[Wien] c/a optimization error

Dear Prof Blaha and wien2k user I am doing volume optimization for a tetragonal structure. First I have done volume optimization along with force minimization.Then I am doing c/a optimization for each volume(-4,-2,0,+2,+4).While doing c/a optimization along with force minimization for -4%, -2% and

[Wien] coordinate system

I don't think you should rotate yourself. Look into case.struct (or outputsymso) to see the local rotation matrix. This matrix defines the coordinate system with respect to the global crystalline one. And your vorb files are taken in this local coordinate system. So if rotloc is 0 0 1 0 1 0 1 0