perft(6) after e4 e5

[Henk]

If I run perft(6) in the position after 1. e4 e5 what should be the correct result ?

[Skipper crashes because of a short castling move after:

1 g4 e5 2 Nf3 Nf6 3 Bg2 Ng4 4 0-0
]

Or is there a website where I can run perft myself.

[zullil]

If I run perft(6) in the position after 1. e4 e5 what should be the correct result ?

My move generator says

Leaf nodes = 673070116
Time taken = 15043 ms

[SMIRF]

Code: Select all

XFEN 00: rnbqkbnr/pppp1ppp/8/4p3/4P3/8/PPPP1PPP/RNBQKBNR w KQkq - 0 2
   +-*--b--c--d--*--f--g--*-+
 8 |[r][n][b][q][k][b][n][r]|  Compiled on Feb 26 2015
 7 |[p][p][p][p]:::[p][p][p]|  MS Vis.Studio C/C++ 64-Bit Vers. 18.0
 6 |   :::   :::   :::   :::|
 5 |:::   :::   [p]   :::   |  Break, when time >= 5.0 sec
 4 |   :::   :::<P>:::   :::|
 3 |:::   :::   :::   :::   |  (run with 4-fold TT hashing)
 2 |<P><P><P><P>   <P><P><P>|
 1 |<R><N><B><Q><K><B><N><R>|
(w)+-*--b--c--d--*--f--g--*-+

Ply       Moves    all [x]   [ep]   all [+]   [++] Prom     Cstl  Time
 1:          29          0      0         0      0    0        0  0.00
 2:         835          8      0         4      0    0        0  0.00
 3:       24825        576      0       284      0    0        0  0.00
 4:      728887      23907      2     10306      1    0        0  0.02
 5:    22273312     998407    420    430046     52    0    19682  0.21
 6:   673070116   36172846  14340  14028981   3418    0   598518  2.36
 7: 21181685531 1359626731 924634 528409498 134777    0 36210043 32.84

[Henk]

If I run perft(6) in the position after 1. e4 e5 what should be the correct result ?

My move generator says

Leaf nodes = 673070116
Time taken = 15043 ms

ok. Thank you. Only 15 seconds ? Perft of skipper uses 13 minutes. But I have to rerun it and compare for I did not add an assertion in the test.

[Henk]

Code: Select all

XFEN 00: rnbqkbnr/pppp1ppp/8/4p3/4P3/8/PPPP1PPP/RNBQKBNR w KQkq - 0 2
   +-*--b--c--d--*--f--g--*-+
 8 |[r][n][b][q][k][b][n][r]|  Compiled on Feb 26 2015
 7 |[p][p][p][p]:::[p][p][p]|  MS Vis.Studio C/C++ 64-Bit Vers. 18.0
 6 |   :::   :::   :::   :::|
 5 |:::   :::   [p]   :::   |  Break, when time >= 5.0 sec
 4 |   :::   :::<P>:::   :::|
 3 |:::   :::   :::   :::   |  (run with 4-fold TT hashing)
 2 |<P><P><P><P>   <P><P><P>|
 1 |<R><N><B><Q><K><B><N><R>|
(w)+-*--b--c--d--*--f--g--*-+

Ply       Moves    all [x]   [ep]   all [+]   [++] Prom     Cstl  Time
 1:          29          0      0         0      0    0        0  0.00
 2:         835          8      0         4      0    0        0  0.00
 3:       24825        576      0       284      0    0        0  0.00
 4:      728887      23907      2     10306      1    0        0  0.02
 5:    22273312     998407    420    430046     52    0    19682  0.21
 6:   673070116   36172846  14340  14028981   3418    0   598518  2.36
 7: 21181685531 1359626731 924634 528409498 134777    0 36210043 32.84

Enough castling moves so it might be a good test.

