restarting umbrella sampling simulation.

From: ipsita basu (ibasu788_at_gmail.com)
Date: Tue Sep 04 2012 - 00:42:09 CDT

Sir,
I have a query regarding restarting umbrella sampling simulation of
membrane protein system.
When I start it one portion of my configuration is:
harmonic {
  name lenpot
  colvars distanceZ
  centers 70.00
  forceConstant 5.0
  targetCenters 60.00
  targetNumSteps 1000000
  targetNumStages 100
where the distance between the two selected group is 70 which I want
to decrease to 60 in 1000000 steps. The output traj is like:
999800 6.04585123909563e+01
# step distanceZ
     1000000 6.04704550193212e+01
Now when I restart the job I set the above portion as :
harmonic {
  name lenpot
  colvars distanceZ
  centers 60.00
  forceConstant 5.0
  targetCenters 50.00
  targetNumSteps 1000000
  targetNumStages 100
But doing this the output traj file is like:
1403600 6.03582445087823e+01
1403800 6.03622946744465e+01
which means the distance is not decreasing anymore, so I omit the
option centers 60.00 and then I get the error: Error: must define the
initial centers of the restraints.
So should I set the value for centers and target centers, then what is
the difference between the two?
Or should I set off the options:
targetCenters 50.00
  targetNumSteps 1000000
  targetNumStages 100
Please help.

-- 
Ipsita Basu
Research Fellow
c/o : Dr. Chaitali Mukhopadhyay
Rajabazar Science College
92 APC Road
Kolkata - 700009

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