Re: L0 translater and runner was finished (PureProlog Project)

[Hoxide Ma]

You had gave some very useful information, then I
found   a lot of old discussions of this in the Google
archives for comp.lang.prolog.

Thank you very much for your help.


 --- Manuel Carro <address@hidden> 的正文：
> 
> >> My question is: "What's a good way to do
> occur-check?".
> 
>     Good question.  Most Prolog systems do not
> implment occur-check
> unification (OCU) by default because of its cost. A
> na�ve algorithm is
> O(n^2) on the size of the terms to be unified. 
> There are however
> algorithms which implement OCU in linear time;
> (Martelli & Montanari,
> 1977) is well known, but not the only one.  The
> usually admitted
> reason why it is not more widely used is because it
> has large
> constants (i.e., its cost is T(n) = C1*n + C2, and
> C1 and C2 are very
> large, thus rendering it impractical).  However,
> some people reported
> that in real programs a good implementation does not
> slow
> implementation that much; there is information at:
> 
>
http://www.cs.kuleuven.ac.be/~dtai/projects/ALP/newsletter/feb04/nav/nettalk.html#occurs
> 
>     On the other hand, it turns that that for some
> applications one
> does not want to have occurs check: see
> http://arxiv.org/abs/cs.DS/0403028 , for example.
> 
> -- 
>
+---------------------------------------------------------------------------+
> |Manuel Carro --- Facultad de Inform�tica -- U.
> Polit�cnica de Madrid (UPM) |
> |mcarro_at_fi_dot_upm_dot_es --- Ph: +34-91336-7455
> --- FAX: +34-91336-7412 |
> |http://clip.dia.fi.upm.es/~mcarro -
> http://clip.dia.fi.upm.es/Software/Ciao|
>  

=====
A student of Math in Soochow University in China.
Intrested in Math, Python, Twisted, Prolog and .NET/MONO.

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