Serialization

This section may be occasionally relevant when wrapping models implemented in languages other than Julia.

The MLJ user can serialize and deserialize machines, as she would any other julia object. (This user has the option of first removing data from the machine. See the Saving machines section of the MLJ manual for details.) However, a problem can occur if a model's fitresult (see The fit method) is not a persistent object. For example, it might be a C pointer that would have no meaning in a new Julia session.

If that is the case a model implementation needs to implement a save and restore method for switching between a fitresult and some persistent, serializable representation of that result.

The save method

MMI.save(model::SomeModel, fitresult; kwargs...) -> serializable_fitresult

Implement this method to return a persistent serializable representation of the fitresult component of the MMI.fit return value.

The fallback of save performs no action and returns fitresult.

The restore method

MMI.restore(model::SomeModel, serializable_fitresult) -> fitresult

Implement this method to reconstruct a valid fitresult (as would be returned by MMI.fit) from a persistent representation constructed using MMI.save as described above.

The fallback of restore performs no action and returns serializable_fitresult.

Example

Refer to the model implementations at MLJXGBoostInterface.jl.