Author: leonid
Date: 19:44:00 08/13/01
Go up one level in this thread
On August 13, 2001 at 16:14:51, Heiner Marxen wrote:
>On August 13, 2001 at 11:53:23, leonid wrote:
>
>>Hi!
>>
>>This position is easy:
>>
>>[D]B2N1qr1/B2Qb2q/Q2Rq3/Q2Q1q2/Q2Q2q1/Q2Q3n/R2Qq2k/1KN2rq1 w - -
>
>Hello Leonid,
Hi, Heiner!
>As far as I can see, this is still the same position in your "correction"
>(i.e. you only changed the second position).
You are right. I did mistake in second position by putting one black queen on
the place of white woman.
>Well, the above is a mate in 8, according to Chest, which needed no less
>than 1.1 hours (and 350 MB hash) to find one solution:
But what was "initial speed"? I speak about 4 moves. I had the impression that
our programs went here on the same speed but I am not sure if your initial speed
is the same as mine. Time is:
Moves Time Branching factor NPS
3 0.11 sec
12.5
4 1.37 sec 82k
6.85
5 9.28 sec 110k
6.85
6 63sec 133k
8.24
7 8 min 44 126k
8 4 min 35 sec. for first mate.
Selective also found mate in 8 and this is why I said that mate is easy.
Selective took 0.5 sec.
Ho, yes, before I will forget. Position that you indicated for February and that
you have said took more that 2 seconds, I verified. On mine it took good 15
seconds to finalize 4 moves by brute force. Branching factor between 4 and 5
moves is 55. Terrible!
>PV: Qxg1+ Qxg1 Bxg1+ Rfxg1 Qxe2+ Qf2 Qee5+ Qf4 Rxf2+ R1g2 Rxg2+ Kh1 Rh2+ Kg1
>Qh1#
>
>Since all white moves are checking, your selective search should find this
>also with depth 8, already, and much faster than Chest.
>
>>Actually original position was this that I changed in order of having more
>>accessible one.
>>
>>[D]B2B1qr1/N2Qb2q/Q2Rq3/Q2Q1q2/Q2q2q1/Q2Q3n/R2Qq2k/1KN2rq1 w - -
>>
>>This last position look like very innocent, since it have initially only 93
>>moves, but take care! When I put it on one professional program, where special
>>mate solving engin was asked to do the work, response was deadly. It reacted on
>>"US" script like true fanatic from the Middle East. Beside committing
>>Selbstmord-Anschlag on the spot it killed my Windows ME as well.
>
>As is above (i.e. not corrected) Chest quite quickly finds "no mate in 8"
>(159 seconds). I did not continue this one.
>I'll followup to the corrected version there.
Second position have no mate in 8, probably you already found this on your own.
It should be between 9 and 12. I say this because it was after my mistake that
you have tried wrong position this time.
Cheers,
Leonid.
>Cheers,
>Heiner
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