mparray_test.py 文件源码

def test_chain(nr_sites, local_dim, rank, rgen, dtype):
    # This test produces at most `nr_sites` by tensoring two
    # MPOs. This doesn't work for :code:`nr_sites = 1`.
    if nr_sites < 2:
        return

    # NOTE: Everything here is in local form!!!
    mpo = factory.random_mpa(nr_sites // 2, (local_dim, local_dim), rank,
                             randstate=rgen, dtype=dtype)
    op = mpo.to_array()

    # Test with 2-factors with full form
    mpo_double = mp.chain((mpo, mpo))
    op_double = np.tensordot(op, op, axes=(tuple(), ) * 2)
    assert len(mpo_double) == 2 * len(mpo)
    assert_array_almost_equal(op_double, mpo_double.to_array())
    assert_array_equal(mpo_double.ranks, mpo.ranks + (1,) + mpo.ranks)
    assert mpo.dtype == dtype

    # Test 3-factors iteratively (since full form would be too large!!
    diff = mp.chain((mpo, mpo, mpo)) - mp.chain((mpo, mp.chain((mpo, mpo))))
    diff.canonicalize()
    assert len(diff) == 3 * len(mpo)
    assert mp.norm(diff) < 1e-6


# local_dim, rank