class_docstr: Regression tree for XGBoost
  - Reference -
  http://xgboost.readthedocs.io/en/latest/model.html
class_docstr_tok: ["Regression","tree","for","XGBoost","-","Reference","-","http",":","\/\/xgboost.readthedocs.io\/en\/latest\/model.html"]
code: def _gain_by_taylor(self, y, y1, y2):
      # Split
      y, y_pred = self._split(y)
      y1, y1_pred = self._split(y1)
      y2, y2_pred = self._split(y2)
  
      true_gain = self._gain(y1, y1_pred)
      false_gain = self._gain(y2, y2_pred)
      gain = self._gain(y, y_pred)
      return true_gain + false_gain - gain
  
imports: from __future__ import division, print_function
  import numpy
  from mlfromscratch.utils import divide_on_feature, train_test_split, standardize, mean_squared_error
  from mlfromscratch.utils import calculate_entropy, accuracy_score, calculate_variance
label_desc: Use image node_id 3 for calling the XGBoostRegressionTree obj's underlying member method code with example usage: obj._gain_by_taylor(y, y1, y2) and returns: unknown