Search found 223 matches
- Tue May 22, 2007 10:20 am
- Forum: CCRL Public
- Topic: CCRL Blitz 40/4 is one year old!
- Replies: 2
- Views: 3453
- Thu May 03, 2007 3:53 pm
- Forum: Endgame Tablebases
- Topic: Progress in fast in-RAM EGTB building
- Replies: 19
- Views: 20881
So far I did not realize this: for the purpose of including the exact consequences of the 50-move rule, it would be necessary to maintain the DTZ in ply, rather than in moves. This would require a different treatment of BTM positions where black is checkmated, and where black is forced to make a los...
- Thu May 03, 2007 1:07 pm
- Forum: Endgame Tablebases
- Topic: Terminology
- Replies: 1
- Views: 3049
- Mon Apr 16, 2007 12:59 pm
- Forum: Endgame Tablebases
- Topic: Progress in fast in-RAM EGTB building
- Replies: 19
- Views: 20881
Perhaps it would be good to explain my approach to speeding up EGTB building. In calculating the index for accessing the TB, I avoid doing any conversions between board positions and index, and vice versa. In stead, I generate board positions from board positions, and indices from indices, in parall...
- Fri Apr 13, 2007 4:15 pm
- Forum: Endgame Tablebases
- Topic: Progress in fast in-RAM EGTB building
- Replies: 19
- Views: 20881
- Fri Apr 13, 2007 11:58 am
- Forum: Endgame Tablebases
- Topic: 6-man zugzwangs ...
- Replies: 4
- Views: 3623
So if I understand you correctly the actual EGTs generated by FEG are useless to anyone except ChessMaster, as the format is not disclosed. So people generate it only for the purpose of generating the statistics file? I was not aware of this state of affairs. This makes it all the more important to ...
- Fri Apr 13, 2007 9:35 am
- Forum: Endgame Tablebases
- Topic: 6-man zugzwangs ...
- Replies: 4
- Views: 3623
I know little about EGTB formats used by others, but why would it be difficult to extract these zugzwangs from FEG files? Is it because you have to compare the .wtm and .btm files with swapped colors, so that the indexing is completely different for opposite sides to move? If so, it seems not so awf...
- Sun Apr 01, 2007 11:11 pm
- Forum: Endgame Tablebases
- Topic: Progress in fast in-RAM EGTB building
- Replies: 19
- Views: 20881
Well, perhaps I am overdoing it. Seems KQKR does not have any stalemates at all. With non-bare black King I guess the number of stalemates will be very very low in general. So it is silly to worry about them. The nice thing about counting black's remaining non-losing moves (as negative numbers) in t...
- Wed Mar 28, 2007 4:22 pm
- Forum: Endgame Tablebases
- Topic: Progress in fast in-RAM EGTB building
- Replies: 19
- Views: 20881
OK, thanks for the references. I had to pause a few days because of the drudgery of normal life (tax declarations and such... :? ). I am currently doubting the wisdom of not counting the black conversion moves. Basically the problems I am facing are due to the fact that the WTM positions in my build...
- Wed Mar 21, 2007 11:53 am
- Forum: Endgame Tablebases
- Topic: Progress in fast in-RAM EGTB building
- Replies: 19
- Views: 20881
Marking black-in-check positions
I tried marking the positions where black is in check as won (for white with white to move) through stepping along Queen lines from the Queen square in the black King dimension, for every constellation of white pieces and the black Rook. (Doing this at a time when all the involved entries are in the...
- Tue Mar 20, 2007 4:09 pm
- Forum: Endgame Tablebases
- Topic: Progress in fast in-RAM EGTB building
- Replies: 19
- Views: 20881
Bulk counting of black moves
One of the areas where I achieved considerable speedup compared to my previous algorithm is the counting of the number of moves in each position. The availability of such a move count for the losing side can speed up the building process greatly: to determine if the precursor of a position that was ...
- Tue Mar 20, 2007 2:58 pm
- Forum: Endgame Tablebases
- Topic: Progress in fast in-RAM EGTB building
- Replies: 19
- Views: 20881
Progress in fast in-RAM EGTB building
I created this thread to post new developments in my project to write an EGTB builder that is fast enough to do its work 'behind the board' (e.g. in ponder time). Apart from the obvious advantage that this would not make an excessive demand on disk storage capacity, the real benifit occurs in end-ga...
