Soft placement

If a TensorFlow operation is placed on the GPU, then the execution engine must have the GPU implementation of that operation, known as the kernel. If the kernel is not present, then the placement results in a runtime error. Also, if the requested GPU device does not exist, then a runtime error is raised. 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 an error. This can be achieved by setting the following config value:

config.allow_soft_placement = True