There are two available model configs (we will add more) under
`configs/experiments/`:
By default, the experiment runs on GPUs. To run on TPUs, one should overwrite
`runtime.distribution_strategy` and set the tpu address. See [RuntimeConfig](https://github.com/tensorflow/models/blob/master/official/core/config_definitions.py) for details.
In general, the experiments can run with the folloing command by setting the