkosFFT_DEPENDENCY_POLICY}" STREQUAL "INSTALLED")
+    find_package(KokkosFFT CONFIG REQUIRED)
+  endif()
 
-if("${Kokkos_ENABLE_HIP}")
-	find_package( hipfft REQUIRED ) # Not compatible with nvidia
-	target_link_libraries( DDC INTERFACE hip::hipfft )
-	target_compile_definitions(DDC INTERFACE hipfft_AVAIL)
+  target_link_libraries(DDC INTERFACE KokkosFFT::fft)
 endif()
 
 if("${DDC_BUILD_KERNELS_SPLINES}")