Dear Raju,

You haven't added any exclusions to your topology. Therefore, the mid point is interacting via the coulomb potential with the Carbon and Oxygen atoms.

If you exclude those interactions this system will probably run.

Richard

On 01/05/13 14:16, 라지브간디 wrote:
Dear
Mark,




As per you suggestion, I have simulated a single CO as well as
CO-with-vsite in a box.




A single CO runs without any problem, BUT the CO-with-vsite
gives an same error as before:




Steepest
Descents:

    Tolerance (Fmax)   =
  1.00000e+03

    Number of steps    =
      50000

Step=    0, Dmax= 1.0e-02 nm, Epot=
-3.73341e+04 Fmax= 3.38911e+05, atom= 2

Step=    1, Dmax= 1.0e-02 nm, Epot=
-4.54970e+04 Fmax= 4.95889e+05, atom= 2

Step=    2, Dmax= 1.2e-02 nm, Epot=
-6.18180e+04 Fmax= 9.34585e+05, atom= 2

Step=    3, Dmax= 1.4e-02 nm, Epot=
-1.10395e+05 Fmax= 3.03088e+06, atom= 1

Step=    5, Dmax= 8.6e-03 nm, Epot=
-2.09874e+05 Fmax= 1.09138e+07, atom= 2

Step=    9, Dmax= 1.3e-03 nm, Epot=
-2.42526e+05 Fmax= 1.45550e+07, atom= 1

Step=   11, Dmax= 7.8e-04 nm, Epot=
-2.67493e+05 Fmax= 1.76910e+07, atom= 2

Step=   14, Dmax= 2.3e-04 nm, Epot=
-2.76005e+05 Fmax= 1.88299e+07, atom= 2

Step=   16, Dmax= 1.4e-04 nm, Epot=
-2.81365e+05 Fmax= 1.95651e+07, atom= 2

Step=   19, Dmax= 4.2e-05 nm, Epot=
-2.83032e+05 Fmax= 1.97967e+07, atom= 1

Step=   23, Dmax= 6.3e-06 nm, Epot=
-2.83281e+05 Fmax= 1.98315e+07, atom= 1

Step=   26, Dmax= 1.9e-06 nm, Epot=
-2.83355e+05 Fmax= 1.98418e+07, atom= 2

Step=   28, Dmax= 1.1e-06 nm, Epot=
        nan Fmax= 0.00000e+00, atom= 0

Stepsize too small, or no change in energy.

Converged to machine precision,

but not to the requested precision Fmax < 1000




Double precision normally gives you higher
accuracy.




writing lowest energy coordinates.




Back Off! I just backed up min.gro to ./#min.gro.1#




Steepest Descents converged to machine precision in
29 steps,

but did not reach the requested Fmax < 1000.

Potential Energy  = -2.8335531e+05

Maximum force     =  1.9841798e+07
on atom 2

Norm of force     =  1.6200760e+07







I am afraid that I am a making any mistakes of setting the
vsite?





My
topology file vsite setting :




[ moleculetype ]


;
Name            nrexcl

Other_chain_A       3



[ atoms ]

;   nr       type  resnr
residue  atom   cgnr     charge       mass
  typeB    chargeB      massB

; residue 157 CMO rtp CMO  q -1.6

      1
  C    157    CMO      C
  1      -0.75     12.011   ; qtot -0.75

      2
  O    157    CMO      O
  2      -0.85    15.9994   ; qtot -1.6

      3
  I     157     CMO      I
   3       1.6      0.0000

[ bonds ]

;  ai    aj funct
        c0            c1
            c2
  c3

     1     2     2
    gb_4

[ virtual_sites2 ]

; Vsite from        funct
   a




3       1     2
     1       0.4376625







My coordiante (.gro) file where i added the vsite xyz: Also included
the vsite atom info in atomypes as well as ffnonbonded.itp.




Gravel
Rubs Often Many Awfully Cauterized Sores


   3


157CMO      C    1   1.625   2.697
0.490


157CMO      O    2   1.722   2.647
0.482


157CMO       I     3   1.673   2.672
   0.486

  0.09660
   0.05040   0.00760

~






Could you tell what mistakes I am making here ?





Thanks in advance.





Raju





On Wed, May 1, 2013 at ��������������� :



I mean simulate a single CO in a box. Then CO-with-vsite in a box.
If you
can do that, then a bunch of problems are known to be solved. Leaping in
the deep end with a complex system means you don't know where the trouble
comes from when you have it.

Mark

On Wed, May 1, 2013 at 8:45 AM, ���������������
<[email protected]> wrote:

Dear Mark,

You mean do the CO simulation and then add V-site upon
production run?

Could you please more specific, what has to be done to avoid this
error?

  >
On Fri, Apr 26, 2013 at 6:16 PM, ������������������������������
<[email protected]> wrote:

Maybe your starting configuration of atoms is too broken to be
useful.
Maybe you have some interaction on atom 2513 that doesn't work.

Make a simple system of CO work, then do CO+vsite. Then apply those
lessons
to your complex system.

Mark






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