How does the constraints work when performing NEB?

[wot19920302]

Dear Quantumwise staffs
           Can I perform NEB for some atoms while fix the other atoms in a system (ATK 2015)? I noitce that there is a option named Constraints in NEB block but I don't understand how does it work. As we know, when performing NEB, the optimized initial geometry and the final geometry should be given in NEB block in VNL. Obviously, there a few differences in positions of atoms between the initial and the final structures.  How does ATK process transistion of atoms which are added to tag of Constraints-Fixed from the initial to the final structure?
            Beset wishes     

[Ulrik G. Vej-Hansen]

If you wish to fix atoms during the NEB, they should also be fixed during the optimization of the initial and final structures, to ensure consistency.