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Groups > comp.lang.prolog > #14104

Re: New milestone float formatting [LoL] (Was: Request for comments, Novacore the sequel to ISO modules)

From Mild Shock <janburse@fastmail.fm>
Newsgroups comp.lang.prolog
Subject Re: New milestone float formatting [LoL] (Was: Request for comments, Novacore the sequel to ISO modules)
Date 2024-07-28 14:38 +0200
Message-ID <v85e3m$falk$2@solani.org> (permalink)
References <db8a6771-3e54-485b-b391-310658dd6f52n@googlegroups.com> <d9588b9c-edcc-4f8b-85d2-7487b5556798n@googlegroups.com> <v85dpo$falk$1@solani.org>

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Further test cases are:

?- X is 370370367037037036703703703670 / 123456789012345678901234567890.
X = 3.0000000000000004.

?- X is 0.1+0.1+0.1+0.1+0.1+0.1+0.1+0.1.
X = 0.7999999999999999.

The first test case doesn't work in SWI-Prolog
since recently it has improve its realization of
(/)/2 arithemetic function. While in most Prolog

systems we should have the above result, since
neither the division equals 3.0 nor the sum equals
0.8 when we use floating point numbers, and

when we convert first to floating point number
before doing the division. The adaptive algorithm
is more expensive than just calling num.toPrecision(17).

It will in mimimum call num.toPrecision(16) and do
the back conversion, i.e. Number(res). So unparsing
has a parsing cost. And for critical numbers, it

has a second unparsing via num.toPrecision(17) cost.
But I guess we can accept this little slow down.

Mild Shock schrieb:
> Hi,
> 
> To capture some critical examples of float to string
> conversion I went with this kind of little excess
> precision and had this float to string conversion:
> 
>           return shape_number(num.toPrecision(17));
> 
> Which gives this unfortunate result, still in release
> 1.2.1 of Dogelog Player for JavaScript seen:
> 
> ?- between(1,10,N), X is (20+N)/10, write(X), nl, fail; true.
> 2.1000000000000001
> 2.2000000000000002
> 2.2999999999999998
> 2.3999999999999999
> 2.5
> 2.6000000000000001
> 2.7000000000000002
> 2.7999999999999998
> 2.8999999999999999
> 3.0
> 
> One work around is to check whether precision 16 would
> also work. Like this code here:
> 
>          let res = num.toPrecision(16);
>          if (Number(res) === num) {
>              return shape_number(res);
>          } else {
>              return shape_number(num.toPrecision(17));
>          }
> 
> The results are much more eye friendly:
> 
> ?- between(1,10,N), X is (20+N)/10, write(X), nl, fail; true.
> 2.1
> 2.2
> 2.3
> 2.4
> 2.5
> 2.6
> 2.7
> 2.8
> 2.9
> 3.0
> true.
> 
> Can we accept this solution? Will it slow down printing?

