Serialization utilities

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serialize_keras_object function

keras.saving.serialize_keras_object(obj)

Retrieve the config dict by serializing the Keras object.

serialize_keras_object() serializes a Keras object to a python dictionary that represents the object, and is a reciprocal function of deserialize_keras_object(). See deserialize_keras_object() for more information about the config format.

Arguments

• obj: the Keras object to serialize.

Returns

A python dict that represents the object. The python dict can be deserialized via deserialize_keras_object().

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deserialize_keras_object function

keras.saving.deserialize_keras_object(
    config, custom_objects=None, safe_mode=True, **kwargs
)

Retrieve the object by deserializing the config dict.

The config dict is a Python dictionary that consists of a set of key-value pairs, and represents a Keras object, such as an Optimizer, Layer, Metrics, etc. The saving and loading library uses the following keys to record information of a Keras object:

• class_name: String. This is the name of the class, as exactly defined in the source code, such as "LossesContainer".
• config: Dict. Library-defined or user-defined key-value pairs that store the configuration of the object, as obtained by object.get_config().
• module: String. The path of the python module. Built-in Keras classes expect to have prefix keras.
• registered_name: String. The key the class is registered under via keras.saving.register_keras_serializable(package, name) API. The key has the format of '{package}>{name}', where package and name are the arguments passed to register_keras_serializable(). If name is not provided, it uses the class name. If registered_name successfully resolves to a class (that was registered), the class_name and config values in the dict will not be used. registered_name is only used for non-built-in classes.

For example, the following dictionary represents the built-in Adam optimizer with the relevant config:

dict_structure = {
    "class_name": "Adam",
    "config": {
        "amsgrad": false,
        "beta_1": 0.8999999761581421,
        "beta_2": 0.9990000128746033,
        "decay": 0.0,
        "epsilon": 1e-07,
        "learning_rate": 0.0010000000474974513,
        "name": "Adam"
    },
    "module": "keras.optimizers",
    "registered_name": None
}
# Returns an `Adam` instance identical to the original one.
deserialize_keras_object(dict_structure)

If the class does not have an exported Keras namespace, the library tracks it by its module and class_name. For example:

dict_structure = {
  "class_name": "MetricsList",
  "config": {
      ...
  },
  "module": "keras.trainers.compile_utils",
  "registered_name": "MetricsList"
}

# Returns a `MetricsList` instance identical to the original one.
deserialize_keras_object(dict_structure)

And the following dictionary represents a user-customized MeanSquaredError loss:

@keras.saving.register_keras_serializable(package='my_package')
class ModifiedMeanSquaredError(keras.losses.MeanSquaredError):
  ...

dict_structure = {
    "class_name": "ModifiedMeanSquaredError",
    "config": {
        "fn": "mean_squared_error",
        "name": "mean_squared_error",
        "reduction": "auto"
    },
    "registered_name": "my_package>ModifiedMeanSquaredError"
}
# Returns the `ModifiedMeanSquaredError` object
deserialize_keras_object(dict_structure)

Arguments

• config: Python dict describing the object.
• custom_objects: Python dict containing a mapping between custom object names the corresponding classes or functions.
• safe_mode: Boolean, whether to disallow unsafe lambda deserialization. When safe_mode=False, loading an object has the potential to trigger arbitrary code execution. This argument is only applicable to the Keras v3 model format. Defaults to True.

Returns

The object described by the config dictionary.

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CustomObjectScope class

keras.saving.custom_object_scope(custom_objects)

Exposes custom classes/functions to Keras deserialization internals.

Under a scope with custom_object_scope(objects_dict), Keras methods such as keras.models.load_model() or keras.models.model_from_config() will be able to deserialize any custom object referenced by a saved config (e.g. a custom layer or metric).

Example

Consider a custom regularizer my_regularizer:

layer = Dense(3, kernel_regularizer=my_regularizer)
# Config contains a reference to `my_regularizer`
config = layer.get_config()
...
# Later:
with custom_object_scope({'my_regularizer': my_regularizer}):
    layer = Dense.from_config(config)

Arguments

• custom_objects: Dictionary of {str: object} pairs, where the str key is the object name.

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get_custom_objects function

keras.saving.get_custom_objects()

Retrieves a live reference to the global dictionary of custom objects.

Custom objects set using custom_object_scope() are not added to the global dictionary of custom objects, and will not appear in the returned dictionary.

Example

get_custom_objects().clear()
get_custom_objects()['MyObject'] = MyObject

Returns

Global dictionary mapping registered class names to classes.

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register_keras_serializable function

keras.saving.register_keras_serializable(package="Custom", name=None)

Registers an object with the Keras serialization framework.

This decorator injects the decorated class or function into the Keras custom object dictionary, so that it can be serialized and deserialized without needing an entry in the user-provided custom object dict. It also injects a function that Keras will call to get the object's serializable string key.

Note that to be serialized and deserialized, classes must implement the get_config() method. Functions do not have this requirement.

The object will be registered under the key 'package>name' where name, defaults to the object name if not passed.

Example

# Note that `'my_package'` is used as the `package` argument here, and since
# the `name` argument is not provided, `'MyDense'` is used as the `name`.
@register_keras_serializable('my_package')
class MyDense(keras.layers.Dense):
    pass

assert get_registered_object('my_package>MyDense') == MyDense
assert get_registered_name(MyDense) == 'my_package>MyDense'

Arguments

• package: The package that this class belongs to. This is used for the key (which is "package>name") to identify the class. Note that this is the first argument passed into the decorator.
• name: The name to serialize this class under in this package. If not provided or None, the class' name will be used (note that this is the case when the decorator is used with only one argument, which becomes the package).

Returns

A decorator that registers the decorated class with the passed names.