cufftHandle is created twice

[tpadioleau]

I suspect we create twice the CUDA plan, once with cufftCreate and again with cufftPlan1d

kokkos-fft/fft/src/KokkosFFT_Cuda_plans.hpp

Lines 39 to 54 in 4b82641

	cufftResult cufft_rt = cufftCreate(&(*plan));
	KOKKOSFFT_THROW_IF(cufft_rt != CUFFT_SUCCESS, "cufftCreate failed");
	cudaStream_t stream = exec_space.cuda_stream();
	cufftSetStream((*plan), stream);
	auto type = KokkosFFT::Impl::transform_type<ExecutionSpace, in_value_type,
	out_value_type>::type();
	auto [in_extents, out_extents, fft_extents, howmany] =
	KokkosFFT::Impl::get_extents(in, out, axes, s, is_inplace);
	const int nx = fft_extents.at(0);
	int fft_size = std::accumulate(fft_extents.begin(), fft_extents.end(), 1,
	std::multiplies<>());
	cufft_rt = cufftPlan1d(&(*plan), nx, type, howmany);
	KOKKOSFFT_THROW_IF(cufft_rt != CUFFT_SUCCESS, "cufftPlan1d failed");

From what I understand in the cuFFT documentation, we should either

• call cufftCreate then cufftMakePlan1d, https://docs.nvidia.com/cuda/cufft/index.html?highlight=cufftMakePlan1d#cufftmakeplan1d
• call directly cufftPlan1d, https://docs.nvidia.com/cuda/cufft/index.html?highlight=cufftMakePlan1d#cufftplan1d

Notice that both cufftCreate and cufftPlan1d take the plan by pointer whereas cufftMakePlan1d takes it by copy.

[yasahi-hpc]

That is true. I will make a fix