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Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-08-17 05:18 -0700
  Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-08-17 06:37 -0700
    Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-08-17 07:00 -0700
      Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-08-17 13:28 -0700
        Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-08-31 02:59 -0700
          Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-08-31 03:04 -0700
            Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-08-31 03:10 -0700
              Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-08-31 10:18 -0700
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-08-31 10:22 -0700
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-10-09 16:06 -0700
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-10-09 16:12 -0700
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-10-09 16:13 -0700
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-10-09 16:14 -0700
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-10-09 23:57 -0700
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-10-09 23:59 -0700
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-10-12 05:11 -0700
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-10-12 10:46 -0700
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-10-12 10:48 -0700
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-10-12 13:22 -0700
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-10-13 05:53 -0700
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-10-13 07:32 -0700
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-10-13 11:16 -0700
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-10-13 11:18 -0700
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-10-13 11:36 -0700
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-10-13 13:28 -0700
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-10-14 01:41 -0700
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-10-14 01:43 -0700
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-10-14 07:41 -0700
  Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <janburse@fastmail.fm> - 2022-10-15 14:30 +0200
    Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-10-19 07:42 -0700
      Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-10-19 07:50 -0700
      Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-10-19 07:51 -0700
        Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-10-19 07:52 -0700
          Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-10-19 18:55 -0700
            Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-10-19 18:58 -0700
              Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-10-19 19:46 -0700
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-10-25 05:55 -0700
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-10-25 05:59 -0700
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-10-25 08:36 -0700
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-10-25 10:53 -0700
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-10-26 07:01 -0700
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-10-26 07:02 -0700
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-11-14 14:21 -0800
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-11-14 14:31 -0800
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-11-17 06:08 -0800
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-11-17 06:21 -0800
  Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2023-01-11 12:45 -0800
    Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2023-01-11 12:52 -0800
      Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2023-01-11 14:24 -0800
        Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2023-01-13 01:56 -0800
          Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2023-01-13 01:58 -0800
            Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2023-01-13 01:59 -0800
            Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2023-01-13 02:01 -0800
              Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2023-01-13 04:49 -0800
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2023-01-16 15:03 -0800
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2023-01-16 15:07 -0800
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2023-01-17 00:49 -0800
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2023-01-17 03:22 -0800
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2023-02-27 03:08 -0800
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2023-02-27 03:08 -0800
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2023-02-27 10:31 -0800
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2023-02-27 10:33 -0800
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2023-02-27 16:05 -0800
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2023-03-01 09:01 -0800
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2023-03-01 09:02 -0800
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2023-03-02 04:06 -0800
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2023-03-02 04:08 -0800
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2023-03-08 01:45 -0800
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2023-03-08 01:47 -0800
  Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2023-03-18 05:55 -0700
    Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2023-03-18 05:56 -0700
      Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2023-03-18 06:01 -0700
        Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2023-03-18 06:06 -0700
  Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2023-05-13 06:36 -0700
    Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2023-05-13 06:41 -0700
  Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2023-05-21 03:54 -0700
    Differences among the "bomb" and "xbetween" (Was: Request for comments, Novacore the sequel to ISO modules) Mild Shock <janburse@fastmail.fm> - 2024-09-24 17:10 +0200
