mm = sin_m * m

[Charrin]

mm = sin_m * m cos_t - mm

What is this mean? thank you!

[auroua]

I think it means if theta ｅｘｃeed the range of [0, pi], the arcface changed into cos face. This code is referenced from official implementation.

[samxuxiang]

Have you tried training the model without this trick? Is there any significant performance drop? Thank you.