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.

ParameterDict is an ordered dictionary that respects

• the order of insertion, and

• in update(), the order of the merged OrderedDict or another ParameterDict (the argument to update()).

Note that update() with other unordered mapping types (e.g., Python’s plain dict) does not preserve the order of the merged mapping.

Parameters

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

Example:

class MyModule(nn.Module):
    def __init__(self):
        super(MyModule, self).__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()

Returns a copy of this ParameterDict instance.

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

get(key, default=None)

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

Parameters

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

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

items()

Return an iterable of the ParameterDict key/value pairs.

keys()

Return an iterable of the ParameterDict keys.

pop(key)

Remove key from the ParameterDict and return its parameter.

Parameters

key (string) – key to pop from the ParameterDict

popitem()

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

setdefault(key, default=None)

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

Parameters

• key (string) – key to set default for

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

update(parameters)

Update the ParameterDict with the key-value pairs from a mapping or an iterable, 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.