[CP2K:4011] Segfault on ia32/MPI in H2O-hfx-1 testcase

Iain Bethune ibet... at epcc.ed.ac.uk
Thu Sep 6 20:47:44 UTC 2012

> Has this been investigated and rejected in the past and/or would this be
> a reasonable and welcome thing to send patches for?

Hi Michael,

CP2K's FFTW3 interface does re-use plans on new arrays, which is likely the cause of this error.  At the time I wrote the code we did not do an ISO_C_BINDING call to fftw_malloc for the following reasons:

1) Several important HPC compilers still did not support ISO_C_BINDING 
2) On x86_64 platforms with gcc all arrays are aligned to 16-byte boundaries anyway
3) For the small number of 32-bit platforms still in use we considered it not worth the effort since the FFTW_ARRAYS_ALIGNED flag can be set 

What I would suggest is that you add -malign-double to FCFLAGS in your arch file, which should force the compiler to align the arrays correctly in every case, and thus solve the problem without any further code changes.

P.S.  The INSTALL file typo is now corrected in the latest SVN - sorry about that!


- Iain

Iain Bethune
Applications Consultant, EPCC

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