AMBER Archive (2004)

Subject: AMBER: vlimit and vmax problem

From: Venkata S Koppuravuri (kvsuneel_at_linus.bmb.wright.edu)
Date: Wed Mar 24 2004 - 12:25:31 CST

Hi Amber users,

I am trying to equlibrate a protein structure and I have got the following
error
-----------------------

 NSTEP = 0 TIME(PS) = 0.000 TEMP(K) = 0.00 PRESS = 0.0
 Etot = -75506.0178 EKtot = 0.0000 EPtot = -75506.0178
 BOND = 34481.4693 ANGLE = 415.2692 DIHED = 903.4396
 1-4 NB = 948.4239 1-4 EEL = 6679.2911 VDWAALS = 12987.2993
 EELEC = -131921.2101 EHBOND = 0.0000 RESTRAINT = 0.0000
 Ewald error estimate: 0.1421E-02

 vlimit exceeded for step 2 ; vmax = 24.48541998723091
 vlimit exceeded for step 3 ; vmax = 35.95753378509406
 vlimit exceeded for step 4 ; vmax = 77.34057453092329
 vlimit exceeded for step 5 ; vmax = 91.32961951303912
 vlimit exceeded for step 6 ; vmax = 31.87861489298826
 .....................
 .............

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

I have searched in google for this error and have tried all the possible
errors mentioned .
1. the minimization went fine.
2. periodic box is correct.
3. checked for overlapping of molecules
4. i am using constant volume i.e. ntb=1
5. i am trying to increase temp in steps of 50k
6. i have increased the vlimit value (not sure whether this helps!)

and i still get the same error. Below is the input file that i used

--------------------
 &cntrl
        imin = 0, irest = 0, ntx = 1,
        nstlim = 10000, nsnb = 25,
        vlimit = 20,
        tempi = 0.0, temp0 = 50.0, ntpr = 100,
        ntt = 1, npscal = 1, ntb = 1, ntp = 0, taup = 0.2,
        ntc = 2, ntf = 2, cut = 8.0, scee = 1.2,
        ntwx= 100, ntwe = 100, ntwv = 100,
 &end
                                                                               
END
END
----------------------

Can someone help me with this please

Regards,
-Venkat

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