Documentation directories structure with multi-fidelity

[AwePhD]

Hi,

I have a question about the choice of the argument previous_pipeline_directory in run_pipeline. I browsed the code and it seems that the optimizer is responsible to get the previous trial, since it's the Optimizer's responsibility to sample trials.

Although, my question is why the argument is not has_previous_fidelity_trial with type bool, or something alike?

I do not know how you manage the workers and the multiprocessing for distributed HPO. So maybe, in some situations, the directory of the previous (fidelity) trial of the same config does not have the same directory of the current one? Or maybe there is a more profound reason that I am not aware.

Note that I am not an HPO practitioner, so my understanding of NePS and PriorBand is fairly limited. I just want to apply HPO on a deep learning model for my research.

The question is more about a sanity check for me, that I understood correctly the documentation about multi-fidelity. The most related piece of documentation that I found is this subsection and the multi fidelity page. Maybe a dedicated didactic page on multi fidelity might be good? The two examples are rich and simple, which is very good. But it might be a bit rough to grasp from a DL perspective, namely not familiar with the multi-fidelity HPO (SH, HP, PB ...). Or maybe it's just/only my personal lack of understanding.

Best, Mathias.