Does it cover all the possibilities? Has someone done a better one already? Any suggested changes?
[d]r3k2r/1bp2pP1/5n2/1P1Q4/1pPq4/5N2/1B1P2p1/R3K2R b KQkq c3 0 1
Thanks
Contrived position for perft
Moderators: hgm, Rebel, chrisw
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Contrived position for perft
If you are on a sidewalk and the covid goes beep beep
Just step aside or you might have a bit of heat
Covid covid runs through the town all day
Can the people ever change their ways
Sherwin the covid's after you
Sherwin if it catches you you're through
Just step aside or you might have a bit of heat
Covid covid runs through the town all day
Can the people ever change their ways
Sherwin the covid's after you
Sherwin if it catches you you're through
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- Joined: Mon May 31, 2010 1:29 pm
- Full name: lucasart
Re: Contrived position for perft
nice one. pins are an important source of bugs. you should add more pins.Michael Sherwin wrote: ↑Sun Apr 21, 2019 5:10 am Does it cover all the possibilities? Has someone done a better one already? Any suggested changes?
[d]r3k2r/1bp2pP1/5n2/1P1Q4/1pPq4/5N2/1B1P2p1/R3K2R b KQkq c3 0 1
Thanks
Theory and practice sometimes clash. And when that happens, theory loses. Every single time.
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Re: Contrived position for perft
Bed time, I will work on that tomorrow!lucasart wrote: ↑Sun Apr 21, 2019 7:12 amnice one. pins are an important source of bugs. you should add more pins.Michael Sherwin wrote: ↑Sun Apr 21, 2019 5:10 am Does it cover all the possibilities? Has someone done a better one already? Any suggested changes?
[d]r3k2r/1bp2pP1/5n2/1P1Q4/1pPq4/5N2/1B1P2p1/R3K2R b KQkq c3 0 1
Thanks
If you are on a sidewalk and the covid goes beep beep
Just step aside or you might have a bit of heat
Covid covid runs through the town all day
Can the people ever change their ways
Sherwin the covid's after you
Sherwin if it catches you you're through
Just step aside or you might have a bit of heat
Covid covid runs through the town all day
Can the people ever change their ways
Sherwin the covid's after you
Sherwin if it catches you you're through
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- Joined: Sat Mar 02, 2013 11:31 pm
Re: Contrived position for perft
Sapeli says:
./sapeli -position fen r3k2r/1bp2pP1/5n2/1P1Q4/1pPq4/5N2/1B1P2p1/R3K2R b KQkq c3 0 1 -perft 6
depth 0 nodes 1 mnps 0.000 time 0.000
depth 1 nodes 60 mnps 0.000 time 0.000
depth 2 nodes 2608 mnps 0.000 time 0.000
depth 3 nodes 113742 mnps 14.218 time 0.008
depth 4 nodes 4812099 mnps 13.256 time 0.363
depth 5 nodes 202902054 mnps 13.964 time 14.530
###
nodes 207830564 mnps 14.304 time 14.530
./sapeli -position fen r3k2r/1bp2pP1/5n2/1P1Q4/1pPq4/5N2/1B1P2p1/R3K2R b KQkq c3 0 1 -perft 6
depth 0 nodes 1 mnps 0.000 time 0.000
depth 1 nodes 60 mnps 0.000 time 0.000
depth 2 nodes 2608 mnps 0.000 time 0.000
depth 3 nodes 113742 mnps 14.218 time 0.008
depth 4 nodes 4812099 mnps 13.256 time 0.363
depth 5 nodes 202902054 mnps 13.964 time 14.530
###
nodes 207830564 mnps 14.304 time 14.530
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Re: Contrived position for perft
How aboud this?Michael Sherwin wrote: ↑Sun Apr 21, 2019 8:29 amBed time, I will work on that tomorrow!lucasart wrote: ↑Sun Apr 21, 2019 7:12 amnice one. pins are an important source of bugs. you should add more pins.Michael Sherwin wrote: ↑Sun Apr 21, 2019 5:10 am Does it cover all the possibilities? Has someone done a better one already? Any suggested changes?
[d]r3k2r/1bp2pP1/5n2/1P1Q4/1pPq4/5N2/1B1P2p1/R3K2R b KQkq c3 0 1
Thanks
[D] r6r/1bp2pP1/R2qkn2/1P6/1pPQ4/1B3N2/1B1P2p1/4K2R b KQ c3 0
It adds pins of the 2 possible kinds:
* the normal pin, where from->to causes self-check through the vacated from square.
* the en-passant special case, where from->to causes self-check, through the square vacated by the captured enemy pawn.
There is actually a third kind of pin, but that only happens in Chess960. It's when you can't castle, because the castling rook is pinned.
Theory and practice sometimes clash. And when that happens, theory loses. Every single time.
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Re: Contrived position for perft
[d]r3k2r/1bp2pP1/5n2/1P1Q4/1pPq4/5N2/1B1P2p1/R1R1K2R b KQkq c3 0 1Michael Sherwin wrote: ↑Sun Apr 21, 2019 5:10 am Does it cover all the possibilities? Has someone done a better one already? Any suggested changes?
After Rxa1 Rxa1 you have rook on A1 that has already moved so castling is impossible. But no rook has ever moved away from A1.
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Re: Contrived position for perft
if my engine is not wrong those are the results:
1: 60
2: 2608
3: 113742
4: 4812099
5: 202902054
6: 8419356881
1: 60
2: 2608
3: 113742
4: 4812099
5: 202902054
6: 8419356881
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- Posts: 855
- Joined: Sun May 23, 2010 1:32 pm
Re: Contrived position for perft
another possibile source of problem is the interaction of "pin" and en passant. I think this is rare but it can happen.
here an example where en passant capture is forbidden (fxe3)
[d]8/K7/8/8/2Q1Pp1k/8/8/8 b - e3 0 1
here an example where en passant capture is forbidden (fxe3)
[d]8/K7/8/8/2Q1Pp1k/8/8/8 b - e3 0 1
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Re: Contrived position for perft
Sorry, but your engine is wrong. Perft 2 of the position "r3k2r/1bp2pP1/5n2/1P1Q4/1pPq4/5N2/1B1P2p1/R1R1K2R b KQkq c3 0 1"is 2659.
Nothing is unstable (Lawrence Krauss)
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Re: Contrived position for perft
Well if you mistype the FEN and search a different position...Maarten Claessens wrote: ↑Sun Apr 21, 2019 11:31 amSorry, but your engine is wrong. Perft 2 of the position "r3k2r/1bp2pP1/5n2/1P1Q4/1pPq4/5N2/1B1P2p1/R1R1K2R b KQkq c3 0 1"is 2659.
Theory and practice sometimes clash. And when that happens, theory loses. Every single time.