  We describe and apply a version of the finite amplitude method for obtaining
the charge-changing nuclear response in the quasiparticle random phase
approximation. The method is suitable for calculating strength functions and
beta-decay rates, both allowed and forbidden, in axially-deformed open-shell
nuclei. We demonstrate the speed and versatility of the code through a
preliminary examination of the effects of tensor terms in Skyrme functionals on
beta decay in a set of spherical and deformed open-shell nuclei. Like the
isoscalar pairing interaction, the tensor terms systematically increase allowed
beta-decay rates. This finding generalizes previous work in semimagic nuclei
and points to the need for a comprehensive study of time-odd terms in nuclear
density functionals.
