Soft placement

When you place a TensorFlow operation on the GPU, the TF must have the GPU implementation of that operation, known as the kernel. If the kernel is not present then the placement results in run-time error. Also if the GPU device you requested does not exist, you will get a run-time error. The best way to handle such errors is to allow the operation to be placed on the CPU if requesting the GPU device results in n error. This can be achieved by setting the following config value:

config.allow_soft_placement = True