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next singular extension test
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Robert Hyatt



Joined: 27 Feb 2006
Posts: 20340
Location: Birmingham, AL

PostPost subject: next singular extension test    Posted: Thu Aug 05, 2010 4:01 am Reply to topic Reply with quote

This is using some code dated 1999, so a bit old. Here's the idea. After the usual stuff in search, before getting into the main loop where I extract the next move, make it, recursively call search, etc... I call a function "SearchSingular()" What it does is search the complete move list, using the normal reduction/extension (except no singular extensions since that would be a never-ending recursive loop) logic, to depth / 2 (for first tests) using an offset null-window of alpha - SINGULAR_MARGIN.

If more than one move fails high on this search, I immediately abandon the search and return(false). If I search 4 moves (currently) without any fail high, I quit and also return(false) (this is a condition that suggests we are at an ALL node where a singular move is not easy to identify).

If I get thru all the moves with just one fail-high on that downward-offset window, that move is flagged as singular, and when it is searched in the normal search, it gets extended by one ply (if no check extension is done).

I am currently not doing this test if I am in check, although I might revise that as testing proceeds. I also do not do it too close to the tips either. I plan the following tests (first two already queued up)...

(1) vary the singular margin between 30 and 100.

(2) vary the depth limit from 4 to 9.

(3) vary the SE search depth (depth of search used to identify that the move is singular). I currently search to whatever remaining depth is divided by 2, but this needs testing as well.

I don't want to get 2/3 running until I get some idea about the best value for the margin, so I am waiting on that to give me some guidance.

I'll post an exact description if this seems to work. I noticed that the date on this file (most of my c files have a "/* last modified xx/yy/zz */" at the front) was 1999. Search depths and speeds were _far_ lower than today, so that this might do something better than what it did in 1999 when I scrapped it. Bruce seemed to like this so maybe he found a better tuning setup than I did. When I explained this previously, I had forgotten some of the details I gave above. But I had to tweak it to fit the current search which has changed a bit from 1999, and discovered a few things that made me think "Hmmm. forgot about that. Some pretty bright guy must have thought of that..." Smile
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Subject Author Date/Time
next singular extension test Robert Hyatt Thu Aug 05, 2010 4:01 am
      Re: next singular extension test Robert Hyatt Thu Aug 05, 2010 4:36 am
      Re: next singular extension test Joona Kiiski Thu Aug 05, 2010 5:27 am
            Re: next singular extension test Robert Hyatt Thu Aug 05, 2010 2:22 pm
                  Re: next singular extension test Joona Kiiski Thu Aug 05, 2010 8:38 pm
                        Re: next singular extension test Robert Hyatt Thu Aug 05, 2010 8:43 pm
                              Re: next singular extension test Joona Kiiski Fri Aug 06, 2010 4:06 pm
                                    Re: next singular extension test Robert Hyatt Fri Aug 06, 2010 7:08 pm
                                          Re: next singular extension test Marco Costalba Fri Aug 06, 2010 7:13 pm
                                                Re: next singular extension test Robert Hyatt Fri Aug 06, 2010 8:15 pm
                                          Re: next singular extension test Joona Kiiski Fri Aug 06, 2010 7:30 pm
                                                Re: next singular extension test Robert Hyatt Fri Aug 06, 2010 8:21 pm
                                    Re: next singular extension test Ralph Stoesser Fri Aug 06, 2010 7:49 pm
                                          Re: next singular extension test Joona Kiiski Fri Aug 06, 2010 8:03 pm
                                                Re: next singular extension test Marco Costalba Fri Aug 06, 2010 8:11 pm
                                                      Re: next singular extension test Robert Hyatt Fri Aug 06, 2010 8:23 pm
                                                            Re: next singular extension test Marco Costalba Fri Aug 06, 2010 8:33 pm
                                                                  Re: next singular extension test Robert Hyatt Fri Aug 06, 2010 9:44 pm
                                                      Re: next singular extension test Ralph Stoesser Sat Aug 07, 2010 1:49 pm
                                                            Re: next singular extension test Ralph Stoesser Sun Aug 08, 2010 11:50 am
                                                                  Re: next singular extension test Marco Costalba Sun Aug 08, 2010 5:18 pm
                                                                        Re: next singular extension test Ralph Stoesser Sun Aug 08, 2010 10:04 pm
                                                                              Re: next singular extension test Marco Costalba Mon Aug 09, 2010 7:24 am
                                                                                    Re: next singular extension test Ralph Stoesser Thu Aug 12, 2010 7:23 am
                                                                                          Re: next singular extension test Marco Costalba Fri Aug 20, 2010 7:22 pm
                                                                                          Re: next singular extension test Ralph Stoesser Fri Aug 20, 2010 7:33 pm
                                                                                          Re: next singular extension test Marco Costalba Fri Aug 20, 2010 7:40 pm
                                                                                          Re: next singular extension test Ralph Stoesser Fri Aug 20, 2010 8:05 pm
                                                Re: next singular extension test Ralph Stoesser Fri Aug 06, 2010 9:08 pm
      Re: next singular extension test Volker Böhm Thu Aug 05, 2010 11:43 am
            Re: next singular extension test Robert Hyatt Thu Aug 05, 2010 2:25 pm
                  Re: next singular extension test Volker Böhm Mon Aug 09, 2010 7:39 am
                        Re: next singular extension test Marco Costalba Mon Aug 09, 2010 7:55 am
                              Re: next singular extension test Volker Böhm Mon Aug 09, 2010 11:26 am
                        Re: next singular extension test Robert Hyatt Mon Aug 09, 2010 5:06 pm
      Re: next singular extension test Robert Hyatt Sat Aug 07, 2010 2:37 pm
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