code: def xloss(logits, labels, ignore=None):
      """
      Cross entropy loss
      """
      return F.cross_entropy(logits, Variable(labels), ignore_index=255)
  
imports: import torch
  from torch.autograd import Variable
  import torch.nn.functional
  import numpy
label_desc: Use image node_id 11 for calling a global function with example usage: xloss(logits, labels, ignore) and returns: F