Author: Chan Rasjid
Date: 11:31:29 02/18/06
Go up one level in this thread
On February 18, 2006 at 07:52:10, David B Weller wrote:
>Hi Vincent,
>
>Thanks.
>
>Yes. That is what I am doing. Will try and remove those.
>
>Let me make sure I understand perfectly:
>
>If a hash entry is LOWER or UPPER bound AND exceeds current search bounds, just
>return bounds. Do NOT return hashed value.
>
>Yes?
>
>-David
Hello David,
I am surprised you understand Vincent. I have a hard time as he gives only
subtle hints.
I have done TT and fail-soft many times over and still have no inkling if there
should be things to take special care of.
If I am right, fail-soft is always better. When a node FL, best may be < alpha
and we hash best and not the bound alpha. When it is FH, best is likely > beta
and we hash best and not beta.The lower/upper in TT will always be more useful
when the bounds are as "tight" as we get; ie smallest upper or greatest lower.
Following a strict coding usually prevents mistakes. eg.
v = hashProbe(&bound);//etc....
switch(bound){
case lower:
if (v >= beta)
return v;//FH
etc...
break;
case upper:
if (v <= alpha)
return v;//FL- search dont get better
etc...
break;
}
Best regards
Rasjid
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