custom loss

1 (pytorch) How to assign weights to each category or even each sample

中文版本：https://www.jianshu.com/p/8c8169d2204c

英文：https://discuss.pytorch.org/t/per-class-and-per-sample-weighting/25530

2 Custom complex loss function in Keras

Keras is a building block deep learning framework (as are other deep learning frameworks), which can be used to build some common deep learning models conveniently and intuitively. Before tensorflow came out, Keras was almost the hottest deep learning framework at that time, with theano as the backend, and now Keras supports four backends at the same time: theano, tensorflow, cntk, and mxnet.

https://www.cnblogs.com/think90/articles/11652213.html