AMBER Archive (2002)

Subject: Re:Re: Running TIP5P with PBC

From: Sarah Tschampel (tschampe_at_sunchem.chem.uga.edu)
Date: Tue Jul 09 2002 - 12:32:32 CDT

After bringing the system (box of tip5p) to 300K at constant volume, i
then switched over to constant pressure (NTP=1)
using NTX=4 there are no problems with the simulation, but when i switch
to NTX=1 I get the following error:

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

restarting only results in a failure after the first step.

(There are also many warning that vlimit has been exceeded.)

Therefore, is it okay to use NTX=4 and will I get results that can be
compared to a different simulation using NTX=1.

Thank you,
Sarah

input file:

 &cntrl
 IREST=1, IMIN=0, NMROPT=1, NTPR=1000,
 NTX=5, IG=71277, TEMPI=300.0, HEAT=0.0,
 NTB=2, NTC=2, TOL=0.0005, NTF=2, NSNB=25,
 NTT=1, TEMP0=300.0, DTEMP=5.0, TAUTP=0.25,
 NTP=1, PRES0=1.0, COMP=44.6,
 NSTLIM=250000, T=0.0, DT=0.001,
 CUT=8.0, SCNB=2.0, SCEE=1.2, DIELC=1.0,
 DX0=0.01, DXM=0.5,
 IBELLY=0, NTWX=500, NSCM=1000,
 lastist=5000000, IWRAP=1,
 &end
 &ewald
  SKINNB=1.5,
 &end
 &wt
   TYPE='TEMP0',ISTEP1=1,ISTEP2=250000,VALUE1=300.0,VALUE2=300.0,
 &end
END