# [0.5.0] - 2019-12-18¶

## Changed¶

• Addition/subtraction of Array: check whether the both arrays have the same labels in differnt order, and in that case raise a warning that we will transpose in the future.

• Made tenpy.linalg.np_conserved.Array.get_block() public (previously tenpy.linalg.np_conserved.Array._get_block).

• groundstate() now returns a tuple (E0, psi0) instead of just psi0. Moreover, the argument charge_sector was added.

• Simplification in the Lattice: Instead of having separate arguments/attributes/functions for 'nearest_neighbors', 'next_nearest_neighbors', 'next_next_nearest_neighbors' and possibly (Honeycomb) even 'fourth_nearest_neighbors', 'fifth_nearest_neighbors', collect them in a dictionary called pairs. Old call structures still allowed, but deprecated.

• issue #94: Array addition and inner() should reflect the order of the labels, if they coincided. Will change the default behaviour in the future, raising FutureWarning for now.

• Default parameter for DMRG params: increased precision by setting P_tol_min down to the maximum of 1.e-30, lanczos_params['svd_min']**2 * P_tol_to_trunc, lanczos_params['trunc_cut']**2 * P_tol_to_trunc by default.