create structure with screw dislocations
use burgers vector to define the extending direction

First re-write the structure to make the crystal axes aligned with XYZ axes
pysc.py --task=redefine --cell_orientation=1 --sc1=10,0,0 --sc2=0,6,0 --sc3=0,0,1

Then run the command to create the dislocated structure
pysc.py --task=screw_dislocation --burgers_vector=0,0,1 --poscar=POSCAR_redefine --screw_idir=2 --display_structure=T


The script "make_screw_diamond.py" provide an alternative way to create the structure
with more flexible and adavnced usages
