Saving LapPE instead of precomputing every run about graphgps

[rampasek]

Hi Rishabh!

Yes that is possible, but would need a little bit of refactoring:

1. PyG Datasets have pre_transform hook, see the doc, which applies a transformation function to each graph example in the dataset and saves that version to the disk, keeping that version cached so it is only computed once -- the first time the dataset is downloaded and processed.
2. The way I precompute the PE/SE stats is already implemented as transformation function applied to each dataset, but I do so after loading the "vanilla" dataset from the disk, having to recompute it each time as you mention. But this could be hooked up to the pre_transform hook and cached.
3. In order to load the correct dataset with the desired precomputed PE/SE you need to rename the dataset accordingly, so it is saved under a unique name and make sure that if the PE/SE config matches what was used to precompute the cached version.

So that is roughly what needs to be done. I haven't implemented yet as it was impractical for me to have many different cached versions of the datasets (I'm a bit storage limited). I don't immediately plan to do it now, hopefully later on.

[rish-16]

That's a great suggestion, thanks! I'll look into it :D

Appreciate the help!