[BUG] Incompatibility of `.log` path with some models

[mmosc]

Hi! I am running some experiments with cornac and would like to decide on where to store the .log file. Although the path can be set with the save_dir parameter, setting a value for this parameter is not possible with all models. The reason is that setting save_dir to something that is not False automatically implies trying to store the model after training, and not all models can be stored.

See documentation:

save_dir: str, optional, default: None Path to a directory for storing trained models and logs. If None, models will NOT be stored and logs will be saved in the current working directory.

Maybe an additional parameter can be added to the Class Experiment, to separate the path of the log from the decision of whether to store the model (until all models support storing, which of course would be even nicer :blush: )

Cheers! Marta