- Mon Mar 19, 2007 10:02 am
- Forum: Endgame Tablebases
- Topic: Why is this forum so quiet?
- Replies: 19
- Views: 11933
Re: The difference between Nalimov and FEG stats
Surely it wouldn't be so difficult to extract the required statstics if you have the corresponding TB? If you have one kind of statistics you can even greatly speedup the process by just probing for the difference. Only 21 out of the 462 King-pair positions have both Kings on the dagonal, so you wou...
- Sun Mar 18, 2007 9:34 pm
- Forum: Endgame Tablebases
- Topic: Why is this forum so quiet?
- Replies: 19
- Views: 11933
Well, I am back from a great vacation, so you will hear from me soon. I came back with lots of ideas. First I had to implement those concerning my engine Joker, though, which is competing in OpenWar2, and coud use some improvement... :? Now that is done, I am going to code my latest EGTB algorithm f...
- Thu Mar 15, 2007 8:22 pm
- Forum: Endgame Tablebases
- Topic: Why is this forum so quiet?
- Replies: 19
- Views: 11933
- Wed Feb 28, 2007 11:11 am
- Forum: Endgame Tablebases
- Topic: fastest EGTB generation
- Replies: 14
- Views: 9551
OK. I will try the e-mail. My guess why escape counting was not working for Ken, while it seems to work for me, is that he was building the TB on disk rather than in memory. Redoing a calculation 4 or 5 times, even a complicated one like a one-ply search, is always much faster than a disk access, bu...
- Tue Feb 27, 2007 9:13 pm
- Forum: Endgame Tablebases
- Topic: fastest EGTB generation
- Replies: 14
- Views: 9551
The 'random' accesses are actually not very random if you design the indexing scheme properly. I use the black piece locations to derive the low-order index bit. So during potential-loss verification you sample the TB very locally, (4KB blocks for 2 black pieces, 256KB for three, nicely fitting in t...
- Tue Feb 27, 2007 12:05 pm
- Forum: Endgame Tablebases
- Topic: fastest EGTB generation
- Replies: 14
- Views: 9551
Re: EGT Generation performance
This paper, 6-Piece Endgames is in the ICCA Journal, v19.4, pp215-226 . Do you happen to have an URL for this paper? I could not find it on the web. I did find the paper by Wu and Beal, that discuss the bit-map strategy. I guess this is very similar to what I do, except that I hide the bit map as o...
- Mon Feb 26, 2007 5:31 pm
- Forum: Endgame Tablebases
- Topic: fastest EGTB generation
- Replies: 14
- Views: 9551
OK, thanks for the reference, I will have a look what Ken Thompson has to say on this. For me it so far is the fastest way I found for end-games that are predominantly won. Only in end-games that are virtually without wins it is a big waste of time to count moves in positions that you will never vis...
- Mon Feb 26, 2007 11:48 am
- Forum: Endgame Tablebases
- Topic: fastest EGTB generation
- Replies: 14
- Views: 9551
My generator experiences a large speedup as the number of won states dry up, as it then can skip all cache lines that do not contain any won states. Before I did that, a single cycle through a 5-men symmetrized TB (128MB) took at least 1.2 sec, even if there was almost nothing in it to process. Now ...
- Sun Feb 25, 2007 11:56 am
- Forum: Endgame Tablebases
- Topic: fastest EGTB generation
- Replies: 14
- Views: 9551
I calculate currently DTM. The advantage of DTC would be that I only need win/loss information on the TBs it converts to. For capture conversions it doesn't really matter, as my current algorithm automatically calculates all TBs with a subset of the pieces as well. (This is included in the quoted ti...
- Thu Feb 22, 2007 6:23 pm
- Forum: Endgame Tablebases
- Topic: fastest EGTB generation
- Replies: 14
- Views: 9551
- Tue Feb 20, 2007 4:59 pm
- Forum: Endgame Tablebases
- Topic: fastest EGTB generation
- Replies: 14
- Views: 9551
fastest EGTB generation
As I want to have my engine construct EGTBs 'behind the board' as it needs them (so that I can handle 9-10 men end-games with Pawns without needing gigabytes of pre-computed information), speed is of the utmost importance. My own EGTB generator for pieces-only, (i.e. applying 8-fold symmetry) now ge...