text: from devito.tools import Tag
  
  
  class Property(Tag):
  
      _KNOWN = []
  
      def __init__(self, name, val=None):
          super(Property, self).__init__(name, val)
          Property._KNOWN.append(self)
  
  
  SEQUENTIAL = Property('sequential')
  """A sequential Dimension."""
  
  PARALLEL = Property('parallel')
  """A fully parallel Dimension."""
  
  PARALLEL_IF_ATOMIC = Property('parallel_if_atomic')
  """A parallel Dimension with local reductions."""
  
  COLLAPSED = lambda i: Property('collapsed', i)
  """Collapsing Dimensions."""
  
  VECTORIZED = Property('vector-dim')
  """A SIMD-vectorized Dimension."""
  
  TILABLE = Property('tilable')
  """A fully parallel Dimension that would benefit from tiling (or "blocking")."""
  
  WRAPPABLE = Property('wrappable')
  """
  A modulo-N Dimension (i.e., cycling over i, i+1, i+2, ..., i+N-1) that could
  safely be turned into a modulo-K Dimension, with K < N. For example:
  u[t+1, ...] = f(u[t, ...], u[t-1, ...]) --> u[t-1, ...] = f(u[t, ...], u[t-1, ...]).
  """
  
  ROUNDABLE = Property('roundable')
  """
  A Dimension whose upper limit may be rounded up to a multiple of the SIMD
  vector length thanks to the presence of enough padding.
  """
  
  AFFINE = Property('affine')
  """
  A Dimension used to index into tensor objects only through affine and regular
  accesses functions. See :mod:`basic.py` for rigorous definitions of "affine"
  and "regular".
  """
  
  
  class HaloSpotProperty(Tag):
      pass
  
  
  OVERLAPPABLE = HaloSpotProperty('overlappable')
  """The HaloSpot supports computation-communication overlap."""
  
  
  def hoistable(i):
      """
      The HaloSpot can be squashed with a previous HaloSpot as all data dependences
      would still be honored.
      """
      return HaloSpotProperty('hoistable', i)
  
  
  def useless(i):
      """
      The HaloSpot can be ignored as a halo update at this point would be completely
      useless.
      """
      return HaloSpotProperty('useless', i)
  