Ín Wien2k the time spent in the FFT is small in all cases that I know of, particularly if you exploit mpi/omp, plus we don't use the algorithms that explore different methods. If you are going to use it for other codes (plane wave) then you might want to post to the fftw list for help. Or read configure.ac to work out what is being looked for, then check your gcc/icc/icx. The second option requires a fair bit of coding expertise, be warned!
___ Emeritus Professor Laurence Marks (Laurie) Department of Materials Science and Engineering, Northwestern University www.numis.northwestern.edu "Research is to see what everybody else has seen, and to think what nobody else has thought" Albert Szent-Györgyi On Tue, Mar 4, 2025, 08:39 Michael Fechtelkord via Wien < [email protected]> wrote: > Dear all, > > when I configure fftw 3.3.10 using: > > C=ifx F77=ifx CC=gcc CFLAGS="-O3 -march=native -mavx2" FCFLAGS="-O3 > -xAVX2"\ > ./configure --prefix=/usr/local/ --enable-shared --enable-mpi > --enable-openmp --enable-threads --enable-avx --enable-avx2 > > > I get a warning from configure: > > > checking whether a cycle counter is available... no > *************************************************************** > WARNING: No cycle counter found. FFTW will use ESTIMATE mode > for all plans. See the manual for more information. > *************************************************************** > > I am using gcc 14.2, ifx 2025.0 on opensuse leap 15.6 > > I am not sure if I had this in older versions of gcc / ifort. > > My question: Is the estimate mode a performance problem or can I just > neglect the warning? > > > Best regards, > > Michael > > > -- > Dr. Michael Fechtelkord > > Institut für Geologie, Mineralogie und Geophysik > Ruhr-Universität BochumUniversitätsstr. 150 > <https://www.google.com/maps/search/Universit%C3%A4tsstr.+150?entry=gmail&source=g> > D-44780 Bochum > > Phone: +49 (234) 32-24380 > Fax: +49 (234) 32-04380 > Email: [email protected] > Web Page: > https://www.ruhr-uni-bochum.de/kristallographie/kc/mitarbeiter/fechtelkord/ > > _______________________________________________ > Wien mailing list > [email protected] > http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien > SEARCH the MAILING-LIST at: > http://www.mail-archive.com/[email protected]/index.html >
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