// Load training and eval data
mnist = learn.datasets.mnist.read_data_sets("MNIST-data-%d" % hvd.rank())
train_data = mnist.train.images // Returns np.array
train_labels = np.asarray(mnist.train.labels, dtype=np.int32)
eval_data = mnist.test.images // Returns np.array
eval_labels = np.asarray(mnist.test.labels, dtype=np.int32)
// Horovod: pin GPU to be used to process local rank (one GPU per process)