docstr: greedy selection
docstr_tok: ["greedy","selection"]
code: def selection(self):
      """
      greedy selection
      """
      X = self.X.copy()
      f_X = self.x2y().copy()
      self.X = U = self.U
      f_U = self.x2y()
  
      self.X = np.where((f_X < f_U).reshape(-1, 1), X, U)
      return self.X
  
file_path: scikit-opt/sko/DE.py
imports: import numpy
  from .base import SkoBase
  from abc import ABCMeta, abstractmethod
  from .operators import crossover, mutation, ranking, selection
  from .GA import GeneticAlgorithmBase, GA
label_desc: Use image node_id 7 for calling the DE obj's underlying member method code with example usage: obj.selection() and returns: self