timeseries: add calculation of RMS error between two timeseries

dataprocessing/timeseries.py

@@ -37,6 +37,12 @@ class TimeSeries:
         ts_phase = TimeSeries(name, self.time, phase_values)
         return ts_phase
 
+    @staticmethod
+    def rmse(ts1, ts2):
+        """ Calculate root mean square error between two time series
+        """
+        return np.sqrt((TimeSeries.diff('diff', ts1, ts2).values ** 2).mean())
+
     @staticmethod
     def diff(name, ts1, ts2):
         """Returns difference between values of two Timeseries objects.