[Wien] FFTW and ifx/icx issue relevant to WIEN2k

Wed Sep 3 06:29:15 CEST 2025

Interesting.

The install instructions using ifx for WIEN2k 24.1 that used Ubuntu 
24.04.2 LTS, ifx version 2025.1.0, and elpa version 2025.01.001 was out 
dated.  I recently updated them at [1] to use Ubuntu 24.04.3 LTS, ifx 
version 2025.2.1, and elpa version 2025.06.001.  When I compiled fftw 
version 3.3.10, I didn't have to use "autoreconf -if".

Are you using a different Linux distribution and/or version than Ubuntu 
24.04.3 LTS?

Did you have all 12 patch files at [2] for WIEN2k 24.1 applied when you 
compiled where some of them are needed for using ifx?

Though, the computer system I used had an AMD 5600G processor.

Was that using the computer system with an AMD processor with the Zen 5 
mircoarchitecture mentioned in your past post at [3]?

[1] 
https://github.com/gsabo/WIEN2k-Docs/blob/main/WIEN2k24.1_Ubuntu22.04_Install_with_OneAPI(ifx).pdf
[2] https://github.com/gsabo/WIEN2k-Patches/tree/master/24.1
[3] 
https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg23783.html

Kind Regards,

Gavin
WIEN2k user

On 9/2/2025 3:40 PM, Straus, Daniel B wrote:
>
> I have been troubleshooting the compilation of WIEN2k on a new 
> workstation using the ifx compiler. The main issue I was having was 
> related to compilation errors in 3ddens as well as in lapw1, but the 
> lapw1 compilation errors only occurred when I attempted to link ELPA.
>
> The cause of the compilation errors was FFTW. The configure script 
> included with FFTW version 3.3.10 is not compatible with the new Intel 
> compilers (icx/ifx etc.) unless an additional step is taken; 
> otherwise, icx is unable to link FFTW to the applicable Fortran 
> libraries.
>
> To fix this issue, the FFTW configure script must be updated using 
> autoconf version 2.70 or greater by running the command “autoreconf 
> -if” in the directory where the FFTW tarball was extracted. Once I did 
> this, recompiled FFTW, and then recompiled WIEN2k, there were no 
> compilation errors for 3ddens and lapw1 with ELPA.
>
> This is documented in the ifx release notes 
> (https://www.intel.com/content/www/us/en/developer/articles/release-notes/fortran-compiler/2025.html):
>
> *Configure Script Reports: "linking to Fortran libraries from C fails"*
>
> *Symptom*
>
> When compiling with ifx, a ./configure script generated by GNU Autconf 
> reports an error message similar to:
>
>     checking for Fortran 77 libraries of ifx...  -loopopt=0 
> -L/lib/../lib64 -L/lib/../lib64/ -L/usr/lib/../lib64 
> -L/usr/lib/../lib64/ -L/lib64 -L/lib/ -L/usr/lib64 -L/usr/lib -lifport 
> -lifcoremt -limf -lsvml -lm -lipgo -lirc -lpthread -lirc_s -ldl
>     configure: WARNING: FLIBS does not work
>     checking for ifx flag to add single underscore to external 
> names... none
>     checking for dummy main to link with Fortran 77 libraries... unknown
>     configure: error: in '/path/to/build/dir':
>     configure: error: linking to Fortran libraries from C fails
>     See `config.log' for more details
>     make: *** [build/config.status] Error 1
>
> Examining the config.log file shows that the error causing 
> ./configure to exit was:
>
>     ld: cannot find -loopopt=0
>
> *Problem *
>
> In trying to determine libraries needed to link Fortran code with C or 
> C++ code, GNU Autoconf 2.69 and earlier mistakenly interprets 
> -loopopt=0 in -mllvm -loopopt=0 in verbose compiler output as a linker 
> flag.  GNU Autoconf then adds -loopopt=0 to the FLIBS variable, which 
> is passed to the linker.  The linker then looks for a non-existent 
> library causing the test to fail.
>
> *Solution for Users Downloading Source Code*
>
> Please inform the maintainers of packages impacted by this error about 
> the problem and refer them to this release note. Projects vary in how 
> they handle configure scripts; however, some general rules apply. 
> Users who need a solution before the package maintainer can respond 
> can update the configure script themselves. The difficulty of updating 
> depends on how the package is distributed.
>
> To update, first, install GNU Autoconf-2.70 or newer, as described in 
> Solution for Package Maintainers 
> <https://www.intel.com/content/www/us/en/developer/articles/release-notes/fortran-compiler/2025.html#solution-for-package-maintainers>, 
> below.
>
> After installing the updated autoconf in the user's path, packages 
> that distribute the configure.ac  file along with the configure  
> script can be updated simply by running:
>
>     autoreconf -if
>
> The resulting configure script should be completed without the above 
> error in FLIBS.
>
> It is not uncommon for project maintainers to remove the configure.ac 
> file from a source distribution in a tar or zip archive.  In that 
> case, the user usually needs to download the project from its code 
> repository, and build according to the project's instructions. 
>  Sometimes a version of the configure script is committed to version 
> control and not automatically regenerated.  In that case, either 
> running autoreconf -if as described above, or deleting the configure 
> script often triggers it to be regenerated.  Ideally, documentation 
> for the project will describe how to rebuild the configure script.
>
> *Solution for Package Maintainers*
>
> To prevent users from seeing errors, update to GNU Autoconf to version 
> 2.70 or later and re-generate the project configure  script.  GNU 
> Autoconf-2.70 was released 
> <https://lists.gnu.org/archive/html/autotools-announce/2020-12/msg00001.html>December 
> 8, 2020.  The source code is available via git clone: 
> http://git.sv.gnu.org/r/autoconf.git.  GNU Autoconf documentation is 
> available through GNU Autoconf Project Page 
> <https://www.gnu.org/software/autoconf/>.
>
> Daniel Straus
>
> Assistant Professor
>
> Department of Chemistry
>
> Tulane University
>
> 5088 Percival Stern Hall
>
> 6400 Freret Street
>
> New Orleans, LA 70118
>
> (504) 862-3585
>
> http://straus.tulane.edu/ <http://straus.tulane.edu/>
>
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