  The nonlocal van der Waals (NL-vdW) functionals [Dion et al., Phys. Rev.
Lett. 92, 246401 (2004)] are being applied more and more frequently in
solid-state physics, since they have shown to be much more reliable than the
traditional semilocal functionals for systems where weak interactions play a
major role. However, a certain number of NL-vdW functionals have been proposed
during the last few years, such that it is not always clear which one should be
used. In this work, an assessment of NL-vdW functionals is presented. Our test
set consists of weakly bound solids, namely rare gases, layered systems like
graphite, and molecular solids, but also strongly bound solids in order to
provide a more general conclusion about the accuracy of NL-vdW functionals for
extended systems. We found that among the tested functionals, rev-vdW-DF2
[Hamada, Phys. Rev. B 89, 121103(R) (2014)] is very accurate for weakly bound
solids, but also quite reliable for strongly bound solids.
