Re: [gmx-users] using trjconv to get a 2x2x2 unit cell for traj.xtc

2009-12-08 Thread Jennifer Williams


Hi Justin

Thanks for the suggestions. However, I don't really want to stop the  
molecule moving into the next image-I start off with an alkyl chain  
where a large portion of the structure overlaps the pbc.


i.e C1-C2-C3 \\ C4-C5-C6

where || is the unit cell boundary. To see the whole alkyl chain I use  
the graphics/representations/periodic tab in VMD. The problem is that  
VMD will not allow me to draw a bond between C3 and C4 meaning I get  
odd looking movies. VMD prefers to join the C3 to the C4 in the same  
unit cell rather than the C4 sitting right next to it on the other  
side of the pbc. This means long bonds stretching the length of my  
unit cell and missing bonds between atoms sitting next to each other!  
I have spent a while trying to solve this and have posted to the VMD  
forum (as it is actually a problem with VMD and not gromacs).


If I could somehow do the same thing to the traj.xtc as I did to  
confgro.out using genconf -nbox 2 2 2 that would solve my  
visualisation problem. Do you know of a way to do this? Even a  
round-about way?  I suppose if I dumped each frame in the trajectory  
as a pdb, used genbox on them to get a 2x2x2 box and then somehow  
stuck them together into an .xtc this might work (but any suggestions  
which are less messy are greatly appreciated!)


Jenny






Quoting "Justin A. Lemkul" :




Jennifer Williams wrote:



Hello,

I am trying to find a way around a visualisation problem I am   
having in VMD. Some of my molecules go over periodic boundary   
conditions meaning that bonds sometimes appear missing when looking  
 at movies (I am trying to fix this using wrap, unwrap and join in   
VMD but as yet no luck).


I was wondering if there is a way in gromacs to multiply the number  
 of unit cells shown in a trajectory. i.e instead of a 1x1x1 I want  
 the new unit cell to be 2x2x2. This would mean the section of the   
structure I want to zoom in doesn't go over the pbc.


For the confout.gro file I have done this using

genconf -nbox 2 2 2 -f confout.gro -o confbig.out

and this enables me to at least see a static image where all bonds   
are present.


but in order to view a movie, I need to carry out something similar  
 on the traj.xtc file. I have seen that with trjconv there is the   
option


-box  Size for new cubic box

but my unit cell is not cubic, it is a parallelepiped. The cell   
dimensions are :


4.64210   3.77847   1.89596   0.0   0.0  -2.18150   0.0  
   0.0   0.0


I tried using this anyway with the following command:

trjconv -box 9.28414 8.72598 3.79192 -f traj.xtc -o trajbig.xtc

but the resulting .xtc file wouldn't load into VMD so I assume that  
 the .xtc file and the .gro file didn't match.




Correcting periodicity should alleviate some of the problems.  Using
trjconv -pbc mol (or -pbc nojump) is typically the best first step.

-Justin


Any ideas?,

Thanks

Jenny









--


Justin A. Lemkul
Ph.D. Candidate
ICTAS Doctoral Scholar
MILES-IGERT Trainee
Department of Biochemistry
Virginia Tech
Blacksburg, VA
jalemkul[at]vt.edu | (540) 231-9080
http://www.bevanlab.biochem.vt.edu/Pages/Personal/justin


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Dr. Jennifer Williams
Institute for Materials and Processes
School of Engineering
University of Edinburgh
Sanderson Building
The King's Buildings
Mayfield Road
Edinburgh, EH9 3JL, United Kingdom
Phone: ++44 (0)131 650 4 861


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Scotland, with registration number SC005336.


