tf.keras.estimator.model_to_estimator

Constructs an Estimator instance from given keras model.

tf.keras.estimator.model_to_estimator(
    keras_model=None, keras_model_path=None, custom_objects=None, model_dir=None,
    config=None, checkpoint_format='checkpoint', metric_names_map=None,
    export_outputs=None
)

If you use infrastructure or other tooling that relies on Estimators, you can still build a Keras model and use model_to_estimator to convert the Keras model to an Estimator for use with downstream systems.

For usage example, please see: Creating estimators from Keras Models.

Sample Weights:

Estimators returned by model_to_estimator are configured so that they can handle sample weights (similar to keras_model.fit(x, y, sample_weights)).

To pass sample weights when training or evaluating the Estimator, the first item returned by the input function should be a dictionary with keys features and sample_weights. Example below:

keras_model = tf.keras.Model(...)
keras_model.compile(...)

estimator = tf.keras.estimator.model_to_estimator(keras_model)

def input_fn():
  return dataset_ops.Dataset.from_tensors(
      ({'features': features, 'sample_weights': sample_weights},
       targets))

estimator.train(input_fn, steps=1)

Example with customized export signature:

inputs = {'a': tf.keras.Input(..., name='a'),
          'b': tf.keras.Input(..., name='b')}
outputs = {'c': tf.keras.layers.Dense(..., name='c')(inputs['a']),
           'd': tf.keras.layers.Dense(..., name='d')(inputs['b'])}
keras_model = tf.keras.Model(inputs, outputs)
keras_model.compile(...)
export_outputs = {'c': tf.estimator.export.RegressionOutput,
                  'd': tf.estimator.export.ClassificationOutput}

estimator = tf.keras.estimator.model_to_estimator(
    keras_model, export_outputs=export_outputs)

def input_fn():
  return dataset_ops.Dataset.from_tensors(
      ({'features': features, 'sample_weights': sample_weights},
       targets))

estimator.train(input_fn, steps=1)

To customize the estimator eval_metric_ops names, you can pass in the metric_names_map dictionary mapping the keras model output metric names to the custom names as follows:

  input_a = tf.keras.layers.Input(shape=(16,), name='input_a')
  input_b = tf.keras.layers.Input(shape=(16,), name='input_b')
  dense = tf.keras.layers.Dense(8, name='dense_1')
  interm_a = dense(input_a)
  interm_b = dense(input_b)
  merged = tf.keras.layers.concatenate([interm_a, interm_b], name='merge')
  output_a = tf.keras.layers.Dense(3, activation='softmax', name='dense_2')(
          merged)
  output_b = tf.keras.layers.Dense(2, activation='softmax', name='dense_3')(
          merged)
  keras_model = tf.keras.models.Model(
      inputs=[input_a, input_b], outputs=[output_a, output_b])
  keras_model.compile(
      loss='categorical_crossentropy',
      optimizer='rmsprop',
      metrics={
          'dense_2': 'categorical_accuracy',
          'dense_3': 'categorical_accuracy'
      })

  metric_names_map = {
      'dense_2_categorical_accuracy': 'acc_1',
      'dense_3_categorical_accuracy': 'acc_2',
  }
  keras_est = tf.keras.estimator.model_to_estimator(
      keras_model=keras_model,
      config=config,
      metric_names_map=metric_names_map)

Args
`keras_model`	A compiled Keras model object. This argument is mutually exclusive with `keras_model_path`. Estimator's `model_fn` uses the structure of the model to clone the model. Defaults to `None`.
`keras_model_path`	Path to a compiled Keras model saved on disk, in HDF5 format, which can be generated with the `save()` method of a Keras model. This argument is mutually exclusive with `keras_model`. Defaults to `None`.
`custom_objects`	Dictionary for cloning customized objects. This is used with classes that is not part of this pip package. For example, if user maintains a `relu6` class that inherits from `tf.keras.layers.Layer`, then pass `custom_objects={'relu6': relu6}`. Defaults to `None`.
`model_dir`	Directory to save `Estimator` model parameters, graph, summary files for TensorBoard, etc. If unset a directory will be created with `tempfile.mkdtemp`
`config`	`RunConfig` to config `Estimator`. Allows setting up things in `model_fn` based on configuration such as `num_ps_replicas`, or `model_dir`. Defaults to `None`. If both `config.model_dir` and the `model_dir` argument (above) are specified the `model_dir` argument takes precedence.
`checkpoint_format`	Sets the format of the checkpoint saved by the estimator when training. May be `saver` or `checkpoint`, depending on whether to save checkpoints from `tf.compat.v1.train.Saver` or `tf.train.Checkpoint`. The default is `checkpoint`. Estimators use name-based `tf.train.Saver` checkpoints, while Keras models use object-based checkpoints from `tf.train.Checkpoint`. Currently, saving object-based checkpoints from `model_to_estimator` is only supported by Functional and Sequential models. Defaults to 'checkpoint'.
`metric_names_map`	Optional dictionary mapping Keras model output metric names to custom names. This can be used to override the default Keras model output metrics names in a multi IO model use case and provide custom names for the `eval_metric_ops` in Estimator. The Keras model metric names can be obtained using `model.metrics_names` excluding any loss metrics such as total loss and output losses. For example, if your Keras model has two outputs `out_1` and `out_2`, with `mse` loss and `acc` metric, then `model.metrics_names` will be `['loss', 'out_1_loss', 'out_2_loss', 'out_1_acc', 'out_2_acc']`. The model metric names excluding the loss metrics will be `['out_1_acc', 'out_2_acc']`.
`export_outputs`	Optional dictionary. This can be used to override the default Keras model output exports in a multi IO model use case and provide custom names for the `export_outputs` in `tf.estimator.EstimatorSpec`. Default is None, which is equivalent to {'serving_default': `tf.estimator.export.PredictOutput`}. If not None, the keys must match the keys of `model.output_names`. A dict `{name: output}` where: name: An arbitrary name for this output. output: an `ExportOutput` class such as `ClassificationOutput`, `RegressionOutput`, or `PredictOutput`. Single-headed models only need to specify one entry in this dictionary. Multi-headed models should specify one entry for each head, one of which must be named using `tf.saved_model.signature_constants.DEFAULT_SERVING_SIGNATURE_DEF_KEY` If no entry is provided, a default `PredictOutput` mapping to `predictions` will be created.

Returns
An Estimator from given keras model.

Raises
`ValueError`	If neither keras_model nor keras_model_path was given.
`ValueError`	If both keras_model and keras_model_path was given.
`ValueError`	If the keras_model_path is a GCS URI.
`ValueError`	If keras_model has not been compiled.
`ValueError`	If an invalid checkpoint_format was given.

tf.keras.estimator.model_to_estimator

Sample Weights:

Args

Returns

Raises