code: public static double transformedRmse(double[] obs, double[] sim) {
          sameArrayLen(sim, obs);
          double error = 0;
          double z_pred = 0.;
          double z_val = 0.;
          for (int i = 0; i < sim.length; i++) {
              z_pred = (Math.pow((1.0 + sim[i]), 0.3) - 1.0) / 0.3;
              z_val = (Math.pow((1.0 + obs[i]), 0.3) - 1.0) / 0.3;
              error += (z_pred - z_val) * (z_pred - z_val);
          }
          return Math.sqrt(error / sim.length);
      }
docs: transformedRootMeanSquareError TRMSE
  
  @param obs
  @param sim
  @return