code: def square_distance(src, dst):
      """
      Adapted from https://github.com/yanx27/Pointnet_Pointnet2_pytorch
      """
      B, N, _ = src.shape
      _, M, _ = dst.shape
      dist = -2 * torch.matmul(src, dst.permute(0, 2, 1))
      dist += torch.sum(src**2, -1).view(B, N, 1)
      dist += torch.sum(dst**2, -1).view(B, 1, M)
      return dist
  
imports: import dgl
  import dgl.function
  import numpy
  import torch
  import torch.nn
  import torch.nn.functional
  from dgl.geometry import farthest_point_sampler
  from torch.autograd import Variable
label_desc: Use image node_id 1 for calling a global function with example usage: square_distance(src, dst) and returns: dist