[gmx-users] LINCS warning

amitbehra at chemeng.iisc.ernet.in amitbehra at chemeng.iisc.ernet.in
Thu Aug 25 12:06:56 CEST 2016

Hello users,
I was trying to energy minimize my system of protein embedded in bilayer.
But I am receiving the following error:

Step -1, time -0.001 (ps)  LINCS WARNING
relative constraint deviation after LINCS:
rms 0.000942, max 0.149038 (between atoms 21616 and 21619)
bonds that rotated more than 30 degrees:
 atom 1 atom 2  angle  previous, current, constraint length

Steepest Descents:
   Tolerance (Fmax)   =  1.00000e+03
   Number of steps    =       500000

Energy minimization has stopped, but the forces have not converged to the
requested precision Fmax < 1000 (which may not be possible for your system).
It stopped because the algorithm tried to make a new step whose size was too
small, or there was no change in the energy since last step. Either way, we
regard the minimization as converged to within the available machine
precision, given your starting configuration and EM parameters.

Double precision normally gives you higher accuracy, but this is often not
needed for preparing to run molecular dynamics.
You might need to increase your constraint accuracy, or turn
off constraints altogether (set constraints = none in mdp file)

writing lowest energy coordinates.

Steepest Descents converged to machine precision in 11 steps,
but did not reach the requested Fmax < 1000.
Potential Energy  =  2.3557852e+30
Maximum force     =            inf on atom 34347
Norm of force     =            inf

what approach should I use to get rid of this problem?

Amit Behera

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