class_docstr: A kernel class. 
class_docstr_tok: ["A","kernel","class","."]
docstr: Evaluates kernel values between X1 and X2 and returns an n1xn2 kernel matrix.
  This is to be implemented in a child kernel.
docstr_tok: ["Evaluates","kernel","values","between","X1","and","X2","and","returns","an","n1xn2","kernel","matrix",".","This","is","to","be","implemented","in","a","child","kernel","."]
code: def _child_evaluate(self, X1, X2):
      """Evaluates kernel values between X1 and X2 and returns an n1xn2 kernel matrix.
      This is to be implemented in a child kernel.
      """
      raise NotImplementedError("Implement in a child class.")
  
imports: from __future__ import print_function
  import numpy
  from scipy.linalg import solve_triangular
label_desc: Use image node_id 4 for calling the Kernel obj's underlying member method code with example usage: obj._child_evaluate(X1, X2) without return types