Re: Motion M006.01: discussion period begins, until October 17
Vincent,
> I don't like the word "difficult" in this context, because it
> may not actually be difficult. I would rather use a word like
> "advanced" / "enhanced" / "extended".
Do you like a word "accuracy-relaxed string" ?
> In §6.7.5, I would replace "any interval" by constraints obtained
> with a basic algorithm to have a reasonable behavior, such as:
I like your suggestion about L and U.
What will your rules say about semi-infinite interval with rational bound like
"[p/q, +inf]" ? I think that U is not relevant here and it should return I such that
[p/q, +oo) included in I include in [hull(hull(p)/hull(q)), +oo).
I would have no doubt to add your specification to 1888 when it was developing.
As for 1788.1, its style should be simpler, and I'm thinking how to express your specification
in simple words.
-Dima
----- Original Message -----
From: vincent@xxxxxxxxxx
To: stds-1788@xxxxxxxxxxxxxxxxx
Sent: Thursday, September 29, 2016 4:21:37 PM GMT +03:00 Iraq
Subject: Re: Motion M006.01: discussion period begins, until October 17
My comments:
Globally I agree on this motion, which basically solves the problem
I mentioned when I voted no on M004.02.
I don't like the word "difficult" in this context, because it
may not actually be difficult. I would rather use a word like
"advanced" / "enhanced" / "extended".
In §6.7.5, I would replace "any interval" by constraints obtained
with a basic algorithm to have a reasonable behavior, such as:
1. Convert l and u to intervals L and U as follows:
A. For a rational literal, compute hull(hull({p})/hull({q})).
B. Otherwise, take the hull of the value.
2. If L < U, then return the hull of x.
3. If L > U, then return Empty.
[Now, L and U have an non-empty intersection, i.e. this is really
a difficult case.]
4. If l <= u, return any interval I such that
[l,u] included in I included in hull(L,U).
5. Otherwise (l > u), return Empty or any interval I such that
[u,l] included in I included in hull(L,U).
"optionally when l <= u": I would then add the requirement that we
are in case 4 above.
Then the note should be updated.
I hope I haven't left any mistake...
--
Vincent Lefèvre <vincent@xxxxxxxxxx> - Web: <https://www.vinc17.net/>
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Work: CR INRIA - computer arithmetic / AriC project (LIP, ENS-Lyon)