Illegal moves 2 #8
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When I paste the commands shown in the debug log, the issue doesn't reproduce, so I'm not immediately sure what's causing the issue. Which exact binary are you using? |
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Ignore that, I'm now able to reproduce. I understand the problem and will work on getting a fix. |
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The 64-bit (POPCNT) one, CRC-32: 5E1414A5. I just retested with Hash sizes 256, 128 and the default 32. Same illegal move a1a1 in every case. edit: Ah, I've been ninja'd. ;) Standing by for the fix. |
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I rolled out something I believe should fix the issue. I'm not 100% confident in the robustness of the patch, so I'll look into it more when I get some time. If this doesn't fix it, I know how to do so. |
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Need a Makefile for Windows, something that would work with MSYS2 and Cygwin. Tried making my own and got tons of errors. |
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I was planning on adding a Makefile at some point, but for me copying and pasting the compilation works fine. |
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The new exec (CRC-32 388D09A3) doesn't fix it. Besides the usual 40/4 and 512 hash I tried 40/20 and 32 hash, same result (a1a1). |
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Ditto for apollopocnt.exe CRC-32 165E3B63. |
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Interesting. I'll take a look at it in the morning. Thank you very much for being patient with me and for reporting this bug. |
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No problemo. An interesting find: if you start the game from the position where it wants to play a1a1, it chooses to play the queen back to d1 and the game goes on: Debug log: On another positive note, I don't see any more crashes under Cute Chess. It does crash under Fritz 16 GUI, will make a separate issue for that. |
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The heart of the issue is that apollo checks if the current position is a repetition, and if so, it returns to cut down on the search time. The problem is apollo previously checked if there was a transposition table entry for the current position, and if so it returned. When outputting the best move, however, apollo uses a triangular pv array. The array was never filled in that case. I just threw together a fix to fill the pv array in this case, however I'd like to look more deeply at this issue and related ideas to make sure I didn't miss anything when I get more time. Could you confirm that the new patch(binarys under release 1.2.1 also updated) fixes this issue? |
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Great, now it's fixed. There only remains a slight issue of nodes, NPS and time all displayed as zeroes for every iteration of the very last move (4.Qd1). |
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Another example found, possibly unrelated to those reported previously. It took 80 games to surface. It would also appear that v1.21 is considerably stronger than v1.1. That's probably not a bug. |
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Still looking at this, not easily reproduced by me. Just settings up the last position and running a search didn't output that move for me, so my best guess is it's an issue with the transposition table. |
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Another example, this one at LTC and involving an e.p capture: Out of 672 games 27 ended in abnormal terminations:
Clearly there's some debugging still to be done. :> |
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Curiously, all five disconnects occurred when 160 moves have been completed for both sides, with Apollo playing black. Another game ended after 159 moves in a stalled connection. Apparently Apollo cannot last longer than four 40-move playing sessions. |
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And now for something different -- Apollo achieves a completely winning position (mate in 6) and its eval goes completely haywire. 30 moves later the game ends in an illegal move. |
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TheBlackPlague/StockNemo#10 - I am developing my own chess engine, StockNemo. Is the lack of ELO on Apollo's part because of that? StockNemo shouldn't be 2K ELO right now (AB-Search, MVVLVA/Promotion Move Ordering, Mate Distance Pruning, Draw Pruning, Transposition Table, Material + PSQT Evaluation, QSearch, Null Move Pruning) ... what are your thoughts? |
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This is a continuation of #7 .
The good news: the Hash option now works as expected.
The bad news: illegal moves are still there.
Debug log:
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