We perform the complete group classification in the class of nonlinear
Schr\"odinger equations of the form
iψt+ψxx+∣ψ∣γψ+V(t,x)ψ=0 where V is an arbitrary
complex-valued potential depending on t and x,γ is a real non-zero
constant. We construct all the possible inequivalent potentials for which these
equations have non-trivial Lie symmetries using a combination of algebraic and
compatibility methods. The proposed approach can be applied to solving group
classification problems for a number of important classes of differential
equations arising in mathematical physics.Comment: 10 page