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Subject: Re: The need to unmake move

Author: Sune Fischer

Date: 13:24:08 08/22/03

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On August 21, 2003 at 11:31:08, Robert Hyatt wrote:

>>I was thinking more about how silly it is to copy the empty bitboards for each
>>ply. If you update the boards that are active, they will stay in the cache.
>>Those that are not used might drop out, unless they are copied once every micro
>>second.
>>
>
>That is a reasonable rate for a program that searches 1M nodes per second.  I'm
>going at 2.4M so make that about once every 400 nanoseconds.  :)  Suddenly it
>begins to add up in a big way.  :)
>

Ehh, if you search 2.4 Mnodes on a dual that's 1.2 nodes on a single (one every
800 ns), I'd say not very far from 1M. I assume you will also have _two_ chips
to do the copying :)

It's still faster to unmake in your case I think, you also have the [64] piece
array which would need copying, I got a ~10% increase in make/unmake over
make/uncopy myself.
But IMO, the real benefit of unmaking is that you don't have to be so cheap in
adding arrays since only one entry needs handling at a move.

-S.



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