Labels "die out" while training

[sgiraudot]

I'm facing some issues while training: it seems that some labels "die out" after some time, meaning that absolutely no points are classified with such labels. Usually they are labels with few inlier points in the training set, so it seems that after some iterations, they get completely ignored. Do you know if there is a way to correct this?

More generally, I'm having a hard time figuring if I set up the programs correctly. There are quite many parameters and ways to use them and it's not clear if I'm having poor results because I'm mis-using the programs or simply because the programs cannot do better. Do you have any advice on how to check if the program is set up correctly? Should I visualize the generated features? Something else?

Thanks in advance for your help!