# Revision history [back]

The reason is that a specific __copy__ method was written for matrices, but not a __deepcopy__ one, hence copy.deepcopy falls back to a generic method which does not care about the subdivision. As you can see, the copy works well:

sage: C = copy.copy(A)
sage: C
[1 2|1 0]
[3 4|0 1]


and you can check in its source code that a special care of subdivision is made:

sage: A.__copy__??


If you need this feature, let me suggest to add a __deepcopy__ method in Sage source code.