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WAC.163: 662 node search tree
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Steven Edwards



Joined: 13 Mar 2006
Posts: 3073
Location: Mud, Bugs, and Taxes, NH, USA
PostPost subject: Re: WAC.163: 662 node search tree    Posted: Tue May 01, 2007 6:37 pm Reply to topic Reply with quote
Pradu wrote:
Search algorithm looks very alpha-betaish eg attacker/defender. The implementation of attack and defense metrics will be rather interesting though.

Well, there aren't any position scores, so there's no alpha and beta. And there isn't any real symmetry, as threats are generated via global selection while refutations are generated along a single variation. Each side has a different search, and both are best first and not depth first.

The attack and defense do take turns as they would in a traditional A/B searcher. But there's no particular "current position" or "current expectation window."

--------

I took another look at the first cut source and plenty of omissions have come to light, including the lack of draw recognition other than stalemates. All draws are correctly marked when a node is generated and inserted into the tree, but the metrics productions don't use this data at the present. The same can be said for a lot of other attributes, so there's lots of room for improvement here.

Somewhat annoyingly, the PV returned by the mate search is almost always not the theoretically best PV but rather a PV with suboptimal moves. It turns out that both sides tend to try the worst moves last, and this is what comes back as a result. It doesn't matter too much for actual play as the attacker's first move in the final result is always correct in the sense that it leads to some forced mate, if not the fastest one.
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Subject Author Date/Time
WAC.163: 662 node search tree Steven Edwards Tue May 01, 2007 4:04 am
      Re: WAC.163: 662 node search tree Pradu Kannan Tue May 01, 2007 5:40 am
            Re: WAC.163: 662 node search tree Steven Edwards Tue May 01, 2007 11:25 am
                  Re: WAC.163: 662 node search tree Pradu Kannan Tue May 01, 2007 3:32 pm
                        Re: WAC.163: 662 node search tree Steven Edwards Tue May 01, 2007 6:37 pm
                              Re: WAC.163: 662 node search tree Tony Wed May 02, 2007 6:27 am
                                    Re: WAC.163: 662 node search tree Steven Edwards Wed May 02, 2007 10:36 am
      Re: WAC.163: 662 node search tree Dann Corbit Tue May 01, 2007 6:19 am
            Re: WAC.163: 662 node search tree Steven Edwards Tue May 01, 2007 11:27 am
                  Re: WAC.163: 662 node search tree Dann Corbit Tue May 01, 2007 10:18 pm
                        Re: WAC.163: 662 node search tree Steven Edwards Tue May 01, 2007 11:59 pm
                              Re: WAC.163: 662 node search tree Slater Wed May 02, 2007 12:46 am
                              Re: WAC.163: 662 node search tree Pradu Kannan Wed May 02, 2007 1:18 am
            Re: WAC.163: 662 node search tree Steve Maughan Tue May 01, 2007 11:33 pm
                  Re: WAC.163: 662 node search tree Steven Edwards Wed May 02, 2007 12:39 am
                        Re: WAC.163: 662 node search tree Steve Maughan Wed May 02, 2007 12:44 am
                              Re: WAC.163: 662 node search tree Steven Edwards Wed May 02, 2007 1:19 am
                                    Re: WAC.163: 662 node search tree Steven Edwards Thu May 03, 2007 9:00 pm
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