[cmake] TTG_ENABLE_CUDA to control whether PaRSEC etc. try to discove…

…r CUDA

CMakeLists.txt

@@ -51,6 +51,7 @@ set(CMAKE_INSTALL_CMAKEDIR "lib/cmake/ttg"
 #### user-defined configuration options
 ########################################
 option(TTG_PARSEC_USE_BOOST_SERIALIZATION "Whether to select Boost serialization methods in PaRSEC backend" ON)
+option(TTG_ENABLE_CUDA "Whether to TTG will look for CUDA" OFF)
 option(TTG_EXAMPLES "Whether to build examples" OFF)
 
 option(TTG_FETCH_BOOST "Whether to fetch+build Boost, if missing" OFF)
@@ -91,17 +92,19 @@ find_package(CXXStdCoroutine MODULE REQUIRED COMPONENTS Final Experimental)
 ##########################
 #### CUDA: must come before PaRSEC
 ##########################
-include(CheckLanguage)
-check_language(CUDA)
-if(CMAKE_CUDA_COMPILER)
+if (TTG_ENABLE_CUDA)
+  include(CheckLanguage)
+  check_language(CUDA)
+  if(CMAKE_CUDA_COMPILER)
     enable_language(CUDA)
-endif(CMAKE_CUDA_COMPILER)
-set(TTG_HAVE_CUDA ${CMAKE_CUDA_COMPILER} CACHE BOOL "True if TTG supports compiling .cu files")
+  endif(CMAKE_CUDA_COMPILER)
+  set(TTG_HAVE_CUDA ${CMAKE_CUDA_COMPILER} CACHE BOOL "True if TTG supports compiling .cu files")
 
-find_package(CUDAToolkit)
-if (TARGET CUDA::cudart)
-  set(TTG_HAVE_CUDART True CACHE BOOL "True support for CUDART was found.")
-endif(TARGET CUDA::cudart)
+  find_package(CUDAToolkit)
+  if (TARGET CUDA::cudart)
+    set(TTG_HAVE_CUDART True CACHE BOOL "TTG supports execution on CUDA devices")
+  endif()
+endif()
 
 ##########################
 #### prerequisite runtimes

cmake/modules/FindOrFetchPARSEC.cmake

@@ -13,6 +13,7 @@ if (NOT TARGET PaRSEC::parsec)
   set(CMAKE_SYSTEM_PROCESSOR ${CMAKE_HOST_SYSTEM_PROCESSOR})
   set(PARSEC_WITH_DEVEL_HEADERS ON CACHE BOOL "Install PaRSEC headers")
   set(BUILD_TOOLS ON CACHE BOOL "Do not build PaRSEC tools")
+  set(PARSEC_GPU_WITH_CUDA ${TTG_ENABLE_CUDA} CACHE BOOL "Enable CUDA support in PaRSEC runtime?")
 
   FetchContent_Declare(
           PARSEC

cmake/modules/FindOrFetchTiledArray.cmake

@@ -17,9 +17,7 @@ if (TARGET tiledarray)
 else (TARGET tiledarray)
 
   # enable CUDA if TTG has it
-  if (TTG_HAVE_CUDA)
-    set(ENABLE_CUDA ON CACHE BOOL "Enable CUDA")
-  endif()
+  set(ENABLE_CUDA ${TTG_HAVE_CUDA} CACHE BOOL "Enable CUDA")
 
   # update CMake cache for TA
   if (DEFINED MADNESS_CMAKE_EXTRA_ARGS)

examples/CMakeLists.txt

@@ -11,12 +11,12 @@ if (TARGET tiledarray)
     # block-sparse needs BTAS ... it's always provided by TA
     # since only need to use matrices, limit BTAS_TARGET_MAX_INDEX_RANK to 2
     add_ttg_executable(bspmm spmm/spmm.cc LINK_LIBRARIES tiledarray TiledArray_Eigen BTAS Boost::boost COMPILE_DEFINITIONS BLOCK_SPARSE_GEMM=1;BTAS_TARGET_MAX_INDEX_RANK=2)
-    if (TARGET CUDA::cublas)
+    if (TTG_HAVE_CUDA)
       add_ttg_executable(bspmm-cuda spmm/spmm_cuda.cc
                          LINK_LIBRARIES tiledarray TiledArray_Eigen BTAS Boost::boost CUDA::cublas
                          COMPILE_DEFINITIONS BLOCK_SPARSE_GEMM=1;BTAS_TARGET_MAX_INDEX_RANK=2
                          RUNTIMES "parsec")
-    endif (TARGET CUDA::cublas)
+    endif()
 endif()
 
 if (TARGET MADworld)

ttg/CMakeLists.txt

@@ -115,12 +115,12 @@ if (TARGET std::coroutine)
           ${CMAKE_CURRENT_SOURCE_DIR}/ttg/util/coroutine.h
           )
 endif ()
-if (TARGET CUDA::cudart)
+if (TTG_HAVE_CUDA)
   list(APPEND ttg-sources
           ${CMAKE_CURRENT_SOURCE_DIR}/ttg/device/cublas_helper.cpp
           )
   list(APPEND ttg-deps CUDA::cudart CUDA::cublas)
-endif (TARGET CUDA::cudart)
+endif ()
 
 set(ttg-public-headers ${ttg-headers};${ttg-impl-headers};${ttg-base-headers};${ttg-util-headers};${ttg_device_headers})
 if (NOT TTG_IGNORE_BUNDLED_EXTERNALS)