Kokkos+Cuda: enforce expt-relaxed-constexpr

diff --git a/cmake/modules/FindDEAL_II_KOKKOS.cmake b/cmake/modules/FindDEAL_II_KOKKOS.cmake
index e39e93ea262d819a12cff307b39848e5d6dbefa2..a750fd820c72742da240579355759315ebe56cf1 100644 (file)
--- a/cmake/modules/FindDEAL_II_KOKKOS.cmake
+++ b/cmake/modules/FindDEAL_II_KOKKOS.cmake
@@ -48,8 +48,10 @@ else()
     # we don't know if CUDA support is enabled in Kokkos
     if(Kokkos_ENABLE_CUDA)
       set(DEAL_II_VECTORIZATION_WIDTH_IN_BITS 0)
-      # Require lambda support to use Kokkos as a backend
-      KOKKOS_CHECK(OPTIONS CUDA_LAMBDA)
+      # Require lambda support and expt-relaxed-constexpr for Cuda
+      # so that we can use std::array and other interfaces with
+      # __host__ constexpr functions in device code
+      KOKKOS_CHECK(OPTIONS CUDA_LAMBDA CUDA_CONSTEXPR)
 
       # Disable a bunch of annoying warnings generated by boost, template code,
       # and in other random places: