On Fri, Nov 28, 2014 at 1:23 AM, W2AGZ <[email protected]> wrote: > Alex, thanks for your quick and wise response! > > I did a cursory pass through of the source code, matdyn.f90 and lambda.f90, > used in QHA (matdyn) and the general phonon packages within QE, and didn't
i don't understand this statement. the two files you mention are part of the standard build and compile fine with gfortran. when people complain about QHA not being compiled with gfortran, they usually refer to the files in the QHA package and they quote error messages that indicated such illegal coding. > find any obvious uses of floating point loop variables. Frankly, I can't > imagine why such assignments would ever be done! On the other hand, most of the time, this would happen "unintentionally" through with implicit variable declarations. the files in the QHA packages have this in spades: [akohlmey@zero QHA]$ find ./ -name \*.f90 -or -name \*.f -or -name *.h | xargs grep -i implicit ./SRC/Partial_phonon_DOS.f90: implicit real*8(a-h,o-z) ./SRC/Ghost_DOS.f90: implicit real*8(a-h,o-z) ./SRC/Atom_projected_properties.f90: implicit none ./SRC/F_QHA.f90: implicit none ./SRC/Mean_square_displacement.f90: implicit none ./Debye/Debye.f90:! implicit none ./Debye/Debye.f90: implicit real*8(a-h,o-z) ./Debye/Debye_T.f: implicit real*8(a-h,o-z) ./Phonon_DOS/parameters.h: implicit real*8(a-h,o-z) they are also full of other things that were accepted programming style when i learned fortran, but are in dire need of refactoring into modern fortran (now here is a self-contradicting description. ;-) ) these days. > occasionally posted on the forum are reports of NaN errors embedded in > phonon calculation output. I wonder if such result from the "very bad" > programming practices you describe. there are plenty possible reasons for NaNs. using floating point math for loops can lead to too few or too many loop iterations. that would more likely lead to slightly different results, not likely to NaNs (unless there is some rounding error involved leading to negative numbers when positive numbers are required (e.g. when taking a logarithm or a square root). > Hope to see you at the March Meeting upcoming in San Antonio. *very* unlikely. axel. > -Paul > -----Original Message----- > From: [email protected] [mailto:[email protected]] On > Behalf Of Axel Kohlmeyer > Sent: Thursday, November 27, 2014 6:24 AM > To: PWSCF Forum > Subject: Re: [Pw_forum] QHA Compile: Using gfortran instead of ifort > > On Wed, Nov 26, 2014 at 11:27 PM, W2AGZ <[email protected]> wrote: >> To the Community: >> >> >> >> I believe I may have raised this question in the far distant past. >> >> >> >> It appears that under QE-5.1.1, it is still necessary to compile the >> source code within QHA using ifort. Are any in the QE community aware >> of a QHA package compile-able with gfortran, or object code resulting >> from such? Is there an equivalent to QHA somewhere within the QE >> package (or outside!) capable of yielding similar results such as, e.g., > Debye temperatures? >> >> >> >> As always, thanks for any advice/guidance. > > for the most part it seems as if all it needs is somebody with a little bit > to time to sit down and replace the loops using floating point variables > with the equivalent using integral loop variables. > > using floating point loop variables is very, *very*, *VERY* bad programming > style (due to limitations of floating point math) and as of the last decade > removed from the fortran standard. > > not really rocket science... > > axel. > >> >> >> >> Paul Michael Grant, PhD >> >> Physicist and Science Writer >> >> Senior Life Fellow, American Physical Society >> >> Fellow, Institute of Physics, United Kingdom >> >> [email protected] >> >> http://www.w2agz.com >> >> >> >> >> >> >> _______________________________________________ >> Pw_forum mailing list >> [email protected] >> http://pwscf.org/mailman/listinfo/pw_forum > > > > -- > Dr. Axel Kohlmeyer [email protected] http://goo.gl/1wk0 College of > Science & Technology, Temple University, Philadelphia PA, USA International > Centre for Theoretical Physics, Trieste. Italy. > _______________________________________________ > Pw_forum mailing list > [email protected] > http://pwscf.org/mailman/listinfo/pw_forum > > _______________________________________________ > Pw_forum mailing list > [email protected] > http://pwscf.org/mailman/listinfo/pw_forum -- Dr. Axel Kohlmeyer [email protected] http://goo.gl/1wk0 College of Science & Technology, Temple University, Philadelphia PA, USA International Centre for Theoretical Physics, Trieste. Italy. _______________________________________________ Pw_forum mailing list [email protected] http://pwscf.org/mailman/listinfo/pw_forum
