You got a different result because you didn't do it correctly, is my guess.Rob wrote:I get a different result.bob wrote:wasn't extreme at all. Here's an opening position searched for 20 seconds:Michael Sherwin wrote:Bob just gave the results for one extreem example to show that there are positions that benifit hugely from the null move huristic. He was not indicating an average expectation.Uri Blass wrote:<snipped>I agree that the difference is more than one ply butbob wrote:
for 10 seconds, with null gets 16 plies in a test position, without gets 8. You can test this by using "sel=0/0" as a command to turn null-move off in Crafty...
for a 10 second limit, with null=16 plies, without = 8.
16 plies against 8 plies seem to me too big difference.
I wonder if you use the same late move reductions in both versions.
Uri
If you have a favorite position for me to run, post it, or you can do it yourself using the "sel=0/0" command to turn null move off...
15 9.58 0.32 1. e4 e6 2. Nf3 Nc6 3. d4 Nf6 4. Bd3
Bb4+ 5. c3 Be7 6. O-O O-O 7. e5 Nd5
8. Qc2 f5
15-> 10.39 0.32 1. e4 e6 2. Nf3 Nc6 3. d4 Nf6 4. Bd3
Bb4+ 5. c3 Be7 6. O-O O-O 7. e5 Nd5
8. Qc2 f5
time=20.20 mat=0 n=32392436 fh=89% nps=1.6M
9 9.13 0.20 1. e4 Nc6 2. d4 Nf6 3. d5 Ne5 4. Nf3
d6 5. Nxe5 dxe5
9-> 11.59 0.20 1. e4 Nc6 2. d4 Nf6 3. d5 Ne5 4. Nf3
d6 5. Nxe5 dxe5
time=20.33 mat=0 n=27355629 fh=84% nps=1.3M
So 9 plies to 15 plies in the same time, from the initial opening position...
Crafty 21.6
On slow computer without null move:
11 18.71 0.23 1. e4 Nc6 2. Nc3 Nf6 3. Nf3 e6 4. d4
d5 5. Qd3 Bb4 6. e5
11-> 33.96 0.23 1. e4 Nc6 2. Nc3 Nf6 3. Nf3 e6 4. d4
d5 5. Qd3 Bb4 6. e5
12 48.56 0.20 1. e4 Nc6 2. Nc3 Nf6 3. Nf3 e6 4. d4
Bb4 5. Qd3 d5 6. e5 Ne4 <HT>
12-> 1:26 0.20 1. e4 Nc6 2. Nc3 Nf6 3. Nf3 e6 4. d4
Bb4 5. Qd3 d5 6. e5 Ne4 <HT>
13 4:01 0.23 1. e4 e6 2. Nf3 Nc6 3. Nc3 d5 4. exd5
exd5 5. Bb5 Qe7+ <HT>
time=5:00 mat=0 n=31563160 fh=94% nps=104K
ext-> check=718K 1rep=44K mate=0 pp=0 reduce=22.0M/2.2M
predicted=0 evals=24.4M 50move=0 EGTBprobes=0 hits=0
hashing-> 25%(raw) 24%(draftOK) 99%(saturation)
hashing-> 0%(exact) 21%(lower) 0%(upper)
SMP-> splits=0 aborts=0 data=0/256 elap=5:00
With nullmove:
13-> 53.32 0.37 1. e4 e5 2. Nc3 Nc6 3. Nf3 Nf6 4. d4
exd4 5. Nxd4 Bb4 6. Nxc6 <HT>
14 1:23 0.31 1. e4 e5 2. Nc3 Nc6 3. Nf3 Bb4 4. Bc4
Nf6 5. O-O d6 6. d3 O-O 7. Be3 Be6
8. Bxe6 fxe6
14-> 1:37 0.31 1. e4 e5 2. Nc3 Nc6 3. Nf3 Bb4 4. Bc4
Nf6 5. O-O d6 6. d3 O-O 7. Be3 Be6
8. Bxe6 fxe6
time=5:00 mat=0 n=35164765 fh=90% nps=117K
ext-> check=1.5M 1rep=96K mate=530 pp=0 reduce=20.8M/2.3M
predicted=0 evals=28.2M 50move=0 EGTBprobes=0 hits=0
hashing-> 21%(raw) 20%(draftOK) 99%(saturation)
hashing-> 0%(exact) 15%(lower) 0%(upper)
SMP-> splits=0 aborts=0 data=0/256 elap=5:00
So it's only a two ply difference, 12 vs 14.
Can you post the log file? I would almost guess you used sel=0 which does _not_ disable null-move completely, it only disables it in part of the tree...
That is _not_ a slow computer if that is correct. Here is a run on my core-2 laptop which is about as fast as they come today:
On slow computer without null move:
11 18.71 0.23 1. e4 Nc6 2. Nc3 Nf6 3. Nf3 e6 4. d4
d5 5. Qd3 Bb4 6. e5
9-> 11.24 0.20 1. e4 Nc6 2. d4 Nf6 3. d5 Ne5 4. Nf3
d6 5. Nxe5 dxe5
There is no way your "slow computer" can get 2 plies deeper than my core-2 unless you made some sort of mistake... so now it becomes an issue of trying to figure out what you did that I didn't do...