[gmx-users] Re: LINCS Warning using mdrun

Yang Ye leafyoung81-group at yahoo.com
Tue Mar 14 16:15:29 CET 2006


Hi, Gaurav

Try to use another gen_seed number.

Yang Ye

Gaurav Chopra wrote:
>> / Hi
> />/
> />/ I get the following error when using mdrun for a protein in 
> solution. />/ I have checked the structure and everything looks fine 
> to me. Could />/ you suggested anything else I could do. /
> How did you energy minimze your structure? What was the output of 
> mdrun during energy minization, especially the last line with Fmax, 
> Epot etc.?
>
> I should look like this:
>
> Step=   48, Dmax= 1.1e-02 nm, Epot= -1.45545e+06 Fmax= 5.58480e+05, 
> atom= 78754
> Step=   49, Dmax= 1.4e-02 nm, Epot= -1.45551e+06 Fmax= 8.80803e+03, 
> atom= 13032
> Step=   50, Dmax= 1.7e-02 nm, Epot= -1.45574e+06 Fmax= 1.60758e+04, 
> atom= 13032
>
> Jochen
>
> Hi Gaurav,
> what is your stepsize during the simulation? what is constrained? And 
> have you run a minimization before starting the simulation?
> hear from you soon
> Steffen
>
>
> -----------------------------------------------------------------------
> Hi
>
> I used the initial minimization run using grompp and mdrun using 
> steepest descent for 400 steps and 0.002 ps as the step size. The 
> constraints are all-atom.
>
> The following is the output from the log file that was generated after 
> the md.
> Any suggestions?
>
> Thanks
>
> Gaurav
>
> ---------------   mdrun log file output ------------------
>
> Initializing LINear Constraint Solver
>  number of constraints is 934
>  average number of constraints coupled to one constraint is 3.6
>
>   Rel. Constraint Deviation:  Max    between atoms     RMS
>       Before LINCS         0.608377    894    898   0.031756
>        After LINCS         0.126305    892    894   0.007000
>
>
> Step -2, time -0.004 (ps)  LINCS WARNING
> relative constraint deviation after LINCS:
> max 0.126305 (between atoms 892 and 894) rms 0.007000
> bonds that rotated more than 30 degrees:
> atom 1 atom 2  angle  previous, current, constraint length
>    898    899   41.6    0.1015   0.0997      0.1010
>    898    900   38.1    0.1038   0.0984      0.1010
> Going to use C-settle (6845 waters)
> wo = 0.888096, wh =0.0559521, wohh = 18.0154, rc = 0.08165, ra = 
> 0.00646074
> rb = 0.0512738, rc2 = 0.1633, rone = 1, dHH = 0.1633, dOH = 0.1
>
> Constraining the coordinates at t0-dt (step -1)
>   Rel. Constraint Deviation:  Max    between atoms     RMS
>       Before LINCS         0.115310    685    686   0.023558
>        After LINCS         0.115624    892    894   0.006694
>
> Started mdrun on node 0 Tue Mar 14 04:21:35 2006
> Initial temperature: 299.541 K
>           Step           Time         Lambda
>              0        0.00000        0.00000
>
> Grid: 12 x 12 x 12 cells
> Configuring nonbonded kernels...
> Testing AMD 3DNow support... not present.
> Testing ia32 SSE support... present.
>
>
> There are 21469 atoms in your xtc output selection
>   Rel. Constraint Deviation:  Max    between atoms     RMS
>       Before LINCS         10.170899    898    899   0.711794
>        After LINCS         3.372058    894    895   0.239340
>
>
> Step 0, time 0 (ps)  LINCS WARNING
> relative constraint deviation after LINCS:
> max 3.372058 (between atoms 894 and 895) rms 0.239340
> bonds that rotated more than 30 degrees:
> atom 1 atom 2  angle  previous, current, constraint length
>    883    886   36.7    0.1540   0.2007      0.1529
>    886    887   36.8    0.1098   0.1474      0.1090
>    886    888   43.6    0.1099   0.1575      0.1090
>    886    889   51.7    0.1526   0.2510      0.1529
>    889    890   60.6    0.1097   0.1917      0.1090
>    889    891   66.2    0.1096   0.2043      0.1090
>    889    892   44.6    0.1561   0.0485      0.1463
>    892    893   55.7    0.1042   0.1304      0.1010
>    894    895   54.6    0.1221   0.5859      0.1340
>    894    898  135.9    0.1495   0.4473      0.1340
>    895    896   77.6    0.1051   0.0671      0.1010
>    895    897   40.4    0.1011   0.1018      0.1010
>    898    899   40.0    0.0997   0.3249      0.1010
>    903    905   40.2    0.1453   0.1959      0.1449
>    905    906   45.2    0.1093   0.1556      0.1090
>    905    907   65.6    0.1542   0.3041      0.1529
>    905    921   35.0    0.1527   0.1990      0.1522
>    907    908   83.4    0.1099   0.2156      0.1090
>    907    909   70.1    0.1099   0.1907      0.1090
>    907    910   43.6    0.1519   0.1400      0.1510
>    910    911   77.9    0.1408   0.3459      0.1400
>    910    913   77.5    0.1407   0.3356      0.1400
>    911    912   80.8    0.1084   0.2512      0.1080
>    911    915   74.9    0.1405   0.2010      0.1400
>    913    914   81.8    0.1084   0.2760      0.1080
>    913    917   65.8    0.1404   0.1278      0.1400
>    915    916   81.7    0.1082   0.2186      0.1080
>    915    919   41.0    0.1402   0.1786      0.1400
>    917    918   82.9    0.1082   0.2569      0.1080
>    917    919   32.7    0.1402   0.1652      0.1400
>    919    920   82.3    0.1082   0.1984      0.1080
> Constraint error in algorithm Lincs at step 0
>   Energies (kJ/mol)
>          Angle    Proper Dih. Ryckaert-Bell.          LJ-14     
> Coulomb-14
>    2.38010e+03    4.15026e+01    8.53343e+02    1.45562e+03    
> 4.52843e+03
>        LJ (SR)   Coulomb (SR)   Coul. recip.      Potential    Kinetic 
> En.
>    1.78128e+05   -3.41925e+05   -3.63116e+04   -1.90849e+05    
> 7.96062e+05
>   Total Energy    Temperature Pressure (bar)
>    6.05213e+05    4.45994e+03    1.19605e+03
>
>
> Step 1, time 0.002 (ps)  LINCS WARNING
> relative constraint deviation after LINCS:
> max 2850322.250000 (between atoms 895 and 897) rms 192971.500000
> bonds that rotated more than 30 degrees:
> atom 1 atom 2  angle  previous, current, constraint length
>    869    871 _______________________________________________
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