[gmx-users] Energy calculation

C.Y. Chang chiayun.chang at gmail.com
Thu Mar 17 10:16:13 CET 2011


Hi,

"Every charge group must be a subset of an energy group or fully disjoint
from it."
Does it mean that I could not set up the HBD and HBA in the ligand at the
same time, but the HBD in ligand and HBA in lipid bilayer could be
calculate?
or Each atoms in the ligand must belong to the disjointed subset?
For the guess 2, I try to modify the .ndx file and add the nHB
(non-HB-system).
The atoms in nHB are excluded from HBA and HBD in the ligand.

[ nHB ]
 17366  17368  17369  17370  17371  17372  17373  17374  17376  17377
17378  17379  17380
 17383  17386  17389  17390  17391  17392  17393  17394  17395
 17396  17397  17398  17399  17401  17402  17403  17405  17406  17407
17408  17409  17410
 17411  17413  17414  17415  17416  17417  17420  17423
 17426  17427  17428  17429  17430  17431  17432  17433  17434  17435
17436  17438  17439  17440
 17442  17443  17444  17445  17446  17447  17448  17450  17451  17452
17453  17454
 17457  17460  17463  17464  17465  17466  17467  17468  17469  17470
 17471  17472  17473  17475  17476  17477  17479  17480  17481  17482
17483  17484  17485
 17487  17488  17489  17490  17491  17494  17497  17500
 17501  17502  17503  17504  17505  17506  17507  17508  17509  17510
17512  17513  17514
 17516  17517  17518  17519  17520  17521  17522  17524  17525  17526
17527  17528
 17531  17534  17537  17538  17539  17540  17541  17542  17543  17544  17545
 17546  17547  17549  17550
[ HBD ]
 17385 17382 17422 17419 17459 17456 17496 17493 17533 17530
[ HBA ]
 17367  17375  17381  17384  17387  17388  17400  17404  17412  17418
17421  17424  17425  17437  17441
 17449  17455  17458  17461  17462  17474  17478  17486  17492  17495
17498  17499  17511  17515  17523
 17529  17532  17535  17536  17548

But the error msg. is alike.
Fatal error:
atoms 17366 and 17367 in charge group 1 of molecule type 'LIG' are in
different energy groups

Do you have any methods for calculating the HB energy in the intramolecules?
Thanks for your any comments.
Best,