[zullil]

Code: Select all

XFEN 00: rnbqkbnr/pppp1ppp/8/4p3/4P3/8/PPPP1PPP/RNBQKBNR w KQkq - 0 2
   +-*--b--c--d--*--f--g--*-+
 8 |[r][n][b][q][k][b][n][r]|  Compiled on Feb 26 2015
 7 |[p][p][p][p]:::[p][p][p]|  MS Vis.Studio C/C++ 64-Bit Vers. 18.0
 6 |   :::   :::   :::   :::|
 5 |:::   :::   [p]   :::   |  Break, when time >= 5.0 sec
 4 |   :::   :::<P>:::   :::|
 3 |:::   :::   :::   :::   |  (run with 4-fold TT hashing)
 2 |<P><P><P><P>   <P><P><P>|
 1 |<R><N><B><Q><K><B><N><R>|
(w)+-*--b--c--d--*--f--g--*-+

Ply       Moves    all [x]   [ep]   all [+]   [++] Prom     Cstl  Time
 1:          29          0      0         0      0    0        0  0.00
 2:         835          8      0         4      0    0        0  0.00
 3:       24825        576      0       284      0    0        0  0.00
 4:      728887      23907      2     10306      1    0        0  0.02
 5:    22273312     998407    420    430046     52    0    19682  0.21
 6:   673070116   36172846  14340  14028981   3418    0   598518  2.36
 7: 21181685531 1359626731 924634 528409498 134777    0 36210043 32.84

Enough castling moves so it might be a good test.

Is likely irrelevant, but Reinhard's FEN is incorrect. Should be

rnbqkbnr/pppp1ppp/8/4p3/4P3/8/PPPP1PPP/RNBQKBNR w KQkq e6 0 2

[SMIRF]

... Is likely irrelevant, but Reinhard's FEN is incorrect. Should be

rnbqkbnr/pppp1ppp/8/4p3/4P3/8/PPPP1PPP/RNBQKBNR w KQkq e6 0 2

As you will have noticed: it is compatible ! XFEN. There only then an e.p. coordinate is set, when an opposite pawn is standing at the side of the double stepped pawn.

[zullil]

... Is likely irrelevant, but Reinhard's FEN is incorrect. Should be

rnbqkbnr/pppp1ppp/8/4p3/4P3/8/PPPP1PPP/RNBQKBNR w KQkq e6 0 2

As you will have noticed: it is compatible ! XFEN. There only then an e.p. coordinate is set, when an opposite pawn is standing at the side of the double stepped pawn.

No, I failed to notice that. Sorry.

http://en.wikipedia.org/wiki/X-FEN#Encoding_en-passant

[jorose]

If you suspect you have a bug in move generation, I can recommend downloading the latest stockfish version and starting it in a terminal (not in a GUI). Then manually enter the position via UCI protocol and call it's perft function, which is extremely fast. The reason I suggest this is that SF actually offers the functionality of a divide function which means it gives a breakdown of perft (n-1) for each legal move when you call perft (n).

This is what I get for perft 6 after e2e4 e7e5:

Code: Select all

position startpos moves e2e4 e7e5
perft 6

Position: 1/1
a2a3: 21100966
b2b3: 23596663
c2c3: 23416950
d2d3: 25540907
f2f3: 15742641
g2g3: 23364786
h2h3: 20760629
a2a4: 24042446
b2b4: 22001165
c2c4: 20896102
d2d4: 38353660
f2f4: 24044398
g2g4: 20005227
h2h4: 24059746
b1a3: 22001586
b1c3: 24912209
g1e2: 14479984
g1f3: 20419850
g1h3: 21454237
f1e2: 19399143
f1d3: 20878923
f1c4: 26828547
f1b5: 20591524
f1a6: 22471973
d1e2: 22164322
d1f3: 34059395
d1g4: 33583821
d1h5: 27807644
e1e2: 15090672

===========================
Total time (ms) : 4158
Nodes searched  : 673070116
Nodes/second    : 161873524

[Henk]

Perft 5 and 6 both did not fail. So I have to look further. Skipper crashed when taking back rook on f1 and it said that the square is not occupied.