Re: [AMBER] vlimit exceeded for step

From: Rilei Yu <yulaomao1983.yahoo.com.cn>
Date: Sat, 10 Apr 2010 15:47:33 +0800 (CST)

Dear Dr. Jason,

Now, the problem has been solved! Next time, I should be more cautious!

Thanks for your remind!

Rilei Yu

--- 10年4月10日,周六, Jason Swails <jason.swails.gmail.com> 写道:

发件人: Jason Swails <jason.swails.gmail.com>
主题: Re: [AMBER] vlimit exceeded for step
收件人: "AMBER Mailing List" <amber.ambermd.org>
日期: 2010年4月10日,周六,上午7:59

On Fri, Apr 9, 2010 at 7:50 PM, Rilei Yu <yulaomao1983.yahoo.com.cn> wrote:
> Thanks for your reply! I have a try, when I set up, ntx=1  irest=5,, dt=0.002,

If you look more closely at the previous email, you will see that it
says "ntx=5, irest=1", you have it backwards.  The manual also
explains this explicitly.

Good luck,
Jason

>  ntf=2, ntc=2. The MD was stopped immediately: IREST (  5) must be 0 or 1.  NTX / IREST inconsistency *** input error(s). Then I checked the email-list, Prof. David, ever suggested someone use  ntx=1  irest=0. When I try this, it worked well! This means it will not use the fomer velocity. Is it ok?
>
>
> Rilei Yu
>
> --- 10年4月9日,周五, Jason Swails <jason.swails.gmail.com> 写道:
>
> 发件人: Jason Swails <jason.swails.gmail.com>
> 主题: Re: [AMBER] vlimit exceeded for step
> 收件人: "AMBER Mailing List" <amber.ambermd.org>
> 日期: 2010年4月9日,周五,下午8:36
>
> Exceeded vlimits are generally indicative of overlapping atoms.  Try
> printing to your trajectory every step for a small number of steps
> (ntwx=1) and visualizing the result to see if you can tell which atoms
> may be causing the problems.
>
> You may try minimizing and carefully heating the system in order to
> relieve those bad contacts.  However, it appears as though you've
> already run a short amount of MD and this run is a restart, so you
> should probably set the variables "irest=1, ntx=5".  Also, if you want
> to run with a 0.002 timestep, you should be SHAKEing bonds involving
> hydrogen atoms (as their frequencies are too high to use such a long
> timestep).  Do this with "ntf=2, ntc=2".  Details can be found in the
> manual.
>
> Good luck!
> Jason
>
> On Fri, Apr 9, 2010 at 2:52 AM, Rilei Yu <yulaomao1983.yahoo.com.cn> wrote:
>>
>> Dear amber users,
>>
>> When I set up dt=0.001,  everything goes well. However, when I try dt=0.002, some bugs appeared! I even found someone even asked such question in the mail-list, but I still found it could not solve my problem. Can anyone give me some help?
>>
>> Thanks in advance!
>> Errors:
>>
>>  NSTEP =        0   TIME(PS) =     520.000  TEMP(K) =   301.82  PRESS =     0.0
>>  Etot   =     -2855.6283  EKtot   =      8299.2936  EPtot      =    -11154.9219
>>  BOND   =      4225.1312  ANGLE   =      3334.7581  DIHED      =      4614.4087
>>  1-4 NB =      1561.4318  1-4 EEL =     17477.0703  VDWAALS    =     -2055.3714
>>  EELEC  =    -40323.2236  EHBOND  =         0.0000  RESTRAINT  =        10.8731
>>  EAMBER (non-restraint)  =    -11165.7950
>>  ------------------------------------------------------------------------------
>>
>> vlimit exceeded for step      2; vmax =    20.7518
>> vlimit exceeded for step      3; vmax =    53.0707
>> vlimit exceeded for step      4; vmax =    91.7254
>> vlimit exceeded for step      5; vmax =    85.5594
>> vlimit exceeded for step      6; vmax =    84.2917
>> vlimit exceeded for step      7; vmax =    86.0951
>> vlimit exceeded for step      8; vmax =    81.3904
>> vlimit exceeded for step      9; vmax =    81.6573
>>
>> Input:
>>
>>  &cntrl
>>   ntx=1,
>>   irest=0,
>>   imin=0,
>>   ntpr=10,
>>   ntwx=10,
>>   ntwr=50,
>>   nstlim=5000,
>>   dt=0.002,
>>   ntt=3,
>>   gamma_ln = 1.0,
>>   temp0=300,
>>   tempi=300,
>>   tautp=1,
>>   igb=0,
>>   ntb=0,
>>   cut=15,
>>   ntr=1,
>>   fcap=10.0,
>>   ivcap=0,
>>   tol=0.000001,
>>   ntr=1, restraint_wt=10.0, restraintmask=':1-90, 93-140, 151-180, 196-234, 242-256, 265-278, 283-310, 322-360, 371-410',
>>   &end
>>
>> Rilei Yu
>>
>>
>>
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>> AMBER.ambermd.org
>> http://lists.ambermd.org/mailman/listinfo/amber
>>
>
>
>
> --
> ---------------------------------------
> Jason M. Swails
> Quantum Theory Project,
> University of Florida
> Ph.D. Graduate Student
> 352-392-4032
>
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>
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>



-- 
---------------------------------------
Jason M. Swails
Quantum Theory Project,
University of Florida
Ph.D. Graduate Student
352-392-4032
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Received on Sat Apr 10 2010 - 01:00:02 PDT
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