[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
RE: [computer-go] Modern brute force search in go
I would want to point out that nullmove doesn't miss positional aspects.
it's more sensitive in fact to tactics.
In chess we do not allow nullmove when side to move is in check.
There is other things with nullmove.
You can detect for example threads with it.
instead of searching with [beta-1,beta] with nullmove (oh dear i forgot
that in my example), you can also search with for example
[alpha-hugemargin,alpha-hugemargin+1].
If that gives back fail low then extend as in this position there is a threat.
Vincent
At 15:15 7-11-2004 -0800, David Fotland wrote:
>Exactly. Insert a pass, and search to lower depth.
>
>David
>
>> -----Original Message-----
>> From: computer-go-bounces@xxxxxxxxxxxxxxxxx
>> [mailto:computer-go-bounces@xxxxxxxxxxxxxxxxx] On Behalf Of Mark Boon
>> Sent: Sunday, November 07, 2004 3:05 PM
>> To: computer-go
>> Subject: RE: [computer-go] Modern brute force search in go
>>
>>
>> I see. Is this the same as inserting a pass, to see if some
>> danger is ahead? In Goliath I do this, when not sure if more
>> reading is necesary, I let the other side move again. If
>> still nothing seems to happen the search gets terminated. But
>> it has a danger when the evaluation is flawed.
>>
>> > -----Original Message-----
>> > From: computer-go-bounces@xxxxxxxxxxxxxxxxx
>> > [mailto:computer-go-bounces@xxxxxxxxxxxxxxxxx]On Behalf Of
>> David Fotland
>> > Sent: Sunday, November 07, 2004 20:58
>> > To: 'computer-go'
>> > Subject: RE: [computer-go] Modern brute force search in go
>> >
>> >
>> > Mark, null move reduces the size of the tree below the sqrt
>> bound you
>> > are thinking of. Null move searches some lines to less depth than
>> > others, typcially going deeper when
>> > there are threats.
>> >
>> > David
>> >
>> > > -----Original Message-----
>> > > From: computer-go-bounces@xxxxxxxxxxxxxxxxx
>> > > [mailto:computer-go-bounces@xxxxxxxxxxxxxxxxx] On Behalf Of
>> Gian-Carlo
>> > > Pascutto
>> > > Sent: Sunday, November 07, 2004 1:06 PM
>> > > To: computer-go
>> > > Subject: Re: [computer-go] Modern brute force search in go
>> > >
>> > >
>> > > Mark Boon wrote:
>> > >
>> > > > I don't understand this. How does the branching factor
>> get to 10
>> > > > in go? Are you referring to another terminology of
>> branch-factor?
>> > >
>> > > Effective branching factor.
>> > >
>> > > With just a PVS alphabeta search, R=3 nullmove, fairly simple
>> > > evaluation, and no other move ordering besides hashtables, I get:
>> > >
>> > > 19x19
>> > >
>> > > d: 1 s: 3 n: 365 t: 0.4s pv: s18
>> > > d: 2 s: 1 n: 1812 t: 0.5s pv: s18 s19
>> > > d: 3 s: 4 n: 8743 t: 0.7s pv: r18 s18 o18
>> > > d: 4 s: 0 n: 249878 t: 6.6s pv: s18 s3 s7 b18
>> > > d: 5 s: 4 n: 638195 t: 18.0s pv: s18 r18 s3 q3 s15
>> > > d: 6 s: 0 n: 13871970 t: 377.2s pv: s18 r18
>> s15 t15 b18 o18
>> > > d: 7 s: 4 n: 57710143 t: 2039.0s pv: s18 r18 s15
>> > > t15 s3 s7 b18
>> > >
>> > > Or an effective branching factor of 7 to 10.
>> > >
>> > > 9x9
>> > >
>> > > d: 1 s: 3 n: 85 t: 0.7s pv: h8
>> > > d: 2 s: 1 n: 412 t: 0.7s pv: h8 h9
>> > > d: 3 s: 4 n: 1993 t: 0.7s pv: g8 h8 d8
>> > > d: 4 s: 0 n: 25846 t: 1.0s pv: h8 f9 h5 b8
>> > > d: 5 s: 4 n: 69288 t: 1.8s pv: h8 g8 g2 h5 b8
>> > > d: 6 s: 0 n: 641869 t: 15.9s pv: h8 g8 b8 b7 b2 b4
>> > > d: 7 s: 5 n: 3558016 t: 83.0s pv: g2 h5 h8
>> b8 e8 g9 b2
>> > > d: 8 s: 0 n: 25101795 t: 480.9s pv: h2 g2 b8
>> c8 h8 h7 b2
>> > >
>> > > Or an effective branching factor of 5 to 7.
>> > >
>> > > --
>> > > GCP
>> > > _______________________________________________
>> > > computer-go mailing list
>> > > computer-go@xxxxxxxxxxxxxxxxx
>> > > http://www.computer-go.org/mailman/listinfo/computer-go/
>> > >
>> >
>> >
>> > _______________________________________________
>> > computer-go mailing list
>> > computer-go@xxxxxxxxxxxxxxxxx
>> > http://www.computer-go.org/mailman/listinfo/computer-go/
>> >
>>
>> _______________________________________________
>> computer-go mailing list
>> computer-go@xxxxxxxxxxxxxxxxx
>> http://www.computer-go.org/mailman/listinfo/computer-go/
>>
>
>
>_______________________________________________
>computer-go mailing list
>computer-go@xxxxxxxxxxxxxxxxx
>http://www.computer-go.org/mailman/listinfo/computer-go/
>
>
_______________________________________________
computer-go mailing list
computer-go@xxxxxxxxxxxxxxxxx
http://www.computer-go.org/mailman/listinfo/computer-go/