Author: Omid David
Date: 10:55:00 10/05/02
Go up one level in this thread
On October 05, 2002 at 12:21:38, Heiner Marxen wrote: >On October 04, 2002 at 19:32:30, Omid David wrote: > >>On October 04, 2002 at 19:09:22, Jeremiah Penery wrote: >> >>>On October 04, 2002 at 18:06:21, Omid David wrote: >>> >>>>On October 04, 2002 at 17:27:05, Jeremiah Penery wrote: >>>> >>>>>On October 04, 2002 at 16:51:38, Roy Eassa wrote: >>>>> >>>>>>On October 03, 2002 at 19:18:16, Jeremiah Penery wrote: >>>>>> >>>>>>>[D]8/7p/6pP/k4pP1/b1p1pP2/KpPpP3/1P1P4/7Q w - - 0 1 >>> >>>>No blockade-detecting algorithm should announce a draw in this position, since >>>>the blockade can be "broken". And I think there might be a victory for white >>>>hidden: >>>> >>>> >>>>1.Qd1 >>>> >>>>A) 1... Kb5 >>>> 2.Qh5 >>>> i) 2... gxh5 >>>> 3.g6 hxg6 4.h7 white winning >>>> ii) 2... Ka5 >>>> 3.Qxg6 hxg6 4.h7 white winning >>>>B) 1...Bc6 (or any other bishop move) >>>> 2. Qxb3 cxb3 3.Kxb3 unclear situation >>> >>>My reasoning is that it's way harder to detect a blockade by search than it is >>>to detect a winning line in some "blockaded" positions. In this position, if >>>Qd1 Bc6 Qxb3 etc. is winning for white, the search will find it pretty quickly. >>>However, without detecting this as a blockade, the program will NEVER detect the >>>draw, and it will shuffle the pieces around forever, while declaring itself >>>winning by 6 pawns or more. Either way, the end result will be a draw. >>> >>>My 'algorithm' is a pretty simple thing. I just wanted it to be fast, and not >>>miss any cases, though I didn't care too much for false cases (because of the >>>above). Unless my thing is 100% correct, and never misses any potential >>>blockade draws, there will be error anyway (without the algorithm, you will say >>>+6 in the position above, and many similar positions, though it is a draw - with >>>the incorrect algorithm, you may say draw in some winning position). >>> >>>If there are cases where my stuff is completely and totally wrong, I will try to >>>fix it. Otherwise, I'll take some inaccuracy and be reasonably happy that it >>>works most of the time. >> >>Your perspective is really interesting, which allows a certain amounts of >>"unharmful" inaccuracies. >> >>My method on the other hand, refrains from declaring a draw, even if it's 99.99% >>sure that it actually is. Anything less than 100.00% accuracy, and the returned >>answer will be "I don't know!" > >Now, that is quite an interesting proporty, since it could be used in a >mate finder/prover like Chest. I'm interested to see your source code! >From your web site I see that you do this as your MSc. Any chance that >your source will be available sometime? We are still working on this blockade-detection algorithm to manage to detect more blockade positions, with greater efficiency. After the work is concluded (hopefully in a few months), it will be published (most probably through ICGA). And this, among other innovations we are currently working on. The first article of which is ready, and will soon be published as a Technical Report in a week or two, and will be submitted to the ICGA shortly afterwards. Omid. > >Cheers, >Heiner
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