def init(
self,
x: tp.Optional[tp.Any] = None,
y: tp.Optional[tp.Any] = None,
batch_size: tp.Optional[int] = None,
class_weight: tp.Optional[tp.Mapping[str, float]] = None,
sample_weight: tp.Optional[np.ndarray] = None,
) -> None:
if self.initialized:
return
if x is None:
x = {}
data_handler = DataHandler(
x=x,
y=y,
sample_weight=sample_weight,
batch_size=batch_size,
class_weight=class_weight,
steps_per_epoch=1,
)
epoch, iterator = next(data_handler.enumerate_epochs())
batch = next(iterator)
x_batch, y_batch, sample_weight = unpack_x_y_sample_weight(batch)
self.init_on_batch(
x=x_batch,
y_true=y_batch,
sample_weight=sample_weight,
class_weight=class_weight,
)
def evaluate(
self,
x: tp.Union[np.ndarray, tp.Mapping[str, np.ndarray],
tp.Tuple[np.ndarray], tp.Iterable, ],
y: tp.Union[jnp.ndarray, np.ndarray, tp.Mapping[str, np.ndarray],
tp.Tuple[np.ndarray], None, ] = None,
verbose: int = 1,
batch_size: tp.Optional[int] = None,
sample_weight: tp.Optional[np.ndarray] = None,
steps: tp.Optional[int] = None,
callbacks: tp.Union[tp.List[Callback], CallbackList, None] = None,
) -> types.Logs:
"""Returns the loss value & metrics values for the model in test mode.
Computation is done in batches.
Arguments:
x: Input data. It could be:
- A Numpy or Jax array (or array-like), or a list of arrays
(in case the model has multiple inputs).
- A dict mapping input names to the corresponding arrays,
if the model has named inputs.
- A generator returning `(inputs,)`, `(inputs, targets)`
or `(inputs, targets, sample_weights)`.
A more detailed description of
unpacking behavior for iterator types generator
is given in the `Unpacking behavior for iterator-like inputs` section
of `Model.fit`.
y: Target data. Like the input data `x`,
it could be either Numpy or Jax array(s).
It should be consistent with `x`. If `x` is a generator,
`y` should not be specified (since targets will be obtained from `x`).
verbose: 0, 1, or 2. Verbosity mode.
0 = silent, 1 = progress bar, 2 = one line per epoch.
batch_size: Integer or `None`.
Number of samples per gradient update.
If unspecified, `batch_size` will default to 32.
Do not specify the `batch_size` if your data is in the
form of generator (since they generate batches).
sample_weight: Optional Numpy/Jax array of weights for
the training samples, used for weighting the loss function
(during training only). You can either pass a flat (1D)
Numpy array with the same length as the input samples
(1:1 mapping between weights and samples). This argument is not
supported when `x` is generator, instead provide the sample_weights
as the third element of `x`.
steps: Integer or `None`. Total number of steps (batches of samples)
before declaring the evaluation round finished. Ignored with the
default value of `None`. This
argument is not supported with array inputs.
callbacks: List of [elegy.callbacks.callback.Callback][] instances.
List of callbacks to apply during training.
See the discussion of `Unpacking behavior for iterator-like inputs` for
[`Model.fit`][elegy.model.model.Model.fit].
Returns:
A dictionary for mapping the losses and metrics names to the values obtained.
Raises:
ValueError: in case of invalid arguments.
"""
data_handler = DataHandler(
x=x,
y=y,
sample_weight=sample_weight,
batch_size=batch_size,
steps_per_epoch=steps,
initial_epoch=0,
epochs=1,
shuffle=False,
training=False,
)
# Container that configures and calls `tf.keras.Callback`s.
if not isinstance(callbacks, CallbackList):
callbacks = CallbackList(
callbacks,
add_history=True,
add_progbar=verbose != 0,
model=self,
verbose=verbose,
epochs=1,
steps=data_handler.inferred_steps,
)
callbacks.on_test_begin()
logs = {}
for _, iterator in data_handler.enumerate_epochs():
self.reset_metrics()
with data_handler.catch_stop_iteration():
for step in data_handler.steps():
callbacks.on_test_batch_begin(step)
batch = next(iterator)
x_batch, y_batch, sample_weight = unpack_x_y_sample_weight(
batch)
tmp_logs = self.test_on_batch(
x=x_batch,
y=y_batch,
sample_weight=sample_weight,
)
tmp_logs.update({"size": data_handler.batch_size})
logs = tmp_logs
callbacks.on_test_batch_end(step, logs)
callbacks.on_test_end()
return logs
def fit(
self,
x: tp.Union[np.ndarray, tp.Mapping[str, np.ndarray],
tp.Tuple[np.ndarray], tp.Iterable, None, ] = None,
y: tp.Union[np.ndarray, tp.Mapping[str, np.ndarray],
tp.Tuple[np.ndarray], None, ] = None,
batch_size: tp.Optional[int] = None,
epochs: int = 1,
verbose: int = 1,
callbacks: tp.Union[tp.List[Callback], CallbackList, None] = None,
validation_split: float = 0.0,
validation_data: tp.Union[tp.Tuple, tp.Iterable, None] = None,
shuffle: bool = True,
class_weight: tp.Optional[tp.Mapping[str, float]] = None,
sample_weight: tp.Optional[np.ndarray] = None,
initial_epoch: int = 0,
steps_per_epoch: tp.Optional[int] = None,
validation_steps: tp.Optional[int] = None,
validation_batch_size: tp.Optional[int] = None,
validation_freq: int = 1,
) -> History:
"""
Trains the model for a fixed number of epochs (iterations on a dataset).
