parameters: (self, n, approx_type)
docstring: Initialize internal matrix.
  
          Allocate internal memory for storing and updating
          the Hessian or its inverse.
  
          Parameters
          ----------
          n : int
              Problem dimension.
          approx_type : {'hess', 'inv_hess'}
              Selects either the Hessian or the inverse Hessian.
              When set to 'hess' the Hessian will be stored and updated.
              When set to 'inv_hess' its inverse will be used instead.
docstring_summary: Initialize internal matrix.
docstring_tokens: Initialize internal matrix .
function: def initialize(self, n, approx_type):
          """Initialize internal matrix.
  
          Allocate internal memory for storing and updating
          the Hessian or its inverse.
  
          Parameters
          ----------
          n : int
              Problem dimension.
          approx_type : {'hess', 'inv_hess'}
              Selects either the Hessian or the inverse Hessian.
              When set to 'hess' the Hessian will be stored and updated.
              When set to 'inv_hess' its inverse will be used instead.
          """
          raise NotImplementedError("The method ``initialize(n, approx_type)``"
                                    " is not implemented.")
function_tokens: def initialize ( self , n , approx_type ) : raise NotImplementedError ( "The method ``initialize(n, approx_type)``" " is not implemented." )