[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"  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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> Gromacs Users mailing list
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> * Please search the archive at
> http://www.gromacs.org/Support/Mailing_Lists/GMX-Users_List before
> posting!
>
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>
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>
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