class_docstr: Return a sufficiently smart, vectorized and lambdified function.
  
  Returns only reals.
  
  Explanation
  ===========
  
  This function uses experimental_lambdify to created a lambdified
  expression ready to be used with numpy. Many of the functions in SymPy
  are not implemented in numpy so in some cases we resort to Python cmath or
  even to evalf.
  
  The following translations are tried:
    only numpy complex
    - on errors raised by SymPy trying to work with ndarray:
        only Python cmath and then vectorize complex128
  
  When using Python cmath there is no need for evalf or float/complex
  because Python cmath calls those.
  
  This function never tries to mix numpy directly with evalf because numpy
  does not understand SymPy Float. If this is needed one can use the
  float_wrap_evalf/complex_wrap_evalf options of experimental_lambdify or
  better one can be explicit about the dtypes that numpy works with.
  Check numpy bug http://projects.scipy.org/numpy/ticket/1013 to know what
  types of errors to expect.
code: def __call__(self, *args):
      np = self.np
  
      try:
          temp_args = (np.array(a, dtype=complex) for a in args)
          results = self.vector_func(*temp_args)
          results = np.ma.masked_where(
              np.abs(results.imag) > 1e-7 * np.abs(results),
              results.real,
              copy=False,
          )
          return results
      except ValueError:
          if self.failure:
              raise
  
          self.failure = True
          self.vector_func = self.vector_func_2
          warnings.warn(
              "The evaluation of the expression is problematic. "
              "We are trying a failback method that may still work. "
              "Please report this as a bug."
          )
          return self.__call__(*args)
  
imports: import re
  from sympy.core.numbers import I, NumberSymbol, oo, zoo
  from sympy.core.symbol import Symbol
  from sympy.utilities.iterables import numbered_symbols
  from sympy.external import import_module
  import warnings
label_desc: Use image node_id 2 for calling the vectorized_lambdify obj's underlying member method code with example usage: obj.__call__() and returns: results, self