[SIESTA-L] How to fix some of the atoms while doing relaxation

[Clutch Q. J. Fan]

Dear SIESTA users:
 
The atoms can fully relax if you do a relaxation.
 
But if I want to fix some atoms, while the others can relax.
 
Or if I want to make some atoms can only relax in z direction but are fixed in 
x and y direction.
 
Can SIESTA do this?
 
Thanks in advance.
 
 
Yours Clutch