def adapt(self, data, batch_size=None, steps=None, reset_state=True):
"""Fits the state of the preprocessing layer to the data being passed.
Arguments:
data: The data to train on. It can be passed either as a tf.data
Dataset, or as a numpy array.
batch_size: Integer or `None`.
Number of samples per state update.
If unspecified, `batch_size` will default to 32.
Do not specify the `batch_size` if your data is in the
form of datasets, generators, or `keras.utils.Sequence` instances
(since they generate batches).
steps: Integer or `None`.
Total number of steps (batches of samples)
When training with input tensors such as
TensorFlow data tensors, the default `None` is equal to
the number of samples in your dataset divided by
the batch size, or 1 if that cannot be determined. If x is a
`tf.data` dataset, and 'steps' is None, the epoch will run until
the input dataset is exhausted. When passing an infinitely
repeating dataset, you must specify the `steps` argument. This
argument is not supported with array inputs.
reset_state: Optional argument specifying whether to clear the state of
the layer at the start of the call to `adapt`, or whether to start
from the existing state. This argument may not be relevant to all
preprocessing layers: a subclass of PreprocessingLayer may choose to
throw if 'reset_state' is set to False.
"""
_disallow_inside_tf_function('adapt')
if not version_utils.should_use_v2():
raise RuntimeError('`adapt` is only supported in tensorflow v2.') # pylint: disable=g-doc-exception
if not self.stateful:
return
if not self.streaming and self._is_adapted and not reset_state:
raise ValueError(
'{} does not supporting calling `adapt` twice without '
'resetting the state.'.format(self.__class__.__name__))
if not self._is_compiled:
self.compile() # Compile with defaults.
if self.built and reset_state:
self.reset_state()
data_handler = data_adapter.DataHandler(
data,
batch_size=batch_size,
steps_per_epoch=steps,
epochs=1,
steps_per_execution=self._steps_per_execution,
distribute=False)
self._adapt_function = self.make_adapt_function()
for _, iterator in data_handler.enumerate_epochs():
with data_handler.catch_stop_iteration():
for _ in data_handler.steps():
self._adapt_function(iterator)
if data_handler.should_sync:
context.async_wait()
self.finalize_state()
self._is_adapted = True
def adapt(self, data, batch_size=None, steps=None):
"""Fits the state of the preprocessing layer to the data being passed.
After calling `adapt` on a layer, a preprocessing layer's state will not
update during training. In order to make preprocessing layers efficient in
any distribution context, they are kept constant with respect to any
compiled `tf.Graph`s that call the layer. This does not affect the layer use
when adapting each layer only once, but if you adapt a layer multiple times
you will need to take care to re-compile any compiled functions as follows:
* If you are adding a preprocessing layer to a `keras.Model`, you need to
call `model.compile` after each subsequent call to `adapt`.
* If you are calling a preprocessing layer inside `tf.data.Dataset.map`,
you should call `map` again on the input `tf.data.Dataset` after each
`adapt`.
* If you are using a `tf.function` directly which calls a preprocessing
layer, you need to call `tf.function` again on your callable after
each subsequent call to `adapt`.
`tf.keras.Model` example with multiple adapts:
>>> layer = tf.keras.layers.Normalization(
... axis=None)
>>> layer.adapt([0, 2])
>>> model = tf.keras.Sequential(layer)
>>> model.predict([0, 1, 2])
array([-1., 0., 1.], dtype=float32)
>>> layer.adapt([-1, 1])
>>> model.compile() # This is needed to re-compile model.predict!
>>> model.predict([0, 1, 2])
array([0., 1., 2.], dtype=float32)
`tf.data.Dataset` example with multiple adapts:
>>> layer = tf.keras.layers.Normalization(
... axis=None)
>>> layer.adapt([0, 2])
>>> input_ds = tf.data.Dataset.range(3)
>>> normalized_ds = input_ds.map(layer)
>>> list(normalized_ds.as_numpy_iterator())
[array([-1.], dtype=float32),
array([0.], dtype=float32),
array([1.], dtype=float32)]
>>> layer.adapt([-1, 1])
>>> normalized_ds = input_ds.map(layer) # Re-map over the input dataset.
>>> list(normalized_ds.as_numpy_iterator())
[array([0.], dtype=float32),
array([1.], dtype=float32),
array([2.], dtype=float32)]
`adapt()` is meant only as a single machine utility to compute layer state.
To analyze a dataset that cannot fit on a single machine, see
[Tensorflow Transform](https://www.tensorflow.org/tfx/transform/get_started)
for a multi-machine, map-reduce solution.
Arguments:
data: The data to train on. It can be passed either as a tf.data
Dataset, or as a numpy array.
batch_size: Integer or `None`.
Number of samples per state update.
If unspecified, `batch_size` will default to 32.
Do not specify the `batch_size` if your data is in the
form of datasets, generators, or `keras.utils.Sequence` instances
(since they generate batches).
steps: Integer or `None`.
Total number of steps (batches of samples)
When training with input tensors such as
TensorFlow data tensors, the default `None` is equal to
the number of samples in your dataset divided by
the batch size, or 1 if that cannot be determined. If x is a
`tf.data` dataset, and 'steps' is None, the epoch will run until
the input dataset is exhausted. When passing an infinitely
repeating dataset, you must specify the `steps` argument. This
argument is not supported with array inputs.
"""
_disallow_inside_tf_function("adapt")
if not version_utils.should_use_v2():
raise RuntimeError(
"`adapt` is only supported in tensorflow v2."
) # pylint: disable=g-doc-exception
if not self._is_compiled:
self.compile() # Compile with defaults.
if self.built:
self.reset_state()
data_handler = data_adapter.DataHandler(
data,
batch_size=batch_size,
steps_per_epoch=steps,
epochs=1,
steps_per_execution=self._steps_per_execution,
distribute=False,
)
self._adapt_function = self.make_adapt_function()
for _, iterator in data_handler.enumerate_epochs():
with data_handler.catch_stop_iteration():
for _ in data_handler.steps():
self._adapt_function(iterator)
if data_handler.should_sync:
context.async_wait()
self.finalize_state()
self._is_adapted = True