Re: [Bug-apl] Problem with modulo arithmetic on Gaussian integers

[enztec]

what is his processor?
https://en.wikipedia.org/wiki/Pentium_FDIV_bug

On Wed, 26 Apr 2017 11:28:00 -0400
Peter Teeson <address@hidden> wrote:

> Works OK on my Early 2009 Mac Pro running macOS 10.10.5 Yosemite and APL 
> #svn927
> 
> You have different HW but same OS & toolchain? 
> So how about trying a different toolchain to see if it is the compiler etc?
> Or what about trying to disassemble the coded at the point of execution?
> Could it be something like missing an overflow?
> 
> Just my 0.02¢
> 
> Peter
> > On Apr 26, 2017, at 1:44 AM, Frederick Pitts <address@hidden> wrote:
> > 
> > To all,
> > 
> >     I have 3 machines running 64-bit Fedora 25 Workstation with g++
> > (GCC) 6.3.1 20161221 (Red Hat 6.3.1-1) and either gnu-apl svn version
> > 889 or 933.  Two of the machines are about 8 years old and one less
> > than a year old.
> > 
> >     On all three platforms, gnu-apl gives:
> > 
> >     3J1 | 23J1 25J25
> > 3J1 0
> > 
> >     Juergen and Xtian (on svn 933) report their setups give the
> > right answer:
> > 
> > 0 0
> > 
> >     Am I the only one seeing this problem?  BTW, I have about 1500
> > more examples of the modulo operator failing out of 6765201 tests with
> > distinct argument values.
> > 
> > Regards,
> > 
> > Fred
> > 
> > 
> > On Tue, 2017-04-25 at 23:01 -0400, Christian Robert wrote:
> >> Same result as Juergen,
> >> 
> >> Xtian.
> >> 
> >> address@hidden:/home/xtian] $ apl
> >> 
> >>                      ______ _   __ __  __    ___     ____   __
> >>                     / ____// | / // / / /   /   |   / __ \ / /
> >>                    / / __ /  |/ // / / /   / /| |  / /_/ // /
> >>                   / /_/ // /|  // /_/ /   / ___ | / ____// /___
> >>                   \____//_/ |_/ \____/   /_/  |_|/_/    /_____/
> >> 
> >>                       Welcome to GNU APL version 1.7 / 933M
> >> 
> >>                  Copyright (C) 2008-2016  Dr. Jürgen Sauermann
> >>                         Banner by FIGlet: www.figlet.org
> >> 
> >>                  This program comes with ABSOLUTELY NO WARRANTY;
> >>                            for details run: apl --gpl.
> >> 
> >>       This program is free software, and you are welcome to
> >> redistribute it
> >>           according to the GNU Public License (GPL) version 3 or
> >> later.
> >> 
> >> SAVED 2017-03-30 22:33:13 (GMT-4)
> >>        23J1 25J25 ÷ 3J1
> >> 7J¯2 10J5
> >>        3J1 | 23J1 25J25
> >> 0 0
> >> 
> >> 
> >> 
> >> On 2017-04-25 21:50, Frederick Pitts wrote:
> >>> Juergen,
> >>> 
> >>>          I did a 'make clean' followed by 'make' and 'make
> >>> install'.  I
> >>> obtained the same result that caused me to report the problem.
> >>> 
> >>>          The version of gnu-apl I'm using is svn rev 933.  From the
> >>> banner in your email, I see you're testing with code from your
> >>> personal
> >>> svn.  Is it possible the changes you recently made to
> >>> (ComplexCell.hh
> >>> and FloatCell.hh) are not yet in the svn from which I clone?
> >>> 
> >>> Regards,
> >>> 
> >>> Fred
> >>> 
> >>> On Tue, 2017-04-25 at 22:05 +0200, Juergen Sauermann wrote:
> >>>> Hi Fred,
> >>>>   
> >>>> actually it does on my machine:
> >>>>   
> >>>>                       ______ _   __ __  __    ___     ____   __
> >>>>                      / ____// | / // / / /   /   |   / __ \ / /
> >>>>                     / / __ /  |/ // / / /   / /| |  / /_/ // /
> >>>>                    / /_/ // /|  // /_/ /   / ___ | / ____// /___
> >>>>                    \____//_/ |_/ \____/   /_/  |_|/_/    /_____/
> >>>>                                          
> >>>>                    Welcome to GNU APL version 1.7 / 12784:12785M
> >>>>                                          
> >>>>                   Copyright (C) 2008-2016  Dr. Jürgen Sauermann
> >>>>                          Banner by FIGlet: www.figlet.org
> >>>>                                          
> >>>>                   This program comes with ABSOLUTELY NO WARRANTY;
> >>>>                             for details run: apl --gpl.
> >>>>                                          
> >>>>        This program is free software, and you are welcome to
> >>>> redistribute it
> >>>>            according to the GNU Public License (GPL) version 3 or
> >>>> later.
> >>>>                                          
> >>>>         23J1 25J25 ÷ 3J1
> >>>> 7J¯2 10J5
> >>>>   
> >>>>         3J1 | 23J1 25J25
> >>>> 0 0
> >>>>   
> >>>>   
> >>>> However, if I remember correctly then some of the changes that I
> >>>> made
> >>>> lately were in
> >>>> header files (ComplexCell.hh and FloatCell.hh). If you did
> >>>> ./configure without options, then
> >>>> your build is probably is a 'fast' one, which may not have
> >>>> detected
> >>>> header file changes.
> >>>>   
> >>>> Please try make clean at the top level and rebuild GNU APL to see
> >>>> if
> >>>> the problem persists.
> >>>>   
> >>>> Best Regards,
> >>>> Jürgen Sauermann
> >>>>   
> >>>>   
> >>>>   
> >>>> On 04/25/2017 09:30 PM, Frederick Pitts wrote:
> >>>>> Jeurgen,
> >>>>>   
> >>>>>      A greatest common divisor of 23J1 and 25J25 is 3J1.
> >>>>> Complex division by of 23J1 and 25J25 by 3J1 yields Gaussian
> >>>>> integers
> >>>>>   
> >>>>>         23J1 25J25 ÷ 3J1
> >>>>> 7J¯2 10J5
> >>>>>   
> >>>>> but mod 3J1 of the same numbers does not consistently yield
> >>>>> zeroes
> >>>>>   
> >>>>>         3J1 | 23J1 25J25
> >>>>> 3J1 0
> >>>>>   
> >>>>> I can provide numerous other examples of this problem if
> >>>>> needed.
> >>>>>   
> >>>>> Regards,
> >>>>>   
> >>>>> Fred
> >>>>>   
> >>>>>   
> >>>>>   
> >>>>>   
> >>>> 
> >>>>    
> >> 
> >> 
> > 
> 
>