AMBER Archive (2006)

Subject: AMBER: vlimit exceeded for step 0, vmax = infinity

From: Rachel (comeonsos_at_googlemail.com)
Date: Wed Nov 08 2006 - 06:59:00 CST

Dear amber users,

I encountered a problem when i tried to run a md to heat up my system with
restraints on the protein, and the error message i got is:

-------------------------------------------------------------------------------------------------------------
 vlimit exceeded for step 0 ; vmax = Infinity

     Coordinate resetting (SHAKE) was not accomplished
     within 3000 iterations

     Note: This is usually a symptom of some deeper
     problem with the energetics of the system.
-------------------------------------------------------------------------------------------------------------

I ran minimization for the water only with restraints on the protein first
and then minimized the whole system before i tried to heat up the system,
and here is how I ran the heat up:

------------------------------------------------------------------------------------------------------------

20ps MD with res on the protein with 1fs timestep
 &cntrl
  imin = 0,
  irest = 0,
  ntx = 1,
  ntb = 1,
  cut = 10,
  ntr = 1,
  ntc = 2,
  ntf = 2,
  tempi = 0.0,
  temp0 = 300.0,
  ntt = 3,
  gamma_ln = 1.0,
  nstlim = 20000, dt = 0.001,
  ntpr = 100, ntwx = 100, ntwr = 1000
 /
Keep the protein fixed with weak restraints
10.0
RES 1 791
END
END
--------------------------------------------------------------------------------------------------------

I searched in the mailing list, however I still couldn't figure out why the
vlimit exceeded at step 0, any suggestion will be appreciated ^_^ thanks

Best regards,

Rachel

-----------------------------------------------------------------------
The AMBER Mail Reflector
To post, send mail to amber_at_scripps.edu
To unsubscribe, send "unsubscribe amber" to majordomo_at_scripps.edu