Hi Mic,

 Did you copy your modified constr.f into the Src directory before
 recompiling Siesta ?.

 Best,
 Roberto

On Sat, 12 May 2012, Michael Shin wrote:

Rurali,
I llokedinto your discussion and it helped us. Then I tried Silican as an 
example.
I have two atoms and I wanted not to relax both the atoms and modified the 
constr.f file andthen recomplie it, but it didnt wirk.
Then I thought lets add constrain on two atoms and I added the following line 
in the constr.f file.
?????? fa(3,1)=0.0d0
?????? fa(3,2)=0.0d0
?
Which means that folrce along z axis on atom 1 and two will be zero.
When I recompiled the code and run it, thn it relaxed both the atoms in the 
unit cell.
I started from the following lines
?
%block AtomicCoordinatesAndAtomicSpecies
??? 0.??? 0.??? 0.3??? 1? Si??????? 1
??? 0.25? 0.25? 0.26?? 1? Si??????? 2
%endblock AtomicCoordinatesAndAtomicSpecies
?
And got the Following relaxed cocordines.
?
??? outcoor: Relaxed atomic coordinates (fractional):
??? 0.00054664??? 0.00054723??? 0.15300834?? 1?????? 1? Si
??? 0.25058586??? 0.25058642??? 0.40284097?? 1?????? 2? Si
?
In principles,if I am right, it should not relax these two atoms, but it does.
Can you help me how to handle it. Actually my system has about 100 atoms and I 
dont need to relax all the atoms, just a few atoms near the surface. So I am 
learning this method and tries Silicon.
?
Mic

Responder a