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A comment on What Every Computer Scientist Should Know About Floating-Point Arithmetic (1991). Parent comment

Re:What Every Computer Scientist Should Know About Floating-... by DarkWiiPlayer on Monday June 29, 2020 @09:20AM (#23677298)
> 0.1 has no finite representation in binary.

b1 / b1010

I don't see the problem. Did you mean to say it has no finite representation in the IEEE float format?

> It was never exact to begin with.

But the format sadly gets used in situations where people expect it to be reasonably accurate, where it isn't, because developers either underestimate the "reasonable" or overestimate the "accurate" part.

It's just sad that most mainstream programming languages have no native accurate data type for rational numbers.

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Re:What Every Computer Scientist Should Know About Floating-... by slavik81 on Sunday July 12, 2020 @06:05PM (#23815156)
I meant in positional notation, but most people know that as "decimal notation". Unfortunately, that implies base 10, so I avoided the term.

I gave both an example in binary and an example in decimal to clarify my imprecise terminology. I worry that by objecting only to the binary example, you may confuse people into thinking the two are different.

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Re:What Every Computer Scientist Should Know About Floating-... by account42 on Monday June 29, 2020 @11:12AM (#23678321)
So are you saying that ⅓ has a finite presentation in decimal? Finite binary rationals ⊋ finite binary numbers.
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Re:What Every Computer Scientist Should Know About Floating-... by DarkWiiPlayer on Thursday July 02, 2020 @09:06AM (#23712706)
> So are you saying that ⅓ has a finite presentation in decimal?

Yes: ⅓

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Re:What Every Computer Scientist Should Know About Floating-... by Gracana on Monday June 29, 2020 @10:55AM (#23678148)
> Did you mean to say it has no finite representation in the IEEE float format?

Of course that's implied.

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Re:What Every Computer Scientist Should Know About Floating-... by DarkWiiPlayer on Thursday July 02, 2020 @09:10AM (#23712734)
It was a rhetoric question; I just wanted to point out that people blame these inaccuracies on "binary representations" when in reality it's just this one binary representation that's broken.
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