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)