ParameterDict

class torch.nn.ParameterDict(parameters=None)

Holds parameters in a dictionary.

ParameterDict can be indexed like a regular Python dictionary, but Parameters it contains are properly registered, and will be visible by all Module methods. Other objects are treated as would be done by a regular Python dictionary

ParameterDict is an ordered dictionary. update() with other unordered mapping types (e.g., Python’s plain dict) does not preserve the order of the merged mapping. On the other hand, OrderedDict or another ParameterDict will preserve their ordering.

Note that the constructor, assigning an element of the dictionary and the update() method will convert any Tensor into Parameter.

Parameters

values (iterable, optional) – a mapping (dictionary) of (string : Any) or an iterable of key-value pairs of type (string, Any)

Example:

class MyModule(nn.Module):
    def __init__(self) -> None:
        super().__init__()
        self.params = nn.ParameterDict({
                'left': nn.Parameter(torch.randn(5, 10)),
                'right': nn.Parameter(torch.randn(5, 10))
        })

    def forward(self, x, choice):
        x = self.params[choice].mm(x)
        return x

clear()

Remove all items from the ParameterDict.

copy()

Return a copy of this ParameterDict instance.

Return type

ParameterDict

fromkeys(keys, default=None)

Return a new ParameterDict with the keys provided.

Parameters

• keys (iterable, string) – keys to make the new ParameterDict from

• default (Parameter, optional) – value to set for all keys

Return type

ParameterDict

get(key, default=None)

Return the parameter associated with key if present. Otherwise return default if provided, None if not.

Parameters

• key (str) – key to get from the ParameterDict

• default (Parameter, optional) – value to return if key not present

Return type

Any

items()

Return an iterable of the ParameterDict key/value pairs.

Return type

Iterable[Tuple[str, Any]]

keys()

Return an iterable of the ParameterDict keys.

Return type

Iterable[str]

pop(key)

Remove key from the ParameterDict and return its parameter.

Parameters

key (str) – key to pop from the ParameterDict

Return type

Any

popitem()

Remove and return the last inserted (key, parameter) pair from the ParameterDict.

Return type

Tuple[str, Any]

setdefault(key, default=None)

Set the default for a key in the Parameterdict.

If key is in the ParameterDict, return its value. If not, insert key with a parameter default and return default. default defaults to None.

Parameters

• key (str) – key to set default for

• default (Any) – the parameter set to the key

Return type

Any

update(parameters)

Update the ParameterDict with key-value pairs from parameters, overwriting existing keys.

Note

If parameters is an OrderedDict, a ParameterDict, or an iterable of key-value pairs, the order of new elements in it is preserved.

Parameters

parameters (iterable) – a mapping (dictionary) from string to Parameter, or an iterable of key-value pairs of type (string, Parameter)

values()

Return an iterable of the ParameterDict values.

Return type

Iterable[Any]