hi users,
the best thing to do is a previous calculation on a little system to get
enough knowledge about this kind of calculation.
well, i did, and conclude: don't put "true" in usesavedata.
remember: phonon calculations are meant to be performed on the equilibrium
configuration, then all the steps must be calculated from the inicial one.
so if "usesavedata" is true, you will get bad results (look at the .FC
values from two calculations: true and false and you will see!). that's
because the program will read the "save positions".
ok, not using save data takes a long time to finish the calculation! i do
agree! but i noticed that using the "save .DM" adds just a little error in
the .FC file (something about 10^-5).
use in your fdf file the following variables, it will be easier to watch
closely the calculations and understand how they are going.
WriteForces true
WriteCoorStep true
hope it was helpful!
best wishes,
bipul rakshit writes:
hello Marcel,
I have only one doubt in the above thing. If consider i have 54 atoms in a
system. So in FC.fdf file its written
MD.FCfirst 27
MD.FClast 28
So the file.FC file contains 649 lines......
consider my calculation stops at 577 lines, means at 48th atom. So what i
have to write in MD.FCfirst and MD.FClast....,,,, is it
MD.FCfirst 48
MD.FClast 49
or what.....
and also in the file-siesta.fdf I have to use the flag,
UseSaveData .true.
and restart the calculation????
please answer these queries.....
this should be helpful for me.....
thanks
Note: forwarded message attached.
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