code: public static double score(ComputationGraph model, DataSetIterator testSet, RegressionValue regressionValue) {
          RegressionEvaluation evaluation = model.evaluateRegression(testSet);
          return getScoreFromRegressionEval(evaluation, regressionValue);
      }
docs: Run a {@link RegressionEvaluation}
  over a {@link DataSetIterator}
  @param model the model to use
  @param testSet the test set iterator
  @param regressionValue  the regression type to use
  @return