code: def RMSE(v, v_):
      """Mean squared error."""
      return np.sqrt(np.mean((v_ - v) ** 2))
  
file_path: PGL/legacy/examples/stgcn/utils/math_utils.py
imports: import os
  import sys
  import time
  import argparse
  import numpy
label_desc: Use image node_id 4 for calling a global function with example usage: RMSE(v, v_) and returns: np