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Re: [gmx-users] using trjconv to get a 2x2x2 unit cell for traj.xtc

2009-12-08 Thread Justin A. Lemkul



Jennifer Williams wrote:


Hi Justin

Thanks for the suggestions. However, I don't really want to stop the 
molecule moving into the next image-I start off with an alkyl chain 
where a large portion of the structure overlaps the pbc.


i.e C1-C2-C3 \\ C4-C5-C6

where || is the unit cell boundary. To see the whole alkyl chain I use 
the graphics/representations/periodic tab in VMD. The problem is that 
VMD will not allow me to draw a bond between C3 and C4 meaning I get odd 
looking movies. VMD prefers to join the C3 to the C4 in the same unit 
cell rather than the C4 sitting right next to it on the other side of 
the pbc. This means long bonds stretching the length of my unit cell and 
missing bonds between atoms sitting next to each other! I have spent a 
while trying to solve this and have posted to the VMD forum (as it is 
actually a problem with VMD and not gromacs).




I still think trjconv -pbc mol would be useful to you.  It will make the 
"broken" molecules whole, such that they are not split over the periodic 
boundaries, which seems like it would eliminate your problem.  I do the same 
with lipid bilayers all the time.


If I could somehow do the same thing to the traj.xtc as I did to 
confgro.out using genconf -nbox 2 2 2 that would solve my visualisation 
problem. Do you know of a way to do this? Even a round-about way?  I 
suppose if I dumped each frame in the trajectory as a pdb, used genbox 
on them to get a 2x2x2 box and then somehow stuck them together into an 
.xtc this might work (but any suggestions which are less messy are 
greatly appreciated!)




The only way to do that is indeed the messy way.

-Justin

--


Justin A. Lemkul
Ph.D. Candidate
ICTAS Doctoral Scholar
MILES-IGERT Trainee
Department of Biochemistry
Virginia Tech
Blacksburg, VA
jalemkul[at]vt.edu | (540) 231-9080
http://www.bevanlab.biochem.vt.edu/Pages/Personal/justin


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Please search the archive at http://www.gromacs.org/search before posting!
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Re: [gmx-users] using trjconv to get a 2x2x2 unit cell for traj.xtc

2009-12-08 Thread Ran Friedman
Dear Jenny,

You can do this directly in VMD, using the Periodic tab under
Graphics->Representations.

Ran

Jennifer Williams wrote:
>
>
> Hello,
>
> I am trying to find a way around a visualisation problem I am having
> in VMD. Some of my molecules go over periodic boundary conditions
> meaning that bonds sometimes appear missing when looking at movies (I
> am trying to fix this using wrap, unwrap and join in VMD but as yet no
> luck).
>
> I was wondering if there is a way in gromacs to multiply the number of
> unit cells shown in a trajectory. i.e instead of a 1x1x1 I want the
> new unit cell to be 2x2x2. This would mean the section of the
> structure I want to zoom in doesn't go over the pbc.
>
> For the confout.gro file I have done this using
>
> genconf -nbox 2 2 2 -f confout.gro -o confbig.out
>
> and this enables me to at least see a static image where all bonds are
> present.
>
> but in order to view a movie, I need to carry out something similar on
> the traj.xtc file. I have seen that with trjconv there is the option
>
> -box  Size for new cubic box
>
> but my unit cell is not cubic, it is a parallelepiped. The cell
> dimensions are :
>
> 4.64210   3.77847   1.89596   0.0   0.0  -2.18150   0.0  
> 0.0   0.0
>
> I tried using this anyway with the following command:
>
> trjconv -box 9.28414 8.72598 3.79192 -f traj.xtc -o trajbig.xtc
>
> but the resulting .xtc file wouldn't load into VMD so I assume that
> the .xtc file and the .gro file didn't match.
>
> Any ideas?,
>
> Thanks
>
> Jenny
>
>
>
>
>
>
>
> --The University of Edinburgh is a charitable body, registered in
> Scotland, with registration number SC005336.
>
>
> --gmx-users mailing listgmx-users@gromacs.org
> http://lists.gromacs.org/mailman/listinfo/gmx-users
> Please search the archive at http://www.gromacs.org/search before
> posting!
> Please don't post (un)subscribe requests to the list. Use thewww
> interface or send it to gmx-users-requ...@gromacs.org.
> Can't post? Read http://www.gromacs.org/mailing_lists/users.php
>

