code: def com_mult(a, b):
      r1, i1 = a[..., 0], a[..., 1]
      r2, i2 = b[..., 0], b[..., 1]
      return th.stack([r1 * r2 - i1 * i2, r1 * i2 + i1 * r2], dim=-1)
  
imports: import dgl
  import torch
label_desc: Use image node_id 1 for calling a global function with example usage: com_mult(a, b) and returns: th