Arguments:
x: Input data. It could be:
- A Numpy or Jax array (or array-like), or a list of arrays
(in case the model has multiple inputs).
- A dict mapping input names to the corresponding arrays,
if the model has named inputs.
- A generator returning `(inputs,)`, `(inputs, targets)`
or `(inputs, targets, sample_weights)`.
A more detailed description of unpacking behavior for generator type
is given below.
y: Target data. Like the input data `x`,
it could be either Numpy or Jax array(s).
It should be consistent with `x`. If `x` is a generator,
`y` should not be specified (since targets will be obtained from `x`).
batch_size: Integer or `None`.
Number of samples per gradient update.
If unspecified, `batch_size` will default to 32.
Do not specify the `batch_size` if your data is in the
form of generator (since they generate batches).
epochs: Integer. Number of epochs to train the model.
An epoch is an iteration over the entire `x` and `y`
data provided.
Note that in conjunction with `initial_epoch`,
`epochs` is to be understood as "final epoch".
The model is not trained for a number of iterations
given by `epochs`, but merely until the epoch
of index `epochs` is reached.
verbose: 0, 1, 2 or 3. Verbosity mode.
0 = silent, 1 = progress bar, 2 = one line per epoch 3 = table.
Note that the progress bar is not particularly useful when
logged to a file, so verbose=2 is recommended when not running
interactively (eg, in a production environment).
callbacks: List of [elegy.callbacks.callback.Callback][] instances.
List of callbacks to apply during training.
validation_split: Float between 0 and 1.
Fraction of the training data to be used as validation data.
The model will set apart this fraction of the training data,
will not train on it, and will evaluate
the loss and any model metrics
on this data at the end of each epoch.
The validation data is selected from the last samples
in the `x` and `y` data provided, before shuffling. This argument is
not supported when `x` is a generator.
validation_data: Data on which to evaluate
the loss and any model metrics at the end of each epoch.
The model will not be trained on this data.
`validation_data` will override `validation_split`.
`validation_data` could be:
- tuple `(x_val, y_val)` of Numpy/Jax arrays, list of arrays or mappings
- tuple `(x_val, y_val, val_sample_weights)` of Numpy/Jax arrays, list
of arrays or mappings
- generator
For the first two cases, `batch_size` must be provided.
For the last case, `validation_steps` should be provided, and should
follow the same convention for yielding data as `x`.
Note that `validation_data` does not support all the data types that
are supported in `x`, eg, dict.
shuffle: Boolean (whether to shuffle the training data
before each epoch). This argument is ignored
when `x` is a generator. Has no effect when `steps_per_epoch` is not `None`.
class_weight: Optional dictionary mapping class indices (integers)
to a weight (float) value, used for weighting the loss function
(during training only).
This can be useful to tell the model to
"pay more attention" to samples from
an under-represented class.
sample_weight: Optional Numpy/Jax array of weights for
the training samples, used for weighting the loss function
(during training only). You can either pass a flat (1D)
Numpy array with the same length as the input samples
(1:1 mapping between weights and samples). This argument is not
supported when `x` is generator, instead provide the sample_weights
as the third element of `x`.
initial_epoch: Integer.
Epoch at which to start training
(useful for resuming a previous training run).
steps_per_epoch: Integer or `None`.
Total number of steps (batches of samples)
before declaring one epoch finished and starting the
next epoch. When training with input arrays such as
jax data arrays, 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.
When passing a generator, you must specify the
`steps_per_epoch` argument. This argument is not supported with
array inputs.
validation_steps: Only relevant if `validation_data` is provided and
is a generator. Total number of steps (batches of
samples) to draw before stopping when performing validation
at the end of every epoch. If 'validation_steps' is None, validation
will run until the `validation_data` dataset is exhausted. In the
case of an infinitely repeated dataset, it will run into an
infinite loop. If 'validation_steps' is specified and only part of
the dataset will be consumed, the evaluation will start from the
beginning of the dataset at each epoch. This ensures that the same
validation samples are used every time.
validation_batch_size: Integer or `None`.
Number of samples per validation batch.
If unspecified, will default to `batch_size`.
