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Re: A useless machine

From Michael S <already5chosen@yahoo.com>
Newsgroups comp.arch
Subject Re: A useless machine
Date 2026-02-20 11:41 +0200
Organization A noiseless patient Spider
Message-ID <20260220114153.0000416f@yahoo.com> (permalink)
References (2 earlier) <10msdau$3vgrg$2@dont-email.me> <10msqc3$4011$1@dont-email.me> <20260218182251.00004e44@yahoo.com> <10n61l5$36tk6$1@dont-email.me> <jwvwm08a3e4.fsf-monnier+comp.arch@gnu.org>

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On Thu, 19 Feb 2026 15:27:07 -0500
Stefan Monnier <monnier@iro.umontreal.ca> wrote:

> I must say I find this whole thread baffling: when searching for
> a counter example and we're already in the order of 2^70, it seems
> clear that constant-factor improvements are completely irrelevant
> (even with large constants).
> 
> I guess it all boils down to the "useless" part of the title?
> 
> 
> === Stefan


As I wrote in earlier post, "useless" sounds too optimistic.
"Useless" in my book is proving or disproving 99% of conjectures known
in the numbers theory, both obscure and extremely famous (Fermat's
Last Theorem). And then 1% process ends up very useful.

But Collatz's conjecture believed to be true. Trying to disprove it by
experiments is futile.
Finding that all sequence with initial value in range [2**71:2**72]
converge to 1, which is by far the most likely outcome of experiment,
leaves us in exactly the same place where we started, i.e. conjecture
believed to be true, but unproven. That's not good enough to warrant a
title of "useless". "Pointless" sounds more proper, but may be we shall
find something more derogatory.

However, it's fun.
My current estimate, after considering how "smart" filtering by modulo
2**20 can be made practical, is that a single FPGA that costs 300 USD
would be able to test 2**71 values in ~500 years. Which means that the
company I am working for can be convinced to build gear capable of
doing calculations in 1 year for something like 1M USD or a little more.
I'd guess that smaller and hungrier engineering firms would accept the
job for 1/3rd of that sum. 
So, who has a pocket money to spend?

