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Subject: Re: Hash and first Fail High

Author: Ricardo Gibert

Date: 18:18:01 08/15/03

Go up one level in this thread


On August 15, 2003 at 15:48:03, Ralf Elvsén wrote:

>On August 15, 2003 at 04:57:07, Peter Fendrich wrote:
>
>>On August 14, 2003 at 21:43:42, Ralf Elvsén wrote:
>>
>
>>>
>>>Hello
>>>
>>>I haven't done any chess programming in over a year now (cured :). As you say
>>>yourself below, this could be a statistical fluctuation. But I'm with Uri here:
>>>I remember implementing a special improvement in move ordering in my program.
>>>It worked fine, the time to search to a certain depth decreased. However, the
>>>measure you call 1FH got worse. I made the same interpretation as Uri, namely if
>>>you produce crappy moves at one ply you can will get a lot of FHs at the next
>>>and your statistics looks fine :) I actually had a more refined statistic then
>>>you:
>>>I had 1FH for each ply, it probably was opposite effects for the last ply and
>>>the ply before that (can't remember for sure though) but there are more nodes
>>>closer to the leafs and they dominate the statistics. Hope I made myself clear,
>>>it's late at night...
>>>
>>>After that I didn't care much about this number anymore.
>>>
>>>Ralf
>>
>>You think you're cured? Why are you engaged in this discussion then ... :-)
>
>Woke up at night and couldn't sleep. That is when you do the most useless
>things :)
>
>>I bet you'll start again soon...
>
>Nope. Last summer I wasted a lot of time on chess programming. What did I get?
>A program ranked nr 200 in the world? :) None of my brilliant ideas worked
>as I thought they would. This summer I have been skydiving instead. Much better
>:)
>

Skydiving! In chess, a player makes so many mistakes. I wonder if you think
about that before you jump?

>>
>>Yes, Uri has a point. I agree on that but not necessary in this case. Hash moves
>>are used as first moves only (in my program). Removing the hash moves should
>>worsen the 1FH that is clearly defined as performance of the first move only.
>>Your example, as you described it in another post, makes sence I think but you
>>should get better values in other meassurements. 1FH is only one dimension.
>>
>>/Peter
>
>Sorry for being a little unclear about what I meant. I wasn't trying to explain
>your numbers, just give my opinion on 1FH as a reliable measure of move
>ordering.
>
>Ralf



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