code: def MMD_Loss(fc_nir, fc_vis):
      mean_fc_nir = torch.mean(fc_nir, 0)
      mean_fc_vis = torch.mean(fc_vis, 0)
      loss_mmd = F.mse_loss(mean_fc_nir, mean_fc_vis)
      return loss_mmd
  
file_path: insightface/recognition/idmmd/utils.py
imports: import os
  import numpy
  import torch
  import torch.nn.functional
label_desc: Use image node_id 3 for calling a global function with example usage: MMD_Loss(fc_nir, fc_vis) and returns: loss_mmd