[Wien] gfortran compilation and run problems for 19.1

[Mikhail Nestoklon]

No, it understands the intention of the person who wrote the code but this is an error.

@ gfortran 7.4.0
if(a == b) then
1
Error: Logicals at (1) must be compared with .eqv. instead of ==
gfort_test.f:15:9:
if(a .eq. b) then
1
Error: Logicals at (1) must be compared with .eqv. instead of .eq.

As far as I remember,some time ago to make the fortran code which compiles with ifort compile with gfortran the good starting point was to switch on all flags which control the strict use of the standard, unfortunately I have no access to ifort  right now and can not check the proper combination, probably it was just "-std90".  
By default, ifort compiles the non-standard code it is able to understand while the  default gfortran behavior is to treat it as an error. This particular case is far beyond the standard, so I do not know if it is even possible to force gfortran to compile this code.

Sincerely,
Mikhail 




>Среда, 26 июня 2019, 8:43 +03:00 от "Fecher, Gerhard" <fecher at uni-mainz.de>:
>
>Dear Gavin, 
>Sorry my question was probably to short, it should read
>     Does anyone know whether "== " works with gfortran ?
>
>With ifort the following test works well, but I cannot test it with gfortran
>The answer in the Intel forum that you quote does not include "=="
>
>     program logicaltest
>      implicit none
>!
>!     test ==, .eq., .eqv.
>!
>      logical   a, b, c
>
>      a=.true.
>      b=.true.
>
>      if(a == b) then
>         write(6,*) 'a = b'
>      end if
>
>      if(a .eq. b) then
>         write(6,*) 'a .eq. b'
>      end if
>
>      if(a .eqv. b) then
>         write(6,*) 'a .eqv. b'
>      end if
>      
>      end
>
>
>Ciao
>Gerhard
>
>DEEP THOUGHT in D. Adams; Hitchhikers Guide to the Galaxy:
>"I think the problem, to be quite honest with you,
>is that you have never actually known what the question is."
>
>====================================
>Dr. Gerhard H. Fecher
>Institut of Inorganic and Analytical Chemistry
>Johannes Gutenberg - University
>55099 Mainz
>and
>Max Planck Institute for Chemical Physics of Solids
>01187 Dresden
>________________________________________
>Von: Wien [wien-bounces at zeus.theochem.tuwien.ac.at] im Auftrag von Gavin Abo [gsabo at crimson.ua.edu]
>Gesendet: Mittwoch, 26. Juni 2019 03:37
>An:  wien at zeus.theochem.tuwien.ac.at
>Betreff: Re: [Wien] gfortran compilation and run problems for 19.1
>
>The == should work for C/C++ language.  I don't recall ever seeing that being used for Fortran.
>
>A quote from a HP Doctor Fortran article [  https://software.intel.com/en-us/forums/intel-visual-fortran-compiler-for-windows/topic/274462 ]:
>
>"The real trouble with making assumptions about the internal value of LOGICALs is when you try testing them for "equality" against another logical expression. The way many Fortran programmers would naturally do this is as follows:
>
>IF (LOGVAL1 .EQ. LOGVAL2) ...
>
>but the results of this can vary depending on the internal representation. The Fortran language defines two operators exclusively for use on logical values, .EQV. ("equivalent to") and .NEQV. ("not equivalent to"). So the above test would be properly written as:
>
>IF (LOGVAL1 .EQV. LOGVAL2) ..."
>
>On 6/25/2019 3:14 PM, Fecher, Gerhard wrote:
>
>Does == work ?
>
>Ciao
>Gerhard
>
>DEEP THOUGHT in D. Adams; Hitchhikers Guide to the Galaxy:
>"I think the problem, to be quite honest with you,
>is that you have never actually known what the question is."
>
>====================================
>Dr. Gerhard H. Fecher
>Institut of Inorganic and Analytical Chemistry
>Johannes Gutenberg - University
>55099 Mainz
>and
>Max Planck Institute for Chemical Physics of Solids
>01187 Dresden
>________________________________________
>Von: Wien [wien-bounces at zeus.theochem.tuwien.ac.at<mailto:wien-bounces at zeus.theochem.tuwien.ac.at>] im Auftrag von Sam Trickey [trickey at qtp.ufl.edu<mailto:trickey at qtp.ufl.edu>]
>Gesendet: Dienstag, 25. Juni 2019 15:13
>An: wien at zeus.theochem.tuwien.ac.at<mailto: wien at zeus.theochem.tuwien.ac.at >
>Betreff: Re: [Wien] gfortran compilation and run problems for 19.1
>
>See below
>
>On 6/25/19 5:47 AM, Peter Blaha wrote:
>Hi,
>
>I can confirm the fix for   inputpars.F.   Of course, according to fortran standards a logical if should have an .eqv. operator (although I never "understood" what that should be good for ...).
>
>Keeps computer scientists occupied introducing needless and annoying distinctions.
>
>peace, Sam
>
>
>--
>Samuel B. Trickey
>QTP, Depts. of Physics and Chemistry
>2324 Physics Building
>Box 118435
>Univ. of Florida
>Gainesville, FL 32611-8435
>Vox: 352-392-6978 (direct)
>Vox: 352-392-1597 (receptionist)
>Fax: 352-392-8722
>http://www.qtp.ufl.edu/ofdft
>http://users.clas.ufl.edu/trickey
>
>
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-- 
Mikhail Nestoklon
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