It would be probably reasonable to add the "-ffpe-summary=none" to the
default gfortran flags to not scare a new users (as this "issue") is being
brought up over and over again (hint to prof. Blaha).
In fact, I tried quite hard to debug lot of those things and in general to
hunt down the uninitialized stuff and the remaining ones (at least in the
common codepaths) should be harmless. IIRC the denormals in lapw0 and lapw2
comes from something like "exp(-big_number)"Â which is completely OK and the
scary ones IEEE_INVALID_FLAG IEEE_DIVIDE_BY_ZERO in mixer come from lapack-
netlib/SRC/ieeeck.f function which is intentionally doing all the divide by
zero and infinity math to check if it can depend on the compliance with the
IEEE 754 standard.
Regarding the ifort vs gfortran, this is mostly a matter of personal taste.
gfrortan strictly adheres to the Fortran specification and this caused some
issues in the Wien2k code. gfortran is also somewhat slower but this is due
to much more conservative default flags. At -O2 gfortran won't do any SIMD
vectorization or loop unrolling in general, no link-time (interprocedural)
optimizations and it strictly adheres to IEEE compliance (and does a lot or
other stuff, like properly setting errno after library calls etc. which
ifort does not do with the Wien2k flags). I can maybe someday write some
blogpost which flags to use to get ifort-like behavior and speed.
Best regards
Pavel
---------- Původnà e-mail ----------
Od: Gavin Abo <***@crimson.ua.edu>
Komu: ***@zeus.theochem.tuwien.ac.at
Datum: 24. 10. 2018 4:19:56
PÅedmÄt: Re: [Wien] Help Request for making WIEN2K (ver18.2) programs
executable.
"Those gfortran warnings have been seen in symmetry [
https://www.mail-archive.com/***@zeus.theochem.tuwien.ac.at/msg17396.html
] and dstart [
https://www.mail-archive.com/***@zeus.theochem.tuwien.ac.at/msg17389.html
], which if I recall correctly were resolved by the fixes seen on the
updated page [ http://susi.theochem.tuwien.ac.at/reg_user/updates/ ]:
VERSION_18.1: 1.6.2018
SRC_dstart: fix of zamt initialization
SRC_symmetry: setting yvec,zvec=0
From the above, you can see that uninitialized variables in the code
tend to be the cause of those type of warnings. Apparently, ifort
either handles them better (or ignores the issue).
It is not surprising and perhaps expected that those warnings might
appear in more programs than just lapw0. As I mentioned before, WIEN2k
compiled with gfortran is less vetted and less maintained by the
developers [
https://www.mail-archive.com/***@zeus.theochem.tuwien.ac.at/msg18018.html
]. I suppose that is one drawback of using that free compiler. Though,
I suppose Intel's recent 2016 or newer ifort compiler standardization
changes breaking some of the WIEN2k code is perhaps not better in some
cases [
https://www.mail-archive.com/***@zeus.theochem.tuwien.ac.at/msg17542.html
]. So, pick your poison.
As mentioned on stackoverflow page at the link in the previous post at
https://www.mail-archive.com/***@zeus.theochem.tuwien.ac.at/msg17385.html ,
I think the statement there describes well the meaning of those warning
messages:
They can be a "hint about numerical problems in your code, but it is not
an error per se."
Adding "-ffpe-summary=none" to the compiler settings might suppress that
warning message when compiling with gfortran. However, I don't recommend
doing that as it might suppress other more important warnings/errors.Â
Someday in the future, 'maybe' the WIEN2k code could be reprogrammed to
remove that warning message (which I think would be the proper way to
remove that message).
In summary, unless you can fix the code yourself to remove the error,
you would have the ignore them and continue on with your calculation
unless it results in something absurdly wrong.
P.S., Pavel has been good at gfortran debugging and resolving those,
which has been quite appreciated. Though, I believe he is a user (not
developer) less obligated to help fix such problems.
Post by Ashwani Kumarthank you, Program compiled successfully withour any error. I tried to
remove manually but still some error occurred, Followed Mr. Gavin's
method (from previous thread) for LIBXC link to R_LIBS. Done
successfully. But while running an example of TiC (to check everything
is fine), STDOUT file shows warning message (for lapw0 and lapw2) but
program executed without error. I checked makefile, makefile.orig (and
makefile.orig_14 also for lapw0) and found nothing suspicious.
**************************************************************************
********
Post by Ashwani Kumarin cycle 9Â Â Â ETEST: .0000154200000000Â Â CTEST: .0009143
STOPÂ LAPW0 END
IEEE_DENORMAL
STOPÂ LAPW1 END
STOPÂ LAPW2 END
IEEE_DENORMAL
STOPÂ COREÂ END
IEEE_INVALID_FLAG IEEE_DIVIDE_BY_ZERO IEEE_UNDERFLOW_FLAG IEEE_DENORMAL
STOPÂ MIXER END
ec cc and fc_conv 1 0 1
in cycle 10Â Â Â ETEST: .0000051000000000Â Â CTEST: .0005302
STOPÂ LAPW0 END
IEEE_DENORMAL
STOPÂ LAPW1 END
STOPÂ LAPW2 END
IEEE_DENORMAL
STOPÂ COREÂ END
IEEE_INVALID_FLAG IEEE_DIVIDE_BY_ZERO IEEE_UNDERFLOW_FLAG IEEE_DENORMAL
STOPÂ MIXER END
ec cc and fc_conv 1 0 1
in cycle 11Â Â Â ETEST: .0000031500000000Â Â CTEST: .0000970
STOPÂ LAPW0 END
IEEE_DENORMAL
STOPÂ LAPW1 END
STOPÂ LAPW2 END
IEEE_DENORMAL
STOPÂ COREÂ END
IEEE_INVALID_FLAG IEEE_DIVIDE_BY_ZERO IEEE_UNDERFLOW_FLAG IEEE_DENORMAL
STOPÂ MIXER END
ec cc and fc_conv 1 1 1
  stop
**************************************************************************
****************************************
Post by Ashwani KumarPlease make me understand why the warning message appearing.
thanks
Ashwani Kumar
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