Re: Are Floating Point Numbers still a Can of Worms?

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From	Mostowski Collapse <janburse@fastmail.fm>
Newsgroups	comp.lang.javascript
Subject	Re: Are Floating Point Numbers still a Can of Worms?
Date	Sat, 15 Oct 2022 18:51:56 +0200
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Versions used, both 64-bit on Windows 10:

Chrome 106.0.5249.119
Firefox 105.0.3

Mostowski Collapse schrieb:
> I wonder whether FireFox always yields the more
> accurate values, or whether this is just one example.
> 
> Here are some more failures of Chrome,
> accuracy of B**E:
> 
> B = 1889, E = 29;
> B = 1470, E = 56;
> B = -1976, E = -49;
> B = 3240, E = -18;
> B = 2154, E = -6;
> B = -182, E = -32;
> B = 852, E = 43;
> B = 3316, E = -37;
> B = 2830, E = 25;
> B = 4075, E = -29;
> B = -2128, E = 64;
> 
> On the other hand Firefox fails here, BTW Python
> fails also here, JDK 19 gives a different result:
> 
> B = 396, E = -1;
> 
> LoL
> 
> Ben Bacarisse schrieb am Samstag, 15. Oktober 2022 um 18:04:24 UTC+2:
>> John Harris <ni...@jghnorth.org.uk.invalid> writes:
>>
>>> On 15/10/2022 15:31, R.Wieser wrote:
>>>
>>> <snip>
>>>> P.s.
>>>> I've got some numbers for you :
>>>> -- 1889*1889*1889*1889*1889* etc. calculated thru the FPU
>>>> 53A891D176398773 - 1.0250068783051204e+095
>>> <snip>
>>>
>>> For what it's worth, the correct value of 1889**29 is :
>>>
>>> 102500687830512064253064716070601123218909116358654017979384519544555980744900395407329380298209
>>>
>>> so the ...206 value is most accurate and ...207 is only slightly less
>>> accurate.
>> True. But neither 1.0250068783051206e95 nor 1.0250068783051207e95 can
>> be represented in binary floating point. The two representable
>> numbers closest to 1889**29 are
>>
>> 1025006878305120[5]6620692472528153354473784341513556365963141787204703693721957646169653433597952
>>
>> and
>>
>> 1025006878305120[7]1442079894904626368690870422625608571181699824406695890772528399182534027509760
>>
>> So the larger of the two is, in fact, the more accurate. There are two
>> kinds of accuracy at this level: (1) what binary floating point number
>> is the closest and, (2) what decimal is the closest representation to
>> /that/ binary number?
>>
>> -- 
>> Ben.

Thread

Are Floating Point Numbers still a Can of Worms? Mostowski Collapse <bursejan@gmail.com> - 2022-10-14 15:52 -0700
  Re: Are Floating Point Numbers still a Can of Worms? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-10-15 01:52 +0100
  Re: Are Floating Point Numbers still a Can of Worms? "R.Wieser" <address@not.available> - 2022-10-15 09:33 +0200
    Re: Are Floating Point Numbers still a Can of Worms? "R.Wieser" <address@not.available> - 2022-10-15 10:00 +0200
    Re: Are Floating Point Numbers still a Can of Worms? John Harris <niam@jghnorth.org.uk.invalid> - 2022-10-15 11:13 +0100
      Re: Are Floating Point Numbers still a Can of Worms? "R.Wieser" <address@not.available> - 2022-10-15 13:43 +0200
        Re: Are Floating Point Numbers still a Can of Worms? John Harris <niam@jghnorth.org.uk.invalid> - 2022-10-15 15:56 +0100
          Re: Are Floating Point Numbers still a Can of Worms? "R.Wieser" <address@not.available> - 2022-10-15 17:44 +0200
  Re: Are Floating Point Numbers still a Can of Worms? Mostowski Collapse <janburse@fastmail.fm> - 2022-10-15 14:25 +0200
    Re: Are Floating Point Numbers still a Can of Worms? "R.Wieser" <address@not.available> - 2022-10-15 16:31 +0200
      Re: Are Floating Point Numbers still a Can of Worms? John Harris <niam@jghnorth.org.uk.invalid> - 2022-10-15 16:22 +0100
        Re: Are Floating Point Numbers still a Can of Worms? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-10-15 17:04 +0100
          Re: Are Floating Point Numbers still a Can of Worms? Mostowski Collapse <bursejan@gmail.com> - 2022-10-15 09:47 -0700
            Re: Are Floating Point Numbers still a Can of Worms? Mostowski Collapse <janburse@fastmail.fm> - 2022-10-15 18:51 +0200
              Re: Are Floating Point Numbers still a Can of Worms? Mostowski Collapse <bursejan@gmail.com> - 2022-10-22 14:35 -0700
                Re: Are Floating Point Numbers still a Can of Worms? Mostowski Collapse <bursejan@gmail.com> - 2022-11-21 09:02 -0800
  Re: Are Floating Point Numbers still a Can of Worms? Julio Di Egidio <julio@diegidio.name> - 2022-10-17 02:00 -0700
    Re: Are Floating Point Numbers still a Can of Worms? Mostowski Collapse <bursejan@gmail.com> - 2022-10-18 07:40 -0700

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