code: public RegressionModelPrediction predictRegression(RowData data, double offset) throws PredictException {
      double[] preds = preamble(ModelCategory.Regression, data, offset);
  
      RegressionModelPrediction p = new RegressionModelPrediction();
      if (enableLeafAssignment) { // only get leaf node assignment if enabled
        SharedTreeMojoModel.LeafNodeAssignments assignments = leafNodeAssignmentExtended(data);
        p.leafNodeAssignments = assignments._paths;
        p.leafNodeAssignmentIds = assignments._nodeIds;
      }
      p.value = preds[0];
      if (enableStagedProbabilities) {
          double[] rawData = nanArray(m.nfeatures());
          rawData = fillRawData(data, rawData);
          p.stageProbabilities = ((SharedTreeMojoModel) m).scoreStagedPredictions(rawData, preds.length);
      }
      if (enableContributions) {
        double[] rawData = nanArray(m.nfeatures());
        rawData = fillRawData(data, rawData);
        p.contributions = predictContributions.calculateContributions(rawData);
      }
      return p;
    }
docs: Make a prediction on a new data point using a Regression model.
  
  @param data A new data point.
  @param offset Prediction offset
  @return The prediction.
  @throws PredictException