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Subsections

12.6 Frequent errors during execution

12.6.0.1 Why is my job crashing with ``segmentation fault''?

Possible reasons: too much memory requested; executable or libraries fitted to a different hardware; code bug; compiler bug. The latter are typically not reproducible on different architectures or compilers; code bugs may sometimes be elusive, but typically yield a more reproducible, pattern of problems.

Mysterious, unpredictable, erratic errors in parallel execution are almost always coming from bugs in the compiler or/and in the MPI libraries and sometimes even from flaky hardware. Sorry, not our fault.

12.6.0.2 Why is the code saying Wrong atomic coordinates?

Because they are: two or more atoms in the list of atoms have overlapping, or anyway too close, positions. Can't you see why? look better (or use XCrySDen: see above) and remember that the code checks periodic images as well.

12.6.0.3 The code stops with an error in davcio

Possible reasons: disk is full; outdir is not writable for any reason; you changed some parameter(s) in the input (like wf_collect, or the number of processors/pools) without doing a bit of cleanup in your temporary files; you were running more than one instance of pw.x in the same temporary directory with the same file names.

12.6.0.4 The code stops with a wrong charge error

In most cases: you are treating a metallic system as if it were insulating.

12.6.0.5 The code stops with a mysterious error in IOTK

IOTK is a toolkit that reads/writes XML files. There are frequent reports of mysterious errors with IOTK not finding some variable in the XML data file. If this error has no obvious explanation (e.g. the file is properly written and read, the searched variable is present, etc) and if it appears to be erratic or irreproducible (e.g. it occurs only with version X of compiler Y), it is almost certainly due to a compiler bug. Try to reduce optimization level, or use a different compiler. If you paid real money for your compiler, complain with the vendor.


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Next: 12.7 Self Consistency Up: 12 Frequently Asked Questions Previous: 12.5 Parallel execution   Contents
Build Daemon user 2011-10-19