code: def revcumsum(U):
      """
      Reverse cumulative sum for faster performance.
      """
      return U.flip(dims=[0]).cumsum(dim=0).flip(dims=[0])
  
imports: import time
  import numpy
  import scipy.special
  import torch
  import torch.nn
  from .None import constants
  from .None import syssettings
  from .fginitialize import ChunkDataLoader
label_desc: Use image node_id 2 for calling a global function with example usage: revcumsum(U) and returns: U