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# Stateful Classes

Below are variations of a [singleton class](https://en.wikipedia.org/wiki/Singleton_pattern) in the sense that all
instances share the same state, which is initialized on the first instantiation.

These classes are immutable and store information about certain configurations or 
states.

[[autodoc]] state.PartialState

[[autodoc]] state.AcceleratorState

[[autodoc]] state.GradientState