Author: Sune Fischer
Date: 16:48:45 01/20/04
Go up one level in this thread
On January 20, 2004 at 13:05:02, Robert Hyatt wrote:
>On January 20, 2004 at 12:55:58, Sune Fischer wrote:
>
>>On January 20, 2004 at 11:55:20, Robert Hyatt wrote:
>>>
>>>OK. Multiply the above by 100x and turn that into times. It takes how long
>>>to copy a complete cache line from memory to cache and back? That is 32 words
>>>which is longer than _most_ PVs. Do that 100 times you can't even measure it
>>>over the rest of the search expense. :)
>>
>>You are not adressing the other issues, the termination stuff and the added
>>code.
>>It's not the copy-cost that mainly keeps me from doing it.
>
>I gave you _exactly_ the code from within Crafty. One store, two calls
>to memcpy() (and one of those could be a store in fact). I don't have any
>"termination stuff" at all in Crafty. When I start a new PV, I store the
>ply for the last move. That's all I need.
There must be some place where you set the length of the PV line, you increment
by one when going back I understand that, but you must terminate somewhere.
if (RepetitionCheck(tree,ply,wtm)) {
value=DrawScore(wtm);
if (value < beta) SavePV(tree,ply,value,0);
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
return(value);
}
That's the kind of stuff I don't have to deal with - *clutterings* ;)
I'm only saying it because I remember I actually did have problems with it, I
always got illegal moves at the end of the PV which indicated it wasn't
terminated correctly.
>>Doesn't that worry you then, that you have to do this at all?
>
>yes. But you miss the point. You don't do this. But you should. Because
>I have found that without the "stuffing the PV" code, my search gets a bit
>bigger. If I don't "stuff the PV" I am using the _same_ information you are
>using, namely residual hash information, and I know that it is going to have a
>bogus best move here and there for the reasons already given.
I'm surprised if a few PV moves can cut down the tree my any significant amount,
but then again I never understood why IID works.. :)
-S.
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