[Wien] Fortran 90 bug (?) causes Segmentation fault in DSTART (doreallocate)

[Laurence Marks]

If the speed is the same, then ifort is probably switching the loop.

This "bug" is also present in lapw2 when the hkl's are generated, and
perhaps in lapw3. I don't think it's a real fortran bug, probably
something in the OS with memory allocation (I have it myself).

On Tue, Mar 3, 2009 at 9:25 AM, Oleg Rubel
<oleg.rubel at physik.uni-marburg.de> wrote:
> Dear All,
>
> thank you very much for the comments and suggestions.
>
> I tried to benchmark Laurence's suggestion
>
>     do j = 1, min2
>         do i = 1 , min1
>         !do j = 1 , min2
>             hilfsfeld(i,j)=tf(i,j)
>         end do
>     end do
>
>     $ x dstart -c
>     DSTART ENDS
>     63.335u 11.743s 1:15.12 99.9%      0+0k 0+0io 0pf+0w
>
> vs
>
>     do i = 1, min1
>         do j = 1 , min2
>             hilfsfeld(i,j)=tf(i,j)
>         end do
>     end do
>
>     $ x dstart -c
>     DSTART ENDS
>     62.678u 11.837s 1:14.59 99.8%      0+0k 0+0io 0pf+0w
>
> It seems that there is no noticeable difference in timing, but thanks anyway.
>
> Gerhard - I did not try full static linking. Switching the
> optimization levels to -O0 does not help with the original code. I
> cannot step down to an older version of the compiler. Regarding size
> of 'tr' and 'hilfsfeld'. It seems that bounds are OK, in the sense
> that 1:min1 and 1:min2 do not go out of the bounds of 'tr' and
> 'hilfsfeld'. Usually size(tr,1)=size(hilfsfeld,1)=3 and
> size(tr,2)=>size(hilfsfeld,2). Just to remind, it works fine for
> smaller size(hilfsfeld,2). It is also not an issue of the memory
> shortage. (16 GB free is more than enough).
>
> So it looks like it is necessary to change the code. Since DSTART is
> not a bottle neck in terms of timing, I would not wary much. Important
> is that it works and probably worth changing in the release version.
>
> Sincerely,
>
> Oleg
>
> --
> Oleg Rubel, Ph.D.
> Thunder Bay Regional Research Institute
> 290 Munro St
> Thunder Bay, Ontario
> P7A 7T1, CANADA
> E-mail: Oleg.Rubel at physik.uni-marburg.de
> Homepage: http://www.staff.uni-marburg.de/~rubel/
>
> _______________________________________________
> Wien mailing list
> Wien at zeus.theochem.tuwien.ac.at
> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
>



-- 
Laurence Marks
Department of Materials Science and Engineering
MSE Rm 2036 Cook Hall
2220 N Campus Drive
Northwestern University
Evanston, IL 60208, USA
Tel: (847) 491-3996 Fax: (847) 491-7820
email: L-marks at northwestern dot edu
Web: www.numis.northwestern.edu
Chair, Commission on Electron Crystallography of IUCR
www.numis.northwestern.edu/
Electron crystallography is the branch of science that uses electron
scattering to study the structure of matter.