From: Ivan Mikhaylov (ivan.mikhaylov_at_gmail.com)
Date: Wed Jun 05 2013 - 16:28:48 CDT
I defined a colvar "distance" and "forceConstant 10.0" asking for
"oneSiteSystemForce" printing.
I have an output in *.colvars.traj as follows:
# step 1st-colvar fs_1st-colvar
0 2.70639531217785e+00 0.00000000000000e+00
1000 2.76803828316001e+00 2.49728670452675e+00
.... ........ ...............
7000 3.14579942428557e+00 -3.41836799520439e+01
As you see, the very first force is zero and there are positive and
negative values in the third column for the forces.
Equation (50) in section 10.3.1:
http://www.ks.uiuc.edu/Research/namd/2.9/ug/node56.html#eq:gradient_vector
does not really help, because it is unclear.
I thought that the force should be equal to distance*forceConstant.
Why is it not?
Could you tell me, please, what "outputSystemForce" outputs?
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