Copyright 2018 Google LLC

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

 http://www.apache.org/licenses/LICENSE-2.0  

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.


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# Get the dependency .py files, if any.
! git clone https://github.com/GoogleCloudPlatform/cloudml-samples.git
! cp cloudml-samples/tpu/templates/tpu_gan_estimator/* .

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import argparse
import numpy as np
import os
import tensorflow as tf

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INPUT_DIM = 5
OUTPUT_DIM = 3

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def generator_fn(generator_inputs):
    outputs = tf.layers.dense(generator_inputs, OUTPUT_DIM)
    return outputs

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def discriminator_fn(data, generator_inputs):
    outputs = tf.layers.dense(data, 1)
    return outputs

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def gen_model_fn(features, labels, mode, params):
    # build model
    global_step = tf.train.get_global_step()

    generator_inputs = features
    real_data = labels

    with tf.variable_scope('shared', reuse=tf.AUTO_REUSE):
        gan_model = tf.contrib.gan.gan_model(generator_fn, discriminator_fn, real_data, generator_inputs)

    predictions = gan_model.generated_data
    loss = None
    train_op = None

    if mode == tf.estimator.ModeKeys.TRAIN:
        # define loss
        gan_loss = tf.contrib.gan.gan_loss(gan_model, add_summaries=False)
        loss = gan_loss.generator_loss

        # define train_op
        optimizer = tf.train.RMSPropOptimizer(learning_rate=0.05)
        dummy_optimizer = tf.train.RMSPropOptimizer(learning_rate=0.05)

        # wrapper to make the optimizer work with TPUs
        if params['use_tpu']:
            optimizer = tf.contrib.tpu.CrossShardOptimizer(optimizer)

        gan_train_ops = tf.contrib.gan.gan_train_ops(gan_model, gan_loss, optimizer, dummy_optimizer)

        # tf.contrib.gan's train op does not manage global steps in it
        train_op = tf.group(gan_train_ops.generator_train_op, global_step.assign_add(1))

    if params['use_tpu']:
        # TPU version of EstimatorSpec
        return tf.contrib.tpu.TPUEstimatorSpec(
            mode=mode,
            predictions=predictions,
            loss=loss,
            train_op=train_op)
    else:
        return tf.estimator.EstimatorSpec(
            mode=mode,
            predictions=predictions,
            loss=loss,
            train_op=train_op)

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def dis_model_fn(features, labels, mode, params):
    # build model
    global_step = tf.train.get_global_step()

    generator_inputs = features
    real_data = labels

    with tf.variable_scope('shared', reuse=tf.AUTO_REUSE):
        gan_model = tf.contrib.gan.gan_model(generator_fn, discriminator_fn, real_data, generator_inputs)

    predictions = {
        'discriminator_gen_outputs': gan_model.discriminator_gen_outputs,
        'discriminator_real_outputs': gan_model.discriminator_real_outputs}
    loss = None
    train_op = None

    if mode == tf.estimator.ModeKeys.TRAIN:
        # define loss
        gan_loss = tf.contrib.gan.gan_loss(gan_model, add_summaries=False)
        loss = gan_loss.discriminator_loss

        # define train_op
        optimizer = tf.train.RMSPropOptimizer(learning_rate=0.05)
        dummy_optimizer = tf.train.RMSPropOptimizer(learning_rate=0.05)

        # wrapper to make the optimizer work with TPUs
        if params['use_tpu']:
            optimizer = tf.contrib.tpu.CrossShardOptimizer(optimizer)

        gan_train_ops = tf.contrib.gan.gan_train_ops(gan_model, gan_loss, dummy_optimizer, optimizer)

        # tf.contrib.gan's train op does not manage global steps in it
        train_op = tf.group(gan_train_ops.discriminator_train_op, global_step.assign_add(1))

    if params['use_tpu']:
        # TPU version of EstimatorSpec
        return tf.contrib.tpu.TPUEstimatorSpec(
            mode=mode,
            predictions=predictions,
            loss=loss,
            train_op=train_op)
    else:
        return tf.estimator.EstimatorSpec(
            mode=mode,
            predictions=predictions,
            loss=loss,
            train_op=train_op)

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def train_input_fn(params={}):
    # make some fake noise
    data_size = 100
    noise_tensor = tf.random_normal((data_size, INPUT_DIM))
    real_data_tensor = tf.random_uniform((data_size, OUTPUT_DIM))

    dataset = tf.data.Dataset.from_tensor_slices((noise_tensor, real_data_tensor))
    dataset = dataset.repeat().shuffle(10)

