Re: Sensible and NonsenSQL Aspects of the NoSQL Hoopla
From: Jan Hidders <hidders_at_gmail.com>
Date: 06 Sep 2013 11:23:08 GMT
Message-ID: <164489674400149284.380204hidders-gmail.com_at_news.xs4all.nl>
>> On 2013-09-04 21:00:22 +0000, Norbert_Paul said:
>>
>> Impressive.
>>
>> Is the description in the following not precise enough? (Only looked
>> briefly myself, busy day tomorrow, sorry.)
>>
>> http://www.geocomputation.org/2009/PDF/Bulbul_et_al.pdf
>> Btw. it might be nice to see if there is no easy fix for this, like for
>> example cutting the difference shape in two. Intutively my first
>> inclination would be to base the proof of termination on the number of
>> vertices being reduced, which indeed in your conterexample does not
>> happen. This raises the question of how to do this optimally, for
>> certain definiitons of optimal (least number of nodes in the tree?).
>>
>> Let's hope so. So let the record show you have also an arxiv paper on
>> this: http://arxiv.org/abs/1205.5691
>>
>> Btw. it has a few typos, you might want to quickly fix those now. ;-)
>> Like "however, can expensive in dimension higher than 2"
>
> Thanks for the "be". I'll do so later.
Date: 06 Sep 2013 11:23:08 GMT
Message-ID: <164489674400149284.380204hidders-gmail.com_at_news.xs4all.nl>
Norbert_Paul <norbertpauls_spambin_at_yahoo.com> wrote:
> Jan Hidders wrote:
>> On 2013-09-04 21:00:22 +0000, Norbert_Paul said:
>>> ``However, with the shape
>>> $$\begin{picture}(75,90)
> ...
>>> \end{picture}$$
>>> that method may not terminate.''
>>>
>>> to avoid backdoor arguments that sloppy specifications always leave open
>>> in the sense of "But I meant it that way ... ".
>>
>> Impressive.
>>
>> Is the description in the following not precise enough? (Only looked
>> briefly myself, busy day tomorrow, sorry.)
>>
>> http://www.geocomputation.org/2009/PDF/Bulbul_et_al.pdf
> > Is apply DecompositionTree equal to apply AHD? I had another publication > at hand. Actually I tried to understand it in a way that noe doubt whatsoever > on every algorithm's detail is left. As not all was perfectly clear to me, > as an engineer, I simply decided to err at the safe side in avoiding the > explicit claim that the algorithm does not always terminate. Hence I wrote > "may" not terminate. >
>> Btw. it might be nice to see if there is no easy fix for this, like for
>> example cutting the difference shape in two. Intutively my first
>> inclination would be to base the proof of termination on the number of
>> vertices being reduced, which indeed in your conterexample does not
>> happen. This raises the question of how to do this optimally, for
>> certain definiitons of optimal (least number of nodes in the tree?).
> > Cutting shapes is not a good idea in 3D and needs much care. > Google for "Chazelle convex partitions of polyhedra". > >>>> Indeed. But also not much of an audience. But who knows, it might come, >>>> and it's easier and less demanding (usually :-)) then a blog. >>> >>> Google archives Usenet. Maybe one day ...
>>
>> Let's hope so. So let the record show you have also an arxiv paper on
>> this: http://arxiv.org/abs/1205.5691
>>
>> Btw. it has a few typos, you might want to quickly fix those now. ;-)
>> Like "however, can expensive in dimension higher than 2"
>
> Thanks for the "be". I'll do so later.
Also "dimension higher than 2" does not sound correct to me. It's the number of dimensions that is higher, not a single dimension. I would say "can be expensive for more than 2 dimensions".
- Jan Hidders