class_docstr: Base class for activation or cost functions and their derivatives. Child classes
  can either implement the below ``__call__`` and ``bprop`` methods, or alternatively
  define ``self.func`` and ``self.funcgrad``. The latter is typically used for code
  compactness when the operations can be fit into a lambda function.
class_docstr_tok: ["Base","class","for","activation","or","cost","functions","and","their","derivatives",".","Child","classes","can","either","implement","the","below","``","__call__","``","and","``","bprop","``","methods",",","or","alternatively","define","``","self.func","``","and","``","self.funcgrad","``",".","The","latter","is","typically","used","for","code","compactness","when","the","operations","can","be","fit","into","a","lambda","function","."]
docstr: Compute f(x)
  
  Args:
      x (Tensor or OpTree): input
  
  Returns:
      func (OpTree): computes the output func(x)
docstr_tok: ["Compute","f","(","x",")","Args",":","x","(","Tensor","or","OpTree",")",":","input","Returns",":","func","(","OpTree",")",":","computes","the","output","func","(","x",")"]
code: def __call__(self, x):
      """
      Compute f(x)
  
      Args:
          x (Tensor or OpTree): input
  
      Returns:
          func (OpTree): computes the output func(x)
      """
      return self.func(x)
  
imports: from neon import NervanaObject
label_desc: Use image node_id 2 for calling the Transform obj's underlying member method code with example usage: obj.__call__(x) and returns: self