[CPMD-list] Segmentation fault for a molecular dynamics run

[Axel Kohlmeyer]

On Wed, 7 Apr 2004, Dai Ling wrote:

DL> I met a problem when runing a molecular dynamics (CP) run with some benzene ring structures. There is some odd marks  as "NaNQ" in the output file as shown below. Then the running failed with "Segmentation fault". Who can help me to point out what goes wrong?
DL>  
DL> Thanks in advance!
DL>  
DL> Scott
DL>  
DL> Outpupt:
DL>  
DL> ....
DL> ....
DL> TOTAL INTEGRATED ELECTRONIC DENSITY
DL>     IN G-SPACE =                                       292.000000
DL>     IN R-SPACE =                                       292.000000
DL>  (K+E1+L+N+X)           TOTAL ENERGY =         -370.10939613 A.U.
DL>  (K)                  KINETIC ENERGY =          247.71353333 A.U.
DL>  (E1=A-S+R)     ELECTROSTATIC ENERGY =         -328.45005481 A.U.
DL>  (S)                           ESELF =          352.39900035 A.U.
DL>  (R)                             ESR =           17.54351703 A.U.
DL>  (L)    LOCAL PSEUDOPOTENTIAL ENERGY =         -214.10105210 A.U.
DL>  (N)      N-L PSEUDOPOTENTIAL ENERGY =           41.28274138 A.U.
DL>  (X)     EXCHANGE-CORRELATION ENERGY =         -116.55456393 A.U.
DL>           GRADIENT CORRECTION ENERGY =           -5.18331838 A.U.
DL>  
DL>        NFI    EKINC   TEMPP           EKS      ECLASSIC          EHAM     DIS    TCPU
DL>          1  3.11966   309.0    -370.10940    -369.96407    -366.84441    .000   48.41

DL>  FILE ./TRAJECTORY EXISTS, NEW DATA WILL BE APPENDED
DL>  FILE ./MOVIE EXISTS, NEW DATA WILL BE APPENDED
DL>          2  4.88578   320.2    -371.88325    -371.73269    -366.84691    .000   49.49

hmmmm, EKINC seems a bit high, and is fluctaing quite a bit.
also EHAM ist not the conserved quantity that is should be.
seems like are not very close to the BO-surface anymore 
(if ever) as you should be.

could you please post your input file, so that we can have
a better guess at the problem. my guess would be that you 
have a too large timestep or starte from a non-converged
wavefunction.

DL>          3  3.92472   319.0    -370.49747    -370.34748    -366.42276    .000   48.96
DL>          4  4.22976   305.3    -371.13380    -370.99025    -366.76049    .000   52.20
DL>          5  3.52748   288.6    -370.19907    -370.06334    -366.53586    .001   55.75
DL>          6  3.28840   276.3    -369.96661    -369.83670    -366.54830    .001   54.76
DL>          7  3.79151   269.8    -370.58147    -370.45460    -366.66309    .001   43.70
DL>          8  3.77854   268.6    -370.52295    -370.39664    -366.61810    .001   43.22
DL>          9  3.59004   273.2    -370.32378    -370.19530    -366.60527    .002   44.05
DL>         10  3.48053   283.8    -370.23346    -370.09998    -366.61946    .002   43.19
DL>       .......................
DL>       .......................
DL>        248  3.57992  1050.5    -370.66655    -370.17254    -366.59262    .270   42.99
DL>        249  3.57719  1046.8    -370.66159    -370.16935    -366.59216    .269   41.47
DL>        250  3.57912  1042.9    -370.66254    -370.17212    -366.59300    .269   38.90
DL>        251  3.57836  1039.3    -370.65993    -370.17121    -366.59285    .268   43.86
DL>        252  3.57595  1036.0    -370.65579    -370.16860    -366.59265    .267   42.58
DL>        253  3.57593  1033.0    -370.65463    -370.16889    -366.59296    .267   40.59
DL>        254  3.57641  1029.8    -370.65402    -370.16977    -366.59335    .266   44.35
DL>        255  3.57504  1026.4    -370.65056    -370.16789    -366.59285    .266   44.05
DL>        256  3.57670  1022.9    -370.65037    -370.16934    -366.59264    .265   43.99
DL>        257  3.58117  1019.5    -370.65368    -370.17426    -366.59308    .265   44.41

ok, your temperature has risen to >1000K (is that intentional?) and your
Kohn-Sham energy has dropped. it seems that your starting structure was
not in equilibrium. OTOH, if you are too far away from the BO-surface,
it could mean anything or nothing.

DL>        258    -NaNQ  1016.4****************************         -NaNQ    .265   42.87
DL>        259     NaNQ   -NaNQ          NaNQ         -NaNQ         -NaNQ    .264   43.87
DL>        260     NaNQ   -NaNQ          NaNQ         -NaNQ         -NaNQ    NaNQ   42.20
DL>        261     NaNQ   -NaNQ          NaNQ         -NaNQ         -NaNQ    NaNQ   37.84
DL>        262     NaNQ   -NaNQ          NaNQ         -NaNQ         -NaNQ    NaNQ   38.56

well seems like the fictitious dynamic of the electronic system 
could not keep up with atoms/ions anymore. again, it could be from a too 
large time step.

hope this helps,
	axel kohlmeyer.

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DL> 
DL> 

-- 


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Dr. Axel Kohlmeyer                        e-mail: axel.kohlmeyer at rub.de
Lehrstuhl fuer Theoretische Chemie          Phone: ++49 (0)234/32-26673
Ruhr-Universitaet Bochum - NC 03/53         Fax:   ++49 (0)234/32-14045
D-44780 Bochum  http://www.theochem.ruhr-uni-bochum.de/~axel.kohlmeyer/
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