[gmx-users] use of Walls in Martini simulations

2014-10-24 Thread Ramon Reigada
Hi,

 I would like to post a question about simulating with Walls in gromacs
and using the Martini force field. 
The question is very simple. I am trying to simulate a simple box of water
molecules with pbc=xy and walls at z=0 and z=z_box. I use Berendsen
T-coupling and no pressure bath.
I am trying:

pbc=xy
nwall =2
wall_atomtype = C1 C1   (C1 are the alkane carbons defined in the martini
force field file)
wall_type = 9-3 
wall_density = 110 110
wall_r_linpot = 1

and all what I have is that the initial box of water molecules breaks in two
pieces that separate each other in the z-direction.
The same result (or a segmentation fault) is obtained by using 10-4 o 12-6
LJ potentials, large wall_r_linpot values, other values of wall_densities,
so I think that the problem is with the wall_atomtype. I tried the water
bead (W) instead, and segmentation fault is obtained. 


  thank you very much in advance,

  Ramon

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Re: [gmx-users] use of Walls in Martini simulations

2014-10-24 Thread HANNIBAL LECTER
What about electrostatics? Ewald summation is probably the culprit here.
On Oct 24, 2014 12:05 PM, Ramon Reigada reig...@ub.edu wrote:

 Hi,

  I would like to post a question about simulating with Walls in gromacs
 and using the Martini force field.
 The question is very simple. I am trying to simulate a simple box of water
 molecules with pbc=xy and walls at z=0 and z=z_box. I use Berendsen
 T-coupling and no pressure bath.
 I am trying:

 pbc=xy
 nwall =2
 wall_atomtype = C1 C1   (C1 are the alkane carbons defined in the martini
 force field file)
 wall_type = 9-3
 wall_density = 110 110
 wall_r_linpot = 1

 and all what I have is that the initial box of water molecules breaks in
 two
 pieces that separate each other in the z-direction.
 The same result (or a segmentation fault) is obtained by using 10-4 o 12-6
 LJ potentials, large wall_r_linpot values, other values of wall_densities,
 so I think that the problem is with the wall_atomtype. I tried the water
 bead (W) instead, and segmentation fault is obtained.


   thank you very much in advance,

   Ramon

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 http://www.gromacs.org/Support/Mailing_Lists/GMX-Users_List before
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