[Wien] Segmentation fault in f7splt (lapw2)

[Oliver Albertini]

Optimization level may also be a factor. It's hard to say what the
difference in compilation is for instance -O0 -> -O3 -> -O5. It is
interesting to note that the seg fault occurs for both of us in f7splt
which (I believe) is a part of the code that calculates the relative
occupation of the f orbitals. I was calculating TiC when I saw that error,
a system where I would not expect that code to be used. I think there are
many 'unnoticed' bugs with these optimizations. For instance, compiling
lapack: -O0 complies with IEEE NaN specs, while -O3 does not. But then
again, it may just be a pwr5 issue.

Maybe try pwr3 -O5, pwr3 -O3, pwr5 -O3, or pwr5 -O0.


On Mon, Oct 7, 2013 at 9:55 AM, Pavel Ondračka <pavel.ondracka at email.cz>wrote:

> Oliver Albertini píše v Po 07. 10. 2013 v 07:56 -0700:
> > I had the same problem when I used the wrong -qarch. I had to specify
> > pwr7 and the default from siteconfig is pwr5. If you want to find out
> > the system architecture issue the prtconf command.
> >
> Dear Oliver,
>
> thank for advice, however prtconf reports: "Processor Type:
> PowerPC_POWER5" so I should be probably fine with -qarch=pwr5, also it's
> kinda strange that you fixed this by setting pwr7. I thought that those
> optimization flags were forward compatible...
>
> For example: IBM docs I've just googled states that -qarch=pwr3
> "Produces object code containing instructions that will run on the
> POWER5, POWER5+, POWER6, or POWER7 hardware platforms"
>
> So IMHO compiling with -qarch=pwr5 for pwr7 shouldn't break anything
> unless some other weird stuff is going on.
>
> Best regards
> Pavel Ondračka
>
> > On Oct 7, 2013 3:00 AM, "Pavel Ondračka" <pavel.ondracka at email.cz>
> > wrote:
> >         Dear WIEN2k mailing list,
> >
> >         this is a follow up to thread "compilation problems on AIX
> >         with xlf90".
> >         I've finally managed to compile WIEN2k_13 on AIX 5.3,
> >         however I'm now getting a segfault when running lapw2.
> >
> >         Segmentation fault in f7splt at line 51 in file "" ($t1)
> >         could not read "f7splt.f"
> >         (dbx) where
> >         f7splt(alm = (...), blm = (...), clm = (...), mult = 2, uenorm
> >         =
> >         0.0028448010014590045, num = 1, coord = '     ', dmat =
> >         (...)), line 51
> >         in "f7splt.f"
> >         csplit(0xfffffffffd8f50c, 0xfffffffffd8f510,
> >         0xfffffffffd8a718,
> >         0xfffffffffd8976c, 0xfffffffffd8f67c, 0x11023fe30,
> >         0x110250590,
> >         0x110260cf0), line 78 in "csplit.f"
> >         l2main(0xfffffffffffe340, 0xfffffffffffdb84,
> >         0xfffffffffffe518,
> >         0x1101ac4b0, 0x110000b88, 0xfffffffffffdb80,
> >         0xfffffffffffdb90,
> >         0xfffffffffffdc48), line 1313 in "l2main_tmp_.F"
> >         lapw2(), line 605 in "lapw2_tmp_.F"
> >
> >         The corresponding lines looks like this:
> >         51  dmat(i,j,num)=dmat(i,j,num) + (alm(j)*conjg(alm(i))+ &
> >         52  blm(j)*conjg(blm(i))*uenorm+clm(j)*conjg(clm(i))+ &
> >         53
> >
> alm(j)*conjg(clm(i))*pi12lo(ipip,3)+clm(j)*conjg(alm(i))*pi12lo(ipip,3)+
> >         &
> >         54
> >
> blm(j)*conjg(clm(i))*pe12lo(ipip,3)+clm(j)*conjg(blm(i))*pe12lo(ipip,3)
> >         ) / mult
> >
> >         Going through all the variables shows suspicious value of ipip
> >         =
> >         -2147483648, which is used as array index for pi12lo an pe12lo
> >         causing
> >         the segfault.
> >         By grepping through SRC_lapw2 directory I can see, that all
> >         other
> >         subroutines which use ipip do something like this:
> >         $grep "ipip=" *
> >         csplit.f: ipip=max(ilo(l),1)
> >         d5splt.f: ipip=max(ilo(2),1)
> >         p3splt.f: ipip=max(ilo(1),1)
> >
> >         I'm wondering if there is some similar initialization
> >         statement missing
> >         in f7splt.f and what should be ipip set to?
> >
> >         Also I hope this isn't just some result of my inexperienced
> >         efforts to
> >         make WIEN compile on ancient AIX 5.3 or some other bad
> >         configuration.
> >
> >         Best regards
> >         Pavel Ondračka
> >
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