class_docstr: Computes root mean squared error 
class_docstr_tok: ["Computes","root","mean","squared","error"]
code: def metric(self, reg, ref):
      return np.sqrt(np.mean(np.square(reg - ref)))
  
file_path: NiftyNet/niftynet/evaluation/regression_evaluations.py
imports: from __future__ import absolute_import, division, print_function
  import numpy
  import pandas
  from niftynet.evaluation.base_evaluations import BaseEvaluation
label_desc: Use image node_id 1 for calling the rmse obj's underlying member method code with example usage: obj.metric(reg, ref) and returns: np