espnet2.iterators.multiple_iter_factory.MultipleIterFactory

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class espnet2.iterators.multiple_iter_factory.MultipleIterFactory(build_funcs: Collection[Callable[[], AbsIterFactory]], seed: int = 0, shuffle: bool = False)

Bases: AbsIterFactory

A factory for creating multiple iterator instances based on provided builder

functions. This class allows for the optional shuffling of the iterator construction order and can be seeded for reproducibility.

build_funcs

A list of callable functions that return instances of AbsIterFactory.

• Type: list

seed

An integer seed for random number generation to control shuffling.

• Type: int

shuffle

A flag indicating whether to shuffle the order of iterator factories.

• Type: bool

• Parameters:

  • build_funcs (Collection *[*Callable [ [ ] , AbsIterFactory ] ]) – A collection of functions that will be called to create iterator factories.
  • seed (int , optional) – The seed for the random number generator. Defaults to 0.
  • shuffle (bool , optional) – Whether to shuffle the order of iterators. Defaults to False.

• Yields:Iterator – An iterator that yields items from the constructed iterators.

####### Examples

>>> def build_func_a():
...     return SomeIterFactoryA()
...
>>> def build_func_b():
...     return SomeIterFactoryB()
...
>>> factory = MultipleIterFactory([build_func_a, build_func_b], seed=42,
...                               shuffle=True)
>>> for item in factory.build_iter(epoch=1):
...     print(item)

NOTE

The order of the iterators can change between different epochs if shuffling is enabled.

build_iter(epoch: int, shuffle: bool | None = None) → Iterator

Generates an iterator by building iterators from a collection of provided

functions.

This method allows for the creation of multiple iterators, which can be shuffled based on the epoch and a specified seed. The iterator is built by calling each of the provided build functions in sequence.

• Parameters:
  • epoch (int) – The current epoch number, used to seed the random number generator for shuffling.
  • shuffle (bool , optional) – If True, the build functions will be shuffled before building iterators. If None, defaults to the instance’s shuffle attribute.
• Yields:Iterator – An iterator that yields elements from the built iterators.

####### Examples

>>> factory = MultipleIterFactory([build_func1, build_func2], seed=42)
>>> for item in factory.build_iter(epoch=1, shuffle=True):
...     print(item)

NOTE

This method is intended for use within the MultipleIterFactory context and assumes that the build functions return instances of AbsIterFactory.

• Raises:AssertionError – If the object returned by a build function is not an instance of AbsIterFactory.