message: Throw error when ek.dot is used with Matrix type
diff: @@ -1898,12 +1898,20 @@ def hmin_nested(a):
  def dot(a, b):
  + if _ek.is_matrix_v(a) or _ek.is_matrix_v(b):
  + raise Exception("dot(): input shouldn't be a Matrix!"
  + "The @ operator should be used instead.")
  +
  if type(a) is not type(b):
  a, b = _var_promote(a, b)
  return a.dot_(b)
  def dot_async(a, b):
  + if _ek.is_matrix_v(a) or _ek.is_matrix_v(b):
  + raise Exception("dot_async(): input shouldn't be a Matrix!"
  + "The @ operator should be used instead.")
  +
  if type(a) is not type(b):
  a, b = _var_promote(a, b)
  @@ -1914,10 +1922,18 @@ def dot_async(a, b):
  def abs_dot(a, b):
  + if _ek.is_matrix_v(a) or _ek.is_matrix_v(b):
  + raise Exception("abs_dot(): input shouldn't be a Matrix!"
  + "The @ operator should be used instead.")
  +
  return abs(dot(a, b))
  def abs_dot_async(a, b):
  + if _ek.is_matrix_v(a) or _ek.is_matrix_v(b):
  + raise Exception("abs_dot_async(): input shouldn't be a Matrix!"
  + "The @ operator should be used instead.")
  +
  return abs(dot_async(a, b))
  