Hi,
this is my problem. I am trying to do MD simulations using TIP4P
water. I have done them using TIP3P and they worked fine. My input
files are below. I first do a minimization of the water molecules,
then minimization of the entire system (water+sugar). then i do
annealling. Up to this point, everything is ok. But when i try to do a
short MD i get the following errors:
THESE ARE THE INPUT FILES USED:
---for minimizing water-----
Constant Volume Minimization
# Control section
&cntrl
ntwx = 50, ntpr = 1, ntwr = 1,
scnb = 1.0, scee = 1.0, nsnb = 25, dielc = 1, cut = 8.0,
ntb = 1,
maxcyc = 2000, ntmin = 0, dx0 = 0.01, dxm = 0.5, drms = 0.0001,
ntp = 0,
ibelly = 0, ntr = 1,
imin = 1,
&end
Group Input for restrained atoms
5.0
RES 1 2
END
END
---for minimizing entire system----
Constant Volume Minimization
# Control section
&cntrl
ntwx = 50, ntpr = 1, ntwr = 1,
scnb = 1.0, scee = 1.0, nsnb = 25, dielc = 1, cut = 8.0,
ntb = 1,
maxcyc = 2000, ncyc = 100, dx0 = 0.01, dxm = 0.5, drms = 0.0001,
ntp = 0,
ibelly = 0, ntr = 0,
imin = 1, ntmin = 1,
&end
---annealling-----
Dynamic Simulation with Constant Volume
# Control section
&cntrl
ntwx = 100, ntpr = 50, ntwr = 1,
ntt = 1, temp0 = 300.0, tempi = 5.0, tautp = 1.0,
scnb = 1.0, scee = 1.0, dielc = 1, cut = 6.0,
ntb = 2, ntc = 2, ntf = 2,
nstlim = 50000, dt = 0.0020,
ntp = 1, taup = 0.1, comp = 44.6, pres0 = 1.0,
ibelly = 0, ntr = 0,
imin = 0, irest = 0, ntx = 1, nmropt = 1,
&end
&ewald
skinnb = 2.0,
nbflag = 1,
&end
&wt
type = 'TEMP0', istep1 = 1, istep2 = 25000, value1 = 5.0, value2 = 300.0,
&end
&wt
type = 'TEMP0', istep1 = 25001, istep2 = 50000, value1 = 300.0, value2 = 5.0,
&end
&wt
type='END'
&end
&rst IAT(1) = 0 &end
END
---short MD---
Dynamic Simulation with Constant Volume
# Control section
&cntrl
ntwx = 100, ntpr = 100, ntwr = 1,
ntt = 1, temp0 = 300.0, tempi = 5.0, tautp = 1.0,
scnb = 1.0, scee = 1.0, dielc = 1, cut = 8.0,
ntb = 2, ntc = 2, ntf = 2,
nstlim = 75000, dt = 0.0020,
ntp = 1, taup = 0.1, comp = 44.6, pres0 = 1.0,
ibelly = 0, ntr = 0,
imin = 0, irest = 0, ntx = 1, nmropt = 1,
&end
&ewald
skinnb = 1.0,
nbflag = 1,
&end
&wt
type = 'TEMP0', istep1 = 1, istep2 = 75000, value1 = 5.0, value2 = 300.0,
&end
&wt
type = 'TEMP0', istep1 = 35001, istep2 = 75000, value1 = 300.0,
value2 = 300.0,
&end
&wt
type='END'
&end
&rst IAT(1) = 0 &end
END
THESE ARE THE ERRORS AT THE END OF SHORTMD.OUT:
Ewald parameters:
verbose = 0, ew_type = 0, nbflag = 1, use_pme = 1
vdwmeth = 1, eedmeth = 1, netfrc = 1
Box X = 17.998 Box Y = 20.229 Box Z = 20.215
Alpha = 90.000 Beta = 90.000 Gamma = 90.000
NFFT1 = 18 NFFT2 = 20 NFFT3 = 20
Cutoff= 8.000 Tol =0.100E-04
Ewald Coefficient = 0.34864
Interpolation order = 4
Ewald PARAMETER RANGE CHECKING:
parameter skinnb+cutoffnb: (nonbond list cut) has value 0.90000E+01
This is outside the legal range
Lower limit: 0.00000E+00 Upper limit: 0.89989E+01
Check ew_legal.h
I tried changing the cut value from 8 to 7.5, but this was
unsuccessful for the production dynamics as you may have seen in my
previous message.
Can you let me know what i am doing wrong. Also, please let me know if
you need anymore information.
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Received on Sun Jul 15 2007 - 06:07:29 PDT