      The issue with free speech Mild Shock <janburse@fastmail.fm> - 2024-10-09 15:29 +0200
        failure of formal verification [software.imdea.org] (Was: The issue with free speech) Mild Shock <janburse@fastmail.fm> - 2024-11-06 09:33 +0100
          Re: failure of formal verification [software.imdea.org] (Was: The issue with free speech) Mild Shock <janburse@fastmail.fm> - 2024-11-06 09:35 +0100
            Re: failure of formal verification [software.imdea.org] (Was: The issue with free speech) Mild Shock <janburse@fastmail.fm> - 2024-11-06 09:37 +0100
      variant_term/2 is faster than variant/1 (Was: Request for comments, Novacore the sequel to ISO modules) Mild Shock <janburse@fastmail.fm> - 2024-10-12 22:02 +0200
        Re: variant_term/2 is faster than variant/1 (Was: Request for comments, Novacore the sequel to ISO modules) Mild Shock <janburse@fastmail.fm> - 2024-10-12 23:16 +0200
        Re: variant_term/2 is faster than variant/1 (Was: Request for comments, Novacore the sequel to ISO modules) Mild Shock <janburse@fastmail.fm> - 2024-10-12 23:34 +0200
          Re: variant_term/2 is faster than variant/1 (Was: Request for comments, Novacore the sequel to ISO modules) Mild Shock <janburse@fastmail.fm> - 2024-10-13 00:54 +0200
  Re: Request for comments, Novacore the sequel to ISO modules Mild Shock <bursejan@gmail.com> - 2023-07-29 04:51 -0700
    Re: Request for comments, Novacore the sequel to ISO modules Mild Shock <bursejan@gmail.com> - 2023-09-07 17:15 -0700
      Re: Request for comments, Novacore the sequel to ISO modules Mild Shock <janburse@fastmail.fm> - 2023-11-19 19:56 +0100
        Re: Request for comments, Novacore the sequel to ISO modules Mild Shock <janburse@fastmail.fm> - 2023-11-19 19:59 +0100
          Re: Request for comments, Novacore the sequel to ISO modules Mild Shock <janburse@fastmail.fm> - 2023-11-19 20:01 +0100
    New milestone float formatting [LoL] (Was: Request for comments, Novacore the sequel to ISO modules) Mild Shock <janburse@fastmail.fm> - 2024-07-28 14:32 +0200
      Re: New milestone float formatting [LoL] (Was: Request for comments, Novacore the sequel to ISO modules) Mild Shock <janburse@fastmail.fm> - 2024-07-28 14:38 +0200
        Re: New milestone float formatting [LoL] (Was: Request for comments, Novacore the sequel to ISO modules) Mild Shock <janburse@fastmail.fm> - 2024-07-28 16:42 +0200
          Re: Differences among the "bomb" and "xbetween" (Was: New milestone float formatting [LoL]) Mild Shock <janburse@fastmail.fm> - 2024-09-24 17:20 +0200
            New milestone time formatting (Was: Differences among the "bomb" and "xbetween") Mild Shock <janburse@fastmail.fm> - 2024-09-26 13:22 +0200
      More Prolog Improvement Proposals (PIPs) [PIP401 - PIP404] Mild Shock <janburse@fastmail.fm> - 2024-10-09 09:43 +0200
        Even More Prolog Improvement Proposals (PIPs) [PIP301 - PIP303] (Was: More Prolog Improvement Proposals (PIPs) [PIP401 - PIP404]) Mild Shock <janburse@fastmail.fm> - 2024-10-09 09:45 +0200
          Re: Even More Prolog Improvement Proposals (PIPs) [PIP301 - PIP303] (Was: More Prolog Improvement Proposals (PIPs) [PIP401 - PIP404]) Mild Shock <janburse@fastmail.fm> - 2024-10-09 10:00 +0200
            Re: Even More Prolog Improvement Proposals (PIPs) [PIP301 - PIP303] (Was: More Prolog Improvement Proposals (PIPs) [PIP401 - PIP404]) Mild Shock <janburse@fastmail.fm> - 2024-10-09 11:22 +0200
    A FFI for evaluable functions Mild Shock <janburse@fastmail.fm> - 2024-10-10 00:14 +0200
      Name resolution is a blackbox (Re: A FFI for evaluable functions) Mild Shock <janburse@fastmail.fm> - 2024-10-10 00:16 +0200
        plonk in discourse (Was: The issue with free speech) Mild Shock <janburse@fastmail.fm> - 2024-10-10 00:48 +0200
          When do two Prolog terms marry? (Was: The issue with free speech) Mild Shock <janburse@fastmail.fm> - 2024-10-14 19:15 +0200
            Re: When do two Prolog terms marry? (Was: The issue with free speech) Mild Shock <janburse@fastmail.fm> - 2024-10-14 19:22 +0200
            native implementation of variant/2 can be fast (Was: When do two Prolog terms marry?) Mild Shock <janburse@fastmail.fm> - 2024-10-15 01:35 +0200
      KISS principle pays off (Was: A FFI for evaluable functions) Mild Shock <janburse@fastmail.fm> - 2024-11-03 00:52 +0100
    Waste of EU money / bread and butter of statistics (Was: failure of formal verification [software.imdea.org]) Mild Shock <janburse@fastmail.fm> - 2024-11-06 09:51 +0100
      Re: Waste of EU money / bread and butter of statistics (Was: failure of formal verification [software.imdea.org]) Mild Shock <janburse@fastmail.fm> - 2024-11-06 10:09 +0100
      Re: Waste of EU money / bread and butter of statistics (Was: failure of formal verification [software.imdea.org]) Julio Di Egidio <julio@diegidio.name> - 2024-11-06 10:43 +0100
        SICStus Prolog is overrated (Was: Waste of EU money / bread and butter of statistics) Mild Shock <janburse@fastmail.fm> - 2024-11-06 12:57 +0100
          Crashing under its own bloath, Scryer Prolog (Was: SICStus Prolog is overrated) Mild Shock <janburse@fastmail.fm> - 2024-11-06 13:03 +0100
            “Luce,” which is Italian for “light.” (Was: Crashing under its own bloath, Scryer Prolog) Mild Shock <janburse@fastmail.fm> - 2024-11-06 13:12 +0100
              More Poisened Meat balls? [NIVIDIA & OpenAI] (Way: “Luce,” which is Italian for “light.”) Mild Shock <janburse@fastmail.fm> - 2024-11-06 13:33 +0100
                Re: More Poisened Meat balls? [NIVIDIA & OpenAI] (Way: “Luce,” which is Italian for “light.”) Julio Di Egidio <julio@diegidio.name> - 2024-11-06 14:17 +0100
    Not all Red-Black Trees are Okasaki (Was: Request for comments, Novacore the sequel to ISO modules) Mild Shock <janburse@fastmail.fm> - 2024-11-07 00:59 +0100
  Re: Request for comments, Novacore the sequel to ISO modules Mild Shock <bursejan@gmail.com> - 2023-11-19 10:54 -0800

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