code: def _complex_dtype(dtype):
      
  
      dt = cp.dtype(dtype)
      if dt == cp.dtype('float128'):
          return cp.dtype('complex256')
      elif dt == cp.dtype('float64'):
          return cp.dtype('complex128')
      else:
          return cp.dtype('complex64')
docs: Patched version of :func:`sporco.linalg.complex_dtype`.