  The roughening phase diagram of the d=3 Ising model with uniaxially
anisotropic interactions is calculated for the entire range of anisotropy, from
decoupled planes to the isotropic model to the solid-on-solid model, using
hard-spin mean-field theory. The phase diagram contains the line of ordering
phase transitions and, at lower temperatures, the line of roughening phase
transitions, where the interface between ordered domains roughens. Upon
increasing the anisotropy, roughening transition temperatures settle after the
isotropic case, whereas the ordering transition temperature increases to
infinity. The calculation is repeated for the d=2 Ising model for the full
range of anisotropy, yielding no roughening transition.
