[CPMD-list] Bug?? Crash after 39000 steps..

[Dave Sherman]

My CPMD NOSE MD run suddenly exploded for no obvious reason:

      39061  0.02146   317.6    -701.37085    -700.89246     
-700.87100   0.170E+02    5.01
      39062  0.02144   317.4    -701.37079    -700.89244     
-700.87100   0.170E+02    5.01
      39063  0.02142   317.3    -701.37074    -700.89241     
-700.87100   0.170E+02    5.05
      39064  0.02140   317.2    -701.37071    -700.89239     
-700.87100   0.169E+02    5.03
      39065  0.02138   317.1    -701.37070    -700.89237     
-700.87100   0.169E+02    5.04
      39066  8.12319   322.1    -701.37071    -700.50728     
-692.38410   0.169E+02    5.01
      39067 49.30128   355.8    -697.35780    -686.55882     
-637.25754   0.169E+02    5.01


  PROGRAM STOPS IN SUBROUTINE DSPEVY| FAILED TO DIAGONALIZE [PROC=   0]

The simulation is Cu + 2CL + 38 H2O's.  The funny thing is that if I  
repeat the exact same calculation but change the isotopic mass of the Cu
from 65 to 63, the simulation works just fine and carries on for  
60,000 + steps.   The crash isn't some computer chip/cosmic ray/power  
surge thing as it will
occur again at timestep 39067 if I start the simulation over.  Notice  
that the cumulative displacement has decreased at timestep 39064!

David M. Sherman
Professor of Geochemistry
Department of Earth Sciences
University of Bristol
Bristol BS8 1RJ UNITED KINGDOM
Phone: 44-(0)117-954-5446
http://mineral.gly.bris.ac.uk

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