Re: Superko detection (was Re: [computer-go] M.Boon-Library)

["Frank de Groot" <frank@xxxxxxxxxxxxx>]

> A question:  do you have to walk through them, or can you just do a single 
> hash table lookup to see if the current position is in the table?
I now walk through them but I can easily envisage a method where I do a 
single lookup or worst-case 2 or 3 lookups.

> How do you do invariance?  Some canonical form?
I maintain 16 hashes.
It's very cheap to do that, it takes just an extra XOR and 16 compares.
That way I don't loose any precision.

Because the hashes are looked up in an enormous database, the cache miss 
delay is very much larger than the extra arithmetic in keeping 16 hashes, 
meaning it does not cost a single clockcycle to maintain those 16 hashes 
because the CPU is waiting 1000 clock cycles just to get a cache line back 
with the next requested hash.

_______________________________________________
computer-go mailing list
computer-go@xxxxxxxxxxxxxxxxx
http://www.computer-go.org/mailman/listinfo/computer-go/