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Subject: Re: Mate in 1 - but Fritz 6 needs 1 hour!!!

Author: Robert Hyatt

Date: 09:12:38 08/14/00

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On August 14, 2000 at 09:39:51, Ed Schröder wrote:

>On August 14, 2000 at 09:27:09, Robert Hyatt wrote:
>
>>On August 13, 2000 at 16:47:33, Ed Schröder wrote:
>>
>>>On August 13, 2000 at 05:23:42, Colin Frayn wrote:
>>>
>>>>On August 13, 2000 at 05:17:29, Colin Frayn wrote:
>>>>
>>>>>Take this position for example;
>>>>>
>>>>>[D]4Q3/2p3p1/7p/p1k1B3/2p1P2P/2P3P1/1r2q3/6K1 w - -
>>>>>
>>>>>which ColChess searches *fully* to depth 13 ply in just over 3 seconds on my
>>>>>p3-450.  It is a mate in 9.  Crafty sees the mate quite early because of its
>>>>>advanced extensions, but after 30 seconds had still only just reached 11 ply in
>>>>>its search.  There are probably better examples where Crafty can't see the mate,
>>>>>and I unfortunately can't remember the board setup before this position, which I
>>>>>know to be one of them.
>>>>
>>>>OK I found the game.  This is one position.  Unfortunately Crafty again sees the
>>>>mate using its impressive extension code, but ColChess manages to search 18 full
>>>>ply *completely* plus seeing the mate immediately at 19 ply in 46.7 seconds.
>>>>After this time, Crafty has just started searching the 13th ply.  See how Faile
>>>>does.
>>>>
>>>>[D]6Q1/2p3p1/5k1p/p3n3/2pBP2P/2P3P1/1r2q3/6K1 w - -
>>>>
>>>>Qf8+ is mate in 12.
>>>>
>>>>Cheers,
>>>>Col
>>>
>>>There are other (cheap) ways. Rebel handles these cases in Q-search.
>>>
>>>00:00:00  04.00  Mate in 12 moves  1.Qf8+ Ke6 2.Qe8+ Kd6 3.Bxe5+ Kc5
>>>
>>>Ed
>>
>>
>>This would make an interesting discussion.  Here is my output on a pretty slow
>>PII/400 notebook:
>>
>>         nss  depth   time  score   variation (1)
>>                1     0.00  -7.46   1. Qd5
>>                1     0.01     ++   1. Bxe5+!!
>>                1     0.01  -6.07   1. Bxe5+ Kxe5 2. Qxg7+ Kxe4 3. Qxh6
>>                1->   0.02  -6.07   1. Bxe5+ Kxe5 2. Qxg7+ Kxe4 3. Qxh6
>>                2     0.03  -6.02   1. Bxe5+ Kxe5 2. Qd5+ Kf6 3. Qf5+ Ke7
>>                                    4. Qxa5 Qxe4 5. Qxc7+
>>                2     0.03     ++   1. Qf8+!!
>>                2     0.04  -4.15   1. Qf8+ Ke6 2. Qe8+ Kd6 3. Qxe5+
>>                2->   0.05  -4.15   1. Qf8+ Ke6 2. Qe8+ Kd6 3. Qxe5+
>>                3     0.05     ++   1. Qf8+!!
>>                3     0.06  -2.83   1. Qf8+ Ke6 2. Qe8+ Kd6 3. Qxe5+ Kd7
>>                                    4. Qxa5
>>                3->   0.09  -2.83   1. Qf8+ Ke6 2. Qe8+ Kd6 3. Qxe5+ Kd7
>>                                    4. Qxa5
>>                4     0.09     ++   1. Qf8+!!
>>                4     0.11   0.00   1. Qf8+ Ke6 2. Qe8+ Kd6 3. Bxe5+ Kc5
>>                                    4. Bd4+ Kd6 5. Be5+
>>                4->   0.14   0.00   1. Qf8+ Ke6 2. Qe8+ Kd6 3. Bxe5+ Kc5
>>                                    4. Bd4+ Kd6 5. Be5+
>>                5     0.17   0.00   1. Qf8+ Ke6 2. Qe8+ Kd6 3. Bxe5+ Kc5
>>                                    4. Bd4+ Kd6 5. Be5+
>>                5->   0.23   0.00   1. Qf8+ Ke6 2. Qe8+ Kd6 3. Bxe5+ Kc5
>>                                    4. Bd4+ Kd6 5. Be5+
>>                6     0.29   0.00   1. Qf8+ Ke6 2. Qe8+ Kd6 3. Bxe5+ Kc5
>>                                    4. Bd4+ Kd6 5. Be5+
>>                6->   0.42   0.00   1. Qf8+ Ke6 2. Qe8+ Kd6 3. Bxe5+ Kc5
