A.L. <l...@a...com> napisał(a):

> On Tue, 31 Jan 2012 04:09:51 +0100, bartekltg <b...@g...com>
> wrote:
>
> >W dniu 2012-01-30 10:43, f...@g...pl pisze:
> >
> >>
> >> szczerze mowiac to malo zajmuje sie matematyka i np
> >> nie bardzo podzielam co poniektorych tutaj zainteresowania
> >> tymi tematami obecnie - nie chce za bardzo skakac po
> >> tematach z mat phys, ew interesuje mnie kwestia symulacji
> >
> >Ale informatyka poważniejsza niż tradycyjnie wspominana
> >"baza gumowców" to matematyka.
> >
> >> algorytmy to tak naprawde matematyka, bo akurat te ktore
> >> znam - sortowania czy A* to mz wogole nie matematyka
> >
>
> fir siedzi u mnie w KF, ale ubawil mnie jego post na temat tego ze A*
> to nei matematyka. Polecam mu wiec ksiazke Judea Perl, Heuristics:
> Intelligent Search Strategies for Computer Problem Solving, stron 360,
> poswiecona w calosci matematyce A*
>
> a gdyby mu sie nie chcialo siegac do ksiazki, to moze siegnac do tego
> artykulu
>
> http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.
1.1.89.3090
>
> Generalized best-first search strategies and the optimality of A*
>
> Abstract
> This paper reports several properties of heuristic best-first search
> strategies whose scoring functions f depend on all the information
> available from each candidate path, not merely on the current cost g
> and the estimated completion cost h. It is shown that several known
> properties of A * retain their form (with the minmax offplaying the
> role of the optimal cost), which helps establish general tests of
> admissibility and general conditions for node expansion for these
> strategies. On the basis of this framework the computational
> optimality of A*, in the sense of never expanding a node that can be
> skipped by some other algorithm having access to the same heuristic
> information that A* uses, is examined. A hierarchy of four optimality
> types is defined and three classes of algorithms and four domains of
> problem instances are considered. Computational performances relative
> to these algorithms and domains are appraised. For each class-domain
> combination, we then identify the strongest type of optimality that
> exists and the algorithm for achieving it. The main results of this
> paper relate to the class of algorithms that, like A*, return optimal
> solutions (i.e., admissible) when all cost estimates are optimistic
> (i.e., h 5 h*). On this class, A * is shown to be not optimal and it
> is also shown that no optimal algorithm exists, but if the performance
> tests are confirmed to cases in which the estimates are also
> consistent, then A * is indeed optimal. Additionally, A * is also
> shown to be optimal over a subset of the latter class containing all
> best-first algorithms that are guided by path-dependent evaluation
> functions.
>
> Z grubsza dotyczy zbieznosci algorytmu przy roznego rodzaju
> oslabionych zalozeniach wzgledem heurystyk
>

potwierdzam swoja uwage ze przynajmniej te algorytmy ktore znam
i uzywalem (a a bylo ich ledwie kilka) to nie byla matematyka
tylko cos co nazwal bym 'klockotyką'






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