[gmx-users] step size too small
minnale_gnos at rediffmail.com
Mon Jun 30 11:26:46 CEST 2008
1) I have embedded protein into popcbilayer
2) Energy minimisation
3) Later added ions by using genion,
4) When I am trying to run minimisation its showing following sentences
Stepsize too small, or no change in energy.
Converged to machine precision,
but not to the requested precision Fmax < 100
Double precision normally gives you higher accuracy.
You might need to increase your constraint accuracy, or turn
off constraints alltogether (set constraints = none in mdp file)
writing lowest energy coordinates.
Steepest Descents converged to machine precision in 49 steps,
but did not reach the requested Fmax < 100.
Potential Energy = -2.1825061e+05
Maximum force = 4.3672461e+03 on atom 7008
Norm of force = 5.5597691e+04
my .mdp file is
cpp = /usr/bin/cpp
define = -DFLEX_SPC
constraints = none
integrator = steep
nsteps = 500
; Energy minimizing stuff
emtol = 100
emstep = 0.01
nstcomm = 1.0
ns_type = grid
rlist = 1.0
rcoulomb = 1.0
rvdw = 1.0
When I run minimisation before adding ions it ran fine but later not why?
I have searched about solve this problem in archives list and I understood that this not an error. Can I proceed further simulations
Any comments will be appreciated.
Thanks in advance.
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