Discrete diffusion in the code

[vadimkantorov]

Hi! Thanks a lot for releasing the codes :)

Do I understand correctly that the main model is in https://github.com/OpenGVLab/DDPS/blob/main/mmseg_custom/models/decode_heads/segformer_head_unet_fc_head_single_step.py#L128 ?

Am I correct that first the discrete class labels are embedded into real-valued vectors, put into the unet which outputs real-valued logits? (and that corruption is done in the discrete label space)