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Re: [Bug-apl] Problem with modulo arithmetic on Gaussian integers
From: |
enztec |
Subject: |
Re: [Bug-apl] Problem with modulo arithmetic on Gaussian integers |
Date: |
Wed, 26 Apr 2017 09:30:52 -0600 |
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
> >>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>>
> >>>>
> >>
> >>
> >
>
>
- Re: [Bug-apl] Problem with modulo arithmetic on Gaussian integers, (continued)
- Re: [Bug-apl] Problem with modulo arithmetic on Gaussian integers, Jay Foad, 2017/04/26
- Re: [Bug-apl] Problem with modulo arithmetic on Gaussian integers, Juergen Sauermann, 2017/04/26
- Re: [Bug-apl] Problem with modulo arithmetic on Gaussian integers, Kacper Gutowski, 2017/04/26
- Re: [Bug-apl] Problem with modulo arithmetic on Gaussian integers, Peter Teeson, 2017/04/26
- Re: [Bug-apl] Problem with modulo arithmetic on Gaussian integers, Juergen Sauermann, 2017/04/26
- Re: [Bug-apl] Problem with modulo arithmetic on Gaussian integers, Frederick Pitts, 2017/04/27
- Re: [Bug-apl] Problem with modulo arithmetic on Gaussian integers, Juergen Sauermann, 2017/04/27
- Re: [Bug-apl] Problem with modulo arithmetic on Gaussian integers, Juergen Sauermann, 2017/04/27
- Re: [Bug-apl] Problem with modulo arithmetic on Gaussian integers, Peter Teeson, 2017/04/27
- Re: [Bug-apl] Problem with modulo arithmetic on Gaussian integers, Peter Teeson, 2017/04/26
- Re: [Bug-apl] Problem with modulo arithmetic on Gaussian integers,
enztec <=
- Re: [Bug-apl] Problem with modulo arithmetic on Gaussian integers, Juergen Sauermann, 2017/04/26
- Re: [Bug-apl] Problem with modulo arithmetic on Gaussian integers, Peter Teeson, 2017/04/26