RuntimeError: CUDA out of memory. Tried to allocate 256.00 MiB (GPU 0; 4.00 GiB total capacity; 2.22 GiB already allocated; 94.64 MiB free; 2.30 GiB reserved in total by PyTorch) If reserved memory is >> allocated memory try setting max_split_size_mb to avoid fragmentation.  See documentation for Memory Management and PYTORCH_CUDA_ALLOC_CONF