LightGCN/NGCF with cornac.hyperopt

[SavvinaDaniil]

Description

Hi! I have an issue when trying to do parameter search with either LightGCN or NGCF. Looking at the param_search.py example, when I run it as is, it works normally. When I try to replace the models with either LightGCN or NGCF, I get an error as shown in the screenshot.

The error happens after the training with the first option of the search. The error does not appear when doing a normal experiment, only with the search (either Grid or Random).

[tqtg]

In order for us to better localize the issue, you should provide us with all the code to reproduce the error.