    # TPUEstimator passes params when calling input_fn
    batch_size = params.get('train_batch_size', 16)
    dataset = dataset.batch(batch_size, drop_remainder=True)

    # TPUs need to know all dimensions when the graph is built
    # Datasets know the batch size only when the graph is run
    def set_shapes(features, labels):
        features_shape = features.get_shape().merge_with([batch_size, None])
        labels_shape = labels.get_shape().merge_with([batch_size, None])

        features.set_shape(features_shape)
        labels.set_shape(labels_shape)

        return features, labels

    dataset = dataset.map(set_shapes)
    dataset = dataset.prefetch(tf.contrib.data.AUTOTUNE)

    return dataset

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def main(args):
    # pass the args as params so the model_fn can use
    # the TPU specific args
    params = vars(args)

    if args.use_tpu:
        # additional configs required for using TPUs
        tpu_cluster_resolver = tf.contrib.cluster_resolver.TPUClusterResolver(args.tpu)
        tpu_config = tf.contrib.tpu.TPUConfig(
            num_shards=8, # using Cloud TPU v2-8
            iterations_per_loop=args.save_checkpoints_steps)

        # use the TPU version of RunConfig
        gen_config = tf.contrib.tpu.RunConfig(
            cluster=tpu_cluster_resolver,
            model_dir=os.path.join(args.model_dir, 'generator'),
            tpu_config=tpu_config,
            save_checkpoints_steps=args.save_checkpoints_steps,
            save_summary_steps=100)

        dis_config = tf.contrib.tpu.RunConfig(
            cluster=tpu_cluster_resolver,
            model_dir=os.path.join(args.model_dir, 'discriminator'),
            tpu_config=tpu_config,
            save_checkpoints_steps=args.save_checkpoints_steps,
            save_summary_steps=100)

        # TPUEstimator
        gen_estimator = tf.contrib.tpu.TPUEstimator(
            model_fn=gen_model_fn,
            config=gen_config,
            params=params,
            train_batch_size=args.train_batch_size,
            eval_batch_size=32,
            export_to_tpu=False)

        dis_estimator = tf.contrib.tpu.TPUEstimator(
            model_fn=dis_model_fn,
            config=dis_config,
            params=params,
            train_batch_size=args.train_batch_size,
            eval_batch_size=32,
            export_to_tpu=False)
    else:
        gen_config = tf.estimator.RunConfig(model_dir=os.path.join(args.model_dir, 'generator'))
        dis_config = tf.estimator.RunConfig(model_dir=os.path.join(args.model_dir, 'discriminator'))

        gen_estimator = tf.estimator.Estimator(
            gen_model_fn,
            config=gen_config,
            params=params)

        dis_estimator = tf.estimator.Estimator(
            dis_model_fn,
            config=dis_config,
            params=params)

    # manage the training loop
    for _ in range(3):
        tf.logging.info('Training Discriminator')
        dis_estimator.train(train_input_fn, steps=100)

        tf.logging.info('Training Generator')
        gen_estimator.train(train_input_fn, steps=10)

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parser = argparse.ArgumentParser()

parser.add_argument(
    '--model-dir',
    type=str,
    default='/tmp/tpu-template',
    help='Location to write checkpoints and summaries to.  Must be a GCS URI when using Cloud TPU.')
parser.add_argument(
    '--train-batch-size',
    type=int,
    default=16,
    help='The training batch size.  The training batch is divided evenly across the TPU cores.')
parser.add_argument(
    '--save-checkpoints-steps',
    type=int,
    default=100,
    help='The number of training steps before saving each checkpoint.')
parser.add_argument(
    '--use-tpu',
    action='store_true',
    help='Whether to use TPU.')
parser.add_argument(
    '--tpu',
    default=None,
    help='The name or GRPC URL of the TPU node.  Leave it as `None` when training on CMLE.')

args, _ = parser.parse_known_args()

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# TODO(user): change this
args.model_dir = 'gs://your-gcs-bucket'

# Get hostname from environment using ipython magic.
# This returns a list.
hostname = !hostname

args.tpu = hostname[0]
args.use_tpu = True

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# Use gcloud command line tool to create a TPU in the same zone as the VM instance.
! gcloud compute tpus create `hostname` \
  --zone `gcloud compute instances list --filter="name=$(hostname)" --format 'csv[no-heading](zone)'`\
  --network default \
  --range 10.101.1.0 \
  --version 1.13

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main(args)

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# Use gcloud command line tool to delete the TPU.
! gcloud compute tpus delete `hostname` \
  --zone `gcloud compute instances list --filter="name=$(hostname)" --format 'csv[no-heading](zone)'`\
  --quiet