AMBER Archive (2002)

Subject: ewald bomb in md equilibration

From: Sophia Kondratova (x357l_at_unb.ca)
Date: Mon Aug 26 2002 - 17:54:37 CDT

I am trying to do an MD run on my ligand/receptor system. The system was first
equilibrated under the NVT ensemble with no problems. However, when trying to
do the MD run under the NPT ensemble,
  irest = 1, ntx = 5,
  ntb = 2, ntp = 1,
  nstlim = 100000,
  dt = 0.0005, vlimit = 0.0,
  ntpr = 1000, tautp = 0.2, taup = 0.4,
  iwrap=1, comp = 108.6, npscal = 1,
  ntt = 1,
  nsnb = 5, vrand = 1000, nscm = 500,
  temp0 = 300.,
  cut = 14.0,
  scee = 1.2,
  ntf = 2,
  ntc = 2,
the following error message comes up:

EWALD BOMB in subroutine ewald_list
  volume of ucell too big, too many subcells
  list grid memory needs to be reallocated, restart sander

How do I fix the problem?

Thanks in advance for any help

Sophia Kondratova
Chemistry Department
University of New Brunswick