Optional Multithreading

[afcarvalho1991]

Hi,

Wouldn't be a good idea to make this a multithread solution?

The rating prediction for the trainset/testset, significantly slows down the training process when the amount of ratings increase significantly. This is a modification that has little to none complexity to implement and influences the performance significantly.

Thats just a suggestion.

Thank you,
André

PS: a parameter would be a good idea. Either the multithreading is activated or not.
PS2: My solution currently does everything in multithreading then when I use LibFM it simply slows down and instead of using 32 cores uses 1 core. Unfortunately, I'm not familiarized enough with libfm source code to develop the modification.