code: def get_RMSE(results, true_params):
      """
      Gets the (normalized) root mean square error.
      """
      diff = results.params.reshape(true_params.shape) - true_params
      raw_RMSE = sp.sqrt(((diff) ** 2).sum())
      param_norm = sp.sqrt((true_params**2).sum())
      return raw_RMSE / param_norm
  
file_path: statsmodels/statsmodels/examples/l1_demo/demo.py
imports: from optparse import OptionParser
  import statsmodels.api
  import scipy
  from scipy import linalg
  from scipy import stats
label_desc: Use image node_id 6 for calling a global function with example usage: get_RMSE(results, true_params) and returns: unknown