From: Hasan haska (hasanhaska_at_yahoo.com)
Date: Tue Mar 10 2015 - 16:51:30 CDT
DearNAMD users,
 
Iwant to minimize and equilibrate a bulk water system that includes 7048water molecules (SPC/E water model) in a rectangular box with the d=0.996 g/cm3experimental density at 300K. Therefore I prepared a namd conf file belowand started to run it. But after minimization was completed I got the error,which is in below. My aim is to run minimization and NPT simulation withkeeping the dimension of the unit cell in the x-y plane constant while allowingfluctuations along the z axis in order to get the real cell sizes ( 55 X 55 X70 Angs ) according to the density. Then run a NVT simulation with these cellsize. How can I solve this problem ?  Could you please share your opinionand experience ? 
 
 
Thanks.
 
 
http://www.filedropper.com/water_1
 
My simulation files are in the linkabove.
 
 
*****************************
Error:
------------- Processor 0 Exiting:Called CmiAbort ------------
Reason: FATAL ERROR: Stray PME gridcharges detected!
 
FATAL ERROR: Seehttp://www.ks.uiuc.edu/Research/namd/bugreport.html
 
Charm++ fatal error:
FATAL ERROR: Stray PME grid chargesdetected!
 
**************************
 
 
#--- This is a test namd configurationfile 
#############################################################
##  
#############################################################
 
paratypeCharmm  on 
parameters    water.PRM 
 
structure             water.psf  # 
coordinates           water_.pdb  # 
outputName            water_1out  # 
 
set temperature    300 
   
temperature $temperature 
                  
firsttimestep     0 
 
# Integrator Parameters 
timestep           1.0 
nonbondedFreq      2 
fullElectFrequency 4     
stepspercycle      16   
 
 
# Force-Field Parameters 
exclude        scaled1-4  
1-4scaling     1.0 
cutoff         18. 
switching      on 
switchdist     15.             
pairlistdist    20. 
 
 
# Constant Temperature Control 
langevin           on   ;# do langevin dynamics 
langevinDamping    1    ;# damping coefficient (gamma) of 5/ps 
langevinTemp       $temperature 
langevinHydrogen   on    ;#  couple langevin bath to hydrogens 
 
 
# Constant Pressure Control (variablevolume) 
 
useGroupPressure     no ;# needed for 2fs steps 
useFlexibleCell      yes  ;# no for water box, yes for membrane 
useConstantArea      yes  ;# no for water box, yes for membrane 
 
langevinPiston       on 
langevinPistonTarget  1.01325;#  in bar -> 1 atm 
langevinPistonPeriod  200. 
langevinPistonDecay   50. 
langevinPistonTemp   $temperature 
 
 #--- PBC 
 
cellBasisVector1  55.0  0.0    0.0 
cellBasisVector2   0.0 55.0    0.0 
cellBasisVector3  0.0   0.0  100.0 
 
 
#--- PME  
PME                yes 
PMEGridSpacing     1.0 
  
#--- Output & Restart 
 
binaryoutput    no 
 
binaryrestart   yes 
 
restartname    water_1restart      # 
DCDfile        water_1out.dcd      # 
  
restartfreq       5000      # 
dcdfreq           5000 
xstFreq           5000 
outputEnergies    5000 
outputPressure    5000 
outputtiming      5000 
 
minimize 10000 
reinitvels         $temperature 
run 10000000 
# 10 ns 2002 record
 
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