>>                                    4. Bd4+ Kd6 5. Be5+
>>                7     0.57   0.00   1. Qf8+ Ke6 2. Qe8+ Kd6 3. Bxe5+ Kc5
>>                                    4. Bd4+ Kd6 5. Be5+
>>                7->   0.81   0.00   1. Qf8+ Ke6 2. Qe8+ Kd6 3. Bxe5+ Kc5
>>                                    4. Bd4+ Kd6 5. Be5+
>>                8     1.25   0.00   1. Qf8+ Ke6 2. Qe8+ Kd6 3. Bxe5+ Kc5
>>                                    4. Bd4+ Kd6 5. Be5+
>>                8->   1.73   0.00   1. Qf8+ Ke6 2. Qe8+ Kd6 3. Bxe5+ Kc5
>>                                    4. Bd4+ Kd6 5. Be5+
>>                9     1.93     ++   1. Qf8+!!
>>                9     2.60  Mat12   1. Qf8+ Ke6 2. Qe8+ Kd6 3. Bxe5+ Kc5
>>                                    4. Bd4+ Kd6 5. Qd8+ Ke6 6. Qd5+ Ke7
>>                                    7. Bc5+ Ke8 8. Qe6+ Kd8 9. Be7+ Ke8
>>                                    10. Bf6+ Kf8 11. Qe7+ Kg8 12. Qxg7#
>>                9->   3.50  Mat12   1. Qf8+ Ke6 2. Qe8+ Kd6 3. Bxe5+ Kc5
>>                                    4. Bd4+ Kd6 5. Qd8+ Ke6 6. Qd5+ Ke7
>>                                    7. Bc5+ Ke8 8. Qe6+ Kd8 9. Be7+ Ke8
>>                                    10. Bf6+ Kf8 11. Qe7+ Kg8 12. Qxg7#
>>               10     5.00  Mat12   1. Qf8+ Ke6 2. Qe8+ Kd6 3. Bxe5+ Kc5
>>                                    4. Bd4+ Kd6 5. Qd8+ Ke6 6. Qd5+ Ke7
>>                                    7. Bc5+ Ke8 8. Qe6+ Kd8 9. Be7+ Ke8
>>                                    10. Bf6+ Kf8 11. Qe7+ Kg8 12. Qxg7#
>>               10->   6.66  Mat12   1. Qf8+ Ke6 2. Qe8+ Kd6 3. Bxe5+ Kc5
>>                                    4. Bd4+ Kd6 5. Qd8+ Ke6 6. Qd5+ Ke7
>>                                    7. Bc5+ Ke8 8. Qe6+ Kd8 9. Be7+ Ke8
>>                                    10. Bf6+ Kf8 11. Qe7+ Kg8 12. Qxg7#
>>               11     9.88  Mat12   1. Qf8+ Ke6 2. Qe8+ Kd6 3. Bxe5+ Kc5
>>                                    4. Bd4+ Kd6 5. Qd8+ Ke6 6. Qd5+ Ke7
>>                                    7. Bc5+ Ke8 8. Qe6+ Kd8 9. Be7+ Ke8
>>                                    10. Bf6+ Kf8 11. Qe7+ Kg8 12. Qxg7#
>>               11->  13.05  Mat12   1. Qf8+ Ke6 2. Qe8+ Kd6 3. Bxe5+ Kc5
>>                                    4. Bd4+ Kd6 5. Qd8+ Ke6 6. Qd5+ Ke7
>>                                    7. Bc5+ Ke8 8. Qe6+ Kd8 9. Be7+ Ke8
>>                                    10. Bf6+ Kf8 11. Qe7+ Kg8 12. Qxg7#
>>               12    20.79  Mat12   1. Qf8+ Ke6 2. Qe8+ Kd6 3. Bxe5+ Kc5
>>                                    4. Bd4+ Kd6 5. Qd8+ Ke6 6. Qd5+ Ke7
>>                                    7. Bc5+ Ke8 8. Qe6+ Kd8 9. Be7+ Ke8
>>                                    10. Bf6+ Kf8 11. Qe7+ Kg8 12. Qxg7#
>>
>>
>>IE it takes me twice as much depth as you to see this, but 1/2 the time,
>>although I don't know what kind of hardware you are using.  For comparison,
>>my quad xeon took .17 seconds...
>
>I can't tell how much time it did as I don't maintain milliseconds. The
>total number of nodes is 12.915 and that's hard to beat I guess.
>
>Ed

Yes it is.  Although Cray Blitz solves it instantly, it is helped by several
things.  Singular extensions.  Checks in the q-search.  Etc.  But in other
positions, it gets bogged down while crafty zips right thru iteration after
iteration.

I'm not sure which way is better.  But I do like simplicity.  And Cray Blitz
definitely wasn't "simplicity".



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