[Magictour] Re: [Magictour]

>I don't like the diagonals. They are not "mathematical" .
If we use diagonals, then I would like to use all 24 diagonals
with the board on a torus

It's called 'pandiagonal'.


>>I'm now quite strong with distributed projects, so I can handle all =
the
>>automatic tools, except for updating the index page :-)

>can't you make the participants to do it by themselves ?

No, since by experience, participants tend to start the computation =
before mailing, and also because maintaining ranges takes some time. In =
this case, there won't be a lot of tours, so we may manually assign =
them, but for example, what happens if a participant with an assigned =
tour doesn't send results after 2 weeks ?
Do you have to mail him to ask him if the computation advances, or do =
you have to wait ?
Mailing takes time, and waiting for answers too.

Another way is to assign every tour TWICE, that is to 2 different =
people, so that the computation is done at least once. This is not a =
very good approach, since the 2 people could cancel their computation, =
and it's also not very motivating.

>yes, maybe we should make it public so everybody can join ?

If you wish, you can publish a link, but I doubt that there will be tons =
of public interested in this kind of mailing list.

>did Fei Lu join ?

No, the only subscribed are: Gunter (twice with magictour and =
stertenaol), me (twice), George, Hugues and Tim.

>JC will hopefully ban the spammers

I just setup the tool so that only members can post messages.

>oops, OK. I see. So not open to everybody. We're still having secrets
>at this point ;-)

No, you can share the email address if you wish.
As I said above, we won't drain a lot of people in this kind of mailing =
list.
Also, it's for the moment a temporary list to display the progress of =
the search.

>this is an interesting field to fight the battle of human ingenuity
as demonstrated on Jelliss' pages vs. brute force computer power
as in JC's program !

>Well, the computers _must_ win one day, since they are much faster.
>But implementing complicated and intelligent algorithms to perform
>the tasks could be more difficult than to prove or search directly
>by human power !

Yes, a typical example is the 8x12 tour. Searching that with a computer =
can require some time !

>On the other hand current computer calculations seem pretty useless
>on a historic scale as long as computers are getting ever faster.
>Just waiting 2 years halfs the effort ! And what's two years compared
>to the timescale of magic knight tour's history.

>Probably a cooperation human+computer is most promising :
>Design some partial-tour and the check by computer whether it can be =
completed.

My intention if we attack the 12x12 is to build a list of all 12 or so =
first moves, and distribute them via a PHP interface. Everything can be =
done automatically, but of course, I have to write some code to make it =
run.
How will that work ?
Simply, the program will connect to http://magictour.free.fr/assign.php =
with some parameters, get back an HTML page and will extract the =
computations to do. When a computation is done, the same page is called =
with parameters to register the tour, and get a new one.
It's very easy to maintain, but no code is ready yet (I have to write a =
PHP program, plus the client server to connect to the page, etc...).
2 years ago, I thought this task was impossible to do, and now, I find =
it quite easy to code :-)

>Also, it may be interesting that you ask for an update of the =
mathematical
>Bible:
>http://mathworld.wolfram.com/MagicTour.html
>
>... and make an entry in Sloane's EIS :
>0,0,0,0,0,0,0,140,0,0,0, (numer of SMKTs on an n*n-board)

>what about 3 dimensional-tours BTW. ?

Well, let's wait for George's answer :-)

BTW, since we have almost enumerated all 8x8, what is worth enumerating =
in 12x12:

- magic tour
- diagonal magic tour
- pandiagonal magic tour

Please, can you 'vote' here, so that I can start the design of the next =
project ?

Thanks !

JC



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Received on Thu Dec 04 14:24:18 2001