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Re: [gmx-users] using trjconv to get a 2x2x2 unit cell for traj.xtc

2009-12-08 Thread Justin A. Lemkul



Jennifer Williams wrote:



Hello,

I am trying to find a way around a visualisation problem I am having in 
VMD. Some of my molecules go over periodic boundary conditions meaning 
that bonds sometimes appear missing when looking at movies (I am trying 
to fix this using wrap, unwrap and join in VMD but as yet no luck).


I was wondering if there is a way in gromacs to multiply the number of 
unit cells shown in a trajectory. i.e instead of a 1x1x1 I want the new 
unit cell to be 2x2x2. This would mean the section of the structure I 
want to zoom in doesn't go over the pbc.


For the confout.gro file I have done this using

genconf -nbox 2 2 2 -f confout.gro -o confbig.out

and this enables me to at least see a static image where all bonds are 
present.


but in order to view a movie, I need to carry out something similar on 
the traj.xtc file. I have seen that with trjconv there is the option


-box  Size for new cubic box

but my unit cell is not cubic, it is a parallelepiped. The cell 
dimensions are :


4.64210   3.77847   1.89596   0.0   0.0  -2.18150   0.0   
0.0   0.0


I tried using this anyway with the following command:

trjconv -box 9.28414 8.72598 3.79192 -f traj.xtc -o trajbig.xtc

but the resulting .xtc file wouldn't load into VMD so I assume that the 
.xtc file and the .gro file didn't match.




Correcting periodicity should alleviate some of the problems.  Using trjconv 
-pbc mol (or -pbc nojump) is typically the best first step.


-Justin


Any ideas?,

Thanks

Jenny









--


Justin A. Lemkul
Ph.D. Candidate
ICTAS Doctoral Scholar
MILES-IGERT Trainee
Department of Biochemistry
Virginia Tech
Blacksburg, VA
jalemkul[at]vt.edu | (540) 231-9080
http://www.bevanlab.biochem.vt.edu/Pages/Personal/justin


--
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Please search the archive at http://www.gromacs.org/search before posting!
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[gmx-users] using trjconv to get a 2x2x2 unit cell for traj.xtc

2009-12-08 Thread Jennifer Williams



Hello,

I am trying to find a way around a visualisation problem I am having  
in VMD. Some of my molecules go over periodic boundary conditions  
meaning that bonds sometimes appear missing when looking at movies (I  
am trying to fix this using wrap, unwrap and join in VMD but as yet no  
luck).


I was wondering if there is a way in gromacs to multiply the number of  
unit cells shown in a trajectory. i.e instead of a 1x1x1 I want the  
new unit cell to be 2x2x2. This would mean the section of the  
structure I want to zoom in doesn't go over the pbc.


For the confout.gro file I have done this using

genconf -nbox 2 2 2 -f confout.gro -o confbig.out

and this enables me to at least see a static image where all bonds are  
present.


but in order to view a movie, I need to carry out something similar on  
the traj.xtc file. I have seen that with trjconv there is the option


-box  Size for new cubic box

but my unit cell is not cubic, it is a parallelepiped. The cell  
dimensions are :


4.64210   3.77847   1.89596   0.0   0.0  -2.18150   0.0
0.0   0.0


I tried using this anyway with the following command:

trjconv -box 9.28414 8.72598 3.79192 -f traj.xtc -o trajbig.xtc

but the resulting .xtc file wouldn't load into VMD so I assume that  
the .xtc file and the .gro file didn't match.


Any ideas?,

Thanks

Jenny







--
The University of Edinburgh is a charitable body, registered in
Scotland, with registration number SC005336.


--
gmx-users mailing listgmx-users@gromacs.org
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