Do not specify the `validation_batch_size` if your data is in the
form of generators (since they generate batches).
validation_freq: Only relevant if validation data is provided. Integer
or `collections_abc.Container` instance (e.g. list, tuple, etc.).
If an integer, specifies how many training epochs to run before a
new validation run is performed, e.g. `validation_freq=2` runs
validation every 2 epochs. If a Container, specifies the epochs on
which to run validation, e.g. `validation_freq=[1, 2, 10]` runs
validation at the end of the 1st, 2nd, and 10th epochs.
Unpacking behavior for iterator-like inputs:
A common pattern is to pass a generator, which will in fact
yield not only features (x) but optionally targets (y) and sample weights.
Elegy requires that the output of such iterator-likes be unambiguous. The
iterator should return a tuple of length 1, 2, or 3, where the optional
second and third elements will be used for y and sample_weight
respectively. Any other type provided will be wrapped in a length one
tuple, effectively treating everything as 'x'. When yielding dicts, they
should still adhere to the top-level tuple structure.
e.g. `({"x0": x0, "x1": x1}, y)`. Elegy will not attempt to separate
features, targets, and weights from the keys of a single dict.
A notable unsupported data type is the namedtuple. The reason is that
it behaves like both an ordered datatype (tuple) and a mapping
datatype (dict). So given a namedtuple of the form:
`namedtuple("example_tuple", ["y", "x"])`
it is ambiguous whether to reverse the order of the elements when
interpreting the value. Even worse is a tuple of the form:
`namedtuple("other_tuple", ["x", "y", "z"])`
where it is unclear if the tuple was intended to be unpacked into x, y,
and sample_weight or passed through as a single element to `x`. As a
result the data processing code will simply raise a ValueError if it
encounters a namedtuple. (Along with instructions to remedy the issue.)
Returns:
A `History` object. Its `History.history` attribute is
a record of training loss values and metrics values
at successive epochs, as well as validation loss values
and validation metrics values (if applicable).
Raises:
ValueError: In case of mismatch between the provided input data
and what the model expects.
"""
if x is None:
x = {}
if validation_split:
# Create the validation data using the training data. Only supported for
# `Jax Numpy` and `NumPy` input.
(x, y, sample_weight), validation_data = train_validation_split(
(x, y, sample_weight),
validation_split=validation_split,
shuffle=False)
self.stop_training = False
data_handler = DataHandler(
x=x,
y=y,
sample_weight=sample_weight,
batch_size=batch_size,
steps_per_epoch=steps_per_epoch,
initial_epoch=initial_epoch,
epochs=epochs,
shuffle=shuffle,
class_weight=class_weight,
)
# Container that configures and calls `tf.keras.Callback`s.
if not isinstance(callbacks, CallbackList):
callbacks = CallbackList(
callbacks,
add_history=True,
add_progbar=verbose != 0,
model=self,
verbose=verbose,
epochs=epochs,
steps=data_handler.inferred_steps,
)
callbacks.on_train_begin()
# data_handler._initial_epoch = ( # pylint: disable=protected-access
# self._maybe_load_initial_epoch_from_ckpt(initial_epoch))
for epoch, iterator in data_handler.enumerate_epochs():
self.reset_metrics()
callbacks.on_epoch_begin(epoch)
logs = {}
with data_handler.catch_stop_iteration():
for step in data_handler.steps():
callbacks.on_train_batch_begin(step)
batch = next(iterator)
# sample_weight = batch[2] if len(batch) == 3 else None
x_batch, y_batch, sample_weight = unpack_x_y_sample_weight(
batch)
tmp_logs = self.train_on_batch(
x=x_batch,
y=y_batch,
sample_weight=sample_weight,
class_weight=class_weight,
)
tmp_logs.update({"size": data_handler.batch_size})
# print(epoch, step, tmp_logs["accuracy"], batch[0].shape)
logs = tmp_logs
callbacks.on_train_batch_end(step, logs)
epoch_logs = copy(logs)
epoch_logs.update({"size": data_handler.batch_size})
# Run validation.
if validation_data and self._should_eval(epoch, validation_freq):
val_x, val_y, val_sample_weight = unpack_x_y_sample_weight(
validation_data)
try:
val_logs = self.evaluate(
x=val_x,
y=val_y,
sample_weight=val_sample_weight,
batch_size=validation_batch_size or batch_size,
steps=validation_steps,
callbacks=callbacks,
# return_dict=True,
)
val_logs = {
"val_" + name: val
for name, val in val_logs.items()
}
epoch_logs.update(val_logs)
except (types.MissingMethod, types.MissingModule) as e:
pass
callbacks.on_epoch_end(epoch, epoch_logs)
# print(
# f"epoch: {epoch} - "
# + " - ".join(f"{key}: {value:.3f}" for key, value in epoch_logs.items())
# )
if self.stop_training:
break
callbacks.on_train_end()
return self.history