the elements is but should
ideally document what operations they will use and what functions they need to
be provided with.

The next-level up is the DDM class which uses these routines but wraps them up
with an interface that handles copying etc and keeps track of the Domain of
the elements of the matrix:

    >>> from sympy.polys.domains import QQ
    >>> from sympy.polys.matrices.ddm import DDM
    >>> M = DDM([[QQ(1), QQ(2), QQ(3)], [QQ(4), QQ(5), QQ(6)]], (2, 3), QQ)
    >>> M
    [[1, 2, 3], [4, 5, 6]]
    >>> Mrref, pivots = M.rref()
    >>> Mrref
    [[1, 0, -1], [0, 1, 2]]

é