Merge pull request #1801 from FluxML/lk/add-gpu-warn

Add warning if the GPU function is called and CUDA is not available

Author: ToucheSir

src/functor.jl

@@ -183,6 +183,10 @@ function check_use_cuda()
     if use_cuda[] && !CUDA.has_cudnn()
       @warn "CUDA.jl found cuda, but did not find libcudnn. Some functionality will not be available."
     end
+    if !(use_cuda[])
+      @info """The GPU function is being called but the GPU is not accessible. 
+               Defaulting back to the CPU. (No action is required if you want to run on the CPU).""" maxlog=1
+    end
   end
 end
 Zygote.@nograd check_use_cuda