Sounds a lot like an approximation to "computing in the limit":
http://portal.acm.org/citation.cfm?id=1096001&coll=ACM&dl=ACM&CFID=56757886&CFTOKEN=99364084&ret=1#Fulltext
Rob
On 6/9/06, Tim Heath <[EMAIL PROTECTED]> wrote:
Is it an insane idea to have a type of heuristic for finding a solution
that says something like:
Find at least 1 solution
Spend an hour or some amount of time looking for a better solution. If
in an hour no superior solution has been found take the first solution.
The reason I like this idea is as the speed of computers go up the
heuristic will improve automatically.
Luis Quesada wrote:
> Dear Torsten,
>> I really like this approximation you propose. Of course, the
>> 'progress bar' may quick go to, say, 90% and then stay there forever
>> and eventually fall back again. Still, that's at least some feedback..
>
> Indeed the progress reported does not evolve monotonically. It is also
> true that you may get stuck at 90%. However, this might suggest that
> it is time to abort your search and have a look at the remaining 10%.
> Maybe the reason why it is so hard to determine them is a bug in the
> input data...
>
> In fact, I have found this approximation useful when dealing with
> tough CSP where finding one solution may take hours.
>
> Cheers,
> Luis
>>
>> On 08.06.2006, at 22:47, Luis Quesada wrote:
>>
>>> Well, you could consider the following approximation: to associate
>>> the status of your search with the number of variables determined
>>> so far.
>>> For this you got two options.
>>> 1. (naive) have a thread per variable that sends a message to a
>>> port when the variable has been determined:
>>> thread {Wait X} {Send P incCountOfVarsDetermined)} end
>>> The thread reading the messages will print the status when
>>> receiving the incCountOfVarsDetermined messages.
>>> 2. To keep a cell and update the contents of that cell at each
>>> distribution step with the number of variables that have been
>>> filtered out. For this you will need to write your own distributor.
>>> Have a look at
>>> http://www.mozart-oz.org/documentation/fdt/node40.html#chapter.user-
>>> defined
>>>
>>> Luis
>>>
>>> Torsten Anders wrote:
>>>
>>>> The short answer is: this is not possible unfortunately.
>>>> To realise this you would need to know the shape of your search
>>>> tree and where the solutions are in this search tree. But if you
>>>> already know that, then there is no search required anyway -- you
>>>> would just directly go to that solution.
>>>> I'm no guru, though ;-)
>>>> Best,
>>>> Torsten
>>>> On 08.06.2006, at 21:45, Tim Heath wrote:
>>>>
>>>>> Hi Oz Gurus,
>>>>>
>>>>> I want to make a kind of status bar showing how the search is
>>>>> going for csp application. Any ideas how to do that? I know if
>>>>> I look at the explorer it shows the tree as it is being
>>>>> populated. What I am not clear on is if there is a way to know
>>>>> if it is like 50% done or 75% done at any period of time
>>>>> programatically.
>>>>>
>>>>> Oz rocks!
>>>>>
>>>>> _____________________________________________________________________
>>>>> __ __________
>>>>> mozart-users mailing list
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>>>>>
>>>>>
>>>> --
>>>> Torsten Anders
>>>> Sonic Arts Research Centre • Queen's University Belfast
>>>> Frankstr. 49 • D-50996 Köln
>>>> Tel: +49-221-3980750
>>>> www.torsten-anders.de
>>>> strasheela.sourceforge.net
>>>
>>>
>>> _______________________________________________________________________
>>> __________
>>> mozart-users mailing list
>>> [email protected]
>>> http://www.mozart-oz.org/mailman/listinfo/mozart-users
>>>
>>>
>> --
>> Torsten Anders
>> Sonic Arts Research Centre • Queen's University Belfast
>> Frankstr. 49 • D-50996 Köln
>> Tel: +49-221-3980750
>> www.torsten-anders.de
>> strasheela.sourceforge.net
>>
>>
>
>
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