The ABINIT Users Mailing List ( CLOSED )

["Anglade Pierre-Matthieu" <anglade@gmail.com>]

Hi,

In fact Prof. Gonze makes reference tests result for distributed
version of Abinit with a PGI compiler and without optimisation , not
intel's compiler. Then, there is no reasons  intrinsic reasons to try
to reproduce flags used by the abinit developers. Yet, usualy Yann
pouillon implements within the Abinit "tricks" the best set of flags
for compiler/arch couples. So default flags should be best ; they work
around known bugs and problems of compiers. However, the safest for
you is generaly to use the flag set wich result in the least number of
failed tests because it is quite possible that we do not have the
exact same platform you use.

If you want more safety, you must not rely fully on the automatic test
analysis. You'd better look at the output of each failed tests and
check what the failing reasons was. There is a lot of reasons that may
produced a FAILED in the log while you'd consider
that the test successfull or at least not a problem.

Best regards.

PMA

On 11/10/06, mperez@mpi-halle.mpg.de <mperez@mpi-halle.mpg.de> wrote:
> Hi
>
>  i was wandering whether there is any point in optimising the code in
> order to get fast runs
>
>  let me explain my point, i have MPI-installed 5.2.3 on an opteron cluster
> for -O3 and -O0, using ifort compiler (and gcc)
> When i  go through the "internal tests", (section 3. How to make the
> internal tests and the speed tests ? (sequential version only)) everything
> is ok, but when i go through the "other tests" (4. How to make the other
> tests ?)
> the number of FAILURES that i get is larger for -O0 (11 cases) than for
> -O3 (6 cases)
>
> Then, if i use -O2 with some extra optimisation, and, including "safety
> options", i get 6 failed cases, whilst using "implicit -O2 with no safety
> options", i get only 3 failed cases (THE BEST I'VE SEEN)
>
> i imagine that the best way to make sure my implementation is not too bad
> is to use "exactly" the same compilation flags for "ifort" that have been
> used by the abinit team in the build up of binaries (for opteron)
>
> Some final point: there are two tests in the section "parall", which FAIL
> for any level of optimisation that i use (always): tests G and I
>
> Please let me know whether i should consider seriously some optimisation,
> and how i should do that
>
> thanks
>
> Manolo
>
>
> PS:
> (a)"safety options":
> -fltconsistency -IPF_fltacc -pc80 -mp1 -fp-model strict -prec-div -prec-sqrt
> (b)"extra optimisation": -xW -tpp7
> (c)"implicit -O2 without safety options": only library linking options =>
> -i-static -Bstatic -static -lmpichf90 -lmpich -lpthread -lrt


--
Pierre-Matthieu Anglade