The document page for Mutable is lost.

[marsggbo]

https://nni.readthedocs.io/en/latest/NAS/NasReference.md#mutables is lost.
Could you explain more about mutables?

[QuanluZhang]

@marsggbo thanks! will fix it.

[QuanluZhang]

@marsggbo the links are fixed by removing section reference, as sphinx does not support cross-file section reference in markdown.

Here I briefly explain mutables. You might be confused about the difference between mutable and mutator. NAS algorithms could use the same approach (i.e., same format) to express their own search space, but how to deal with search space are very different for different NAS algorithms. mutable mainly tackles the former part, it is a common interface (derivatives of mutable, e.g., LayerChoice, InputChoice) for specifying search space in model code, does not depend on any specific NAS algorithm. mutator mainly tackles the latter part. For a LayerChoice, NAS algorithms have different logic to handle it, for example DARTS connects all the choices into the model, ENAS sample one choice every minibatch. This can be seen as different interpretation of LayerChoice. That is why you can see DartsMutator EnasMutator in source code, but there is no DartsMutable or EnasMutable.