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A useless machine Thomas Koenig <tkoenig@netcologne.de> - 2026-02-14 09:57 +0000
  Re: A useless machine MitchAlsup <user5857@newsgrouper.org.invalid> - 2026-02-14 18:48 +0000
    Re: A useless machine David Brown <david.brown@hesbynett.no> - 2026-02-14 20:18 +0100
      Re: A useless machine MitchAlsup <user5857@newsgrouper.org.invalid> - 2026-02-14 21:22 +0000
        Re: A useless machine Stephen Fuld <sfuld@alumni.cmu.edu.invalid> - 2026-02-14 13:30 -0800
        Re: A useless machine David Brown <david.brown@hesbynett.no> - 2026-02-15 12:50 +0100
          Re: A useless machine BGB <cr88192@gmail.com> - 2026-02-21 13:48 -0600
            Re: A useless machine Terje Mathisen <terje.mathisen@tmsw.no> - 2026-02-21 21:40 +0100
              Re: A useless machine BGB <cr88192@gmail.com> - 2026-02-21 15:17 -0600
                Re: A useless machine BGB <cr88192@gmail.com> - 2026-02-22 04:50 -0600
              Re: A useless machine Tim Rentsch <tr.17687@z991.linuxsc.com> - 2026-03-12 21:01 -0700
            Re: A useless machine David Brown <david.brown@hesbynett.no> - 2026-02-22 14:43 +0100
              Re: A useless machine BGB <cr88192@gmail.com> - 2026-02-22 12:38 -0600
                Re: A useless machine David Brown <david.brown@hesbynett.no> - 2026-02-23 10:51 +0100
                Re: A useless machine MitchAlsup <user5857@newsgrouper.org.invalid> - 2026-02-26 01:27 +0000
                Re: A useless machine David Brown <david.brown@hesbynett.no> - 2026-02-26 09:21 +0100
                Re: A useless machine Tim Rentsch <tr.17687@z991.linuxsc.com> - 2026-03-12 21:11 -0700
      Re: A useless machine Terje Mathisen <terje.mathisen@tmsw.no> - 2026-02-15 14:58 +0100
      Re: A useless machine BGB <cr88192@gmail.com> - 2026-02-21 12:27 -0600
        Re: A useless machine David Brown <david.brown@hesbynett.no> - 2026-02-22 15:14 +0100
      Re: A useless machine Stefan Monnier <monnier@iro.umontreal.ca> - 2026-02-22 11:41 -0500
        Re: A useless machine David Brown <david.brown@hesbynett.no> - 2026-02-23 10:53 +0100
          Re: A useless machine Stefan Monnier <monnier@iro.umontreal.ca> - 2026-02-23 10:52 -0500
  Re: A useless machine Tim Rentsch <tr.17687@z991.linuxsc.com> - 2026-02-14 21:19 -0800
  Re: A useless machine Robert Finch <robfi680@gmail.com> - 2026-02-15 03:58 -0500
    Re: A useless machine David Brown <david.brown@hesbynett.no> - 2026-02-15 13:14 +0100
      Re: A useless machine Thomas Koenig <tkoenig@netcologne.de> - 2026-02-15 15:46 +0000
      Re: A useless machine Robert Finch <robfi680@gmail.com> - 2026-02-15 10:56 -0500
        Re: A useless machine MitchAlsup <user5857@newsgrouper.org.invalid> - 2026-02-15 19:16 +0000
          Re: A useless machine Terje Mathisen <terje.mathisen@tmsw.no> - 2026-02-15 22:40 +0100
            Re: A useless machine Thomas Koenig <tkoenig@netcologne.de> - 2026-02-26 19:31 +0000
        Re: A useless machine Michael S <already5chosen@yahoo.com> - 2026-02-18 18:22 +0200
          Re: A useless machine Robert Finch <robfi680@gmail.com> - 2026-02-18 22:56 -0500
            Re: A useless machine Michael S <already5chosen@yahoo.com> - 2026-02-19 12:10 +0200
              Re: A useless machine Robert Finch <robfi680@gmail.com> - 2026-02-21 01:56 -0500
                Re: A useless machine Michael S <already5chosen@yahoo.com> - 2026-02-21 19:23 +0200
                Re: A useless machine Michael S <already5chosen@yahoo.com> - 2026-02-21 20:36 +0200
                Re: A useless machine Michael S <already5chosen@yahoo.com> - 2026-02-22 10:46 +0200
                Re: A useless machine Terje Mathisen <terje.mathisen@tmsw.no> - 2026-02-22 12:45 +0100
                Re: A useless machine Michael S <already5chosen@yahoo.com> - 2026-02-22 16:35 +0200
                Re: A useless machine Robert Finch <robfi680@gmail.com> - 2026-02-22 19:12 -0500
                Re: A useless machine Robert Finch <robfi680@gmail.com> - 2026-02-22 19:47 -0500
                Re: A useless machine EricP <ThatWouldBeTelling@thevillage.com> - 2026-02-21 15:39 -0500
                Re: A useless machine Michael S <already5chosen@yahoo.com> - 2026-02-22 03:16 +0200
                Re: A useless machine EricP <ThatWouldBeTelling@thevillage.com> - 2026-02-22 14:48 -0500
                Re: A useless machine Michael S <already5chosen@yahoo.com> - 2026-02-22 23:25 +0200
            Re: A useless machine Terje Mathisen <terje.mathisen@tmsw.no> - 2026-02-19 11:51 +0100
              Re: A useless machine Michael S <already5chosen@yahoo.com> - 2026-02-19 23:12 +0200
                Re: A useless machine Terje Mathisen <terje.mathisen@tmsw.no> - 2026-02-20 15:11 +0100
            Re: A useless machine Stefan Monnier <monnier@iro.umontreal.ca> - 2026-02-19 15:27 -0500
              Re: A useless machine Michael S <already5chosen@yahoo.com> - 2026-02-20 11:41 +0200
              Re: A useless machine BGB <cr88192@gmail.com> - 2026-02-22 18:41 -0600
                Re: A useless machine Thomas Koenig <tkoenig@netcologne.de> - 2026-02-23 11:10 +0000
                Re: A useless machine BGB <cr88192@gmail.com> - 2026-02-23 17:24 -0600
                Re: A useless machine Thomas Koenig <tkoenig@netcologne.de> - 2026-02-24 06:44 +0000
                Re: A useless machine BGB <cr88192@gmail.com> - 2026-02-24 01:38 -0600
                Re: A useless machine BGB <cr88192@gmail.com> - 2026-02-24 03:16 -0600
                Re: A useless machine BGB <cr88192@gmail.com> - 2026-02-24 04:52 -0600
                Re: A useless machine Thomas Koenig <tkoenig@netcologne.de> - 2026-02-24 11:16 +0000
                Re: A useless machine BGB <cr88192@gmail.com> - 2026-02-24 13:19 -0600
                Re: A useless machine Tim Rentsch <tr.17687@z991.linuxsc.com> - 2026-03-12 21:14 -0700
          Re: A useless machine Thomas Koenig <tkoenig@netcologne.de> - 2026-02-20 08:01 +0000
    Re: A useless machine Michael S <already5chosen@yahoo.com> - 2026-02-15 15:35 +0200
      Re: A useless machine Michael S <already5chosen@yahoo.com> - 2026-02-15 18:33 +0200
        Re: A useless machine Thomas Koenig <tkoenig@netcologne.de> - 2026-02-15 19:19 +0000
          Re: A useless machine Michael S <already5chosen@yahoo.com> - 2026-02-16 12:31 +0200
            Re: A useless machine Michael S <already5chosen@yahoo.com> - 2026-02-17 15:41 +0200
              Re: A useless machine Michael S <already5chosen@yahoo.com> - 2026-02-17 18:17 +0200
    Re: A useless machine anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-02-15 22:41 +0000
  Re: A useless machine Terje Mathisen <terje.mathisen@tmsw.no> - 2026-02-15 14:52 +0100
    Re: A useless machine Thomas Koenig <tkoenig@netcologne.de> - 2026-02-15 16:45 +0000
      Re: A useless machine Terje Mathisen <terje.mathisen@tmsw.no> - 2026-02-15 18:01 +0100
        Re: A useless machine Thomas Koenig <tkoenig@netcologne.de> - 2026-02-15 19:42 +0000
          Re: A useless machine Terje Mathisen <terje.mathisen@tmsw.no> - 2026-02-15 22:59 +0100
            Re: A useless machine Robert Finch <robfi680@gmail.com> - 2026-02-15 21:53 -0500
              Re: A useless machine Michael S <already5chosen@yahoo.com> - 2026-02-16 12:40 +0200
                Re: A useless machine Michael S <already5chosen@yahoo.com> - 2026-02-16 20:34 +0200
              Re: A useless machine Terje Mathisen <terje.mathisen@tmsw.no> - 2026-02-16 16:08 +0100
  Re: A useless machine Stephen Fuld <sfuld@alumni.cmu.edu.invalid> - 2026-02-16 07:50 -0800
    Re: A useless machine Michael S <already5chosen@yahoo.com> - 2026-02-16 18:31 +0200
    Re: A useless machine Terje Mathisen <terje.mathisen@tmsw.no> - 2026-02-18 21:56 +0100

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