                                                            Chia-yun Chang


2011/3/16 Mark Abraham <mark.abraham at anu.edu.au>

>
>
> On 16/03/11, *"C.Y. Chang" * <chiayun.chang at gmail.com> wrote:
>
> Hi,
>
> I try to calculate the Hbond in the ligand and remove the duplicate atoms
> in the .ndx file dumped from g_hbond.
> This is the contents in the .ndx file.
>
> [ HBD ]
>  17385 17382 17422 17419 17459 17456 17496 17493 17533 17530
> [ HBA ]
>  17367  17375  17381  17384  17387  17388  17400  17404  17412  17418
> 17421  17424  17425  17437  17441
>  17449  17455  17458  17461  17462  17474  17478  17486  17492  17495
> 17498  17499  17511  17515  17523
>  17529  17532  17535  17536  17548
>
> And then, I perfrom the grompp.
> It shows the error msg.
>
> Fatal error:
> atoms 17366 and 17367 in charge group 1 of molecule type 'LIG' are in
> different energy groups
>
> How should I deal with the problem?
>
>
> Redefine charge or energy groups as appropriate for whatever you're trying
> to do. Non-bonded interactions are calculated by looping over atom-atom
> interactions grouped by charge group and then by energy group. Every charge
> group must be a subset of an energy group or fully disjoint from it.
>
>
> On the other side, I read the information in the web page (
> http://www.mail-archive.com/gmx-users@gromacs.org/msg34617.html)
> I remove the lines in the [bonds] region in .top files.
> But I still get these terms
>
>   1  Angle            2  G96Angle         3  Proper-Dih.      4
> Ryckaert-Bell.
>   5  Improper-Dih.    6  LJ-14            7  Coulomb-14       8  LJ-(SR)
>   9  Disper.-corr.   10  Coulomb-(SR)    11  Coul.-recip.    12
> Position-Rest.
>  13  Potential       14  Kinetic-En.     15  Total-Energy    16
> Temperature
>  17  Pres.-DC        18  Pressure        19  Constr.-rmsd    20  Box-X
>  21  Box-Y           22  Box-Z           23  Volume          24  Density
>  25  pV              26  Enthalpy        27  Vir-XX          28  Vir-XY
>  29  Vir-XZ          30  Vir-YX          31  Vir-YY          32  Vir-YZ
>  33  Vir-ZX          34  Vir-ZY          35  Vir-ZZ          36  Pres-XX
>  37  Pres-XY         38  Pres-XZ         39  Pres-YX         40  Pres-YY
>  41  Pres-YZ         42  Pres-ZX         43  Pres-ZY         44  Pres-ZZ
>  45  #Surf*SurfTen   46  Mu-X            47  Mu-Y            48  Mu-Z
>  49  Coul-SR:LIG-LIG                     50  LJ-SR:LIG-LIG
>  51  Coul-14:LIG-LIG                     52  LJ-14:LIG-LIG
>  53  Coul-SR:LIG-DPPC_SOL                54  LJ-SR:LIG-DPPC_SOL
>  55  Coul-14:LIG-DPPC_SOL                56  LJ-14:LIG-DPPC_SOL
>  57  Coul-SR:DPPC_SOL-DPPC_SOL           58  LJ-SR:DPPC_SOL-DPPC_SOL
>  59  Coul-14:DPPC_SOL-DPPC_SOL           60  LJ-14:DPPC_SOL-DPPC_SOL
>  61  T-DPPC          62  T-SOL           63  T-LIG           64  Lamb-DPPC
>  65  Lamb-SOL        66  Lamb-LIG
>
> And I try to remove lines in [bonds], [pairs], [angles] and [ dihedrals ],
> but it is the same.
> Where is the wrong process? And how could I get the angle and dihedral
> energy in the intramolecules?
> Thanks for your any comments.
>
>
> You're decomposing PME electrostatics. That produces garbage values for
> quantities that have little meaning, like it says in the thread I suggested
> you read the whole of. I'm going to stop helping :-)
>
> Mark
>
>
>
> Best,
>
>                                                                 Chia-yun
>
>
> 2011/3/14 Mark Abraham <mark.abraham at anu.edu.au>
>
>>
>>
>> On 14/03/11, *"C.Y. Chang" * <chiayun.chang at gmail.com> wrote:
>>
>> Hi,
>>
>> I try to calculate hydrogen bond (HB) energy.
>> The g_energy does not have this term.
>> And I find the g_hbond function in Gromacs.
>> But the HB energy calculation is not in g_hbond.
>>
>>
>> There's good reasons for this. How would you define the "HB energy" in
>> terms of the kind of information accessible to MD simulations?
>>
>>
>> Therfore, I also try to dump the .ndx file including the HB_donor,
>> HB_acceptor and HB_system from g_hbond, and perfrom the grompp
>> But there is a error msg,
>>
>> Atom 17380 in multiple Energy Mon. groups
>>
>>
>> Look up energy groups in the manual - start of section 3.3. Your .mdp file
>> is defining an illegal combination of atoms and energy monitor groups.
>>
>>
>> Another problem is about calculating the intramolecular energy e.g.
>> 1,4-nonbonded, van der waal, electrostatic etc. of the ligand in lipid
>> layer-ligand complex system.
>> I could set up the energy_grp and calculate energy between the ligand
>> group and the lipid layer group.
>> But I need the intramolecular energy in the groups.
>> How should I deal with these problems?
>>
>>
>> An inter-group energy doesn't mean anything much, so don't bother. Please
>> read the whole of this thread
>> http://lists.gromacs.org/pipermail/gmx-users/2010-November/055687.html
>>
>> Mark
>> --
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>
>
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